Marker assisted introgression of blast (Pi-2 and Pi-54) genes in to the genetic background of elite, bacterial blight resistant indica rice variety, Improved Samba Mahsuri
Marker assisted introgression of blast (Pi-2 and Pi-54) genes in to the genetic background of elite, bacterial blight resistant indica rice variety, Improved Samba Mahsuri
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DOI：
10.1007/s10681-016-1784-1
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发表时间：
2016-11-01
期刊：
影响因子：
1.9
通讯作者：
Prasad, M. Srinivas
中科院分区：
文献类型：
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作者：
Madhavi, K. Ratna;Rambabu, R.;Prasad, M. Srinivas
改良Samba Mahsuri(ISM)是一种抗白叶枯病(Bb)(拥有Xa21、Xa13和Xa5)的高产水稻品种，具有细粒型，最近被推广种植，在印度许多地区越来越受欢迎。然而，新品种对稻瘟病高度敏感，这限制了它的传播。在本研究中，我们试图通过两组不同的回交将两个主要的抗稻瘟病基因(PI-2和PI-54)导入ISM，其中一个涉及PI-2的转移，另一个涉及PI-54的转移。在每个回交世代，利用紧密连锁的基于PCR的标记选择具有Pi-2(一交)或Pi-54(二交)的植株以及Xa21、Xa13，并利用供体和轮回亲本之间多态的微卫星标记从轮回亲本基因组中选择贡献最大的植株(背景选择)。将含有Pi-2的BC2F1植株与含有Pi-54的BC2F1植株杂交，得到具有两个抗稻瘟病基因和两个抗BB基因的杂交F1。杂交F1代在纯合子条件下产生具有不同抗病基因组合的杂交F2代，包括四基因金字塔系。通过系谱选择方法进一步推进纯合品系的选育。筛选出同时具有BLAST和BBB抗性基因的基因金字塔品系，表现出较高的抗病水平。此外，所有的基因金字塔系都具有与ISM相同的粒型，产量与原始品种相当或更好。这是第一个记录BLAST(PI-2？)两个主要基因堆积的报告。Pi-54)和Bb的两个主要基因(Xa21？Xa13)在水稻优良品种Samba Mahsuri中进行分子标记辅助回交育种。
Improved Samba Mahsuri (ISM), a bacterial blight (BB) resistant (possessing Xa21, xa13 and xa5), high-yielding rice variety possessing fine-grain type has been recently released for cultivation and is becoming increasingly popular across many parts of India. However, the new variety is highly susceptible to blast disease, which limits its spread. In the present study, we attempted to improve blast resistance of ISM by introgressing two major blast resistance genes (Pi-2 and Pi-54) by marker-assisted backcross breeding through two separate sets of backcrosses, one involving transfer of Pi-2 and another involving Pi-54. At each backcross generation, closely linked PCR-based markers were used to select plants possessing either Pi-2 (first cross) or Pi-54 (second cross) along with Xa21, xa13 and microsatellite markers polymorphic between donor and recurrent parents were used to select plants that have maximum contribution from the recurrent parent genome (background selection). Selected BC2F1 plant possessing Pi-2 was intercrossed with a selected BC2F1 plant possessing Pi-54 and the resultant intercross F1 was selfed to generate intercross F1 possessing the two blast and two BB resistance genes. The intercross F1s were then selfed to generate intercross F2s possessing different combination of resistance genes in homozygous condition including the four-gene pyramid lines. The homozygous lines were advanced further through pedigree method of selection. When selected gene-pyramid lines possessing both blast and BB resistance genes were screened against the two diseases, they exhibited high level of disease resistance. Further, all the gene-pyramid lines possessed grain type identical to ISM and yielded equivalent to or better than the original variety. This is the first report documenting the stacking of two major genes for blast (Pi-2 ? Pi-54) and two major genes for BB (Xa21 ? xa13) in rice through marker-assisted backcross breeding in a elite cultivar Improved Samba Mahsuri.