Lint Yield Genotype ✕ Environment Interaction in Upland Cotton as Influenced by Leaf Canopy Isolines1
- William Meredith2
In order to develop a strategy in cotton (Gossypium hirsutum L.) for determining the optimum leaf canopy type for each major environment and linking physiology with breeding, the interaction of leaf canopy types with environments was investigated. The lint yield genotype ✕ environment interaction of normal, Okra leaf (Lo2, Lo2), and their F1 and F2 near-isogenic leaf canopy types of eight cotton cultivars and strains was investigated at Stoneville in 1979 and 1980. The 32 combinations were planted on two dates each year at seeding rates of 9.7, 19.4, and 38.8 seeds m,-2. Average yields for the 27 April and 15 May 1979 plantings were 937 and 654 kg ha-1, respectively; the 21 April and 14 May 1980 plantings were 577 and 539 kg ha-1, respectively. Cultivar-strains average yields ranged from 550 to 816 kg ha-1. No leaf type consistently produced highest yields. Average yields of normal, Okra leaf, F1, and F2 cotton were 682, 660, 687, and 677 kg ha-1, respectively. Interactions with the four leaf canopy types accounted for 29% of the total genetic variance, whereas interactions with the eight cultivar-strains accounted for 13% of the total genetic variance. Significant negative dominance was detected in 1979 and significant positive dominance was detected in 1980. In 1979, there was a trend for negative compensation in the F2; the F2 yielded less than expected based on its three genotypic components. In 1980, there was a trend for positive F2 compensation. As a result, F2 leaf canopy types produced the most stable (least variance) yields across all environments and management variables. This study indicates the high interactive effects of leaf canopy types on yield, which are probably linked to leaf canopy types' known association with leaf area and crop maturity.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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