PJB-2017-677
Reproductive behabiour of mungbean [Vigna radiata (L.) Wilczek] genotypes under high temperature stress
Gurdev Chand
Abstract
Abstract Mungbean [Vigna radiata (L.) Wilczek] at reproductive stage, to heat stress (>35oC or higher as day/night temperatures) with consequent substantial loss of potential yields at high temperatures. The physiological mechanisms associated with reproductive behavior constitute the basis of this study. This study was conducted to examine the physiological responses and yield of contrasting mungbean [Vigna Radiata (l.) Wilczek] genotypes viz., MH 421, MH 318 and Basanti differing in their sensitivity to high temperature raised in earthen pots (30 cm diameter) filled with 5.5 kg of dune sand (Typic Torrispamments) was investigated under screen house conditions. Initially screened moongbean genotypes against heat stress and identified heat-tolerant and heat-sensitive genotypes. Three genotypes were sown during the normal time of sowing (12th March, 2013) and late (29th March, 2013) to expose them to heat stress during reproductive stage (>35oC). The genotypes were assessed for damage by heat stress to the leaves and reproductive organs using various indicators of stress injury and reproductive functions. In the heat-stressed plants, phenology accelerated as days to flowering and podding, and biomass decreased significantly. The significant reduction in pod set (%) was associated with reduced pollen viability and pollen germination (in vitro) in all three genotypes. Heat stress inhibited pollen function more in the sensitive genotypes than in the tolerant ones, and consequently showed significantly less pod set. As a result, pollen had considerably lower sucrose levels, resulting in reduced pollen function, impaired fertilization and poor pod set in heat-sensitive genotypes. Key words: Flower shedding, heat tolerance, heat susceptibility, mungbean and Vigna radiate
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