不同基因型小麦麦茬对杂草的化感抑制作用

采用改进的田间抑制圈生物测定方法,分析了10种不同基因型小麦材料麦茬对杂草生长的影响.结果表明,不同基因型之间以及同一基因型的不同材料之间对杂草的影响均呈现显著差异,说明化感作用基因在稳定遗传的同时存在一定的变异.以现代品种"丰产3号"麦茬地杂草的生物量为对照,其他小麦品种麦茬对杂草均有一定的抑制作用;对10个小麦品种麦茬地杂草的生物量与残茬滞留时间(天)逐步回归分析发现,杂草生长与时间存在明显的正相关关系,其中小麦残茬抑制杂草生长的化感作用有效天数为3～29天,而后杂草生物量逐渐增大,最后达到稳定;染色体组型为AA、AABB及AABBDD的麦茬化感抑制作用均随残留时间的变化而逐渐减弱,抑制杂草的平均有效期分别为21、24和25天,说明小麦在从二倍体到四倍体到六倍体的染色体组变异与倍体变化的长期进化过程中,小麦的遗传可塑性可能有助于化感作用的增强.

Allelopathic effect of wheat stubbles with different genotypes on weed suppression

The growth difference of weeds in stubble fields of 10 varieties of wheat, which responses to different genotypes, is analyzed with an improved method based on the bioassay of inhibitive circle in fields. The preliminary study shows that in stubble fields of wheat materials belonging to related varieties from different or same genotype the growth of weeds differ significantly, which means evident variation of allelopathic genes while happening causing a constant heredity. When the biomass of weeds in the stubble field of the accession "Fengchan 3" is considered as the control the rest almost exhibit certain effect of inhibition on the growth of weeds in counterpart fields. The positive correlation exists in the biomass of weeds in 10 cultivars of wheat stubble fields and the resorting time of remnant stubbles by the analysis of step regression. Meanwhile, the efficient days are verified for 3-29 days when evaluated the effect of stubbles on the growth of weeds. After that the biomass of weeds will begin to increase. In the end the growth of weeds will come to stabilization. With the change of stubbles left period the allelopathy intensity of wheat stubbles with different genomes will decline uniformly and gradually, and the mean effective period of inhibition on the growth of weeds is 21, 24, and 25 d respectively. The results on genomes explain perhaps that the genetic elasticity is available for an enhancing trend of the allelopathic effect in wheat during the long evolution of wheat in the genome change from diploid, tetraploid to hexaploid.