Molecular breeding in rice

The knowledge of the extent and pattern of diversity in the crop species is a prerequisite for any crop improvement as it helps breeders in deciding suitable breeding strategies for their future improvement. Rice is the main staple crop in India with the large number of varieties released every year. Studies based on the small set of rice genotypes have reported a loss in genetic diversity especially after green revolution. However, a detailed study of the trend of diversity in Indian rice varieties is lacking. SSR markers have proven to be a marker of choice for studying the genetic diversity. Therefore, the present study was undertaken with the aim to characterize and assess trends of genetic diversity in a large set of Indian rice varieties (released between 1940-2013), conserved in the National Gene Bank of India using SSR markers. A set of 729 Indian rice varieties were genotyped using 36 HvSSR markers to assess the genetic diversity and genetic relationship. A total of 112 all...

Rice, one of the most important cereal crops, serves as a staple food for over half of the global population. Chhattisgarh often referred to as "Rice bowl of India" possesses immense genetic diversity in rice. Genetic diversity represents the heritable variation within and between populations of organisms and is a prerequisite for improvement of any crop species. Genetic diversity defines all the available variability and desirable alleles in any crop species/ population which may be exploited in crop breeding programs. Hence, the objective of this study was to assess the genetic diversity and population structure of 48 rice accessions using 31 simple sequence repeats (SSR) markers to identify the diverse and useful genotypes for further breeding programmes. The mean polymorphic information content (PIC), major allele frequency and gene diversity were 0.48, 0.56 and 0.54 respectively, suggesting the high polymorphism of the SSR markers used for genotyping of the rice accessions. The population structure revealed two major sub-populations based on their morphological differences. UPGMA algorithm and genetic dissimilarity coefficient based Dendrogram as well as principal component analysis also grouped the rice genotypes into two groups with wide variation among the accessions and strongly supported the outcomes of population structure analysis. Moreover, analysis of molecular variance (AMOVA) detected a significant genetic differentiation between two sub-populations. Total molecular variance was partitioned into two, of which, 6% explained variation among populations and the remaining 94% explained variation within the populations. The study established the existence of considerable genetic diversity among the tested 48 accessions. The selected genetic resources will be useful in further rice breeding activities.

High head rice and low chalky grain percentages are key grain quality traits selected in developing rice cultivars. The objectives of this research were to characterize the phenotypic variation of head rice and chalky grain percentages in a diverse collection of rice accessions, identify single nucleotide polymorphism (SNP) markers associated with each of these traits using genome-wide association studies (GWAS), and identify putative candidate genes linked to the SNPs identified by GWAS. Diverse rice varieties, landraces, and breeding lines were grown at the Texas A&M AgriLife Research Center in Beaumont. Head rice percentages (HRP) and chalky grain percentages (CGP) of 195 and 199 non-waxy accessions were estimated in 2018 and 2019, respectively. Phenotypic data were analyzed along with 854,832 SNPs using three statistical models: mixed linear model (MLM), multi-locus mixed model (MLMM), and fixed and random model circulating probability unification (FarmCPU). Significant variatio...

Apparent amylose and protein concentrations (AAC and PC) affect the milling, cooking, and eating quality of rice. This study was conducted to assess the phenotypic and genotypic variation and to identify genomic regions and putative candidate genes associated with AAC and PC in milled rice grain. Two hundred and seventeen and 207 diverse rice accessions were grown at the Texas A&M AgriLife Research Center in 2018 and 2019, respectively. Milled rice samples were analyzed for AAC and PC using the iodine colorimetry and Dumas method, respectively. Genome-wide association studies (GWAS) for AAC and PC were conducted using 872,556 single nucleotide polymorphism (SNP) markers following the mixed linear model. Significant variation among the accessions was found for both variables each year. Associations between 32 SNPs with PC and seven SNPs with AAC were detected. Gene models linked to these SNPs have a wide range of biological functions, including protein and carbohydrate metabolism, DN...

Super Basmati is an elite variety with extra-long grains and superior quality but its yield is severely affected by water stress. Recombinant inbred lines (RILs) developed from the cross of Super Basmati and IR55419-04 (a coarse grained variety with high yield potential) were used to identify and map yield-related quantitative trait loci (QTLs) under normal field conditions. Genotypes for 244 KASP markers were obtained from 188 F9 RILs and a linkage map constructed of 1369.4 cM, with average marker interval of 10.5 cM. Eleven agronomic traits were phenotyped in RILs and parents. Composite interval mapping and inclusive composite interval mapping model identified 21 common QTLs related to nine agronomic traits; of the QTLs identified, twelve mapped at novel positions. LOD scores ranged from 2.51 for number of filled grains (qFG1.1) to 16.8 for plant height (qPH1.1). Four major effect QTLs could explain 20% of variation related for plant height, hundred-grain weight and grain width. A...

Twenty rice genotypes had been characterized to assess the yield attributing traits under the research programme in two different seasons, Pre-Kharif and Kharif following RBD with 3 replications. Statistical analysis was carried out to compute genotypic coefficient of variation, phenotypic coefficient variation, Broad Sense heritability and Genetic advance as percentage of mean for all the yield attributing traits. ANOVA, PCV and GCV revealed significant variations to all characters under study. All the Characters except grain length showed high heritability coupled with high genetic advance. Genotypic correlation studies revealed that days to 50% flowering was significantly correlated with yield. Path coefficient studies revealed that characters like plant height, days to 50% flowering, number of effective tillers plant -1 , filled grain panicle -1 , grain breadth, grain L:B ratio and harvest index had positive direct effect on yield. The study also revealed that the potentially high yielding genotypes were Piolee, Haripowasali, Borosolpana and Satyaranjan.

The current study was to understand the genes action in salt tolerance of rice and its use in the future breeding program. The research was carried out in Niger Republic. 120 F 3 lines derived from F 2 individual plants were evaluated along with their parents in farmer’s field affected by the salt problem. The experimental design was 25*5 Alpha lattice with three replications. Data were analyzed using SAS software version 9.2. Hayman method was used to estimate gene effect.  A significant additive gene action was notified in terms of tiller number (at P= 0.01), panicle number (P=0.05) and panicle weight (P=0.05). Suggesting that selection for high tillering ability, tillers fertility and panicle fertility in salt stress conditions at early generation would be fruitful. Partial dominance effect was detected in traits including the height and duration. This implied that breeding for early maturing height can be influenced by segregation. The additive maternal effect was found for dura...

