Generation mean analysis of near-long-staple fiber length in TAM 94L-25 upland cotton
The U.S. traditionally markets upland cotton with a high volume instrument (HVI) upper-half mean length (UHML) of 27 mm (34 staple) although international trade requires a minimum of 27.8 mm (35 staple). Genotypes have been developed that exhibit UHML of approximately 30 mm (~38 staple) that are referred to as near-long-staple uplands (NLSU). The objective of this research was to determine gene action and heritability for near-long-staple length in a unique set of upland cotton genotypes. TAM 94L-25, an NLSU, was crossed with three programmatically diverse NLSU phenotypes and a short-staple upland (SSU) to produce the F1, F2, BCP1, and BCP2 generations for generation mean analysis (GMA). Generations were grown in a randomized complete block design at College Station, TX in 2001 and 2002. Seedcotton was ginned on a laboratory gin and advanced fiber instrument system (AFIS) fiber properties were determined. Additional improvement in fiber length is possible by crossing TAM 94L-25 with the other NLSU phenotypes included in this study. Environment affected genetic expression with narrow sense heritability (h2) for fiber length generally lower in the TAM 94L-25/NLSU families. Transgressive segregates were found in all families.