油菜类型和品种对外来入侵杂草小子虉草的替代控制作用

外来入侵植物小子虉草（Phalaris minor Retz.）是世界公认的冬季农田恶性杂草，掌握农作物对其替代控制作用具有重要的研究价值。前期研究表明，油菜是替代控制小子虉草的优良农作物，然而，目前尚不清楚油菜类型与品种对其控制能力的影响。为此选取与小子虉草同域发生的不同类型（白菜型油菜、芥菜型油菜和甘蓝型油菜）油菜品种各3种，通过田间小区实验和室内化感作用测定，对比研究其对小子虉草的生长、繁殖、表型以及化感作用的影响。田间实验显示：竞争方式（种内或种间竞争）和油菜类型对小子虉草的地上生物量、种子数、株高、分枝数、叶面积和比叶面积存在极显著（P=0.0001）影响；而油菜品种对小子虉草的地上生物量（P=0.6064）、种子数（P=0.3577）、株高（P=0.4279）、分枝数（P=0.6357）、叶面积（P=0.8839）和比叶面积（P=0.3424）均无显著影响。3种类型油菜对小子虉草生长、繁殖以及表型的影响存在明显差异，其中芥菜型油菜对小子虉草的上述指标的影响最强，而白菜型油菜的影响最弱。室内生物测定显示，油菜对小子虉草具有化感抑制作用，当供试油菜叶片水提液浓度为0.1 g/mL时，小子虉草种子的萌发和幼苗的株高、根长、生物量均被显著抑制；研究也表明不同类型油菜对小子虉草的化感作用显著不同，同等条件下，芥菜型油菜对小子虉草的化感抑制作用最强。综上所述，油菜类型对外来入侵小子虉草的控制作用存在显著差异，其中芥菜型油菜对植物小子虉草的替代控制作用明显优于白菜型油菜和甘蓝型油菜，而其强的化感抑草特性或许是其强控草能力的原因之一。另外，本研究也为进一步利用油菜替代控制入侵植物小子虉草提供了参考。

Replacement control of the invasive weed littleseed canarygrass (Phalaris minor Retz.) by different types and cultivars of rapeseed

Littleseed canarygrass (Phalaris minor Retz.) is one of the most troublesome invasive weeds infesting winter crops in the world. Exploring replacement control using higher value crops was thought to be the most potential green control method. Our previous study found that rapeseed was a logical candidate crop to control this weed in agroecosystems, however, the control efficiency of different types of rapeseed (Brassica rape, Brassica juncea and Brassica napus) to the invasive weed littleseed canarygrass were unknown. In this paper, nine rapeseed cultivars of Brassica rape, Brassica juncea and Brassica napus, which occurred in the same region with P. minor, were selected to study their effects on the growth, reproduction, phenotype and allelopathic effects of this invasive weed both in the field and in laboratory experiments. In field experiments, we found that competition modes (intraspecific or interspecific competition) and rapeseed types had significant effects(P=0.0001)on the aboveground biomass, seed number, plant height, branch number, leaf area and special leaf area (SLA) of P. minor, while rapeseed varieties had no significant effects on aboveground biomass (P=0.6064), seed number (P=0.3577), plant height (P=0.4279), branch number (P=0.6357), leaf area (P=0.8839) and specific leaf area (P=0.3424). We also found that the effects of different rapeseed types on P. minor were significantly different, the growth, reproduction and phenotype of P. minor were most affected by Brassica juncea and least by Brassica rape(P<0.05). In laboratory experiments, we found that rapeseeds have strong allelopathy on P. minor, the seed germination, plant height, root length and fresh biomass of P. minor were significantly inhibited when the water extract concentration of the rapeseed leaves was 0.1g/mL. We also found that the allelopthic effects of different rapeseed types on P. minor were significantly different (P<0.05), the species with the strongest allelopathic ability on weed was Brassica juncea under the same conditions. Together, the control efficiency of different rapeseed types on invasive weed P. minor were significant differences, and the control effect of Brassica juncea was better than that of Brassica rape and Brassica napus, its strong allelopathic characteristics may play an important role in replacement control. In addition, our study also suggest that replacement control by different rapeseed varieties is potentially a feasible and sustainable means of suppressing littleseed canarygrass.