Assimilates mobilization, stable canopy temperature and expression of expansin stabilizes grain weight in wheat cultivar LOK-1 under different soil moisture conditions

• Published in: Botanical studies 2017-03, Vol.58 (1), p.14-14, Article 14
• Main Authors: Kumar, Mahesh, Raina, Susheel Kumar, Govindasamy, Venkadasamy, Singh, Ajay Kumar, Choudhary, Ram Lal, Rane, Jagadish, Minhas, Paramjit Singh
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Canopies; Carbohydrates; Crop yield; Cultivars; Defoliation; Ecology; Elongation; Endosperm; Environmental effects; Gene expression; Genes; Genotypes; Grain growth; Levels; Life Sciences; Limiting factors; Original; Original Article; Physiology; Plant Genetics and Genomics; Plant Sciences; Reserves; Soil conditions; Soil moisture; Soil stabilization; Triticum; Wheat
• ISSN: 1817-406X; 1999-3110; 1999-3110
• DOI: 10.1186/s40529-017-0169-7

Background Grain yield of wheat is primarily determined by both grain number and grain weight, which often influence each other in response to environmental stimuli. Some of the genotypes are capable of maintaining high single grain weight (SGW) across the environments. Understanding mechanisms and factors associated with the superiority of such genotypes over others is necessary to enhance productivity of wheat. Results Experiments were conducted to elucidate the physiological basis of high SGW of LOK-1, a wheat cultivar grown in dry and hot environments in the central and peninsular zones of India. SGW of LOK-1 was least affected by removal of spikelets indicating little competition between the grains within the spike for assimilates. Reduction in SGW due to defoliation was less and the contribution of stem reserves to the grain development was high in LOK-1 relative to other cultivars. It seems that high level of expression of genes such as expansin (TaExpA6) contributes to the high SGW of LOK-1. Conclusions Source was not a limiting factor for grain growth of LOK-1 in contrast to other cultivars, whereas sink appeared to be a limiting factor in recently released/identified cultivars. Differences in the amounts of water soluble stem carbohydrate reserves translocated to grain could be one of the factors contributing to higher grain weight in LOK-1. High level expression of TaExpA6 , one of the genes contributing to the elongation of endosperm, seems to be crucial for grain growth in wheat.