Tiller Phenology and Yield of Spring Wheat in a Semiarid Environment

Abstract

Cereal grain yields are, in part, determined by tillers formed during the plant's vegetative phase. This study was conducted to determine the extent of genotypic differences in tiller phenology and yield characteristics of individual tillers of spring wheat (Triticum aestivum L.) grown in a semiarid environment. Time to emergence, percent emergence, and survival of individual tillers were determined for 10 genetically diverse genotypes seeded into a Typic Haploborall clay loam at Saskatoon, SK on two dates (4 and 28 May) in 1983. Genotypes differed significantly for percent tiller emergence and survival. Tiller emergence was more rapid (11–12 d) for the later seeding date. Genotype differences in time of tiller emergence (2–6 d) were significant for specific tillers. Main stem Haun stage at the time of tiller emergence (MSHE) was not influenced by seeding date but varied significantly among genotypes (0.40–1.07 Haun units). At maturity, the main stem and tillers T0, Tl, T2, and T3 contributed an average of 26.0, 4.4, 21.8, 18.8, and 12.2 % to plant grain yield, respectively, at a seeding rate somewhat below that used commercially. Tillers Tl, T2, and T3 did not differ from the main stem in culm length, spikelets spike−1, or harvest index; but produced fewer, lighter kernels. Tiller grain yields, spikelets spike−1, and culm length were negatively correlated with MSHE. Days to tiller emergence was not related to mature plant traits. The ability of MSHE to detect small differences in tillering pattern among genotypes and its relationship to yield should prove useful in the study of genotype‐environmental interaction.