Rice drought breeding has selected for longer flag leaves and lower stomatal density

Direct selection for yield under drought has resulted in the release of a number of drought-tolerant rice varieties across Asia. In this study, we characterized physiological traits affected by that strategy in breeding trials across sites in Bangladesh, India, and Nepal. The drought breeding lines...

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Bibliographic Details
Published in:	Journal of experimental botany
Main Authors:	Kumar, Santosh, Tripathi, Santosh, Singh, Suresh Prasad, Prasad, Archana, Akter, Fahamida, Syed, Md Abu, Badri, Jyothi, Prasad Das, Sankar, Bhattarai, Rudra, Natividad, Mignon A, Quintana, Marinell, Venkateshwarlu, Challa, Raman, Anitha, Yadav, Shailesh, Singh, Shravan K, Swain, Padmini, Anandan, A, Yadaw, Ram Baran, Mandal, Nimai P, Verulkar, S B, Kumar, Arvind, Henry, Amelia
Format:	Journal Article
Language:	English
Published:	England 14-04-2021
Subjects:	GxE drought vapor pressure deficit physiology stomatal density flag leaf rice breeding
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Summary:	Direct selection for yield under drought has resulted in the release of a number of drought-tolerant rice varieties across Asia. In this study, we characterized physiological traits affected by that strategy in breeding trials across sites in Bangladesh, India, and Nepal. The drought breeding lines and drought-tolerant varieties showed consistently longer flag leaves and lower stomatal density than the drought-susceptible check, IR64. The influence of environmental parameters other than drought treatments on leaf traits was evidenced by the close grouping of treatments within a site. Flag leaf length and width appeared to be regulated by different environmental parameters. In separate trials in the Philippines, the same breeding lines studied in South Asia showed that canopy temperature under drought and harvest index across treatments were most correlated with grain yield. Both atmospheric and soil stress increased the relationship between leaf traits and yield. The stable expression of leaf traits among genotypes and the identification of the environmental conditions in which they contribute to yield, as well as the observation that some breeding lines showed longer time to flowering and higher canopy temperature than IR64, suggest that selection for additional physiological traits may result in further improvement of this breeding pool.
ISSN:	1460-2431