Stacking effective ASR and APR rust genes for multiple disease resistance in bread wheat cultivars

Abstract Rusts and powdery mildews pose serious threats to wheat and have caused substantial yield losses worldwide. Host resistance is the most economical and sustainable approach for managing such diseases. In this study, an effective leaf rust resistance gene Lr45-derived from Secale cereale L. and a linked stem rust and powdery mildew resistance gene Sr36/Pm6-derived from Triticum timopheevii were successfully pyramided. They were validated into well-adapted Indian wheat cultivars that were already carrying the APR stem rust gene Sr2/Lr27/Yr30 through marker-assisted backcross selection (MABC) following two parallel backcrossing schemes. Three efficiently linked microsatellite markers, G372185 (Lr45), Stm773-2(Sr36), and Xgwm533 (Sr2), were used to confirm introgression of these genes. Lines with resistance genes in each background showed improved agronomic traits in comparison to their recurrent parents. These lines could be used in wheat improvement programs as potentially resistant stocks for leaf, stem rusts and powdery mildew to develop new wheat cultivars.

锈病与白粉病严重威胁小麦生产，在全球范围内造成了显著的产量损失。寄主抗病性是防治此类病害最经济且可持续的手段。本研究中，来自栽培黑麦（Secale cereale L.）的有效叶锈病抗性基因Lr45，以及来自提莫菲维小麦（Triticum timopheevii）的兼抗茎锈病与白粉病的连锁抗性基因Sr36/Pm6被成功聚合。本研究通过两套平行回交方案，借助标记辅助回交选择（marker-assisted backcross selection, MABC），将上述基因导入已携带成株抗茎锈病基因Sr2/Lr27/Yr30的适应性优良印度小麦品种中，并完成了有效性验证。研究使用G372185、Stm773-2与Xgwm533这三个高效连锁的微卫星标记，分别验证了Lr45、Sr36与Sr2这三个基因的导入情况。各遗传背景下携带抗性基因的株系，与其对应的轮回亲本相比，农艺性状均得到改良。这些株系可作为抗叶锈病、茎锈病及白粉病的潜在种质资源，应用于小麦遗传改良项目以培育新型小麦品种。