Registration of Arkot 9721 Germplasm Line of Cotton

Abstract

Arkot 9721 (Reg. No. GP‐918, PI 654511) is a noncommercial breeding line of cotton (Gossypium hirsutum L.) released by the Arkansas Agricultural Experiment Station in August 2008. Arkot 9721 was derived from a 1997 cross between Arkot 8712 and Ark 8708‐31‐06, an advanced breeding line. Arkot 9721 was evaluated in 15 replicated tests in Arkansas from 2004 through 2007. Lint yield, lint percentage, and seed produced per area for Arkot 9721 were about 5 to 8% lower than two check cultivars when data from 2006 were excluded (due to poor seed germination of Arkot 9721). Arkot 9721 produced larger seed with an equal amount of lint per seed as the check cultivars. Maturity and plant height of Arkot 9721 were similar to ‘PSC 355’. Leaf pubescence and bract trichome density of Arkot 9721 was intermediate between the smooth‐leaf and hairy‐leaf check cultivars. Arkot 9721 produced significantly longer, more uniform, and finer fibers than PSC 355. Compared with check cultivars, Arkot 9721 expressed improved resistance to bacterial blight [caused by Xanthomonas campestris pv. malvacearum (Smith) Dye], equal resistance to root‐knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood], and less resistance to Verticillium wilt (caused by Verticillium dahliae Kleb.). Resistance of Arkot 9721 to tarnished plant bug was equal to PSC 355 and greater than ‘SG 105’. The improved fiber properties in conjunction with relatively good yield, maturity, and line‐specific host plant resistance traits make Arkot 9721 valuable as a breeding line to cotton breeding programs.