F2 Hybrids of Host Plant Germplasm and Cotton Cultivars: II. Heterosis and Combining Ability for Fiber Properties

Abstract

Estimates of combining ability and heterosis for fiber properties among pest‐resistant cotton ( Gossypium hirsutum L.) gene pools and cultivars are necessary for efficient F 2 hybrid development. Four cultivars were crossed as female with 16 pest‐resistant germplasm lines in a North Carolina Design II to evaluate combining ability and potential heterosis of F 2 hybrids for six fiber characteristics. The 20 parents and 64 F 2 hybrids were evaluated in four environments at Mississippi State, MS. Environment × hybrids interactions were significant for strength and micronaire, but not for length, uniformity, or elongation. Parent populations generally were more sensitive to the environment than were their F 2 hybrids for most characteristics. General combining ability (GCA) effects were more importan than specific combining ability (SCA) effects. Except for 2.5% span length, GCA effects for ‘DES119’ were significant, positive, and consistent for all characteristics. ‘C315’, MHR10 and ‘Deicot 344’ had significant, positive GCA effects for strength, 50% span length and 2.5% span length. In general, fiber traits of F 2 hybrids were similar to mid‐parental values. Very few F 2 hybrids wre superior in fiber properties to their high parent, but approximately 50% of the F 2 hybrids were not significantly different from their high parents for most fiber traits except micronaire. These results are encouraging for the potential of utilizing pest‐resistant germplasms as parents with cuitivars to produce F 2 hybrids that combine acceptable yield and fiber properties.