Ramalingam Jegadeesan, Raveendra Chandavarapu, Savitha Palanisamy, Vidya Venugopal, Chaithra Thammannagowda Lingapatna, Velprabakaran Senthilvel, Saraswathi Ramasamy, Ramanathan Ayyasamy, Arumugam Pillai Madhavan Pillai, Arumugachamy Samudrakani, Vanniarajan Chockalingam
Centre of Excellence for Innovations, Department of Biotechnology, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai, India.
Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, India.
Front Plant Sci. 2020 Nov 19;11:591457. doi: 10.3389/fpls.2020.591457. eCollection 2020.
Bacterial blight, blast, and sheath blight are the commonest diseases causing substantial yield loss in rice around the world. Stacking of broad-spectrum resistance genes/QTLs into popular cultivars is becoming a major objective of any disease resistance breeding program. The varieties ASD 16 and ADT 43 are the two popular, high yielding, and widely grown rice cultivars of South India, which are susceptible to bacterial blight (BB), blast, and sheath blight diseases. The present study was carried out to improve the cultivars (ASD 16 and ADT 43) through introgression of bacterial blight (, , and ), blast (), and sheath blight (, , and ) resistance genes/QTLs by MABB (marker-assisted backcross breeding). IRBB60 (, , and ) and Tetep (; , , and ) were used as donors to introgress BB, blast, and sheath blight resistance into the recurrent parents (ASD 16 and ADT 43). Homozygous (BCF generation), three-gene bacterial blight pyramided ( + + ) lines were developed, and these lines were crossed with Tetep to combine blast () and sheath blight (, , and ) resistance. In BCF generation, the improved pyramided lines carrying a total of seven genes/QTLs ( + + + + + + ) were selected through molecular and phenotypic assay, and these were evaluated for resistance against bacterial blight, blast, and sheath blight pathogens under greenhouse conditions. We have selected nine lines in ASD 16 background and 15 lines in ADT 43 background, exhibiting a high degree of resistance to BB, blast, and sheath blight diseases and also possessing phenotypes of recurrent parents. The improved pyramided lines are expected to be used as improved varieties or used as a potential donor in breeding programs. The present study successfully introgressed , and QTLs (, , and ) from Tetep and major effective BB-resistant genes (, , and ) from IRBB60 into the commercial varieties for durable resistance to multiple diseases.
白叶枯病、稻瘟病和纹枯病是导致全球水稻产量大幅损失的最常见病害。将广谱抗性基因/QTL导入流行品种正成为任何抗病育种计划的主要目标。ASD 16和ADT 43是印度南部两种流行、高产且广泛种植的水稻品种，它们对白叶枯病（BB）、稻瘟病和纹枯病易感。本研究通过标记辅助回交育种（MABB）导入白叶枯病（Xa21、Xa13和xa5）、稻瘟病（Pi9）和纹枯病（ShB1、ShB2和ShB3）抗性基因/QTL来改良品种（ASD 16和ADT 43）。利用IRBB60（Xa21、Xa13和xa5）和特特普（Pi9；ShB1、ShB2和ShB3）作为供体，将白叶枯病、稻瘟病和纹枯病抗性导入轮回亲本（ASD 16和ADT 43）。培育出了纯合的（BCF代）、三基因白叶枯病聚合（Xa21 + Xa13 + xa5）株系，并将这些株系与特特普杂交，以聚合稻瘟病（Pi9）和纹枯病（ShB1、ShB2和ShB3）抗性。在BCF代，通过分子和表型分析选择了总共携带7个基因/QTL（Xa21 + Xa13 + xa5 + Pi9 + ShB1 + ShB2 + ShB3）的改良聚合株系，并在温室条件下对其对白叶枯病、稻瘟病和纹枯病病原菌的抗性进行了评估。我们在ASD 16背景中选择了9个株系，在ADT 43背景中选择了15个株系，这些株系对白叶枯病、稻瘟病和纹枯病表现出高度抗性，并且还具有轮回亲本的表型。改良的聚合株系有望用作改良品种或在育种计划中用作潜在供体。本研究成功地将来自特特普的ShB1、ShB2和ShB3 QTL以及来自IRBB60的主要有效抗白叶枯病基因（Xa21、Xa13和xa5）导入商业品种，以实现对多种病害持久抗性。
