Genotype by Environment and Biplot Analyses for Yield and Fiber Traits in Upland Cotton

Stability and desired response of genotypes across different environments is very important for plant breeders. Therefore, plant breeders always test their breeding material across diverse environments to assess consistency of superior genotypes for wider adaptation. Twenty-eight upland cotton genotypes (G) were studied across six environments (E) during two crop seasons (2012 and 2013) at three locations i.e., Peshawar, Dera Ismail Khan (D.I. Khan) and Faisalabad, Pakistan. Genotypes, genotype x year, genotype x location and genotype x year x location (G x Y x L) showed significant (p < 0.01) differences for all the traits. On an average, genotypes produced significantly more bolls per plant and lint % during 2013 than 2012. By comparing the locations, overall the genotypes performed better for yield and lint traits at Peshawar. In G x Y x L interactions, maximum bolls per plant produced by cultivar CIM-473 grown during 2013 at Peshawar. For lint %, genotypes CIM-506 and IR-NIBGE-3701-38 were leading, grown during 2012 and 2013 at D.I. Khan. According to genotype, genotype by environment (GGE) biplot analysis, the genotype CIM-473 was found as best cultivar during 2012 at D.I. Khan and Faisalabad as confirmed by genotype by environment interaction (GEI). During 2012 and 2013 at Peshawar and 2013 at D.I. Khan, the genotypes CIM-554 and IR-NIBGE-3701-38 were the vertex cultivars and more stable with high lint yield. Cultivars CIM-554 and CIM-506 were identified as best genotypes across all the environments for lint %. Genotypes CIM554 and CIM-506 were relatively steady across environments thus, identified as ideal genotypes for lint %. However, majority of the cotton genotypes were inconsistent. Therefore, this study emphasizes that efforts should be made to synthesize the cotton cultivars for the specific environment rather than mere broad adaptation. (C) 2018 Friends Science Publishers