Genotype-environment interaction poses an outmost barrier to the breeders in the process of development of improves rice varieties. Understanding the causes and extent of Genotype-environment interaction is highly useful to frame breeding objectives, identifying ideal test locations, and formulating varietal release recommendations. The objectives of this study were to: (i) know the effect of environment on gene action, (ii) assess yield stability across environment, (iii) know the ideal environment to discriminate the F3 population and (iv) assess ideal genotype to discriminate the environment. Thus, 120 rice families, 4 parents and local check were evaluated on 2 saline environments. Collected data were analyzed using SAS software version 9.2 and Genstat 18 th . Non significant effect of environment on gene action was noticed for all the traits, tiller excepted. The genotype by environment interaction was highly significant implying differential performance of families at different locations. However, there was crossover G × E interaction, suggesting that different winners can be evaluated in different environments.

Bacterial Blight (BB) caused by Xanthomonas oryzae pv. oryzae is one of the most devasting diseases in rice which causes significant yield loss. The present study was conducted at the Department of Plant Breeding and Genetics, College of Agriculture Vellanikkara, Kerala to screen rice accessions for BB response. One hundred and fifty rice genotypes along with resistant and susceptible checks were assessed for BB at the seedling stage using the artificial inoculation method and were scored based on IRRI, SES, 2014. Among the 150 rice genotypes screened, 5 genotypes scored resistant (R), 26 moderately resistant (MR), 85 moderately susceptible (MS), and 34 susceptible (S) reaction to BB incidence. Among the tested genotypes, Karuthamodan (1.22%), Pallipuram Pokkali (1.53%), and Tulasi (5.25%) showed minimum disease leaf area percentage for the disease incidence while IET 18318 Sel 2 (40.27%), Japan violet (37.03%), and Erunazhi (35.85%), showed maximum disease leaf area percentage. The...

Since introduction of rice into Uganda in 1904, improvement of the irrigated and rain-fed lowland types was undertaken to address a number of production and quality constraints in three consecutive and overlapping phases. The initial phase was achieved through evaluation of introduction, selection of promising lines and subsequent release of the selected lines for production by the farmers. In the second phase, genetic potential of traits and characteristics of interest were analyzed and used to guide selection of suitable parents for hybridization and the third phase employed genotyping approach in screening and selection of the parental lines and the segregating populations to enhance the breeding efficiency for the traits of importance. Simultaneously, the key production constraints addressed included resistance to rice yellow mottle virus (RYMV), rice blast, bacterial leaf blight and narrow leaf spot diseases as well as submergence tolerance and cold tolerance. The quality trait...

Joha rice of Assam is a unique class of specialty rice having tremendous potential in domestic and international markets. The poor yielding ability of Assam's Joha rice demands its systematic characterization for an effective breeding program. This study investigates the morphological, molecular and biochemical profiles of twenty popular Joha (aromatic) rice cultivars indigenous to Assam. Distinctiveness, Uniformity and Stability (DUS) characterization of the cultivars revealed polymorphism in thirty-seven traits, establishing distinctiveness for their utilization in breeding programs. Unweighted Neighbor Joining (UNJ) clustering based on usual Euclidean distances for the polymorphic morphological markers grouped the cultivars into three clusters with eight, eleven, and one genotypes. The Joha rice cultivars showed significant differences for all the quantitative traits except for panicle length. The genotypic and phenotypic coefficients of variability (GCV & PCV) were high for grain yield ha -1 (24.62 & 24.85%) and filled grains panicle -1 (23.69 & 25.02%). Mahalanobis D 2 analysis revealed three multi-genotypic and four mono-genotypic clusters of the cultivars. The first five principal components explain 85.87% of the variation among the cultivars for the traits under study; filled grain panicle -1 (0.91) and stem thickness (0.55) positively contributed to the first PC. The cultivars' average polyunsaturated fatty acids were 37.9% oleic acid, 39.22% linoleic acid, and 0.5% linolenic acid. Kon Joha 4 and Ronga Joha contained the highest iron (82.88 mg kg -1 ) and zinc (47.39 mg kg -1 ), respectively. Kalijeera, Kunkuni Joha, Kon Joha-5, Manimuni Joha and Kon Joha-2 accorded a strong aroma. PCR amplified 174 alleles with a mean value 2.64 across the 66 polymorphic SSR markers. PIC values ranged from 0.091 to 0.698, with an average of 0.326. The highly informative (PIC > 0.50) markers were RM316, RM283, RM585, RM1388, RM3562, RM171, R1M30, RM118, RM11and RM29 for identification of the twenty aromatic rice cultivars. PCR amplification of 27 SSR markers identified 28 unique alleles (97-362 bp) in 13 Joha rice cultivars, which can help their identification/DNA fingerprinting. The UNJ clustering based on Jaccard's coefficients classified the cultivars into three distinct clusters with eight, ten, and two genotypes. Our study revealed the nutritional richness of these specialty Joha rice cultivars and sufficient scope for yield enhancement through their interbreeding to keep quality intact. Globally, rice is planted in approximately 162 million ha and 755 million tons of produce are harvested annually 1 . Ninety per cent of the production and consumption of the world's rice occur in Asia. India has the world's largest area under rice with 44.0 million ha and is the second-largest producer (96.0 million tonnes in 2010), next only to China, contributing 21.5% of global rice production. The FAO 2 estimated a 70 per cent more food requirement for over nine billion people expected to inhabit planet Earth by 2050. As the staple food for most Indians, rice's future demand will increase with the growing population, projected at 1.378 billion by 2030 3 . In Assam, rice occupies approximately 70% of the total cropped area, dominating the state's agriculture 4 . Rice, the primary agricultural GDP source, plays a significant role in the state economy.

Population and environmental pressure have imposed a great challenge on agriculture in China to explore innovative and effective solutions to its pressing plant nutritional problems. Plant nutriomics is a new frontier in plant biology that can provide innovative solutions for improving plant nutrient efficiency, thus increasing crop productivity through genetic and molecular approaches. This review summarizes current efforts and progress in plant nutriomic research in China with examples from several case studies. It also points out potential obstacles and depicts future perspectives in this emerging frontier of plant nutrition. Although plant nutriomics is still at a conceptual stage, substantial efforts are being made in China aimed at increasing plant nutrient efficiency through a nationwide, co-ordinated project on plant nutriomics. Future studies involving both national and international collaborations are needed to develop nutrient-efficient, stress-tolerant and high-quality c...

Generating a new crop variety with certain desirable traits requires germplasm collection with wide genetic diversity to facilitate accelerated development of improved cultivars. This study was conducted to characterize genetic diversity of Indonesian rice accessions using SSR markers and their agro-morphological characters to allow the identification of Marker Trait Association (MTA). A survey of genetic diversity among 72 traditional landraces of 15 provinces in Indonesia and 24 improved varieties was conducted using four multiplex panels of 14 fluorescent-labeled SSR markers and 22 agro-morphological characters. A total of 140 alleles with an average of 10 alleles per locus and Polymorphism Information Content (PIC) values at 0.73. The population structure identified five subgroups. A total of 4 highly significant MTA were identified. One character with highly significant MTA was number of panicle associated with RM277. Based on SSR marker, RM105 had two MTAs for auricle color and ligule shape. After validation, these MTAs may be deployed to improve rice productivity.

