Genotypic variation in the effect of drought stress on phenology, morphology and yield of aus rice
By: KM Shamsul Haque, M Abdul Karim, M Nasimul Bari, M Rafiqul Islam
Key Words: Genotype, Drought, Tolerance, Aus rice, Yield.
Int. J. Biosci. 8(6), 73-82, June 2016.
In Bangladesh, rainfed lowland rice occupies about 5.8 million hectares of which 40 percent is severely affected by drought. Variety(s) tolerant to drought is imperative for increasing aus rice production in such a drought-prone areas. For this, a systematic evaluation was carried out to observe the drought stress effects on the variability of aus rice genotypes. Drought stress was imposed once at the vegetative and three times at the reproductive stage. In each time, drought was relieved after curling of leaves. The impact of the drought on phenology, morphology, growth and grain yield of the genotypes was assessed. There were significant differences in plant traits of the genotypes in response to drought. In general, drought stress delayed phenological events, i.e. days to flowering and maturity. Plant height was found to reduce significantly under drought stress condition. All the genotypes showed a marked reduction in root dry weight, albeit some recovered to a great extent. Flowering time was the most sensitive stage to adverse impact of drought showing 39% reduction in grain yield compared to that of 24% at the vegetative stage drought. Among the genotypes, Bhora Bhadui, BRRIdhan 42, Bhadai, and BRRIdhan 48 were the best entries possessing some desirable traits like less reduction in tillers, panicles per plant, grain sterility and grain production under drought condition. The result suggests that these genotypes have the capability to withstand drought and could be used as breeding materials for the development of drought-tolerant variety after affirming through further study.