Registration of CA 4005 and CA 4006 Cotton Germplasm Lines with Partial Resistance to Feeding Injury from Thrips

Thrips (Thysanoptera: Thripidae) are common pests of cotton (Gossypium spp.) worldwide, typically causing economic damage within the first few weeks after planting of a cotton crop. With the loss of granular aldicarbs and resistance development to other insecticides in recent years, host plant resistance could play an important role in the integrated management of thrips. Two breeding lines originally developed for cold tolerance in the Texas A&M AgriLife Research cotton improvement program at Lubbock, TX, exhibited characteristics associated with thrips tolerance. These G. hirsutum lines, CA 4005 (Reg. No. GP‐1023, PI 681593) and CA 4006 (Reg. No. GP‐1024, PI 681594), are germplasm lines that were subsequently evaluated for potential resistance to thrips feeding injury. Both lines were evaluated in field and greenhouse tests from 2012 to 2014. CA 4005 and CA 4006 consistently displayed greater resistance to thrips feeding injury than the commercial and susceptible checks at the field level. Greenhouse evaluations, however, revealed that these lines are only partially resistant and can be overcome at high thrips densities. Yield potential, high‐volume instrument (HVI) fiber quality, and other agronomic characteristics of CA 4005 and CA 4006 were comparable to the evaluated commercial checks. These germplasm lines exhibited improved thrips resistance and competitive agronomic potential for the Texas High Plains and would be valuable sources of partial thrips resistance in adapted G. hirsutum germplasm.