Genetic Evaluation of Major Traits in Fuzzless Upland Cotton Germplasm

A total of 102 fuzzless seed upland cotton varieties(G.hirsutum) as female parents were crossed with genetic standard line TM-1(as male parent) to analyze the main traits in the F1 population with random blocks design with three replications.The results showed that there were significant differences among eleven agronomic traits between different parents,and the difference of yield traits(plant height,fruit branch number,boll number,boll weight,lint percentage,and seed index) was higher than those of fiber quality traits(length,strength,micronaire,uniformity,elongation rate),especially for lint percentage,boll number,except for fruit branch number,micronaire and elongation rate,the mean values of other traits in parent populations were lower than those in F1 populations,however,the coefficient of variation in fuzzless seed parents was higher than that of F1.The heterosis including mid-parent heterosis and heterobeltiosis highly varied in different varieties.Some traits of some varieties with negative heterosis showed inferior descendants,The mid-parent heterosis and heterobeltiosis in fiber quality traits showed negative correla-tion with fuzzless rate,but yield traits showed positive correlation with fuzzless rate,indicating that the heterosis could be applied for fiber quality improvement but might be limited for the yield improvement,No significant correlation was found between ge-netic similarity coefficients based on SSR markers and heteroses in all traits,indicating that it is difficult to predict heterosis by using genetic background similarity of parents in fuzzless cotton breeding.