Identifying and Breeding Drought Tolerant Cottons (Gossypium spp.) Treated with EMS-Mutant Agent on the Texas High Plains

The semi-arid climate of the Texas High Plains often leads to periods of water deficit stress or drought, which can greatly reduce the yield and quality of cotton (Gossypium spp.). It is known that cultivated cotton lacks genetic diversity which is necessary when breeding for drought tolerance. Ethyl MethaneSulfonate (EMS) is chemical mutagen, which has been used to create new genetic diversity in plants. In this study, we investigated if diverse EMS treated/generated populations will have enough genetic diversity to be used for selecting breeding lines with improved drought tolerance and good fiber quality. We evaluated a diverse EMS treated panel of 13 Upland (G. hirsutum L.) and one G. arboreum L. cultivars and germplasm, advancing from M₁ to M₄ as populations. From 2014-2016, derived plant selections from these populations were assessed under different irrigation regimes to induce drought stress in different locations. Each year, experimental design was assigned based on seed availability and included original-cultivar source, two commercial cultivars as controls, and selections in a complete randomized design (CRD), augmented (ARCBD), and randomized complete block design (RCBD) RCBD with three replications, respectively. Response of drought tolerance was assessed by measuring more than 19 above and below ground agronomic traits, yield, and fiber quality. In this report, yield and fiber strength traits are presented. Preliminary analyses in 2014 revealed differences for seed cotton yield between populations and in 2015 for selected lines and controls, suggesting enough genetic diversity in these populations for yield improvement. In 2016, differences for yield between selected lines and controls was not different. However, we were able to significantly (p ≤ 0.05) increase the fiber strength over the control under water limited conditions. We will explore the possibility of a public germplasm release for those identified superior fiber quality lines under stress conditions with good yield.