Impact of heterozygosity and heterogeneity on cotton (Gossypium hirsutum L.) lint yield stability: II. Lint yield components

Abstract

An 18-environment field study was undertaken to observe the mean and coefficient of variation (as a measure of stability) for cotton (Gossypium hirsutum L.) lint yield components in population types that differed for lint yield stability to determine which yield components contributed to yield stability. Hybrids and blends of hybrids (heterozygous populations) were more stable than the parents and blends of parents (homozygous populations) for lint yield. No within-boll yield component showed convincing evidence of differences between population types with respect to stability. Stability observed for bolls/hectare followed the same trend as lint yield in which the heterozygous populations were more stable than homozygous populations. Heterosis for boll production was not consistent across locations and declined with increasing environmental mean. Ultimately, the difference between population types, with respect to yield and stability, was attributed to the heterozygous entries producing more bolls in the low-yielding environments while producing numbers that were similar to the homozygous populations in the high-yielding environments. This reduced the range of lint yield, reduced the variation across locations, and resulted in increased lint yield stability. Manipulating within-boll components might not increase lint yield stability.