Ruiz-Santaella J P, Bastida F, Franco A R, De Prado R
Department of Agricultural Chemistry and Edaphology, University of Córdoba, Córdoba, Spain.
J Agric Food Chem. 2006 Feb 22;54(4):1166-72. doi: 10.1021/jf0520746.
Echinochloa P. Beauv. is an important genus because many of its species are weeds infesting most paddy fields, which can reduce the rice grain production by up to 80%. A controversy exists about the taxonomy of the genus due to the high level of morphological variations found in these species. Cyhalofop-butyl, an aryloxyphenoxy-propionate herbicide, is used to control Echinochloa spp. in paddy fields, although differences in susceptibility were found between different Echinochloa species. E. colona was highly susceptible [ED50= 34 g of active ingredient (ai) ha(-1)]; very similar results were obtained with the remaining species. By contrast, E. oryzicola (170 g of ai ha(-1)) was less sensitive, with the herbicide symptoms appearing later. Because of this differential susceptibility, morphological and molecular studies were carried out. A morphological study, using 21 characters both quantitative and qualitative of spikelets and seedlings, was capable of clearly distinguishing closely related E. crus-galli plants (two populations), E. muricata and E. crus-pavonis, and E. oryzicola, E. utilis, and E. colona species. The resolution of Echinochloa species at the molecular level, based on RAPD analyses, was fairly consistent with morphological analysis results. Among the 60 primers screened, 21 primers exhibited polymorphic bands and produced a total of 136 RAPD markers. Of all the amplified fragments, 90 were found to be polymorphic. E. oryzicola and E. colona were clearly separated, and the RAPD analyses showed that both E. crus-galli populations were 100% related and 51% related to E. utilis, whereas E. crus-pavonis and E. muricata (73% similarity) appeared as being clearly separated from this group.
稗属是一个重要的属，因为它的许多物种都是杂草，侵扰着大多数稻田，可使稻谷产量降低多达80%。由于在这些物种中发现了高度的形态变异，该属的分类存在争议。氰氟草酯是一种芳氧苯氧丙酸酯类除草剂，用于稻田防除稗属杂草，不过不同稗属物种之间存在敏感性差异。双穗雀稗高度敏感[半数有效剂量（ED50）= 34克活性成分（ai）公顷-1]；其余物种也得到了非常相似的结果。相比之下，稻稗（170克ai公顷-1）不太敏感，除草剂症状出现较晚。由于这种敏感性差异，开展了形态学和分子研究。一项形态学研究使用了小穗和幼苗的21个定量和定性特征，能够清楚地区分亲缘关系密切的稗草植株（两个种群）、疣粒稗、孔雀稗，以及稻稗、疣粒野生稻和双穗雀稗物种。基于随机扩增多态性DNA（RAPD）分析的稗属物种分子水平分辨率与形态学分析结果相当一致。在筛选的60个引物中，21个引物呈现出多态性条带，共产生了136个RAPD标记。在所有扩增片段中，发现90个具有多态性。稻稗和双穗雀稗被明显区分开，RAPD分析表明，两个稗草种群之间的相关性为100%，与疣粒野生稻的相关性为51%，而孔雀稗和疣粒稗（相似度73%）明显与该组分开。