Relationship between phosphorus, nitrogen and potassium contents and the emergence rate of T1 (tiller in axils of the first leaf on main stem) in wheat cultivars differing in their adaptability to low available phosphoric acid was examined in an Andosol. Three wheat cultivars were in a field with low available phosphoric acid in soil and in a field with soil amended by the application of additional phosphoric acid and stable manure. In the case of cv. Asakazekomugi and Norin 61 which show a low adaptability to low available phosphoric acid in soil, the emergence rates of T1 decreased when the phosphorus content of shoot was less than 0.5%. In cv. Norin 64 which shows a high adaptability to low available phosphoric acid in soil, the emergence rate of T1 was maintained at 0.3% phosphorus content in shoot. The application of additional phosphoric acid and stable manure increased not only the phosphorus content, but also the nitrogen and potassium contents in wheat plants. Partial corre...

Abating the approaching yield plateau in rice requires taking advantage of potential technologies that requires knowledge on genetic diversity. Hybrid breeding, particularly in indica rice, requires the recruitment of large genetic variability from outside because the available genetic diversity of the cultivated pool has already been utilized to a great extent. In this study, we examined an assembly of 200 tropical japonica lines collected worldwide for population genetic structure and variability in yield-associated traits. Tested along with 30 indica and six wild rice lines belonging to India, the tropical japonica lines indicated great phenotypic variability, particularly related to new plant type (NPT) phenology, and formed six clusters. Furthermore, a marker-based characterization using a universal diversity marker panel classified the genotype assembly into four clusters, of which three encompassed tropical japonica lines, while the last cluster included mostly indica lines. ...

Molecular markers are useful tools for evaluating genetic diversity and determining cultivar identity. A total of 50 upland rice accessions, 24 from Peninsular Malaysia and 26 from West Malaysia (Sabah state) were investigated using 10 microsatellite (SSR) markers distributed across the rice genome to study the genetic diversity. A total of 49 alleles were detected across the 50 accessions. The number of alleles per locus ranged from 2 to 11 with an average of 4.9. The average Polymorphism Information Content (PIC) value was 0.710. A dendrogram was constructed using Jaccard's similarity coefficient, and accessions were clustered into 7 groups. The most of the accessions were clustered according to their geographical origin. Shannon's information index ranged from 0.5269 to 2.0050. Neiʼs gene diversity (h) ranged from 0.3432 to 0.8273. Overall gene flow was 0.0011. In order to develop suitable upland rice varieties, accessions 03838,

The field experiment was conducted at the Instructional Farm of Faculty of Agricultural Engineering, BCKV, Nadia, West Bengal during the year of 2016-17. The study was conducted with the objectives to determine the water requirements of summer rice under drip irrigation, to compare the water requirements of summer rice under drip and conventional (flooding) irrigation and yield of summer rice cultivation under drip irrigation. In the study, there were four irrigation treatments with four replications. The different irrigation treatments were (i) T1- Conventional irrigation with 5 cm of water in each irrigation after disappearance of water, (ii) T2-0.8 Epan under drip irrigation @ 4 l/h at 3 days interval, (iii) T3-1.0 Epan under drip irrigation @ 4 l/h at 3 days interval and (iv) T4-1.2 Epan under drip irrigation @ 4 l/h at 3 days interval. The amount of irrigation water required under drip irrigation at 0.8 Epan treatments had been found to be the lowest i.e., 258 mm and the highes...

Este artigo é resultado de uma pesquisa que teve como objetivo analisar os desdobramentos da Base Nacional Comum Curricular -BNCC na autonomia do trabalho docente, os objetivos específicos incidiram a contextualizar a BNCC na Educação Básica e identificar as estratégias de preservação da autonomia através da narrativa das Professoras. A metodologia da investigação baseou-se na abordagem qualitativa, com a realização de entrevistas semiestruturadas com os professores efetivos dos anos iniciais do ensino fundamental, de três escolas do município de Quixadá, no Sertão Central cearense. Os resultados apontaram que, mesmo diante das desigualdades sociais, há possibilidades pontuais de incitar a autonomia coletiva, como estratégias de ensino que permitem a ampliação de conhecimentos críticos da realidade. Concluímos, portanto, com a certeza de ser, o trabalho docente, essencial para promover mudanças no ensino e aprendizagem.

Wheat (Triticum aestivum L.) flour represents one of the primary sources of calories and proteins for the human diet. The increase in the wheat yield without losing its baking and milling quality is an important breeding objective. The use of QTL analysis is an expedient methodology to help breeders to face this multifaceted challenge. Here, a population of 129 recombinant inbred lines (RILs) developed from a cross between 'Steele-ND' cultivar and 'ND 735' advanced line was used to evaluate several yield and quality traits and map the genomic regions controlling these traits. The phenotypic data were collected from field experiments conducted at four North Dakota (ND), USA environments. Transgressive segregation was observed for all traits, with RILs outperforming the most adapted parent and commercial cultivars. Using a linkage map of 392 markers, composite interval mapping identified a total of 13 environment-specific QTLs, all explaining large phenotypic variations (R 2 =16-44%). The genotypic values of these "reserve" alleles were directly used as criteria of selection in breeding programs.

The conservation of traditional rice landraces, along with their associated farming practices and indigenous knowledge, plays a vital role in ensuring long-term food security. However, the progressive disappearance of these landraces from cultivation has not been adequately addressed by researchers. This study examines genetic erosion, variability, and trait relationships among 12 traditional ahu rice varieties cultivated by Mising tribal farmers in Assam's Jorhat and Golaghat districts. The results demonstrate a concerning decline in landrace diversity, highlighting the risk of genetic erosion. Statistical analysis revealed significant differences among the varieties for most measured traits, with the exception of radicle length, leaf area index, photosynthetic rate, and stomatal conductance. The recently introduced Kolong variety achieved the highest grain yield, along with superior performance in filled grains per panicle and total spikelets per panicle. Genetic analysis showed considerable heritable variation in chlorophyll stability index, while days to 50% flowering exhibited strong genetic control. Grain yield displayed significant positive correlations with tiller density, panicle density, spikelet number per panicle, filled grain count, and spikelet fertility at both genetic and observable levels. These findings underscore the critical need to preserve traditional ahu rice varieties to mitigate genetic erosion while incorporating high-performing cultivars into farming systems. Coordinated efforts involving farmers, policymakers, and researchers are necessary to maintain agricultural biodiversity and secure future food production.

