Developing Cold-Tolerant Cultivars with Seedling Disease Resistance to Pythium Species: Evidence for and Nature of Resistance in RU0701124

Pythium species are the most common seedling disease pathogens isolated from rice in producers’ fields in Arkansas. These studies examined the value of Pythium resistance in breeding lines with cold tolerance in early-season planting environments. These lines show promise for reliable stand establishment in Arkansas. The breeding line RU0701124 had more plants/acre and greater relative root weight and above-ground dry matter than ‘Kaybonnet’ and was similar to the moderately resistant PI evaluated in these studies. In addition, the research demonstrated that the breeding line RU0701124 had lower frequency of isolation of the Pythium spp. and less root discoloration than Kaybonnet in the field. The research points to the value of screening rice for resistance to Pythium spp. in developing breeding lines as part of the cold tolerance breeding program.