DEVELOPMENT OF PCR MARKERS LINKED TO RESISTANCE TO WHEAT STREAK MOSAIC-VIRUS IN WHEAT

Wheat streak mosaic virus (WSMV), vectored by the wheat curl mite (Ace r tulipae), is an important disease of wheat (Triticum aestivum L.) in the North American Great Plains. Resistant varieties have not been de veloped for two primary reasons. First, useful sources of resistance h ave not been available, and second, field screening for virus resistan ce is laborious and beyond the scope of most breeding programs. The fi rst problem may have been overcome by the development of resistance to both the mite and the virus by the introgression of resistance genes from wild relatives of wheat. To help address the second problem, we h ave developed polymerase chain reaction (PCR) markers linked to the WS MV resistance gene Wsm1. Wsm1 is contained on a translocated segment f rom Agropyron intermedium. One sequence-tagged-site (STS) primer set ( WG232) and one RAPD marker were found to be linked to the translocatio n containing Wsm1, The diagnostic RAPD band was cloned and sequenced t o allow the design of specific PCR primers. The PCR primers should be useful for transferring Wsm1 into locally adapted cultivars.