Tolerance to mid-season drought in peanut can be achieved by high water use efficiency or high efficient use of water

Authors: ZHANG, QIONG - Auburn University; Dang, Phat; CHEN, CHARLES - Auburn University; FENG, YUCHENG - Auburn University; BATCHELOR, WILLIAM - Auburn University; Lamb, Marshall; SANZ-SAEZ, ALVARO - Auburn University

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2022
Publication Date: 7/28/2022
Citation: Zhang, Q., Dang, P.M., Chen, C., Feng, Y., Batchelor, W., Lamb, M.C., Sanz-Saez, A. 2022. Tolerance to mid-season drought in peanut can be achieved by high water use efficiency or high efficient use of water. Crop Science. https://doi.org/10.1002/csc2.20806.
DOI: https://doi.org/10.1002/csc2.20806

Interpretive Summary: Peanut is an important economic crop grown in the United States and around the world, relying on rainfall for growth but are challenged with more severe and persistent drought events. Breeders are constantly in search for peanut plants with drought adaptive traits to maintain high yield under water-limited environments. Recently, several peanut varieties have been identified that exhibit drought tolerant characteristics. The ultimate goal of this research is to identify stable physiological traits that are associated with yield. Research on other crops demonstrated that drought tolerance can be achieved by two different mechanisms: either by saving water (water saver cultivars) or by being able to extract more water from soils (water spender cultivars). In peanut, water spender cultivars have not been characterized until this date. To study the physiological effects of drought stress and differentiate between this two types of drought tolerance mechanisms, a 2-year experiment was performed with drought tolerant and sensitive cultivars in rain-out shelters. Cultivars PI 502120 and AU 17 were classified as water spender cultivars as they showed high yield and high photosynthesis under drought. This study is the first time that water spender cultivars are identified in peanut. In the other hand, cultivars Line-8 and AU16-28 were classified as water savers as they showed equally high yields but moderate photosynthesis and low gas exchange. In this study, water spender cultivars did not show a yield advantage in comparison with water savers ones, so both types or cultivars are recommended to be introgressed in breeding lines to produce mid-season drought tolerant lines. The drought tolerant mechanism of maintaining photosynthesis under drought condition was shown to be an advantageous trait for peanut varieties, which produced higher simulated rainfed yield. Research results enhance knowledge of peanut drought characteristics and will facilitate the development of drought tolerant peanut varieties.

Technical Abstract: Peanut is an economic cash crop mainly planted in arid and semi-arid regions where the drought causes around 20% loss of peanut production every year. In other crops it has been demonstrated that drought tolerance can be achieved by two different mechanisms: either by saving water (water saver cultivars) or by being able to extract more water from soils (water spender cultivars). In peanut, water spender cultivars have not been characterized until this date. To study the physiological effects of drought stress and differentiate between this two types of drought tolerance mechanisms, a 2-year experiment was performed with drought tolerant and sensitive cultivars in rain-out shelters. Plants were grown under irrigated conditions until mid-pod filling moment at which drought started. Gas exchange parameters were measured regularly during the drought period and at maturity, yield components and samples for '13C were taken. Cultivars PI 502120 and AU 17 were classified as water spender cultivars as they showed high yield, '13C, photosynthesis and stomatal conductance under drought. This study is the first time that water spender cultivars are identified in peanut. In the other hand, cultivars Line-8 and AU16-28 were classified as water savers as they showed equally high yields but with low '13C, stomatal conductance and moderate photosynthesis. In this study, water spender cultivars did not show a yield advantage in comparison with water savers ones, so both types or cultivars are recommended to be introgressed in breeding lines to produce mid-season drought tolerant lines.