Resistance to Wheat streak mosaic virus and Triticum mosaic virus in wheat lines carrying Wsm1 and Wsm3

Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are important viruses of wheat (Triticum aestivum L.) in the Great Plains of United States. In addition to agronomic practices to prevent damage from these viruses, temperature sensitive resistance genes Wsm1, Wsm2 and Wsm3, have been identified. However, threshold temperatures for Wsm1 and Wsm3 have not been clearly defined. To better understand these two resistance genes, wheat lines C.I.15092 (Wsm1), KS96HW10-3 (Wsm1), and KS12WGGRC59 (Wsm3) were evaluated for WSMV resistance at 27, 30, 33 and 35 A degrees C and for TriMV resistance at 18, 21, 24, 27, 30, 33 and 35 A degrees C. The results showed that only C.I.15092 remained resistant at 30 A degrees C for both viruses. This line also tolerated TriMV at 33 and 35 A degrees C with less sever symptom and lower infection rates. Wheat lines KS96HW10-3 and KS12WGGRC59 hold resistance to TriMV up to 21 A degrees C. Molecular marker results suggested that the resistance in C.I.15092 is most probably conditioned by the resistance gene Wsm1 and additional gene(s) other than Wsm2 and Wsm3.