Relative Fiber Uniformity between Parent and F1 and F2 Generations in Cotton
- Jane K. Dever and
- John R. Gannaway
Hybrids (F2) of cotton (Gossypium hirsutum L.) reportedly offer improved seedling vigor, disease tolerance, and yield for this major crop of the Texas High Plains but raise concern about increased fiber property variability. Our objective was to compare fiber variability in the F2 generation with that in pure lines and in F1 hybrid cultivars. A four-parent complete diallel mating system using lines with similar and divergent fiber types resulted in 28 treatments: 4 parents, 12 F1 hybrids, and 12 F2 hybrids. The variance (converted to base 10 logarithm) of 10 plants in each treatment was analyzed by a randomized block design analysis of variance with three blocks. Subsets of the treatments (parents, F1's , and F2's) and orthogonal contrasts (parents vs. F1 and F2, F1 vs. F2; parents and F1 vs. F2, wide F1 vs. wide F2 [fineness]; wide F1 vs. narrow F1, wide F2 vs. narrow F2 [fineness]; wide F1 vs. narrow F1, wide F2 vs. narrow F2 [length/strength]) were analyzed. When environmental influence is high, strength and standard fineness show more variability in the F2 than in the F1 hybrid. The higher variability for strength and standard fineness disappears when environmental influence is minimal; the variability that does occur, both in the F1 hybrid and in the F2 hybrid, appears to be a function of original parental variability, especially for fiber fineness or agronomic properties. When original parental variability was low and the strength and standard fineness of the two parents were similar, fiber variability in the F2 hybrid was not greater than variability on a single plant in any generation.
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