Assessing the adaptability and stability of promising rice genotypes is one of the important steps for accurate evaluation. This study determined the genotype × environment interaction (GEI) and stability performance of 12 promising rice genotypes in four environments during 2009 Aman season. The experiment used randomized complete block design with three replications. Yield stability and adaptability of yield performance were analyzed by combined analysis and additive main effects and multiplicative interaction (AMMI) model. The environment, genotype main effects, and the GEI were all highly significant (P<0.001). The study indicated that the tested genotypes, such as BRRHA G1 (5.47 tha -1 ), G2 (5.68 tha -1 ), G3 (6.29 tha -1 ) and G4 (5.27 tha -1 ) had higher average yields, which indicated these genotypes adapted to favourable environments (E1 and E3). Whereas the environment, E3 could be regarded as a more stable site for high yielding hybrid rice improvement than the other locations. Based on AMMI biplot analysis, genotypes BRRI1A/BRRI827R (G1), IR58025A/BRRI10R (G2), BRRI 10A/BRRI 10R (G3) and BRRI hybrid dhan1 (G4) have higher average mean yields with high main (additive) effects and positive IPCA1 score, among them BRRI 10A/BRRI10R (G3) being the overall best. Locations E1 and E3 could be regarded as a good selection site for rice hybrid improvement due to stable yields.

Background: Salt affected areas have increased day by day because of excessive use of irrigation water with improper drainage coupled with the poor quality of irrigation water. The assessment of genetic divergence existing in the germplasm collections is very important for success of hybridization programme leading to development of high yielding varieties. Methods: The experiment on 113 genotypes (aromatic and non-aromatic rice) including three checks viz., Sarjoo 52, FL 478 and CSR 10 (salt tolerant) of rice (Oryza sativa L.) was conducted to work out the genetic divergence. Result: The 113 genotypes were grouped in to eleven different non-overlapping clusters. Cluster II, having 20 genotypes, emerged with highest number of entries. The highest intra-cluster distance was found for cluster X. The maximum inter-cluster distance was recorded between cluster VII and XI. The highest cluster mean for grain yield per plant was observed in cluster III. Presence of substantial genetic diversity among the germplasm lines screened in the present study indicating that this material may serve as good source for selecting the diverse parents for further hybridization program aimed at isolating desirable segregants for grain yield and other important characters.

The knowledge of the extent and pattern of diversity in the crop species is a prerequisite for any crop improvement as it helps breeders in deciding suitable breeding strategies for their future improvement. Rice is the main staple crop in India with the large number of varieties released every year. Studies based on the small set of rice genotypes have reported a loss in genetic diversity especially after green revolution. However, a detailed study of the trend of diversity in Indian rice varieties is lacking. SSR markers have proven to be a marker of choice for studying the genetic diversity. Therefore, the present study was undertaken with the aim to characterize and assess trends of genetic diversity in a large set of Indian rice varieties (released between 1940-2013), conserved in the National Gene Bank of India using SSR markers. A set of 729 Indian rice varieties were genotyped using 36 HvSSR markers to assess the genetic diversity and genetic relationship. A total of 112 all...

Major research activities and literature reviews (1994 -present) 2010-present (UMR AGAP, Cirad-BIOS, Montpellier, France): Senior Crop Physiologist  Copping rice with climate change: o Spikelet sterility under heat and high vapor pressure deficit: escape, avoidance and tolerance strategies, microclimate, leaf and panicle transpiration, time of the day of anthesis, phenotyping, Genome Wide Association Studies, QTL identification o Reduced yield and high night temperature: microclimate, maintenance and growth respiration, soluble sugar concentration, Q10 value and implications for crop models o Adaptation to transient soil water deficit: fraction of transpirable soil water, plant transpiration, leaf, internode and root elongation, shoot and root biomass partitioning, dissection for panicle initiation, phenotyping, Genome Wide Association Studies o Simulation of crop yield under future scenarios: simulation exercises of biomass and grain yield with the Samara crop model, model inter-comparison under AgMIP Initiative  Increasing rice yield potential: o Whole-plant regulation of panicle architecture: primary and secondary branch size and number and spikelet number, relative growth rate, tillering rate, soluble sugar concentration, near-isogenic lines, yield components and grain yield o Traits for higher yield and superiority of hybrid rice: growing season and maturity group dependent relevant traits, crop phenology, sink regulation, organ vigor, biomass partitioning and harvest index, delayed leaf senescence, whole-plant architecture, yield components and grain yield 2005-2010 (CESD, IRRI, Los Baños, Philippines): Senior Crop Physiologist  Increasing rice yield potential: hybrid/inbred, seedling vigor, plant architecture (plant height, leaf angle, light interception), radiation use efficiency, biomass and leaf area production, sink regulation (tillering dynamics, root growth, culm elongation, panicle growth, leaf and culm vigor, grain filling dynamics), soluble sugar content, sink size, tiller and root senescence, yield components, grain yield  Saving water in rice: water control, perched water table, soil and meristem temperature, soil and plant water potential, stomatal conductance, root distribution, fraction of transpirable soil water, shoot/root ratio, water productivity, yield components and grain yield  Copping rice with climate change: elevated temperature and CO2, vapor pressure deficit, staggered planting, leaf and panicle temperature, leaf and panicle transpiration, radiation use efficiency, crop phenology, leaf elongation rate, threshold temperature, sink regulation, soluble sugar content, leaf senescence, spikelet sterility, panicle architecture, yield components and grain yield 2002-2005 (CSWS, IRRI, Los Baños, Philippines): Crop Physiologist  Improving rice crop establishment: transplanting/broadcasting/row seeding, seed rate (direct seeding and nursery), seedling age at transplanting, planting density, leaf and tiller emergence, clump architecture (tiller angle) and plasticity, yield components and grain yield  Increasing rice yield potential: hybrid/inbred, seedling vigor, plant architecture (plant height, leaf angle, light interception), radiation use efficiency, biomass and leaf area production, tillering dynamics, leaf vigor, sink size, tiller senescence, yield components, grain yield 1998-2001 (APSRU, DPI, Toowoomba, Queensland, Australia, and LEPSE, INRA, Montpellier, France): Crop Physiologist  Simulating sorghum leaf area production: micro-climate and thermal time, leaf emergence, tiller emergence and mortality, phyllochron, leaf area index and leaf area profile, organ biomass, specific leaf area, yield components, grain yield 1994-1998 (UR FPV, Cirad-CA, Montpellier, France, and IER, Bamako, Mali): PhD student  Simulating sorghum leaf area production: micro-climate and thermal time, leaf initiation and emergence, leaf, sheath and internode elongation, plastochron and phyllochron, leaf area index and leaf area profile Leadership and Research Management

The present study was carried out on 32 upland rice genotypes (including checks), which were analysed for grain yield (GY) and related traits under contrasting moisture regimes (irrigated and drought stress). Analysis of variance showed that all the characters studied were significantly different. Highest GCV and PCV values were recorded for GY and FLW under drought stress and non-stress conditions respectively. Five characters namely DTF, PH, FLW, FGPP and GY were recorded to have very high heritability as well as GAM under both stress and control conditions. GY, FGPP and ETN were observed to have high or very high GAM values under both conditions. Furthermore, these traits also recorded high to moderately-high heritability and thus, emerged as most promising traits for improvement through selection. Association study revealed that GY is positively and significantly correlated to PH, FGPP and SF% at both genotypic and phenotypic level. Path coefficient analysis revealed a very high...

