Role of secondary metabolites of wild marigold in suppression of Johnson grass and Sun spurge

Objective: To analyze the wild marigold [(Tagetes minuta L.)(T. minuta)] leaf extract with respect to phytochemicals and allelopathic activity. Methods: The aqueous extracts of T. minuta leaves at concentrations of 50%, 75% and 100% were prepared. Preliminary phytochemical analysis was carried out and then allelopathic ef ect of T. minuta on root length, shoot length, germination, fresh and dry weight of Johnson grass and Sun spurge was tested on i lter paper and in soil.Results: Qualitative phytochemical analysis showed the presence of alkaloids, tannins, saponins, l avonoides and terpenoids. The higher concentrations proved to be signii cantly ef ective in reducing almost all the parameters of Sun spurge and Johnson grass in i lter paper bioassay. Supplemented with the soil, all concentrations of leaf extract showed reduction in germination, root and shoot growth, fresh and dry weight of Sun spurge; however, 100% concentration signii cantly reduced the germination of Johnson grass. Conclusions: This study suggests that marigold allelochemicals can be used as an integrated weed management for the production of better crop yield.

同源四倍体高粱与约翰逊草杂交及其后代表现

本试验研究了高粱同源四倍体与约翰逊草远缘杂交的结实性及其后代表现。结果表明 ,四倍体高粱与约翰逊草正、反交均能结实 ,而且后代性状遗传较稳定 ,具有强大的杂种优势 。

四倍体高粱与约翰逊草间的亲缘关系分析

本研究以四倍体高粱与约翰逊草为材料,利用SSR分子标记和细胞遗传学方法分析了高粱与约翰逊草问的亲缘关系,SSR分析结果表明,高粱与约翰逊草的遗传背景差异较大,SSR差异位点和相似位点在连锁群上的分布具不平衡性:按照差异引物出现频率高低,将连锁群分为两类:高度差异区和低度差异区。细胞学分析结果表明:(1)双亲及杂交种都是不规则的四倍体遗传群体。(2)花粉母细胞减数分裂中期Ⅰ,双亲及杂交种染色体配对以二价体和四价体为主,杂交种平均每个细胞二价体数为17.00,四倍体高粱为15.23、约翰逊草为15.83,四价体数分别为0.95,2.15和1.60个。但杂交种减数分裂过程中也出现一定数量的单价体,减数分裂会形成一定比例的非整倍配子。SSR检测结果与细胞学分析结果具有一致性,约翰逊草与高粱的染色体组间存在一定程度的同源性。二者杂交不能形成稳定遗传的双二倍体。

重庆市沙坪坝区假高粱的发生与铲除

假高粱(Sorghum halepense(L.)Pers.)是世界恶性杂草之一,也是我国的一种重要农业植物检疫性有害生物,重庆市于2009年首次在沙坪坝区土主镇发现该杂草发生。随后在该区12个乡镇展开了详细调查,其中9个乡镇有假高粱的发生、分布,总发生面积78403.92 m2,其中耕地面积29068.12m2。发现疫情后,按照"一月一查"和"挖根、装袋、晾晒、烧毁"铲除程序开展了假高粱灭除行动。通过3年的铲除行动,2012年4月经重庆市农委和沙坪坝区有关部门组织专家验收鉴定,重庆市沙坪坝区假高粱已被彻底灭除。