Association Mapping Of Qtls With Yield And Lint Traits In Elite Upland Cotton Germplasm

Field testing across different environments can help to identify the cotton genotypes with relatively stable performance. To ascertain quantitative trait locus (QTL) associations with yield and lint traits, 28 upland cotton (Gossypium hirsutum L.) genotypes were field tested during two consecutive years at three locations of Pakistan i.e., Peshawar, Dera Ismail Khan and Faisalabad. Combined analysis of variance for genotypes across years and locations (G x Y x L) interactions showed substantial variances among the genotypes for all the variables. Molecular characterization of the cotton germplasm was conducted at the National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad. Hundred simple sequence repeat (SSR) markers were used to characterize these cotton genotypes wherein 22 markers were polymorphic, which justified the further analysis. Population structure analysis divided all the cotton genotypes into two main groups at delta (K = 2). In the first group, three cotton genotypes i.e., NIBGE-115, NN-3 and NIBGE-2472 exhibited some relationship with the genotypes of the second group. Based on association mapping, a total of 23 QTLs were identified in which 22 QTLs associated with yield and lint traits were identified through general linear model (GLM) approach while one QTL was identified through mixed linear model (MLM) approach for bolls per plant. The identified QTLs would be effective in considering the genetic basis of the aforementioned traits and maintaining diversity in the upland cotton germplasm. The favorable QTLs might also facilitate the breeders in genomic selection in upland cotton for efficient breeding. (C) 2020 Friends Science Publishers