Improved Rice Varieties Developed for High-Altitude Tropical Upland Areas of Indonesia

Abstract

Sustainability of rice (<em>Oryza sativa</em> L.) production in high-altitude tropical upland is challenged by various abiotic and biotic problems. The main problems include low temperatures and blast disease. Farmers in high-altitude tropical uplands of Indonesia are still growing traditional rice varieties due to the absence of improved adaptive varieties. Development of improved varieties which are adapted to the high-altitude upland environment is therefore needed to increase productivity. This study aimed to investigate the interaction of genotype and environment of upland rice varieties across ten high-altitude upland locations in Indonesia and to determine their adaptability in the target areas. In addition, screening on blast disease and grain quality analysis was performed to characterize the genotypes. Significant interaction effects between genotype and the environment were observed for all agronomic characters. Genotype adaptability was determined based on the regression coefficient of grain yield and the environmental index. Genotypes such as B14168E-MR-10 adapted well in locations with low environmental indexes. In contrast, genotypes such as B11592F-MR-23-2-2 adapted well in locations with high environmental indexes. Screening using ten rice blast races showed that upland rice genotypes had a broad spectrum of resistance. Most of the genotypes had intermediate amylose content in the grains. Recently, the lines B14168E-MR-10 and B11592F-MR-23-2-2 have been approved to be released as new, improved rice varieties for high-altitude upland in Indonesia, namely Luhur 1 and Luhur 2, respectively. Both varieties are expected to be adopted by farmers in high-altitude upland to increase rice productivity in this environment.