|LI, WENQI - Jiangsu Academy Agricultural Sciences|
|YANG, JIE - Jiangsu Academy Agricultural Sciences|
Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/19/2018
Publication Date: 10/16/2018
Citation: Li, W., Jia, Y., Yang, J. 2018. Genetic analysis of rice blast disease resistance genes using USDA rice mini-core and a mapping population. Proceedings of 37th Rice Technical Working Group Meeting, February 19-22, 2018, Long Beach, California. p 87. Electronic Publication.
Technical Abstract: Rice blast disease caused by the fungal pathogen Magnaporthe oryzae (M. oryzae) is one of the most destructive diseases of cultivated rice, resulting in significant yield loss each year all over the world. Developing and utilizing blast resistant rice varieties is the most economical and effective method to reduce the damages by M. oryzae. However, resistance to M. oryzae mediated by major resistance (R) gene can be easily lost after a few years. Resistance mediated by quantitative trait loci (QTL) is more durable and long lasting. Identification and utilization of effective QTL is now the new focus for rice breeders worldwide. Toward this goal, the objectives of the present study were to 1) determine leaf and panicle disease reactions of the USDA mini-core collection consisting of 217 diverse rice germplasm accessions, and 2) evaluate leaf blast reactions of 249 recombinant inbred lines (RILs) derived from the cross of two US rice varieties, Cypress and LaGrue (MY2), under greenhouse conditions. For the first objective, leaf blast reactions were determined one week after inoculation of rice seedlings at V3 to V4 stages using a mixture of blast races (IB-49, IC-17, and IB-54 at 1-5 X 105 spores/mL) and the same mixture was used to inoculate rice at the booting stage with a syringe, and panicle blast was rated three weeks after inoculation. We found that 11 accessions were resistant and 168 accessions were susceptible to leaf and panicle blast diseases, respectively. However, 38 accessions were only resistant to panicle blast, 12 were only resistant to leaf blast. The observed discrepancies of leaf and panicle blast can be due to environmental conditions during inoculation or difference in host gene expression at different growth stages. Cypress was reportedly susceptible to IB-1, IB-49, and IC-17 and resistant to IB54, whereas LaGrue is susceptible to the blast races IB-54, IG-1, IH-1, IC-17, and IB-49. For the second objective, disease reactions of 249 MY2 RILs are being evaluated with one isolate from each race, IB-1, IB-49, IC-17, IB-54, IH-1, and IG-1, for leaf blast reaction using the same procedure described above, and results will be presented.