Yield and Fiber-Quality Potential for Second-Generation Cotton Hybrids
Due primarily to the difficulty of producing F1, seed, use of heterosis in cotton (Gossypium hirsutum L.) has been limited. The objective of this study was to evaluate the potential of using F2 hybrids by comparing them with parents and F1's for yield, fiber quality, and interaction with environments. The genetic design was a half-diallel consisting of seven mid-South parents, 21 F1's, and 21 F2's. The 49 genotypes were grown in 1987 and 1988 at three sites near Stoneville, MS. At each site, April and May planting was made, resulting in a total of 12 environments. Yield, yield components, and fiber length, strength, and micronaire reading were determined from four replications. Yarn tenacity was determined from two 1987 tests, and short-fiber content from three 1987 tests. Average first-harvest yield was 594, 688, and 643 kg ha−1 for the parents, F1's and F2's, respectively; total yield was 953, 1065, and 1025 kg ha−1, respectively. Average yarn tenacity was 130, 134, and 132 kN m kg−1 for the parents, F1, and F2 hybrids, respectively. Both F1 and F2 hybrids had significantly fewer short fibers than the parents. The highest-yielding parent was ‘DES 119’, which averaged 1031 kg ha−1, while ‘Deltapine 50’, the most commonly grown cultivar in the USA, averaged 959 kg ha−1. The highest-yielding F1 hybrids DES 119 ✕ ‘Delcot 344’ and DES 119 ✕ ‘Coker 81–613’ averaged 1145 and 1143 kg ha−1, respectively, ~15% higher than the average of DES 119 and Deltapine 50; their F2 hybrids averaged 8% higher. No differences in adaptive ability between parents, F1's, and F2's were detected. The results indicate that F2 hybrids have the genetic potential for increasing cotton yields and fiber quality.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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