Drought tolerant sorghum and cotton germplasm

• Published in: Agricultural water management 1983-01, Vol.7 (1), p.207-222
• Main Authors: Rosenow, D.T., Quisenberry, J.E., Wendt, C.W., Clark, L.E.
• Format: Article
• Language: English
• Subjects: drought tolerance; Gossypium hirsutum; plant breeding; Sorghum bicolor
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/0378-3774(83)90084-7

Sorghum ( Sorghum bicolor (L.) Moench) and cotton ( Gossypium hirsutum L.) are the summer crops traditionally grown in the rainfed or supplementary irrigated areas of the semi-arid southern Great Plains. Both crops have the ability to withstand periods of water deficit and to yield an economic return to the farmer. Numerous traits contribute to drought tolerance in both sorghum and cotton. Only limited breeding effort has been expended on identifying or combining such traits. Drought tolerance has seldom been a primary breeding objective, usually addressed indirectly under major objectives such as improved yield, pest resistance, and adaptation. In sorghum, recent emphasis on field screening under severe drought stress has led to significant developments in the understanding of drought tolerance. Two distinct types of stress responses have been identified. One type is expressed when plants are stressed prior to flowering, while the other is expressed when stress occurs during grain fill. Excellent sources of tolerance to each type of stress have been identified, but high levels of both types of tolerance have not been found in the same genotype. Crosses among contrasting types of tolerance are being evaluated. In cotton, emphasis has been placed on screening primitive photoperiodic-sensitive strains from the world collection. Primary effort has been expended on identifying parental strains that have unique responses to water stress and determining why these responses occur. Physiological evaluations are used extensively to define potentially useful traits. These traits are then incorporated into agronomically desirable germplasm. Germplasm lines chosen through this approach yielded more than commercial varieties under water deficient conditions in preliminary evaluations. Field screening at more than one location with different water regimes can be used to insure stress at different stages of growth. Rainout shelters and irrigation gradient systems can be used to supplement field screening.