【作者】 谢坚；

【导师】 屠乃美； 陈欣；

【作者基本信息】 湖南农业大学 ， 作物栽培学与耕作学， 2008， 硕士

【摘要】 研究农业生物多样性控制病虫草效应,试图通过生物学的途径降低病虫草的发生和化学农药的使用,越来越受到关注。本研究主要是从物种多样性和水稻遗传多样性两个方面开展农业生物多样性控制稻田虫草效应的研究:(1)以具有1200年历史的全球重要农业文化遗产传统稻鱼系统为范例,通过野外试验和调查,研究物种多样性的作用效应和机理;(2)将品质优良但抗草能力弱的品种秀水63、春江016、中健2号,分别与具有强化感能力的品种PI312777和具有强竞争能力的国稻1号构建水稻遗传多样性群体,通过田间试验研究水稻遗传多样性对稗草发生的影响,取得以下主要研究结果:1稻田物种多样性控制虫草效应物种共存的稻鱼系统中,栽种水稻同时养殖田鱼的处理小区(以下简称“稻鱼处理”)的稻飞虱数目与水稻单独种植的处理小区(以下简称“种稻处理”)相比,虫口密度下降了24.6%-37.1%,但稻鱼处理和种稻处理稻飞虱的密度均显著高于使用农药的常规种稻处理;稻鱼处理和种稻处理的稻纵卷叶螟幼虫和蛹的数量没有显著性的差异,这两个处理稻纵卷叶螟的发生均高于常规种稻处理。2006年和2007年的结果表明,稻鱼处理杂草的的生物量和密度均显著下降,与水稻单种相比,2006年稻鱼处理杂草生物量减少了89.05%;2007年的稻鱼处理杂草密度和生物量分别减少了82.14%和88.91%。2稻田物种多样性控制害虫的机理稻鱼系统中,稻飞虱密度的降低主要是鱼和蜘蛛的共同作用。鱼的行为观察和田鱼取食稻飞虱的模拟试验表明,平均每蔸水稻被田鱼碰撞1.52次/小时,每次有3.2头稻飞虱被击落水面;田鱼直接撞击水稻基部取食掉落在水面的稻飞虱若虫,而蜘蛛主要取食稻飞虱的成虫。3稻田物种多样性的生产力效应水稻和田鱼共存的稻田系统(稻鱼处理),2006年的水稻产量比种稻处理水稻产量增加了12.48%,2007年稻鱼处理的水稻产量与种稻处理和常规种稻处理无显著差异;2006年和2007年的试验均表明,稻鱼处理的田鱼产量明显高于不种水稻只养田鱼的处理,即养鱼处理;稻鱼处理总生产力显著提高。4稻田水稻遗传多样性控制草害的效应和机理水稻化感抗草品种(PI312777)和竞争抗草品种(国稻1号)与弱抗草水稻品种(秀水63、春江016、中健2号)进行混种时能降低稗草的发生。与单种相比,与抗草品种混种后,弱抗草水稻品种处理稗草的密度降低28.9%-54.3%,稗草的生物量减少了10.2%-40.8%,水稻的产量可以提高32%-115%。其机理主要是在混合种植后,水稻化感抗草品种抑制稗草萌发和分蘖,竞争抗草品种在后期通过强的竞争能力抑制稗草的生长。更多还原

【Abstract】 Developing species-diversified cropping systems by increasing the number of crop species has been becoming main approach to harmful organisms control in agroecosystems.Two experiments were conducted to exam whether and how agro-biodiversity could control pests and weeds and thus enhance productivity in rice system in this study:(1) effects of species diversity on pests and weeds were investigated through field experiment in a Chinese 1200-year-history traditional rice-fish system that was listed by FAO and UNDP as Globally-important Ingenious Agriculture Heritage Systems(GIAHS) in 2005;2) effects of rice genetic diversity on barnyard grass(Echinochloa crus-galli) by mixed-planting two weed-suppressive rice (Oryza sativa) varieties Guodao No.1(GD) and PI312777(PI),and three non-suppressive varieties Xiushui No.63(XS),Zhongjian No.2(ZJ) and Chunjiang No.016(CJ).The main results were as follows:1 Pest and weed controlCompared to rice treatment(rice monoculture),density of rice brown hopper in rice-fish treatment(rice co-culture with fish in the plot) decreased by 24.6%-37.1%. However,the density in both rice-fish treatment and rice monoculture treatment was significantly higher than that of conventional rice treatment(rice monoculture with pesticide).There was no significant difference in numbers of rice leaf roller (Cnaphalocrocis medinalis) in both treatments rice-fish and rice monoculture,but numbers of rice leaf roller were significantly lower in conventional rice treatment than that in rice-fish and rice monoculture.The result showed that the density and biomass of weed in rice-fish treatment were significantly lower than rice monoculture.The biomass decreased by 89.05%in rice-fish treatment compared to rice treatment in 2006.The biomass and density decreased by 82.14%and 88.91%respectively in 2007.2 Mechanisms of pest and weed control by species diversityTo reveal why rice brown hopper density in rice-fish treatment were lower than that in rice monoculture,the relation between fishes and plant hopper was further examined through scanning technology.Results showed that predation and swimming activities of fishes could reduce the population of plant hopper in rice-fish co-culture system.Each hill of rice was hit by fishes 1.52 times and 4.9 plant hoppers fell down onto water surface and were eaten by fishes in one hour.Spiders,one of plant hopper’s natural enemies,also contributed to plant hopper reduction by directly feeding on adult plant hoppers.3 Rice and fish productionThe yield of rice increased by 12.48%in rice-fish treatment compared to rice treatment.There was no significant difference among rice-fish treatment,rice monoculture treatment and conventional rice treatment.The yield of fish in rice-fish treatment was higher than that in fish treatment(only fish cultivated without rice) in both 2006 and 2007.4 Weed control by rice genetic diversityCompared to monocultures of non-suppressive rice varieties Xiushui No.63(XS), Zhongjian No.2(ZJ) and Chunjiang No.016(CJ),mixed-planting of non-suppressive rice varieties with weed-suppressive varieties Guodao No.1(GD) and PI312777(PI) could significantly reduce barnyard grass infections.Weed density and biomass were reduced by 28.9%-54.3%and 10.2%-40.8%respectively in mixtures compared to monocultures.Rice yield increased by 32%-115%in mixtures with non-suppressive rice varieties compared to monoculture.更多还原