The investigation was undertaken to generate the information on magnitude of variability, correlation and path analysis for yield and yield contributing characters of 50 aromatic rice genotypes. The results of analysis of variance indicated significant amount of variation present in this population for all traits. Medium to high values of GCV and PCV were observed for number of grains per panicle, grain yield per plant, panicle weight, plant height, test weight, head rice recovery, grain L:B ratio and alkali spreading value. High heritability coupled with high genetic advance observed in days to 50% flowering, plant height, panicle length, panicle weight, number of productive tillers per plant, number of grains per panicle, grain yield per plant, harvest index, test weight, grain L:B ratio, milling percentage, head rice recovery and alkali spreading. Grain yield per plant showed significant positive correlation with number of grains per panicle and panicle weight and negative correlation with days to 50% flowering. Panicle weight has maximum direct effect on grain yield per plant followed by number of productive tillers per plant and panicle length. Hence, these characters are identified as key traits for improving grain yield per plant.

Background: The insight concerning genetic diversity and relationship among the rice genotypes is a basic contribution to the crop improvement programs. The present field experiment was conducted to study the level of diversity present in 47 rice genotypes using both morphological and molecular analysis. Methods: The experiment was carried out at Agricultural Research Farm, Banaras Hindu University, Varanasi (U.P.), during Kharif-2019 with 47 rice genotypes. Mahalanobis' D 2 analysis was carried out to evaluate the morphological diversity present among the genotypes and 24 polymorphic SSR markers were used for molecular analysis using the NTSYSpc software. Result: Mahalanobis' D 2 grouped 47 rice genotypes into 6 clusters based on the inter-se genetic distance. The highest inter-cluster distance (1134.14) was observed between clusters II and IV indicating the genotypes present in these clusters to be highly divergent. Molecular diversity analysis grouped the 47 rice genotypes into 3 main clusters i.e., cluster I, cluster II and cluster III, which were further divided into sub-clusters. Polymorphic Information Content varied from 0.12 to 0.86, with an average of 0.465. The highest PIC value was observed for locus RM 507 (0.86). All the 24 primers showed polymorphism and the number of alleles was common for all i.e., 2. Together, the morphological and molecular diversity analysis revealed that Desi Dhan and IR 91143-AC 293-1, Desi Dhan and BD 105, IR 85850 and Lal Sundiya, Chauli and Swarna were the most diverse genotypes among the 47 rice genotypes included in the study.

Background:
To achieve the Sustainable Development Goals: Zero Hunger, a stable and accessible water supply in agriculture is essential. The projected steady increase in population will contribute to a moderate increase in consumption, which in turn will require the development of technologies that increase soil productivity. With the increasing impact of global warming, droughts are becoming increasingly common in the northern region of Bangladesh. Notably, Bangladeshi farmers currently allocate about 37% of the total cost of rice production to irrigation.

Objectives:
The current study aims to overcome the problem of water shortage in agriculture, particularly in rice cultivation. It is expected that the use of biological sponge extracted from dried Luffa cylindrica will help retain water for its uptake by rice roots. That is, it is expected that by using Luffa cylindrica it will be possible to prevent or significantly reduce evapotranspiration and water seepage into the soil.

Methods:
This work is an experimental study on rice cultivation in soil with and without Luffa cylindrica. The study controlled the main factors contributing to water loss: evaporation and percolation, for the quantitative measurement of which different systems and methods were used. In addition, other extensive measurements related to irrigation were carried out and contribute to the understanding of the effectiveness/ineffectiveness of the studied approach to reducing water use.

Results:
A comparison of fields with and without Luffa cylindrica shows a marked contrast in water storage capacity. Initial observations indicate that integrating Luffa cylindrica into rice paddies improves water retention, thereby reducing losses due to evaporation and seepage. It was found that the irrigation frequency was above the optimum threshold to achieve the desired result. In addition, more water was required to fill the Luffa-containing field than the Luffa-containing field, as the dry Luffa cylindrica also had to be saturated. Despite these issues, the use of Luffa cylindrica resulted in water savings of 26.97%.

Conclusion:
improving soil moisture retention in rice paddies. By utilizing the fibrous structure of dry Luffa cylindrica, water losses due to evapotranspiration and seepage were significantly reduced, resulting in substantial water savings and reduced costs for farmers. The eco-friendliness and cost-effectiveness of Luffa cylindrica highlights its potential as a sustainable water management solution for agricultural practices. Its availability and ease of cultivation make it a viable option for farmers, with minimal investment required to implement the technique on a large scale.

The results were indicated that, biological yield per plant, harvest index, spikelet fertility, 1000-grain weight, L/B ratio, plant height and panicle length showed positive and significant correlation with grain yield per plant to emerge as most important associates of grain yield in rice. Path analysis identified biological yield per plant followed by harvest-index as most important direct yield contributing traits and biological yield per plant followed by 1000-grain weight and panicle length exhibited high order of positive indirect effect as most important indirect components which merit due consideration at time of devising selection strategy aimed at developing high yielding varieties in rice. Out of 82 entries tested under natural condition, none were found to be immune or resistant. However, 30 genotypes were found moderately resistant, 47 genotypes moderately susceptible, while 3 genotypes susceptible and rest two genotypes were highly susceptible.

Genetic variability studies provide basic information regarding the genetic properties of the population based on which breeding methods are formulated for further improvement of the crop. The estimates of heritability, coefficients of variability and genetic advance computed for 12 yield contributing traits. Genetic parameters for yield and its correspondent characters in rice were estimated from a trial with four CMS lines, fifteen testers, three checks and sixty crosses evaluated for twelve characters related to yield. In general, the magnitude of phenotypic coefficient of variation (PCV) was higher than the corresponding genotypic coefficient of variation (GCV) for all the traits. High estimates of heritability and genetic advance in broad sense and narrow sense were recorded for all characters viz., spikelet fertility, days to 50% flowering, days to maturity, spikelets per panicle, harvest-index, L/B ratio, 1000-grain weight, plant height, grain yield per plant, biological yield per plant, panicle bearing tillers per plant, panicle length. High heritability coupled with high genetic advance in percent of mean was observed for all the traits.

