Background

Direct-seeded rice (DSR) is a potential technology for sustainable rice farming as it saves water and labor. However, higher incidence of weed under DSR limits productivity. Therefore, there is a need to develop herbicide tolerant (HT) rice varieties.

Results

We used marker assisted backcross breeding (MABB) to transfer a mutant allele of Acetohydroxy acid synthase (AHAS) gene, which confers tolerance to imidazolinone group of herbicides from the donor parent (DP) “Robin” into the genetic background of an elite popular Basmati rice variety, Pusa Basmati 1121 (PB 1121). Foreground selection was done using the AHAS gene linked Simple Sequence Repeat (SSR) marker RM6844 and background selection was performed using 112 genome-wide SSR markers polymorphic between PB 1121 and Robin. Phenotypic selection for agronomic, Basmati grain and cooking quality traits in each generation was carried out to improve the recovery of recurrent parent phenome (RPP). Finally, a set of 12 BC₄F₄ near isogenic lines (NILs), with recurrent parent genome (RPG) recovery ranging from 98.66 to 99.55% were developed and evaluated. PB 1121-HT NILs namely 1979-14-7-33-99-10, 1979-14-7-33-99-15 and 1979-14-7-33-99-66 were found superior to PB 1121 in yield with comparable grain and cooking quality traits and herbicide tolerance similar to Robin.

Conclusion

Overall, the present study reports successful development of HT NILs in the genetic background of popular Basmati rice variety, PB 1121 by introgression of mutated AHAS allele. This is the first report on the development of HT Basmati rice. Superior NILs are being evaluated in the national Basmati trials, the release of which is likely to provide a viable option for the adoption of DSR technology in Basmati rice cultivation.

中文翻译：

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标记辅助开发和鉴定了超级巴斯马蒂大米品种“ Pusa Basmati 1121”的抗除草剂同基因品系。

背景

直播稻（DSR）可以节省水和劳动力，因此是可持续稻谷种植的潜在技术。但是，在DSR下杂草的发生率较高，限制了生产力。因此，需要开发耐除草剂（HT）的水稻品种。

结果

我们使用标记辅助回交育种（MABB）将乙酰羟酸合酶（AHAS）基因的突变等位基因转移，使对供体父母（DP）“罗宾”的咪唑啉酮类除草剂具有耐受性，进入了广受欢迎的印度香精的遗传背景。水稻品种，Pusa Basmati 1121（PB 1121）。使用AHAS基因连锁的简单序列重复（SSR）标记RM6844进行前景选择，并使用PB 1121和Robin之间多态的112个全基因组SSR标记进行背景选择。对每一代的农艺，印度香米和烹饪品质性状进行表型选择，以提高复发亲本表型（RPP）的回收率。最后一组12 BC ₄ F ₄开发并评估了近等基因系（NIL）和近亲基因组（RPG）回收率从98.66％到99.55％。发现PB 1121-HT NIL即1979-14-7-33-99-10、1979-14-7-33-99-15和1979-14-7-33-99-66在产量上优于PB 1121可比的谷物和烹饪质量性状和除草剂耐受性与罗宾相似。

结论

总体而言，本研究报告了通过突变的AHAS等位基因的渗入，在印度香米大米PB 1121的遗传背景下成功开发了HT NIL 。这是有关印度香米的发展的第一份报告。优质的NIL正在印度香米的国家试验中进行评估，释放该香精可能为在香米种植中采用DSR技术提供可行的选择。