Registration of Arkot 9623 and Arkot 9625 Germplasm Lines of Cotton

Abstract

Arkot 9623 (Reg. No. GP‐908, PI 651858) and Arkot 9625 (Reg. No. GP‐909, PI 651859) are noncommercial breeding lines of cotton (Gossypium hirsutum L.) released by the Arkansas Agricultural Experiment Station in January 2008. Both lines were derived from 1996 crosses using one common parent, Arkot 8712. The second parent of Arkot 9623 was DES 119 N Sm ne. The other parent of Arkot 9625 was ST 474. The lines were evaluated in 16 replicated tests in Arkansas from 2003 to 2006. Lint yields, lint percentage, and seed produced per area for each line were equal to two check cultivars. Both lines are early maturing, with Arkot 9625 significantly earlier than Arkot 9623 and the short‐season cultivar SG 105, and Arkot 9623 equal to SG 105. Yield components of Arkot 9623 were similar to the checks, but Arkot 9625 produced larger seed with more lint per seed. Compared with check cultivars, Arkot 9623 fiber length was shorter and strength of both lines was weaker. Leaf pubescence and bract trichome density of the two lines were intermediate between the smooth‐leaf and hairy‐leaf check cultivars. Compared with the checks, both lines expressed improved resistance to bacterial blight [caused by Xanthomonas campestris pv. malvacearum (Smith) Dye], Fusarium wilt [caused by Fusarium oxysporum Schlect. F. sp. vasinfectum (Atk.) Snyd. & Hans.], root‐knot nematode [Meloidogyne incognita (Kofoid & White, 1919) Chitwood, 1949], and a seedling disease pathogen. The relative yield, maturity, and line‐specific host plant resistance traits make these lines valuable to cotton breeding programs.