Introgression of Asian soybean rust resistant genes into elite soybean lines from Uruguay

Soybean is the main agricultural crop in Uruguay. One of the diseases with the greatest damage potential is Asian soybean rust, with estimated grain yield losses up 80% in the region. Throughout history, different authors have stated the importance of genetic resistance as a fundamental tool to decrease the adverse effects of phytopathogens, leading to agriculture sustainability. The objective of this work was to introduce rust resistance genes into elite lines of INIA’s soybean breeding program and to evaluate the enhanced resistance. Introgression of resistant genes was carried out in a greenhouse, through three backcrosses from F₁. Two donors: Py7-1-47 and No6-12-B handed by JIRCAS with two resistant genes combinations (<i>Rpp1-b</i> + <i>Rpp5</i> and <i>Rpp4</i> +<i> Rpp5</i>, respectively) and three elite lines: SJ10-122-040, SJ10-158-039, and SJ10-173-072 from INIA’s breeding program were used. After each backcross, plants carrying both genes were selected with marker assisted selection. Each third backcross was self-pollinated (BC₃F₂) and single plant families were inoculated in the greenhouse. Percentage of rust resistant plants within the introgressed families ranged from 42% to 98%, compared to fully susceptible recurrent parents.

大豆是乌拉圭的主要农作物，其中危害潜力最大的病害之一为亚洲大豆锈病，该区域预估谷物产量损失高达80%。既往诸多学者均指出，遗传抗性作为减轻植物病原菌不利影响的核心工具，对实现农业可持续发展至关重要。本研究的目标是将抗锈病基因导入乌拉圭国家农业研究所（INIA）的大豆育种优良品系，并评估其抗性提升效果。抗性基因的导入在温室环境中通过从F₁代起始的三次回交（backcross）完成。供体材料共两份：分别携带抗锈基因组合Rpp1-b + Rpp5的Py7-1-47，以及携带Rpp4 + Rpp5的No6-12-B，二者均由日本国际农业科学研究中心（JIRCAS）提供；同时选用INIA育种项目中的三份优良品系：SJ10-122-040、SJ10-158-039与SJ10-173-072。每一轮回交（backcross）后，均通过标记辅助选择（Marker Assisted Selection）筛选同时携带两个抗性基因的植株。将第三次回交后代进行自交得到BC₃F₂代，随后在温室中对单株家系进行锈病接种鉴定。相较于完全感病的轮回亲本（recurrent parent），导入抗性基因的家系中抗锈植株占比介于42%至98%。