Genetic analysis of grain protein percentage in wheat.

Diallel analysis techniques were used to study the genetic basis of grain protein percentage expression in wheat using eight wheats ranging from high to low in grain protein percentage and assumedly genetically diverse for this character.The F2 set of crosses exhibited strong genetic interaction for protein percentage attributable greatly to the general behaviour of Argentine IX, of high grain protein percentage, in combination with the other seven wheats. Removal of its interaction revealed additive genetic variance and moderately strong overdominance averaged over the crosses of the remaining seven parents.In the F3 and F4 generations grain protein content exhibited additive genetic variance with evidence of some non-allelic interaction in the F3. The F3 exhibited partial dominance in the inheritance of protein percentage while in the two F4 trials in different environments one exhibited a strong degree of average dominance and the other exhibited only a small degree of average dominance over all arrays.Close correspondence in the order of ranking of protein percentage of the lines (parents and hybrids) in the two F4 trials in two different environments, indicated a significant influence of genotype on the expression of this character in wheat. However, sharp differences in the nature of inheritance of high grain protein percentage between the two environments, whether by dominant or recessive genes, indicates the magnitude of the influence of the environment on its genetic expression in populations segregating for this character.