Potential for Increasing Cotton Yields Through Enhanced Partitioning to Reproductive Structures

Abstract

Yield increases in cotton ( Gossypium hirsutum L.) have been primarily through changes in partitioning dry matter from vegetative to reproductive structures. The objective of this study was to determine if yield increases would likely continue through continued changes in dry matter partitioning. Five obsolete cultivars, five popular and high yielding cultivars from five cotton breeding organizations, and 15 advanced strains from five cotton breeding organizations were used for yield and growth analyses at three environments, two in 1985 and one in 1986. Obsolete cultivars averaged 24% less lint than the 20 more modern genotypes and showed greater investment of dry matter into vegetative rather than reproductive structures. There was no major difference in mean yield or growth characteristics detected between the five currently used cultivars and the 15 strains. However, these 20 genotypes showed significant ( P < 0.05) genetic variability for yield and most growth characteristics. Plant height and stem wt. to total dry wt. ratio showed strong negative genetic correlations with yield ( r = −0.44 to −0.80). Strong positive genetic associations with yield were found for boll wt. to total dry wt. ratio ( r = 0.86) and the late sampling of reproductive‐vegetative ratio ( r = 0.91). This study suggests that yield increases through the use of conventional breeding methods are likely to be achieved through continued partitioning of dry matter from vegetative to reproductive structures.