Tests of Rice Seedlings' Resistance to Drought Stress (Oryza sativa L.)

Abstract

The need to enhance yield by creating drought-resistant rice varieties is driven by the ever-increasing demand for rice. There is a great deal of genotype-specific variability in drought tolerance, a complicated polygenic characteristic that is heavily dependent on plant developmental phases. At the glasshouse of the Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh, researchers characterized the seedling stage drought tolerance and revealed genotype variability for morphological and biochemical traits using drought tolerant (Binadhan-19, BRRI dhan83) and drought susceptible (BRRI dhan26, BRRI dhan48) rice genotypes. In the experiment, a fully randomized design (CRD) was used with three replications. The treatments included a control group and one group that was subjected to drought stress caused by 20% PEG. With the use of the right breeding equipment, we collected and evaluated data on length of shoots and roots, weight of fresh roots and shoots, weight of dried roots and shoots, chlorophyll content (SPAD value), MDA, and H2O2. Shoot length, root length, root fresh weight, shoot fresh weight, root dry weight, shoot dry weight, chlorophyll, H2O2, and MDA were among the variables identified as showing significant variation (p<0.01) in relation to genotype and treatment. Root and shoot growth are both drastically reduced by drought stress, while levels of hydrogen peroxide and malondialdehyde are dramatically elevated. Genotypes BRRI dhan28 and BRRI dhan48, which are sensitive, showed a steeper decline in root and shoot development than genotypes BRRI dhan71 and Binadhan-19, which are resistant. When comparing susceptible and tolerant genotypes, it was shown that tolerant genotypes showed a much smaller rise in H2O2 and MDA. H2O2 exhibited a strong positive association with root and shoot traits in the control condition, but a strong negative association with chlorophyll content in the drought condition. Under circumstances of adequate watering, MDA had a strong negative association with the majority of the characteristics that were examined. After analyzing all of the seedling-stage traits, the genotype Binadhan-19 was chosen for additional field studies and genetic improvement against drought stress because it is tolerant of both well-watered and drought conditions.