Latif Mohammad Abdul, Kayess Omar, Hasan Rakibul
Plant Pathology Division, Bangladesh Rice Research Institute (BRRI), Gazipur, 1701, Bangladesh.
Biotechnol Lett. 2025 Sep 16;47(5):106. doi: 10.1007/s10529-025-03646-9.
Diseases are a global threat to rice production. Among them, rice blast and bacterial blight (BB) are most significant. To enhance targeted disease resistance, the marker-assisted backcross breeding (MABB) approach was employed to pyramid two blast (Pi9 and Pb1) and three BB resistant (R) genes (Xa4, xa13, and Xa21) into a high-quality rice cultivar BRRI dhan100. The donor parents Pi9-US2 (Pi9), Pb1-US2 (Pb1), and IRBB58 (Xa4, xa13, and Xa21) contributed these five genes. We followed a triple-cross breeding strategy, followed by backcrossing, selfing, and foreground selection to produce BCF progenies. Chi-square analysis of 420 BCF individuals confirmed the inheritance patterns of blast and BB resistance were controlled by a simple Mendelian fashion. Finally, we selected 38 advanced lines (ALs), and among them, twelve lines possessed all 5 candidate R genes, while fifteen consisted of 4 genes in different combinations. The disease rating scale of these ALs varied from 0 to 3 for both blast and BB diseases, while BRRI dhan100 ranging from 7 to 9. The G23, G13, G5, G10, G15, and G29 ALs exhibited higher yields ranging from 7.22-7.34 ton ha compared to the check, BRRI dhan100. Marker-trait association analysis displayed molecular markers negatively associated with disease susceptibility. Therefore, gene introgression by MABB could effectively identify and functionally validate the candidate R genes with high accuracy to develop a resistant variety to multiple diseases in rice breeding programs.
病害是全球水稻生产面临的威胁。其中，稻瘟病和白叶枯病最为严重。为增强靶向抗病性，采用标记辅助回交育种（MABB）方法，将两个稻瘟病抗性基因（Pi9和Pb1）和三个白叶枯病抗性基因（R）（Xa4、xa13和Xa21）导入优质水稻品种BRRI dhan100中。供体亲本Pi9-US2（Pi9）、Pb1-US2（Pb1）和IRBB58（Xa4、xa13和Xa21）贡献了这五个基因。我们采用三交育种策略，随后进行回交、自交和前景选择，以产生BCF后代。对420个BCF个体进行卡方分析，证实稻瘟病和白叶枯病抗性的遗传模式受简单孟德尔方式控制。最后，我们筛选出38个高级品系（ALs），其中12个品系拥有全部5个候选抗性基因，15个品系由4个不同组合的基因组成。这些ALs对稻瘟病和白叶枯病的病害评级从0到3不等，而BRRI dhan100的评级为7到9。与对照品种BRRI dhan100相比，G23、G13、G5、G10、G15和G29等ALs表现出更高的产量，范围为7.22 - 7.34吨/公顷。标记-性状关联分析显示分子标记与感病性呈负相关。因此，通过MABB进行基因渗入可以有效且高精度地鉴定和功能验证候选抗性基因，从而在水稻育种计划中培育出对多种病害具有抗性的品种。
