Inheritance of Yield and Fiber Quality Traits and Inbreeding Depression in F3, F4 and F5 Generations of Cotton (Gossypium hirsutum L.)

The improvement of new cotton varieties with high yield and superior fiber quality is of crucial importance for maintaining genetic diversity and meeting the requirements of the textile industry. A total of 13 different bulk populations were compared with F3/F4 evaluated in 2022 and F4/F5 in 2023 for yield and fiber quality. The experiments were designed using a split-plot design, with generations assigned to the main plots and populations to the subplots. Variance analysis indicated that generation × population interactions were significant for seed cotton yield, ginning out-turn, fiber length, fiber fineness and fiber strength. Due to high inbreeding depression and low heritability, it was determined that seed cotton yield is influenced more by environmental factors than by genetic factors. Therefore, it has been concluded that the single plant should be selected in later generations in breeding programs targeting increased seed cotton yield. (Julia × ST-468) × (Carmen × Carisma), (Carisma × Carmen) × (Gloria × Carisma), (Julia × ST-468) × (Gloria × Flash), and (ST-468 × Claudia) × (Gloria × Flash) were identified as optimal populations with high yield and superior fiber quality characteristics.