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Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/5/2017 Publication Date: 6/22/2017 Citation: Mahalingam, R. 2017. Phenotypic, physiological and malt quality analyses of US barley varieties subjected to short periods of heat and drought stress. Journal of Cereal Science. 76:199-205. doi: 10.1016/j.jcs.2017.06.007. Interpretive Summary: Drought and heat are two major abiotic stresses that negatively impact seed yield and quality. In barley, especially the quality of the seeds is a critical factor for the malting and brewing industries. To the best of our knowledge no systematic assessment of the performance of the currently growing barley varieties to heat and drought stress and the impact of these stresses on barley malting quality has been done. To fill this important knowledge gap, we assessed the performance of 18 barley varieties that are currently under cultivation for their performance in response to a short-term heat and drought stress. Performance evaluations were based on dry biomass, seed yield and six important malting quality parameters currently used by the brewing industry. Significant variations in the performance of these varieties were observed when the stresses were applied singly. However, majority of the varieties performed poorly when heat and drought were applied in combination. This suggests that new germplasm sources with resistance to combined heat and drought stress have to be introduced into the breeding programs to develop new varieties to combat co-occuring heat and drought stresses predicted for the future. Technical Abstract: Drought and heat are major abiotic stresses that significantly reduce crop yield and seed quality. In this study, we examined the impact of heat, drought and combined effect of heat and drought stress imposed during the grain filling stage in 18 US spring barley varieties. These impacts were assessed based on dry biomass, seed yield and six important malting quality traits, namely, beta-glucan, free amino nitrogen, soluble protein, refractive index, diastatic power and alpha-amylase activity. Singly applied heat or drought stress evoked a diverse set of responses among these varieties with respect to biomass, seed yield and malt quality traits suggesting these varieties can be exploited for enhancing barley production based on local conditions. Majority of the tested varieties performed poorly with reference to seed yield when the stresses were applied in combination, suggesting a lack of genetic diversity in the currently grown spring barley varieties to overcome co-occurring episodic drought and heat regimes, especially during heading stages. In the wake of global climate change, enhancing adaptive capacity of barley varieties by introducing novel germplasm into breeding programs or via new technologies is vital to sustain US barely production and meet the demands of the rapidly growing brewing industry. |
