Monday, November 13, 2006 - 9:00 AM

Perfomance of Cotton Converted Race Stocks in a BC2F2 Generation.

Christopher Souder1, C. W. Smith1, and Peggy Thaxton2. (1) Texas A&M Univ, 716 A Vassar Ct, College Station, TX 77840, (2) USDA, Delta Research & Extension Center, PO Box 197, Stoneville, MS 38776

Twenty-two BC2F2 populations developed by crossing a Converted Race Stock (CRS) with TAM 94L-25 followed by two backcrosses to TAM 94L-25 were evaluated in replicated designs at Tifton, Georgia, College Station, Texas, and Thrall, Texas during 2002 and 2003 (data not shown). Data analyses indicated several genotype x location and genotype x location x year interactions. While none of the BC2F2 populations out performed the commercial cultivar, PSC 355, several performed better than the recurrent parent for yield. Compared with the recurrent parent, the high quality parent, several BC2F2 populations exhibited better fiber UHM length and better fiber bundle strength. Since none of these CRS appear in pedigrees of U.S. cotton cultivars, these data suggest that they could be used to improve fiber quality and possibly lint yield potential.  Performance evaluation of 56 additional BC2F2 populations was conducted at College Station and Thrall, Texas and Tifton, Georgia in 2004 and 2005. Exceptional CRS material identified in previous years was used in crosses to improve fiber and yield properties of strains adapted to central and south Texas.  In 2005, F4 progeny rows from these crosses were grown in Weslaco, TX.  Over one half of the progeny rows resulting from CRS parent material had UHM fiber length of at least 1.20 in.    05P-47 and 05P-7 had lint percentages of 46 and 40%, respectively.   All fiber properties of the commercial checks were exceeded by many of the CRS derived progeny rows, confirming previous suggestions that the CRS material contains new and beneficial alleles for improving fiber properties.