Quantitative trait variation in phenotypically normal regenerants of cotton
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Somaclonal variation for quantitative traits could affect the practical utilization of regenerants in cotton improvement. Three groups of experimental lines were derived to analyze variation, including one control group from the explant-source cultivar and two groups of R 3 somaclones from different R 0's (R 0 = initial regenerant) free of observable chromosomal rearrangements. A three-environment field trial was conducted to evaluate group means, genetic variance, and line performance. Mean seedcotton yields of the somaclonal groups were reduced by 21 and 26% relative to the Coker 310 standard at two locations, but lint percentage and certain fiber properties were improved. Group-by-environment interactions were significant (P<0.05) for 10 of the 12 measured traits. Genetic variance tended to decrease in the somaclones, plant height being an exception. Line performance of the somaclones indicated that 50-boll weight, seed index, and fiber length did not reach the Coker 310 group means. These data suggest that genetic gain will be improved if regenerants of cotton are self-pollinated and the progenies evaluated for quantitative traits before crossing somaclones with the explantsource cultivar or other elite germplasm. 1991 Tissue Culture Association.