Inheritance of Tillering in a Winter Wheat Population
- David A. Van Sanford and
- Herry Utomo
Tillers are an important component of wheat (Triticum aestivum L. emend. Thell.) grain yield, yet there is uncertainty in the literature about improving yield by selecting for tiller number. The objectives of this study were to estimate the heritability of tiller number, to quantify genotype × environment (G × E) interaction, and to assess tiller number as an indirect selection criterion. We measured tiller number at five growth stages, grain yield, and kernel size in 92 soft red winter wheat F4 lines in 1987 and in their bulk F5 progeny at two planting dates in 1988. Heritability (h2) of tiller number at Feekes growth stages 2, 4, 7, 10.1, and 11.2 in a single environment ranged from 0.05 to 0.60. When G × E interaction was accounted for in a combined analysis, however, heritability estimates were much lower, ranging from −0.14 to 0.19. Genotype rank changes were common among pairs of environments, though in certain cases, scale differences predominated. Tiller number at growth stage 10.1 was highly correlated with yield (r = 0.58, P < 0.01) and had higher heritability (h2 = 0.19) than yield (h2 = 0.05), and thus, we predict a higher response (36%) to indirect selection than to direct selection for yield itself. Indirect selection for tiller number with visual keys would be most appropriate in early generations when direct yield assessment is difficult, followed by direct selection for yield in later generations.
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