The results were indicated that, out of 60 crosses, the most desirable five crosses showing high significant positive heterosis over better parent for grain yield per plant were IR 79156A X NDR 370132 (72.19%), IR 68888A X NDR 370132 (66.69%), IR 68897A X NDR 370131 (43.33%), IR 58025A X CR 2499 (40.71%) and IR 79156A X NDR 2701 (35.80%). Eighteen crosses showed positive and significant heterosis over standard variety and the best five crosses among them were IR 58025A X NDR 1127 (20.78%), IR 79156A X IR 27723 (14.87%), IR 68888A X IR 27723 (14.81%), IR 58025A X Sugandha 5 (12.84%) and IR 68897A X NDR 2701 (12.46%). The cross, IR 58025A X NDR 1127, showed highest mean performance (28.70g), heterobeltiosis (22.48%) and standard heterosis (20.78%) for grain yield per plant while highest yielding parent, NDR-359, produced mean grain yield 23.78 g.

Rice (Oryza sativa L.) is the staple food for a majority of the world's population, and uses 30% of the global fresh water during its life cycle. Drought at the reproductive stage is the most important abiotic stress factor limiting grain yield. The United States is the third largest exporter of rice, and Arkansas is the top rice-producing state. The Arkansas rice-growing region in the Lower Mississippi belt is among the 10 areas with the highest risk of water scarcity. Adapted U.S. rice cultivars were screened for drought resistant (DR) traits to find sources for breeding U.S. rice cultivars for a water saving agricultural system. A recombinant inbred line (RIL) population, derived from varieties Kaybonnet (DR) and ZHE733 (drought sensitive), termed K/Z RILs was chosen for genetic analysis of DR traits. The objectives of this research were to 1) analyze the phenotypic and grain yield components of the K/Z RIL rice population for drought-resistance-related traits, 2) evaluate the Abscisic Acid (ABA) response of the K/Z RIL rice population on root architectural traits in relation to drought stress resistance, 3) screen polymorphic molecular markers to identify genes linked to productivity traits of grain yield under drought stress, measured by number of filled grain per panicle using bulk segregant analysis (BSA), and 4) identify QTLs and candidate genes in the K/Z RIL population for drought resistance associated with vegetative morphological traits, grain yield components under drought stress and well-watered conditions, and root architectural traits related to ABA response. The

Commercial rice production in California has been underway since 1912 initially relying on selections from japonica plant introductions from Japan and China followed by release of the founding medium grain Calrose in 1948. The establishment of a grower-funded accelerated rice breeding program at the Rice Experiment Station in 1969 has supported California rice production with the release of 45 rice cultivars including medium-, short-, long-grains as well as specialty market types. Support, structure, methods, and objectives of the RES Rice Breeding Program are described.

Apparent amylose and protein concentrations (AAC and PC) affect the milling, cooking, and eating quality of rice. This study was conducted to assess the phenotypic and genotypic variation and to identify genomic regions and putative candidate genes associated with AAC and PC in milled rice grain. Two hundred and seventeen and 207 diverse rice accessions were grown at the Texas A&M AgriLife Research Center in 2018 and 2019, respectively. Milled rice samples were analyzed for AAC and PC using the iodine colorimetry and Dumas method, respectively. Genome-wide association studies (GWAS) for AAC and PC were conducted using 872,556 single nucleotide polymorphism (SNP) markers following the mixed linear model. Significant variation among the accessions was found for both variables each year. Associations between 32 SNPs with PC and seven SNPs with AAC were detected. Gene models linked to these SNPs have a wide range of biological functions, including protein and carbohydrate metabolism, DNA methylation, and response to abiotic and biotic stresses. Seven of the identified SNPs colocalized with previously reported quantitative trait loci (QTL) for protein concentration. Fine-mapping of significant genomic regions and gene validation are necessary for this information to aid in marker-assisted breeding for improved grain quality.

High head rice and low chalky grain percentages are key grain quality traits selected in developing rice cultivars. The objectives of this research were to characterize the phenotypic variation of head rice and chalky grain percentages in a diverse collection of rice accessions, identify single nucleotide polymorphism (SNP) markers associated with each of these traits using genome-wide association studies (GWAS), and identify putative candidate genes linked to the SNPs identified by GWAS. Diverse rice varieties, landraces, and breeding lines were grown at the Texas A&M AgriLife Research Center in Beaumont. Head rice percentages (HRP) and chalky grain percentages (CGP) of 195 and 199 non-waxy accessions were estimated in 2018 and 2019, respectively. Phenotypic data were analyzed along with 854,832 SNPs using three statistical models: mixed linear model (MLM), multi-locus mixed model (MLMM), and fixed and random model circulating probability unification (FarmCPU). Significant variations in HRP and CGP were observed between rice accessions. Two significant marker-trait associations (MTAs) were detected on chromosomes 1 and 2, respectively, based on best linear unbiased prediction (BLUP) values in 2018, while in 2019, one SNP was significantly associated with HRP in each of chromosomes 6, 8, 9, and 11, and two in chromosome 7. CGP was significantly associated with five SNPs located in chromosomes 2, 4, 6, and 8 in the 2018 study and ten SNPs in chromosomes 1, 2, 3, 4, 7, 8, 11, and 12 in the 2019 study. The SNPs are located within or linked to putative candidate genes involved in HRP and CGP. This study reports five and ten novel MTAs for HRP and CGP, respectively, while three and five MTAs co-located with previously reported quantitative trait loci for HRP and CGP, respectively. The validation of candidate genes for their roles in determining HRP and CGP is necessary to design functional molecular markers that can be used to effectively develop rice cultivars with desirable grain quality.

This study aimed to develop and genetically characterize thermosensitive genic male-sterility (TGMS) lines for use in hybrid rice (Oryza sativa L.) breeding. Male-sterile F2 to F4 generation lines were screened during the high-temperature summer season, and ratoon crops of selected male-sterile rows were harvested for pure seed. Sixty-six F5 TGMS lines were genotyped using DNA markers controlling 16 traits from the LSU80 QA/QC Rice PlexSeq SNP Panel. Ten TGMS lines with desirable traits that included semidwarf, glabrous, non-aromatic, long-grain, narrow brown leaf spot resistance, and blast resistance genes were selected for further genotypic characterization using markers for low chalkiness (chalk5), wide compatibility (S5-n), cold tolerance (qSCT-11 and qCST-12), and anaerobic germination (AG1 and AG2). TGMS lines TIL21051S and TIL21052S possess favorable alleles for each of the genes evaluated in this study and are desirable parents for two-line hybrid breeding in the southeast United States. TIL21044S, TIL21095S, TIL21060S, and TIL21066S each contain three blast resistance genes and have potential as parental lines. TIL21014S-2, TIL21015S, and TIL21016S-1 include the fgr allele for aroma and can also be used as parental lines for aromatic two-line hybrids.

