Analysis of polyethylene glycol (PEG) and proline to evaluate drought stress of double haploid new type upland rice lines

The characterization and selection of rice were evaluated for tolerant to drought stress. The selection process of double haploid lines, especially related to drought tolerance, was done by observing the morphological features on the root system in each genotype. The polyethylene glycol (PEG) solution in the planting medium is created the stress condition because of the water availability for plants reduced. Molecular size and the concentration of PEG determined the osmotic potential. The defense mechanisms used in plants on drought stress is the accumulation of proline to adjust osmotic, production and accumulation of free amino acids like proline in plant tissues during drought stress, an adaptation response in these conditions. The result showed that PEG 6000 inhibited the germination (33.9 percent), root length (60.8 percent), and shoot length (80 percent) of upland rice lines. Drought stress treatment (60 per cent of field capacity) at the flowering period showed a non-significant reduction in the growth of doubled haploid upland rice but reduced the weight of grains per hill (52.11 percent). Drought stress decreased in total chlorophyll (20.7 μmol/cm) and increased proline content in leaves (30.3 μmol/g). The content of proline in the leaves varied in inbreds due to drought stress. The high contained proline of tolerant genotype based on PEG 6000 are P3-31, followed by P6-95, respectively 30.33, 20.82 µmol/g, and genotype moderate line P6- 291 at 20.42 µmol/g. Stress drought led to a decrease in total chlorophyll, and increase the proline content in the leaves