Physiological contributors to yield in advanced cotton breeding lines

Abstract

AbstractCotton (Gossypium hirsutum L.) yield can be expressed as the product of intercepted photosynthetically active radiation (IPAR), radiation use efficiency (RUE), and harvest index (HI). Studies comparing genetic diversity in functional yield drivers for the progeny of elite breeding lines are limited or non‐existent. A field study was conducted during the 2020 and 2021 growing seasons to characterize crop development and to evaluate yield and underlying yield drivers in 16 advanced breeding lines (F7 generation). Significant breeding line differences existed for lint yield, cutout date, reproductive, vegetative, and total biomass, RUE, and HI but not for IPAR. The lint yield for the lowest yielding lines was 24% lower than the highest yielding line with a lint yield of 1706 kg ha−1. Differences in RUE were not associated with single‐leaf photosynthetic rates. HI positively contributed to lint yield gain for most lines evaluated, whereas RUE was negatively correlated with lint yield for the majority of breeding lines evaluated. However, in the two highest‐yielding lines, two different strategies of yield maximization were identified. One line exhibited the earliest cutout date, reduced biomass production, low RUE, and the highest HI values, whereas the other line had the latest cutout date and produced the highest total biomass, highest RUE, and a low to intermediate HI. Breeding lines used in the current study achieved high yields by differentially manipulating underlying physiological components such as RUE, biomass accumulation, or dry matter allocation to fiber. Our work provides future direction for efforts aimed at maximizing yield through the selection for functional yield drivers.