1Department of Plant Breeding & Genetics, SAU, Tandojam, Sindh-Pakistan
2 Agriculture Research Institute, Tandojam, Pakistan
The selection of high-yielding cotton lines is critical for the evaluation of phenotypic characteristics. For Cotton Breeders, it is always in preference to select desirable genotypes, based on the diversified characters from the available germplasm. The selected phenotypic diversity can be useful for aiding information in parental selection, adherence to this, a set of 12 advanced cotton lines were evaluated for genetic diversity at Cotton Research Institute, Tandojam during Kharif season in the year of 2020. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications while seven agronomical traits, were included in the experiment. The mean square of genotypes, was differed significantly (P<0.05) for all studied traits, representing that genetic diversity exists in these cotton germplasms and can be used in further utilization. Considering the agronomic performance, the genotype of B-2 was on the top in average values including plant height (174.40 cm), bolls plant-1 (42.067), seed cotton yield plant-1(139.34 g), GOT% (37.800%), and staple length (28.00 mm), hence indicating its valuable breeding resources for future cotton breeding. A Genetic Distance of 92.683 was found between B5 and B2 genotypes, which is high enough, and revealing that this pair may be used in a hybridization program for vigorous hybrid production and better selection in subsequent generations. The Variance Percentages for the first, second, and third principal components were 42.70, 23.10, and 17.20, respectively. The first three components contributed 83.00 percent of the variation for genotypes, which is high enough for the cotton crop improvements. The cotton genotypes, were divided into three categories, based on phenotypic data. The number of groups obtained, might be beneficial in generating cotton genotypes with a variety of characteristics and diversifying the Cotton Gene Pool.
Keywords: cotton, genetic variations, morphological traits, seed yield.