Application of prognostic breeding in maize

Journal of Agricultural Sciences, Belgrade, 2004

Historically speaking, both the introduction of double-cross hybrids and use of single crosses have caused the increase in grain yield and significantly improved agricultural practice. Nowadays, the uniformity of crops is regarded as an advantage of modern agriculture, since the uniformity of products is crucial in global market. Thus, uniformity of crop maturation provides both planning and efficient mechanized harvest. F1 single-cross hybrids of maize, which is an allogamous species, not only exploit heterosis, but also impose homogeneity. Basically, the uniformity of hybrids has been regarded as their crucial advantage. There are two aspects of hybrid maize uniformity: (i) genetic homogeneity and (ii) genetic stability. Genetic homogeneity refers to presence of identical genotypes, whereas genetic stability refers to phenotypic uniformity (homeostasis) in different environments. At present, yield performance of inbreds has not advanced as rapidly as performance of hybrids, especi...

Euphytica, 2015

A marker-assisted recurrent selection (MARS) program was undertaken in sub-Saharan Africa to improve grain yield under drought-stress in 10 biparental tropical maize populations. The objectives of the present study were to evaluate the performance of C1S2-derived hybrids obtained after three MARS cycles (one cycle of recombination (C1), followed by two generations of selfing (S2), and to study yield stability under both drought-stress (DS) and well-watered (WW) conditions. For each of the 10 populations, we evaluated hybrids developed by crossing 47–74 C1S2 lines advanced through MARS, the best five S5 lines developed through pedigree selection, and the founder parents with a single-cross tester from a complementary heterotic group. The hybrids and five commercial checks were evaluated in Kenya under 1–3 DS and 3–5 WW conditions with two replications. Combined across DS locations, the top 10 C1S2-derived hybrids from each of the 10 biparental populations produced 0.5–46.3 and 11.1–5...

A maize population was subjected to three different selection procedures to determine the best method for its improvement in a study conducted at Ibadan, Nigeria. Considerable genetic variability existed within the population for effective selection for each of the traits considered, using any of the procedures namely full-sib, half-sib and S1 family selection. Heritability estimates were from moderate to large for most traits. Direct selection for grain yield is expected to result in favourable increases in other traits except that the selected materials will flower earlier. Since increases in plant height due to selection for grain yield is undesirable, it was concluded that the best selection method for yield improvement that will increase height, the least would be full-sib family selection.

Crop Science, 2007

Australian Journal of Crop Science, 2019

In the context of the mutants, polyembryony in maize (PEm) has agronomic potential; therefore, the inclusion of the PEm in new varieties may be useful when considering the ascending demand for food. The objective of this study was to develop new genotypes with high productivity potential, superior to in local area, and useful for family and extensive agriculture. In this work, single crosses were carried out between three pure lines and the high frequency polyembryonic populations. The resulting F1 were advanced to the third generation (G3) and the genotypes obtained from this last generation were used as progenitors of a mating plan, according to the Griffing method 4. The resulting crosses were evaluated in a yield test measuring common characteristics of economic importance (Days to Male Flowering (MF), Plant Height (PH), Cob Height (CH), Fusarium Rotten cobs, Cobs (CFUS), Yield (YLD), and analyzed with the computer routine DIALLEL-SAS05. The results allowed to indicate that both...

Field Crops Research, 2002

Average commercial maize yield in the US has increased from about 1 Mg/ha in the 1930s to about 7 Mg/ha in the 1990s. Although the increase has been the result of both genetic and agronomic-management improvements, we contend that most of this improvement is the result of the genotype  management interaction. The genetic improvement in maize yield is associated neither with yield potential per se, nor with heterosis per se, but it is associated with increased stress tolerance, which is consistent with the improvement in the genotype  management interaction. The potential for future yield improvement through increased stress tolerance of maize in the US is large, as yield potential is approximately three times greater than current commercial maize yields. The mechanism by which maize breeders have improved stress tolerance is not known, but we speculate that increased stress tolerance may have resulted from the selection for yield stability. Stability analyses were performed on a number of high-yielding maize hybrids, including three hybrids that have been involved in some of the highest maize yields recorded in producers' ®elds, to examine the relationship between yield and yield stability. Results of the stability analyses showed that high-yielding maize hybrids can differ in yield stability, but results do not support the contention that yield stability and high grain yield are mutually exclusive. # 2002 Published by Elsevier Science B.V.

Australian Journal of Crop Science, 2018

G3 (Bethesda, Md.), 2012

Genomic prediction is expected to considerably increase genetic gains by increasing selection intensity and accelerating the breeding cycle. In this study, marker effects estimated in 255 diverse maize (Zea mays L.) hybrids were used to predict grain yield, anthesis date, and anthesis-silking interval within the diversity panel and testcross progenies of 30 F(2)-derived lines from each of five populations. Although up to 25% of the genetic variance could be explained by cross validation within the diversity panel, the prediction of testcross performance of F(2)-derived lines using marker effects estimated in the diversity panel was on average zero. Hybrids in the diversity panel could be grouped into eight breeding populations differing in mean performance. When performance was predicted separately for each breeding population on the basis of marker effects estimated in the other populations, predictive ability was low (i.e., 0.12 for grain yield). These results suggest that predict...

Euphytica, 2010

Maize (Zea mays L.) is a very important cereal to world-wide economy which is also true for Brazil, particularly in the South region. Grain yield and plant height have been chosen as important criteria by breeders and farmers from Santa Catarina State (SC), Brazil. The objective of this work was to estimate genetic-statistic parameters associated with genetic gain for grain yield and plant height, in the first cycle of convergent-divergent half-sib selection in a maize population (MPA1) cultivated by farmers within the municipality of Anchieta (SC). Three experiments were carried out in different small farms at Anchieta using low external agronomic inputs; each experiment represented independent samples of half-sib families, which were evaluated in randomized complete blocks with three replications per location. Significant differences among half-sib families were observed for both variables in all experiments. The expected responses to truncated selection of the 25% better families in each experiment were 5.1, 5.8 and 5.2% for reducing plant height and 3.9, 5.7 and 5.0% for increasing grain yield, respectively. The magnitudes of genetic-statistic parameters estimated evidenced that the composite population MPA1 exhibits enough genetic variability to be used in cyclical process of recurrent selection. There were evidences that the genetic structure of the base population MPA1, as indicated by its genetic variability, may lead to expressive changes in the traits under selection, even under low selection pressure.

The Journal of Agricultural Science, 1977

SUMMARYOne hundred and ninety hybrids involving 20 broad-based yellow maize populations were evaluated together with their parents for stability in expression of their grain yield potential by means of linear regression on to an environmental index. Both linear and non-linear components were observed to be significant; the linear component, in general, being the more important. Two high yielding parents, namely variety A 3D and composite Jawahar, had general adaptability, while synthetic A 22 was suited to poor environment and variety SO 4D to good environment. Seventeen hybrids had above average yield and the majority of these exhibited general adaptability.Combining ability analysis revealed that GCA (general combining ability) was more important than SCA (specific combining ability) in the expression of mean yield. Inheritance of linear regression was controlled predominantly by GCA whereas both GCA and SCA were equally important in the expression of non-linear fluctuations. Vari...