Seedling-stage screening method for tolerance of upland rice genotypes to low pH stress

Abstract

One of the causes of generally low upland rice productivity in Indonesia is low fertility and soil pH. The use of genotypes with high yielding capacity and tolerant of acid soils can increase rice productivity. This study aimed to develop an early and efficient selection method, to determine rice genotypes tolerant to low pH. This research was conducted using a seed germination technique on rice paper medium with varied acidity level (pH 6.5, 5.5 and 4.5). Research data on the germination test showed that germination variables: growth uniformity, relative growth rate, vigour index, T50, and root length can be used as early indicators for determining rice genotypes tolerant to low pH. Research data showed that genotype Pae Huko is relatively more tolerant to low pH than the other three tested genotypes. Pae Huko had the highest values for relative growth rate, growth uniformity, vigour index, and T50 of 92.12%, 87%, 73.3, and 1.6 days, respectively. It had also the highest root length of 14.27 cm. The results give an indication that the method can be used as an early screening for determining tolerant rice genotypes to low pH. Further test (glasshouse experiment) is required to confirm the current results.