ICAR-National Rice Research Institute, Cuttack 753006, India.
Environmental Science Laboratory, School of Applied Sciences, KIIT Deemed to be University, Bhubaneswar 751024, India.
Biomolecules. 2023 Jan 18;13(2):198. doi: 10.3390/biom13020198.
Ranidhan is a popular late-maturing rice variety of Odisha state, India. The farmers of the state suffer heavy loss in years with flash floods as the variety is sensitive to submergence. Bacterial blight (BB) disease is a major yield-limiting factor, and the variety is susceptible to the disease. BB resistance genes , , and , along with the QTL, for submergence stress tolerance were transferred into the variety using marker-assisted backcross breeding approach. Foreground selection using direct and closely linked markers detected the progenies carrying all four target genes in the BCF, BCF, and BCF generations, and the positive progenies carrying these genes with maximum similarity to the recipient parent, Ranidhan, were backcrossed into each segregating generation. Foreground selection in the BCF generation progenies detected all target genes in 11 progenies. The progeny carrying all target genes and similar to the recipient parent in terms of phenotype was backcrossed, and a total of 321 BCF seeds were produced. Ten progenies carried all target genes/QTL in the BCF generation. Screening of the BCF progenies using markers detected 12 plants carrying the target genes. A total of 1270 BCF seeds were obtained from the best BCF progeny. Foreground selection in the BCF progenies detected four plants carrying the target genes in the homozygous condition. The bioassay of the pyramided lines conferred very high levels of resistance to the predominant isolates of bacterial blight pathogen. These BB pyramided lines were submergence-tolerant and similar to Ranidhan in 13 agro-morphologic and grain quality traits; hence, they are likely to be adopted by farmers.
拉尼丹是印度奥里萨邦一种广受欢迎的晚熟水稻品种。由于该品种对淹没敏感，该邦农民在遭遇洪水时损失惨重。细菌性枯萎病（BB）是主要的产量限制因素，该品种易受该病影响。利用标记辅助回交育种方法，将 BB 抗性基因 、 、 和 ，以及耐淹没胁迫的 QTL 转入该品种。使用直接和紧密连锁标记进行前景选择，在 BCF 、BCF 和 BCF 世代的后代中检测到携带所有四个目标基因的植株，并且携带这些基因的阳性后代与受体亲本拉尼丹最大程度相似，被回交到每个分离世代中。在 BCF 世代后代的前景选择中，在 11 个后代中检测到所有目标基因。携带所有目标基因并在表型上与受体亲本相似的后代被回交，共产生了 321 个 BCF 种子。在 BCF 世代中，有 10 个后代携带所有目标基因/QTL。使用标记对 BCF 后代进行筛选，检测到 12 株携带目标基因的植株。从最佳 BCF 后代中总共获得了 1270 个 BCF 种子。在 BCF 后代中进行前景选择，在纯合状态下检测到 4 株携带目标基因的植株。对聚合系进行生物测定，发现其对主要的细菌性枯萎病病原菌分离物具有很高的抗性。这些 BB 聚合系具有耐淹没性，并且在 13 个农艺和谷物品质性状上与拉尼丹相似；因此，它们很可能被农民采用。
