Screening and Identification of Upland Rice Lines Derived Recurrent Selection for Drought Tolerance

Variety assemblings for higher yield capacity of upland rice which tolerant to drought stress and highly adaptable to climate change has been needed to support the effort to increase both rice yield and the upland rice field extensification. This research aims to screen and identify an agronomic character of upland rice lines as the result of recurrent selection to a seedling stage on the drought stress. Materials were 180 rice lines as the result of recurrent selections from two local varieties Sriwijaya and Bugis with other two drought tolerant lines IR7858-1 and N148+. Twenty seeds each genotype were seeding in seed pods adjusted with stripe check such Situbagendit and Inpari 6 as tolerant and susceptible lines respectively. Drought stress treatment had conducted in a week, began at two weeks seedling age with a scoring value 0-9 (SES IRRI), at the same time were taken sample soil to measure the soil water content was done at a depth of 20 cm. Then, the crops were watered again to observe the recovery capacity of the crops, with the scoring 1-9 (SES IRRI).  Anatomically stomatal proximation was observed for both susceptible and tolerant rice lines. The selected lines would transplant in the field to record the yield capacity and other agronomic characters. The SES screening resulted in 53 tolerant lines, 99 moderate tolerant, and 28 susceptible to the drought stress which had the soil water content ranged from 11.9 to 12.7 percent. Anatomic stomatal observation showed that the stomatal structure and density of susceptible lines were closer and more than tolerant lines. The highest percentage of filled grains showed by the intercross line Sriwijaya/IR7858-1 about 77.4 to 85.1 percent with averagely 80.7 percent, which was a high category with the scale of 3 SES IRRI. The selected drought stress lines with better agronomic character would continuously test to know the yield capacity in the environmentally specific location.