Registration of Two Upland Cotton Germplasm Lines Possessing Superior Fiber Quality Traits

The upland cotton (Gossypium hirsutum L.) germplasm lines PX06520-42-2-1 (Reg. No. GP-1005, PI 677343) and PX06520-42-2-3 (Reg. No. GP-1006, PI 677344) were jointly released by the USDA-ARS and Cotton Incorporated in 2016. The lines were released to provide broadly adapted, high fiber quality resources for facilitating fiber improvement efforts across the US Cotton Belt. PX06520-42-2-1 and PX06520-42-2-3 originated from the cross SG747/NM49//AGC85/436443, followed by individual plant selection in the F-2, F-3, and F-4 generations. The two best progeny lines, determined from replicated tests conducted at College Station, TX, and Florence, SC, in 2011 and 2012, were entered into the Regional Breeders Testing Network tests across the US upland Cotton Belt in 2013 and 2014. In 2013, both PX06520-42-2-1 and PX06520-42-2-3 were superior to the check cultivars 'DP 393', 'FM 958', and 'SG 105' for fiber length, fiber length uniformity, fiber strength, and short fiber content. In 2014, PX06520-42-2-1 produced a fiber length, fiber length uniformity, and fiber strength that were superior to the five check cultivars DP 393, FM 958, SG 105, 'UA 222', and 'DP 491'. Fiber yield of PX06520-42-2-1 did not differ significantly from any of the five check cultivars used in 2014. The two lines are excellent sources of fiber quality, with acceptable yield potentials that appear to be stable across production environments.