Abstract:

An insight into ideotype of cotton is essential for improvement of lint yield and fiber quality. The objective of this study was to elucidate the genetic contributions of plant type characters to lint yield and find indicator characters for indirect selection of lint yield. A 2-year study was conducted to evaluate nine plant type traits and lint yield for nine cultivar (or breeding lines) and resultant twenty F1 crosses, which were grown at the agriculture experimental station of JXAU, Nanchang, in 2007 and 2008. The data was subject to multivariable conditional analysis based on a genetic model containing additive-dominance and their interaction with environments. The phenotypic contribution of nine plant type characters to lint yield ranged from 0.1% to 11.1%. Additive effects contribution to lint yield was positive and significant at 0.01 level for internodal length (IL), and at 0.05 level for Height of the first sympodial branch (HFSB) and number of fruiting sites per plant (NFS), which were 29.8%, 6.2% and 5.7%, respectively. Sympodial branch angle (SBA) had a high constrain effect on additive effects of lint yield (-39.9%). The contribution of dominant variance of NFS to lint yield was larger than other plant type traits. There was a significant positive contribution of additive by environment interaction effects of IL on lint yield (17.7%). Small or no significant contributions of dominant by environment interaction were detected for all plant type traits investigated. There were largest additive contribution to lint yield of these parents from NFS of parents 2 and 4, HFSB of parents of 3, 5 and 6, IL of parent 7. Indicating no identical trait of diverse parents was showing the largest contribution to additive effect of lint yield. NFS had the highest contribution to dominance effects of lint yield for most F1 crossed, and could be used for selecting the crosses with high lint yield.