Genetic evaluation of early- and late-maturing cotton genotypes and their F2 hybrids for fruiting habits and yield distribution

In 1997 and 1999, fruiting patterns and the distribution of lint were evaluated for five parents and four F2 cotton ( Gossypium hirsutum L.) hybrids that varied in maturity. DES119, an early-maturing cultivar, was crossed to an early-maturing cultivar Sure-Grow 501, mid-maturing cultivars Deltapine 5415 and Paymaster H1244 and late-maturing cultivar Deltapine 90. The parents and their F2's were grown at the R.R. Foil Plant Science Research Center, Mississippi State, MS, where plant height, number of mainstem nodes, yield, yield components, distribution of yield, and boll retention were measured. Variance components, genetic effects, predicted heterosis, and trait means for later generations were calculated utilizing an Additive-Dominance (AD) model. The parents and F2 hybrids were similar for lint percent, plant height and number of mainstem nodes. Retention of bolls at lower fruiting zones of the plant was greatest on DES119 and Sure-Grow 501. Lint yield and boll retention in the upper zones were greatest on Deltapine 90. Rarely did the performance of the F2-hybrids exceed that of the higher parent for lint yield at any fruiting zone; however, it was greater than the lower parent. Genetic variance for lint distribution varied with zone. Lint yield at zones 1, 3, 4, and 5 were primarily controlled by additive genetic effects and zone 2 was controlled by dominance genetic effects. Dominance genetic effects were significant for lint percentage, boll size, and lint yield. Use of early-maturing DES119 as a parent in crosses increased lint yield at zone 1 and decreased lint yield at zones 4 and 5. Combining the yield distribution of early and late maturing cotton cultivars may be achieved in F1 or F2 hybrids or, through selection without significantly altering plant height or number of mainstem nodes.