Preliminary studies have suggested that maximum node production rate and main culm node number may be useful as selection criteria in breeding for improved rice (Oryza sativa L.) cultivars. The objective of this research was to determine the significance of the direct effects of maximum node production rate and main culm node number on 15 yield-related traits (filled grain percentage, mass per panicle, maximum tiller density, number of degree-days to heading, LAI at heading, number of spikelets per panicle, panicle density, plant height, panicle length, and the masses of panicles, leaves, and stems at heading and at harvest) and their subsequent direct effects on grain yield. Correlation and path analyses were used to analyze data from field experiments involving 15 lines that represented the combinations of low and high levels of four important yield determinants — maximum number of tillers, grain mass, main culm node number, and panicle mass. Maximum node production rate had a negative direct effect on degree-days to heading (p=−0.35) and positive direct effects on maximum tiller density (p=0.59), panicle mass at harvest (p=0.48), panicle density (p=0.40), LAI at heading (p=0.37), panicle weight (p=0.36), and on the masses of leaves (p=0.39), panicles (p=0.35), and stems (p=0.32) at heading. Main culm node number had significant direct effects on degree-days to heading (p=0.98), plant height (p=0.75), LAI at heading (p=0.54), maximum tiller density (p=0.33), stem mass at harvest (p=0.53), and the masses of stems (p=0.58), leaves (p=0.54), and panicles (p=0.42) at heading. Five of the traits that maximum node production rate and main culm node number directly affected (degree-days to heading, mass per panicle, panicle density, and stem mass at heading and harvest) had subsequent direct effects on grain yield.

The economic value of different rice varieties depends on their characteristics. Knowing the genetic control of the traits will help the breeder. Genetic diversity of 85 rice genotypes evaluated using six iPBS, one IRAP, and nine ISSR markers. The studied traits included the grain area, grain length, grain width, and diameter and grain perimeter, eccentricity of brown and white. The polymorphic alleles detected by each marker (varied from 3 to 8 alleles), and an average of 5.33 alleles per locus was observed. The iPBS1854 and iPBS2242 markers with 11 bands have the highest number of bands and the iPBS2240 and iSSR55 markers with 5 bands of the least band bands. The content of the polymorphic information varied from 0.018 (iPBS2241) to 0.241 (iPBS2240) and averaged 0.195. The iPBS2240 marker with high levels of polymorphic information identified as the best marker for genetic diversity evaluation. Regression analysis was performed between phenotypic traits and molecular data for association analysis. 54 alleles were identified for evaluated traits. Of these, in a normal condition of one allele linked to the area, length, width, the eccentricity of the brown rice grain. Also, two, three, four alleles associated with the area, length and width of the white grain. In Drought stress, one single allele correlated to the area, length and width of the brown rice grain. Eight and one alleles detected for exertion from canter and perimeter of the brown rice. Also, two, four, four and eight alleles associated with the area, length, width, from canter and perimeter of the heard rice grain, respectively. Among identified alleles, ISSR1-2, iPBS2241-2, ISSR16-4, ISSR55-1, ISSR57-1, iPBS2242-2 and iPBS2240-1 associated with several traits in both normal and stress conditions The presence of common alleles is probably due to the linkage of genetic locations which control these traits or pleiotropy. We suggest that linked markers with common traits be used for breeding programs.

The present investigation was comprised of fifteen advanced mutant lines and a control, were evaluated for correlation and direct and indirect effects of different characters on fruit yield. The analysis reveals that fruit yield per plant was significantly and positively correlated with length of main stem, number of primary branches, days to 50% flowering, number of fruiting nodes on main stem, length of fruit, girth of fruit, average fruit weight and ascorbic acid at both genotypic and phenotypic level. Average fruit weight, number of fruits per plant, days to 50% flowering, total soluble solids, length of fruit and number of fruiting nodes on main stem showed direct effect on fruit yield per plant. Hence, more emphasis should be given on these component traits that can be further considered as selection index in snake gourd.

Genetic variability studies provide basic information regarding the genetic properties of the population based on which breeding methods are formulated for further improvement of the crop. The estimates of heritability, coefficients of variability and genetic advance computed for 12 yield contributing traits. Genetic parameters for yield and its correspondent characters in rice were estimated from a trial with four CMS lines, fifteen testers, three checks and sixty crosses evaluated for twelve characters related to yield. In general, the magnitude of phenotypic coefficient of variation (PCV) was higher than the corresponding genotypic coefficient of variation (GCV) for all the traits. High estimates of heritability and genetic advance in broad sense and narrow sense were recorded for all characters viz., spikelet fertility, days to 50% flowering, days to maturity, spikelets per panicle, harvest-index, L/B ratio, 1000-grain weight, plant height, grain yield per plant, biological yield per plant, panicle bearing tillers per plant, panicle length. High heritability coupled with high genetic advance in percent of mean was observed for all the traits.

The results were indicated that, out of 60 crosses, the most desirable five crosses showing high significant positive heterosis over better parent for grain yield per plant were IR 79156A X NDR 370132 (72.19%), IR 68888A X NDR 370132 (66.69%), IR 68897A X NDR 370131 (43.33%), IR 58025A X CR 2499 (40.71%) and IR 79156A X NDR 2701 (35.80%). Eighteen crosses showed positive and significant heterosis over standard variety and the best five crosses among them were IR 58025A X NDR 1127 (20.78%), IR 79156A X IR 27723 (14.87%), IR 68888A X IR 27723 (14.81%), IR 58025A X Sugandha 5 (12.84%) and IR 68897A X NDR 2701 (12.46%). The cross, IR 58025A X NDR 1127, showed highest mean performance (28.70g), heterobeltiosis (22.48%) and standard heterosis (20.78%) for grain yield per plant while highest yielding parent, NDR-359, produced mean grain yield 23.78 g.

Grasses are the main botanical component of grasslands, a major plant community covering a surface of approximately 3.3 billion hectares. The phenology of grasses is crucial for understanding the variations of both quantity and quality of the biomass in grasslands. In temperate regions, both the start of growth in winter and the maximum production at the end of spring are linked to flowering, which is induced by the exposition to specific conditions of temperature and photoperiod. However, current simulation models of biomass production poorly account for floral induction, which impedeces the assessement of interannual climatic variations and climate change impacts on grassland production and management. In particular, these models focus on the canopy scale, which makes themselves ineffective in accounting for the diversity of tiller in regards to their phenological state. In order to better simulate grassland phenology, we propose an approach, which accounts for tiller demography and functioning in relation with environmental conditions. Based on a Functional Structural Plant Model calibrated for ryegrass (L-Grass model), we aimed at simulating the floral induction and growth of individual tiller, from apex initiation to spike appearance. The L-Grass model simulates the vegetative growth of individual tillers of multiple phenotypes based on the concept of self-organisation i.e. the length of the pseudostem drives some morphogenetic dynamics such as leaf length and the timing of leaf and tiller recruitment. The model leads to realistic 3D virtual canopies that can be used to calculate radiation interception and biomass of each tiller. From this initial version, we implemented a sub-model of floral transition at apex scale and its consequences on each tiller morphology and development. Floral induction of each apex is calculated independently according to the temperature and photoperiod. Depending on these factors, a final number of both vegetative (internode, leaf and lateral apex) and reproductive phytomers (internode and spikelet) is calculated, inducing a potential delay in floral transition between tillers. Finally, spike heading is simulated according to the floral transition date and the elongation rate of internodes, which mainly depends on temperature. The first simulation outputs of the model are described.

