How rising temperatures would be detrimental for cool and warm-season food legumes uri icon

abstract

  • Rising temperatures are a major concern for the productivity offood legumes, grown in winter as well as summer-season, especiallyin tropical and sub-tropical regions. Our studies haveindicated marked damage to the reproductive stage, resulting inreduction in pod set and seed yield of chickpea, lentil (cool-seasonlegumes) and mungbean (warm-season legume) under hightemperatures. Studies done in controlled and outdoor environments(late sowing) revealed that temperatures >35/20°C (asday and night) were highly detrimental for winter-season legumes;while >38/25°C markedly affected the summer-seasonlegumes (mungbean). Urdbean, (a summer season legume),was found to be relatively more tolerant. The degree of damagevaries depending upon the duration, timing and severityof stress. Among the reproductive components, pollen grainswere more sensitive, became deformed and showed reductionin pollen viability, reduced germination and pollen tube growth.Stigma receptivity and ovule viability were also inhibited, whichaffected the pollen germination on stigma surface and restrictedtube growth through style, and impaired fertilization to causeflower abortion. Assessment of the physiology of leaves, anthersand styles indicated decrease in sucrose production in all theseorgans due to inhibition of enzymes, which possibly affected thestructural and functional aspects of the pollen grains and tubegrowth through style. Seed filling is another stage which becomesimpaired as a result of inactivation of enzymes related tosucrose production, causing inhibition in sucrose translocationinto seeds. Additionally, the composition of the seeds was adverselyaffected, resulting in small size and poor quality of seeds.The data related to these processes would be presented. Geneticvariation for heat tolerance exists in our target legume crops,which needs further probing and use of heat tolerant germplasmin breeding programs. Screening for high temperature tolerancehas led to identification of few heat-tolerant genotypes, whichare able to maintain their gamete function at high temperature,unlike the sensitive genotypes. Future studies should focus onhigh throughput phenotyping techniques and/or physiological,biochemical or genetic markers that control the reproductivefunction. Information about the effects of heat stress on reproductivebiology and seed filling events of chickpea, lentil andmungbean will be discussed

publication date

  • 2017