Abstract
BackgroundGrain 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.ResultsExperiments 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.ConclusionsSource 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.
Highlights
Grain yield of wheat is primarily determined by both grain number and grain weight, which often influence each other in response to environmental stimuli
To meet the food demand of the world population projected to reach over 9 billion by 2050, production of wheat (Triticum aestivum L.) needs to be increased by 70–100% (Godfray et al 2010). This has to be accomplished with available natural resources including the land vulnerable to abiotic stresses caused by supraoptimal ambient temperature and soil moisture deficit
The key components of wheat grain yield viz., grain number and grain weight are highly vulnerable to high temperatures and soil moisture deficit (Dreccer et al 2009; Vignjevic et al 2015)
Summary
Grain yield of wheat is primarily determined by both grain number and grain weight, which often influence each other in response to environmental stimuli. To meet the food demand of the world population projected to reach over 9 billion by 2050, production of wheat (Triticum aestivum L.) needs to be increased by 70–100% (Godfray et al 2010). This has to be accomplished with available natural resources including the land vulnerable to abiotic stresses caused by supraoptimal ambient temperature and soil moisture deficit. The key components of wheat grain yield viz., grain number and grain weight are highly vulnerable to high temperatures and soil moisture deficit (Dreccer et al 2009; Vignjevic et al 2015).
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