Crop wild relatives of rice (Oryza sativa L.) are an important reservoir of genes for broadening the genetic base of commercial varieties. India is the centre of genetic diversity of some of the wild as-well-as the cultivated rice species. In order to collect genetic diversity, explorations were undertaken in six states located in different agro-ecological zones of India. Forty-four accessions belonging to four wild species (Oryza rufipogon Griff., Oryza nivara Sharma et Shastry, Oryza officinalis Wall. ex Watt and Oryza sativa L. f. spontanea Roshev.) including two accessions of cultivated rice (Oryza sativa L. subsp. indica Kato) were collected from different ecological niches. The rice accessions were characterized using 28 morphological descriptors, which included 15 qualitative and 13 quantitative traits. Wild rice accessions displayed a broad range of phenotypic variation for plant height, main heading days, days to 50% flowering, flag-leaf length and width, panicle shape and size, peduncle length, awning pattern, awn length and colour, seed length and width, seed length/width ratio and 100-seed weight. Cluster analysis based on Jaccard’s similarity coefficients derived from 28 morphological traits grouped 44 accessions into three clades. DNA sequencing revealed that internal transcribed spacer (ITS) region of 18S–5.8S–28S nuclear ribosomal cistron varied from 574 to 577 bp with mean of 576.1 bp in AA-genome species. GC content was high in ITS region, which varied from 69.57 to 70.36% with mean value of 69.99%. Neighbour-joining phylogenetic tree distinguished Oryza sativa–nivara–rufipogon complex from other species of AA-genome. The wild germplasm characterized in this study could be utilized in the genetic enhancement of cultivated rice.

水稻的野生近缘种（Oryza sativa L.）是扩大商业品种遗传基础的重要基因库。印度是一些野生以及栽培稻种的遗传多样性的中心。为了收集遗传多样性，在印度不同农业生态区的六个州进行了勘探。属于四个野生物种（四十四种质野生稻格里夫，尼伐拉稻夏尔马等Shastry，药用野生稻长城。当然瓦和水稻L. F。spontanea茅），包括栽培稻两个种质（水稻L.亚种 印度Kato）是从不同的生态位中收集的。利用28个形态学指标对水稻品种进行了鉴定，其中包括15个定性和13个定量性状。野生稻种在植株高度，主要抽穗期，开花至50％的天数，旗叶长度和宽度，穗形状和大小，花序长度，遮篷模式，遮篷长度和颜色，种子长度和长度方面表现出广泛的表型变异。宽度，种子长/宽比和100种子重量。基于从28个形态性状得出的Jaccard相似系数进行聚类分析，将44个种质分为三个进化枝。DNA测序表明，AA基因组物种中18S–5.8S–28S核糖体顺反子的内部转录间隔区（ITS）区域为574至577 bp，平均为576.1 bp。ITS区域的GC含量很高，从69.57到70.36％，平均值为69.99％。相邻的系统发育树其他AA基因组物种的水稻–涅瓦拉– rufipogon复合体。本研究表征的野生种质可用于栽培稻的遗传改良。