Diallel Analysis of Correlated Sequential Characters in Durum Wheat1

Abstract

Diallel regression analysis was applied to four correlated sequential yield component characters in durum wheat (Triticum turgidum L. var. durum): (i) number heads per plant; (ii) number of spikelets per head; (iii) number of grains per spikelet; and (iv) 100‐kernel weight. The untransformed (correlated) data indicated that all of the characters showed predominantly additive genetic effects with some degree of dominance and a general lack of epistatic effects. Analysis of the transformed (uncorrelated) data showed a higher level of dominance and/ or epistasis with a concomitant decrease in the narrowsense heritability estimate for each of the four characters. The phenotypic expression for heads per plant and grains per spikelet was independent of other characters, while that of spikelets per head and 100‐kernd weight was influenced by characters developed previously along the developmental sequence.