Genetic analysis of diallel cross in breadwheat under different environmental conditions in Egypt. 2. F₂ and parents

Five traits, namely, plant height, spike length, grains/spike, grain yield/plant, and 100-grain weight were studied in 15 F₂ populations obtained from a 6 X 6 half-diallel set in wheat. The parents showed difference for gca depending on their genotype and environment. For sea the 15 F₂ populations differed from location to location. All the traits were influenced by additive as well as dominance gene effects. Unequal allele frequency was observed in the parents with asymmetrical distribution among these parents for the proportion of positive and negative alleles with an excess of dominant over recessive genes. Some traits showed partial dominance, others showed overdominance depending on location. Narrow sense heritability was low for all the traits in F₂ except for grains/spike which was maximum at Ismailia. Data of graphic analysis of F₂ showed variation in the dominance or recessive genes in parents. This agreed with the results of statistical analysis. There were significant phenotypic and genotypic correlation coefficients between grain yield/plant and the four other traits.