Wheat–Thinopyrum intermedium introgression lines enhancing wheat streak mosaic virus (WSMV) resistance

Abstract Wheat streak mosaic virus (WSMV) is an important yield constraint of wheat (Triticum aestivum L., AABBDD) throughout the world. Currently, effective WSMV resistance of wheat origin is reported in only one case the Wsm2 gene; excellent disease resistances have been identified in the wild gene pool of Thinopyrum group. Transfer of desirable genes from wild sources has long been a fruitful practice in widening the genetic base of wheat, and Thinopyrum group have enormous genetic variability. WMSV may be controlled by improving agronomic conditions or by applying chemicals (herbicides/miticides), transgenic, or natural resistance sources. Nonetheless, among the available control measures, genetic or naturel resistance to WSMV offers an enduring solution for disease control. This chapter focuses on diverse wheat–Thinopyrum intermedium breeding lines with potential to address WSMV resistance in wheat. The T. intermedium–derived alien chromatin in these hybrid lines carried the Wsm1 gene associated with WSMV resistance in field. The chromosomal translocation was confirmed as 4Ai#2S.4DL with genomic in situ hybridization. Furthermore, for marker-assisted selection breeding, tightly linked PCR-based marker to the alien chromatin was used, and it detected the presence of 4Ai#2S.4DL chromatin. These wheat–T. intermedium recombinant lines increase our arsenal to combat the disease and may allow the development of agronomically desirable WSMV-resistant wheat cultivars.