Molecular Marker Based Design for Breeding Wheat Lines with Multiple Resistance and Superior Quality

Abstract

There has not been a major wheat stem rust epidemic worldwide since the 1970s, but the emergence of race TTKSK of Puccinia graminis f. sp. tritici in 1998 presented a great threat to the world wheat production. Single disease-resistance genes are usually effective for only several years before the pathogen changes genetically to overcome the resistance. Stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is one of the most common and persistent wheat diseases worldwide. The development of varieties with multiple resistance is the most economical and effective strategy for preventing stripe rust and stem rust, the two main rust diseases constraining wheat production. Plateau 448 has been widely used in the spring wheat growing region in northwest China, but it has become susceptible to stripe rust and is susceptible to TTKSK. To produce more durable resistance to race TTKSK as well as to stripe rust, four stem rust resistance genes (Sr33, Sr36, Sr-Cad, and Sr43) and three stripe rust resistance genes (Yr5, Yr18, and Yr26) were simultaneously introgressed into Plateau 448 to improve its stem rust (Ug99) and stripe rust resistance using a marker-assisted backcrossing strategy combined with phenotypic selection. We obtained 131 BC1F5 lines that pyramided two to four Ug99 resistance genes and one to two Pst resistance genes simultaneously. Thirteen of these lines were selected for their TTKSK resistance, and all of them exhibited near immunity or high resistance to TTKSK. Among the 131 pyramided lines, 95 showed high resistance to mixed Pst races. Nine lines exhibited not only high resistance to TTKSK and Pst but also better agronomic traits and high-molecular-weight glutenin subunit compositions than Plateau 448.

Exploitation of Drought Tolerance-Related Genes for Crop Improvement

“…Molecular design breeding, a highly integrated system based on biotechnology and bioinformatics [ 146 ], may be an effective approach to enhance drought tolerance [ 147 ]. It can design and manipulate genotypes to meet various breeding objectives in different ecological regions under diverse water conditions [ 148 ].…”

Transfer of the high-temperature adult-plant stripe rust resistance gene Yr62 in four Chinese wheat cultivars

“…QYr.cimmyt-6BL was mapped to 6BL with SSR markers Xgwm58 and Xgwm626 in Pavon76 (William 2006). Four stem rust resistance genes (Sr33, Sr36, Sr-Cad, and Sr43) and three stripe rust resistance genes (Yr5, Yr18, and Yr26) were simultaneously in ltrated into Plateau448 by marker-assisted backcrossing hybridization combined with phenotypic selection, which improved the resistance to stem rust (Ug99) and stripe rust (Liu 2020).…”