Marker-assisted breeding of new wheat germplasm with adult-plant resistance to stripe rust in the genetic background of Longmai479

Abstract

In response to the worsening severity of wheat stripe rust in recent years, which poses a serious threat to food security, new wheat germplasm with adult-plant resistance and superior agronomic traits is being developed. We developed five hybrid combinations by crossing Longmai479 with 50212-2, Xikemai11, Chuanmai98, Chuanyu34, and 50212-12, yielding 164 families. We subjected mixed seeds from the F2 to F4 generations to artificial selection, followed by manual screening for superior disease-resistant individual plants in the F5 generation. In the F6 generation, marker-assisted selection was performed using molecular markers tightly linked to Yr10, Yr15, Yr17, Yr18, Yr26, Yr29, and Yr30 for PCR amplification and genotyping. By combining field-based disease resistance identification with agronomic trait evaluation, wheat families exhibiting both disease resistance and superior agronomic traits, including those with single-gene or multi-gene pyramiding, were comprehensively selected. Ultimately, 18 families with disease resistance and superior agronomic traits were obtained. Among these, two families carried none of the target Yr genes, two carried one Yr gene, seven carried two Yr genes, four carried three Yr genes, and three carried four Yr genes. These new wheat germplasm lines, which exhibit disease resistance and superior agronomic traits, hold promise for development into high-quality new cultivars. They will make significant contributions to stripe rust control and wheat production by providing important genetic resources for breeding disease-resistant wheat varieties.