QTL Mapping of Agronomic and Economic Traits for Four F2 Populations in Upland Cotton

Abstract

Background: Upland cotton (Gossypium hirsutum) accounts for more than 90% of annual world cotton output due to its high yield potential. However, yield traits and fiber quality traits exhibit negative correlations in most cases. Here, we constructed four F2 populations, using two normal lines and two introgression lines, for simultaneously detection the genetic basis underlying complex traits such as yield and fiber quality in upland cotton. Subsequently, the phenotyping of 8 agronomic and economic traits along with quantitative trait loci (QTL) mapping was implemented. Results: Extensive phenotype variations and transgressive segregation were found across segregation populations. Four genetic maps were constructed with the length of 585.97cM, 752.45cM, 752.45cM and 1163.66cM. The mapping resulted in the identification 50 QTLs (27 were for fiber quality traits and 16 for yield traits) across four populations. Multiple QTLs having the common maker, such as qBW4 and qBW2, or residing in the same QTL cluster, such as qLP9 and qFL9-1, were prioritized for further research. Conclusions: These findings will provide insight into the genetic basis of simultaneous improvement of yield and fiber quality in upland cotton breeding.