Genetic architecture of some physiological traits in wheat

A triple test cross involving 15 diverse lines of bread wheat (Triticum aestivum L. cm Theil) was studied to investigate the genetic architecture of physiological traits viz., flag-leaf area (em²), peduncle length (cm), stomata number, coleoptile length (cm) and grain filling period. Non-allelic interaction was found to be an integral component of the genetic architecture of all the traits except flag-leaf area. Partitioning of non-allelic interaction revealed the influence of additive x dominance (j) and dominance x dominance (1) interaction in the inheritance of peduncle length, coleoptile length and grain filling period, whereas additive x additive interaction was important for stomata number. Both additive and dominance genetic variances were present for all the traits except peduncle length for which only additive genetic variance was present. The direction of dominance was ambidirectional for stomata number and coleoptile length; dominance of increasing alleles for flag-leaf area and dominance of decreasing alleles for peduncle length and grain filling period. Selection in early segregating generations for stomata number and in later generations for remaining traits is expected to be more effective.