Globally, blast incited by Magnaporthe oryzae and sheath blight (ShB) by Rhizoctonia solani Kuhn forms two major fungal diseases that cause significant yield loss in rice. Pusa 6B, the Basmati quality maintainer line of the popular superfine grain aromatic rice hybrid Pusa RH10, is highly susceptible to both the diseases. The rice cultivar Tetep was used as the donor for transferring a major blast resistant gene, Pi54 and three ShB resistant quantitative trait loci (QTLs) namely, qSBR11-1, qSBR11-2 and qSBR7-1 into Pusa 6B using a marker assisted backcross breeding scheme with restricted number of backcrosses. Plants heterozygous for the alleles of interest and phenotypic similarity to the recurrent parent were used for generating BC 1 F 2 population by selfing selected BC 1 F 1 plants. Selected BC 1 F 2 plants homozygous for Pi54 were selfed to generate BC 1 F 3 families that were subjected to a stepwise reductive screening for the three ShB resistant QTLs. Final selections were advanced to BC 1 F 5 generation through selfing while subjecting to stringent phenotypic selection. The advanced selections carrying blast and ShB resistant genes (Pi54, qSBR11-1, qSBR11-2, qSBR7-1) in the background of Pusa 6B were resistant to highly virulent strains of rice blast as well as ShB isolates without compromising the grain and cooking quality of Pusa 6B. Marker assisted transfer of blast and ShB resistance into Pusa 6B will aid in developing CMS lines with inbuilt resistance to these diseases. When combined with restorer lines possessing resistant genes/QTLs for these diseases, the improved Pusa6A lines will aid in development of improved Pusa RH10 and other novel aromatic hybrids with resistance to blast and ShB diseases. The present study demonstrates successful use of a restricted backcrossing strategy for introgression of multiple loci conferring resistance to two important fungal diseases in rice.

Pusa RH10, a popular high yielding superfine grain aromatic rice hybrid and its parents Pusa6A and PRR78 are highly susceptibility to blast disease. Marker assisted backcross breeding (MABB) approach was employed to incorporate blast resistance genes viz., Piz-5 and Pi54, from the donor lines C101A51 and Tetep into the genetic background of PRR78 to develop Pusa1602 (PRR78 + Piz5) and Pusa1603 (PRR78 + Pi54), respectively. Foreground selection for the genes Piz-5 and Pi54 was effected using tightly linked molecular markers, AP5930 and RM206, respectively in two independent backcross series. Further, foreground selection was coupled with stringent phenotypic selection for agronomic, grain and cooking quality traits, to accelerate recurrent parent phenome recovery. Five superior BC 2 F 2 plants homozygous from each of the backcross series were selected and advanced to BC 2 F 5 generation through pedigree selection to develop improved versions of PRR78 with blast resistance. Background analysis revealed the recurrent parent genome recovery up to 89.01% and 87.88% in Pusa1602 and Pusa1603 lines, respectively. The hybrids produced by crossing Pusa6A with improved lines of PRR78, were on par with original Pusa RH10 in terms of yield, grain and cooking quality traits with an added advantage of blast resistance.

Upto now, a lot of drought related genes were cloned and individual gene showed positive effects under controlled stress experiments, but were not effective in the field. However, the progresses by conventional breeding approaches were achievable as some drought varieties have been released to the farmers in the recent years. Although, this is not adequate to cope up with the future demand of high yield for rice, as drought seems to spread to more regions and seasons across the country. Therefore, marker assisted selection came into lime light for accelerating and giving pace to plant breeding. The identification of QTLs with a major effect on grain yield raises a new hope of improving grain yield under drought through marker assisted breeding. The availability of the major effect QTL for drought tolerance, a theoretical frame-work for marker assisted selection and the existence of intolerant varieties that are widely accepted by farmers provides an opportunity to develop cultivars that would be suitable for larger areas of drought prone rice. In case of (Sarjoo -52 × Birsa Gora) × Sarjoo -52, two drought tolerant genes were incorporated. Only those plants were therefore selected which showed polymorphism for the genes MQTL1.1 and qDTY3.2. Thus, plant number

A sustainable food system ensures food security and nourishment for future generations. Rice (Oryza sativa L.) requires emergence
stress tolerance for successful cultivation in germination and early establishment stages. According to the FAO (Food and
Agriculture Organization) study, rice is one of the most important worldwide cereal crops and a staple food for more than half of
the world’s population. Over the past few years, drastic climatic changes have been subjected to many abiotic and biotic stresses.
Global estimates express that a total of 1000 million hectares of cultivated land is affected by abiotic and biotic stress. Besides this
around 30% of the irrigated land area is also disturbed. This review discusses the mechanisms of stress-tolerant variants and
understanding the recent developments of complex tolerance phenomena. Here, we have compiled the logical pieces as evidence
of successful applications of potent molecular tools for boosting stress tolerance in rice, their prospects and limitation. This
information would help researchers better understand the genetic enhancement of stress tolerance in rice.

Salinity is a major constraint to higher crop production in the southern coastal soils of Bangladesh. To overcome this problem, a study was undertaken with the application of different mulch materials and potassium fertilizer doses during 2017-18 and 2018-19 at Barguna district of Bangladesh. The test crop was a bitter gourd. The experiments were laid out in a two-factor randomized complete block design with three replications. The first factor was different types of mulch material (M1: no mulch, M2: rice straw mulch, and M3: polythene mulch), and the second factor was different rates of potassium (K) fertilizer (K1: no K fertilizer, K2: 100% recommended K fertilizer, and K3: 150% recommended K fertilizer). The effect of mulch materials and potassium fertilizer doses recorded significantly higher yield, yield components, and nutrient uptake of bitter gourd in both the years over control treatment. In the case of mulching, the polythene mulch treatment had the best performance in all tested parameters, followed by rice straw mulch and no mulch treatment. The polythene mulch treatment resulted in a 136% and 198% higher yield over no mulch treatment in two years, respectively. Regarding the K effect, the 150% recommended K fertilizer gave the best performance, followed by the 100% recommended K fertilizer and control treatment. Application of 150% recommended K increased 39 and 68% higher yield over K control treatment in two years, respectively. The polythene mulch and/or 150% recommended K fertilizer gave the highest positive results among all the tested treatments. On the other hand, the use of polythene mulch and/or 150% recommended K fertilizer gave the lowest soil EC and exchangeable soil Na. Therefore, polythene mulch and/or 150% recommended K fertilizer could be a new package for increasing bitter gourd yield by reducing salinity in coastal saline soil of Bangladesh.