Cotton is a long duration crop which effects the timely sowing of wheat in Pakistan. Information of various earliness and yield related traits are pre-requisite to develop early maturing and high yielding cotton cultivars. Therefore, the present research was conducted to determine the heterotic potential for six earliness and six yield related. For this purpose, 10 F1 hybrids were developed through crossing between nine upland cotton cultivars. These hybrids along with their parental lines were sown in the field conditions of Faisalabad, Pakistan. All the hybrids showed significant differences for observed traits. The maximum recorded values of heterosis for earliness index and seed cotton yield were 66.05% and 70.39%, respectively. Hybrid VH-289 × AGC-501 showed maximum significant heterosis (66.05%), heterobeltiosis (50.43%) and standard heterosis (32.52%) for earliness index was due to the negative heterosis in days to flowering, days to first boll opening, node number for first fruiting branch and height of first fruiting branch. Hybrid ARK-3 × AGC-501 showed maximum significant heterosis (70.39%), heterobeltiosis (28.52%) and standard heterosis (72.01%) for seed cotton yield was due to the positive heterosis showed by its yield contributing traits. This study can be used for breeding program to develop early maturing and high yielding varieties.

Cotton is a prominent fiber crop all across the world, including Pakistan.. But the production of cotton is relatively low in Pakistan. As boll is the basic determinant for yield in cotton crop, the study on within boll yield parameters was carried out using twenty exotic accessions of cotton to check their variability for within boll yield components. The experiment was performed at the research area of the department of Plant Breeding and Genetics, University of Agriculture, Faisalabad. The genotypes were seeded in three replications following randomized complete block design (RCBD). At maturity, data were collected for different within boll yield parameters. The analysis of variance showed significant results for nine out of eleven parameters studied. Principal component analysis revealed that genotype ZB-18015 showed maximum variation with respect to all parameters because it was at a maximum distance from the origin followed by genotype ZB-18020, ZB-18019 and ZB-18018 respectively. Cluster analysis identified particular groups of genotypes that were having maximum similarity with each other. In addition, the findings of the current study revealed the potential of different accessions of cotton for development of high yielding varieties. This information may be used to devise breeding strategies in the future to enhance cotton production and variety development.