Yield and Fiber-Quality Potential for Second-Generation Cotton Hybrids
1990
Meredith, William R.
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.
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