Cotton, Gossypium hirsutum L., Cultivars Differential Response to Salinity
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Arable land for crop production is increasingly affected by soil salinization, including the irrigated land in western and southwestern regions of the United States. The primary water source for irrigated cotton in the Texas High Plains production region is the Ogallala Aquifer, whose depletion has led to increasing amounts of salts in the water and more salt sediment deposited in soil. Research to facilitate identification and development of salt tolerant cotton cultivars was conducted in response to accumulation of salt in soil and water, coupled with decreasing water supply. Germination and hydroponic growth salinity screening methods were evaluated for feasibility in identifying current commercial cotton cultivars that perform relatively well in saline conditions, and in selecting parents for breeders to use for breeding improved cultivars and germplasm. Thirty-three commercial cultivars, 31 breeding lines and one accession were evaluated for response to salinity in germination experiments at 175mM L-¹ NaCl concentration and hydroponic experiments at 175mM L-¹ and 225mM L-¹NaCl concentration. Differences were detected among these genotypes in germination percent and hypocotyl length. Cultivars PHY 499 WRF, PHY 367 WRF, and Nitro 44 B2RF germinated relatively well under the imposed salt stress compared with no salt stress conditions. Breeding lines 13-9-218S, 12-18-314V, and 10-B-9 exhibited higher levels of germination among the breeding lines evaluated under salt stress, but not better than cultivar FM 989 and accession TX 65. Evaluations to detect differences among cultivars and breeding lines for changes in shoot and root length and plant biomass associated with salinity tolerance using a hydroponic system were inconclusive. Germination technique was most feasible for detecting differences in salinity response, but no inference could be made regarding associated salinity tolerance in field production.
Elkins, Heather D'Ann (2017). Cotton, Gossypium hirsutum L., Cultivars Differential Response to Salinity. Master's thesis, Texas A & M University. Available electronically from