Division of Crop Improvement, National Research Institute, Cuttack, 753006, India.
Sci Rep. 2018 Feb 9;8(1):2773. doi: 10.1038/s41598-018-20693-7.
The inter relationships between the two progenitors is interesting as both wild relatives are known to be the great untapped gene reservoirs. The debate continues on granting a separate species status to Oryza nivara. The present study was conducted on populations of Oryza rufipogon and Oryza nivara from Eastern India employing morphological and molecular characteristics. The cluster analysis of the data on morphological traits could clearly classify the two wild forms into two separate discrete groups without any overlaps i.e. lack of intermediate forms, suggesting the non-sympatric existence of the wild forms. Amplification of hyper variable regions of the genome could reveal 144 alleles suggesting high genetic diversity values (average He = 0.566). Moreover, with 42.37% of uncommon alleles between the two wild relatives, the molecular variance analysis (AMOVA) could detect only 21% of total variation (p < 0.001) among them and rest 59% was within them. The population structure analysis clearly classified these two wild populations into two distinct sub-populations (K = 2) without any overlaps i.e. lack of intermediate forms, suggesting the non-sympatric existence of the wild forms. Clear differentiation into two distinct groups indicates that O. rufipogon and O. nivara could be treated as two different species.
两个祖先后代之间的相互关系很有趣，因为已知这两个野生亲缘种都是巨大的未开发基因库。关于是否给予 Oryza nivara 一个独立的物种地位的争论仍在继续。本研究以印度东部的 Oryza rufipogon 和 Oryza nivara 种群为研究对象，采用形态学和分子特征进行研究。对形态特征数据的聚类分析可以清楚地将两种野生形式分为两个独立的离散组，没有任何重叠，即缺乏中间形式，这表明野生形式的非共生存在。基因组高变区的扩增可以揭示 144 个等位基因，表明具有较高的遗传多样性值（平均 He=0.566）。此外，由于两个野生亲缘种之间有 42.37%的罕见等位基因，因此分子方差分析（AMOVA）只能检测到它们之间 21%的总变异（p<0.001），其余 59%的变异存在于它们内部。种群结构分析清楚地将这两个野生种群分为两个不同的亚群（K=2），没有任何重叠，即缺乏中间形式，这表明野生形式的非共生存在。明显的分化成两个不同的组表明，O. rufipogon 和 O. nivara 可以被视为两个不同的物种。
