Submitted to: Journal of Plant Growth Regulation
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/8/2011
Publication Date: 9/1/2011
Citation: Selvaraj, M., Burow, G.B., Burke, J.J., Belamkar, V., Puppala, N., Burow, M. 2011. Heat stress screening of peanut seedlings for acquired thermotolerance. Journal of Plant Growth Regulation. 65:83-91. Interpretive Summary: Heat stress is a major abiotic stress condition that adversely impinges crop production worldwide at different stages of plant development. However, a major challenge in developing heat tolerant cultivars in many crops is that field screening for heat tolerance can be inconsistent and seasonally-limited. Therefore, it is important to develop a reliable protocol under controlled conditions that allows simultaneous screening of multiple genotypes. This research evaluated the use of acquired thermotolerance (ATT) mechanism in peanut seedlings as a measure heat stress tolerance and the applicability of ATT as a screening tool. Results from the study revealed that genotypic ranking for mean seedling ATT values were highly correlated in both experiments and field ranking for heat tolerance. This study provide evidence that measurement of seedling ATT in peanut is a relatively simple and inexpensive method that can possibly be developed to screen a large number of genotypes for heat tolerance in peanut.
Technical Abstract: The objective of this research was to develop a user-friendly and medium throughput laboratory protocol using acquired thermotolerance (ATT) in peanut seedlings as a measure of one mechanism of heat stress tolerance. Sixteen genotypes, including selected accessions of the U.S. peanut minicore collection along with standard checks, were evaluated for acquired themotolerance in two independent experiments.A change in the temperature sensitivity of chlorophyll accumulation was used as an indicator of acquired thermotolerance. Pre-incubation at 38 °C for 4 hrs before the 30-min 50°C challenge triggered the acquired thermotolerance system of the leaf disks, resulting in chlorophyll accumulation upon exposure to light. There was considerable variation among genotypes for ATT in both experiments. Genotypic ranking for mean ATT values were highly correlated (0.949) in both experiments and field heat tolerance ranking. The effect of seed weight on ATT was not significant. This method is relatively simple and inexpensive and can be used to screen a large number of genotypes.