Morphological and physiological responses of different wheat genotypes to chilling stress: A cue to explain yield loss

Li, P.F., B.L. Ma*, Y.C. Xiong, and W.Y. Zhang. 2017. Morphological and physiological responses of different wheat genotypes to chilling stress: A cue to explain yield loss. J. Sci. Food Agric. (in press).

Abstract

BACKGROUND: The eco-physiological mechanism of wheat yield loss resulting from chilling stress is a critical fundamental scientific issue. However, most of the previous studies have focused on hexaploid wheats, and there were few studies on the morphological and physiological plasticity of wheat plants. Six different wheat genotypes were tested under chilling stress to investigate the physio-morphological parameters as well as the loss of grain yield in growth chambers. RESULTS: Chilling stress resulted in significant loss in grain yield in all genotypes. Under chilling stress, diploid wheats generated zero harvest, and tetraploid genotypes also suffered from a pronounced loss in grain yield compared with control group. In contrast, hexaploid genotypes acquired relatively high maintenance rate of grain yield among three species. CONCLUSIONS: Diploid and tetraploid wheat genotypes maintained relatively large leaf area and high photosynthetic rates, but they were subjected to greater declines in vascular bundle number and productive tillers as a consequence of the inhibition by sink growth under chilling stress. While hexaploid genotypes were found to have relatively low leaf area and photosynthetic rates, they turned to store more soluble carbohydrates and exhibit stronger sink enhancement, ensuring the translocation and redistribution of assimilates. Our finding provided a new theoretical implication on yield stabilization in the domestication process of wheat genotypes under chilling stress.

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