Genetic variation in peanut leaf maintenance and transpiration recovery from severe soil drying

Abstract Peanut ( Arachis hypogaea L.) is an important food crop that is often grown in areas prone to intermittent drought. After drought is relieved, plant recovery from soil drying is an important factor for continued productivity. While recovery can involve a multitude of physiological processes, transpiration is one of the most important for carbon fixation. Two greenhouse experiments and a field experiment were conducted to screen and evaluate a total of 19 peanut genotypes for transpiration recovery and leaf maintenance after experiencing a drying cycle. In the greenhouse experiments, plants were allowed to transpire all available transpirable soil water from their pots before being re-watered. The transpiration of plants was measured in subsequent days and a visual rating scale was used to rate leaf maintenance on plants. Significant differences were detected among genotypes for both transpiration recovery and leaf maintenance, and superior genotypes were identified for both traits. The superior genotypes included ICGV 86015, TMV 2, PI 497579 and PI 404020 in the greenhouse. In the field, a regression between stomatal conductance before and after re-watering gave an estimate for recovery of stomatal conductance. Breeding lines N05006 and SPT 06-07 had the greatest estimated stomata conductance recovery in the field. Genotypes which recovered poorly in the greenhouse also had low estimated recovery in the field.