ICAR-Indian Institute of Rice Research, Rajendranagar, Hyderabad, 500030, India.
Sci Rep. 2018 Jun 15;8(1):9200. doi: 10.1038/s41598-018-27484-0.
With the priority of the low input sustainable rice cultivation for environment friendly agriculture, NUE of rice becomes the need of the hour. A set of 472 rice genotypes comprising landraces and breeding lines were evaluated for two seasons under field conditions with low and recommended nitrogen and >100 landraces were identified with relative higher yield under low nitrogen. Donors were identified for higher N uptake, N translocation into grains and grain yield under low N. Grains on secondary branches, N content in grain and yield appears to be the selection criterion under low N. Through association mapping, using minimum marker set of 50 rice SSR markers, 12 genomic regions were identified for yield and yield associated traits under low nitrogen. Four associated genomic regions on chromosomes 5, 7 and 10 were fine mapped and QTL for yield under low N were identified from the marker delimited regions. Three candidate genes viz., 2-oxoglutarate /malate translocator (Os05g0208000), alanine aminotransferase (Os07g0617800) and pyridoxal phosphate-dependent transferase (Os10g0189600) from QTL regions showed enhanced expression in the genotypes with promising yield under low N. Marker assisted selection using SSR markers associated with three candidate genes identified two stable breeding lines confirmed through multi-location evaluation.
在优先考虑低投入可持续水稻种植以实现环境友好型农业的情况下，水稻的氮肥利用率（NUE）成为当务之急。本研究在低氮和推荐氮水平下，对 472 个水稻基因型（包括地方品种和育成系）进行了两个季节的田间评估，鉴定出 100 多个地方品种在低氮条件下具有相对较高的产量。鉴定出了具有更高氮吸收、氮向籽粒转运和低氮下籽粒产量的供体。在低氮条件下，次级枝上的籽粒、籽粒中的氮含量和产量似乎是选择的标准。通过关联作图，利用最小的 50 个水稻 SSR 标记标记集，在低氮条件下鉴定出 12 个与产量和产量相关的性状的基因组区域。对染色体 5、7 和 10 上的四个关联基因组区域进行了精细作图，并从标记限定区域鉴定出低氮下产量的 QTL。来自 QTL 区域的三个候选基因，2-酮戊二酸/苹果酸转运蛋白（Os05g0208000）、丙氨酸转氨酶（Os07g0617800）和吡哆醛磷酸依赖性转移酶（Os10g0189600），在低氮下具有较高产量的基因型中显示出增强的表达。利用与三个候选基因相关的 SSR 标记进行的标记辅助选择，鉴定出了两个通过多点评估确认的稳定育成系。
