江苏沿江地区杂草稻的生物学特性及危害调查

Investigation of the Biological Characteristics and Harmfulness of Weedy Rice(Oryza sativa L.f.spontanea) Occurred in the Regions Along the Yangtze River of Jiangsu Province

【目的】明确江苏沿江地区杂草稻的发生现状、危害和生物学特性,掌握其鉴别方法。【方法】采用目测法和样方法点面结合,调查江苏沿江地区6个市的28个县(市、区)的直播稻田杂草稻的发生率、发生密度、综合危害指数,定点研究6个地点的杂草稻生物学特性及其危害性。【结果】杂草稻在各县(市)的发生率从78%—100%不等,发生密度最低的县(市)约2株/m2,平均最高约9株/m2,综合危害指数都在20%以上,导致栽培稻减产8.3%—82.3%;泰州、扬州和常州的危害相对更重。综合6个地点的调查结果显示杂草稻与栽培稻主要区别为:杂草稻的叶环和叶耳呈紫红色,植株基部褐色;苗期生长旺盛,分蘖力强、分蘖角大于栽培稻20°以上,株高高出8—10 cm;株型松散;单株结实量高于栽培稻3倍以上,繁育系数显著高于栽培稻,但结实率较低,为78%—86%,千粒重仅为18.93—20.10 g;成熟期早1月左右并显早枯。【结论】江苏沿江地区的杂草稻发生量大且危害严重;杂草稻与栽培稻有形态学差异;杂草稻的分蘖初期、扬花期是人工拔除的适宜时期。

【Objective】The objective of this study is to define the occurrence and damage,biological characteristics of weedy rice with cultivated rice in Jiangsu Province along the Yangtze River and to master the identification method.【Method】 The incidence,density and harmfulness of weedy rice were surveyed in direct-seeded rice fields in 28 county-level cities of 8 prefecture-level cities through visual scoring of the level of weed infestation on a seven-class scale.And the biology characteristics of weedy rice were observed at the selected 6 sites along the Yangtze River where weedy rice infested seriously by means of plot sampling.【Result】 The proportion of weedy rice occurrence ranged from 78% to 100%,the average density was about 2-9 individuals/m2 and the overall value of weedy rice was more than 20%,which caused 8.3%-82.3% loss of rice yield.Weedy rice more seriously infested the paddy fields in Taizhou,Yangzhou and Changzhou.The investigation results outlined from the selected 6 sites demonstrated that weedy rice had some differences in amaranthine of leaf ring and auricle and the brown basilar stalk from cultivated rice.The weedy rice grew flourisher,produced more tillers than cultivated rice at seedling stage,and the tiller angle of weedy rice was 20°bigger than cultivated rice.Weedy rice,in general,was 8-10 cm taller than cultivated rice,but its plant-type was looser.Though the weedy rice produced larger quantity of seeds per plant than cultivated rice,the seed fertility was only from 78% to 86% which was lower than cultivated rice.The 1 000-seed-weight was only about 18.93-20.10 g.Weedy rice was about one month earlier matured and early browning compared with cultivated rice.【Conclusion】The weedy rice infestation is serious in the cities along the Yangtze River in Jiangsu Province.There are some morphological differences between weedy rice and cultivated rice.The optimum time for manual removal of weedy rice is at the beginning of tillering and the flowering due to easy identifying for farmers.