Progress in development of perennial rice in Uganda

The National Agricultural Research Organization (NARO) received perennial rice to Uganda from the Rice Breeding Program of Yunnan University, China, in 2017 under a collaborative research arrangement for evaluation and integration into the Uganda Rice Breeding Program (RBP). The objectives of this research were to: 1) Identify genotypes tolerant to major biotic and abiotic stresses 2) Evaluate promising under Preliminary Yield Trials (PYT) and National Performance Trials (NPT) for high ratoon performance, 3) Select parental lines and use in breeding for high ratooning ability. This report covered research undertaken in the period 2017 to 2022. Results of screening for tolerance to biotic stresses namely rice leaf blast, brown spot, Rice Yellow Mottle Virus (RYMV) and Bacterial Leaf Streak as well as abiotic stresses namely Submergence tolerance and Cold tolerance revealed that genotype PR 107 was the most adapted but lower yielding than PR 26 and PR 23 that had higher yield potential but susceptible to brown spot and RYMV. Evaluation for ratooning ability showed that PR 26 and PR 23 had higher ratooning ability than PR 107. The PYT was conducted in 3 locations while NPT was tested in 5 locations, all with PR 107 inclusive. The line PR 107 had the highest stability index both in the main crop and the first ratoon. Test genotype PR 107 had the highest-yield, with 26.4% higher than the aromatic best-inbred check KOMBOKA and 22.5% higher than the non-aromatic best-inbred check in the first ratoon crop. Also, PR 107 was ranked first for their better grain quality both in cooked and uncooked state. Based on these attributes, PR 107 was released in Uganda in 2022 as a commercial variety for production as NARORICE-1. Also, populations were generated from crosses involving PR 23, PR 26 and PR 107 and genotyped for presence of interest. Results showed that the population had genes for most diseases of interest except RYMV. The new high ratooning lines were introgressed into known RYMV resistant lines in Uganda. Although PR 107 is ratooned only once in Uganda, it has demonstrated its potential to stabilize fragile lands while contributing to grain harvest.