Abstract:

【Objective】 To understand, prevent and control the invasive species of Phalaris paradoxa L. and Phalaris minor Retz., their biological characteristics, competitive effects, yield characteristics and economical threshold to wheat Yunxuan 2 were studied. 【Method】 With wheat Yunxuan 2 as receptor and control plant, additive series experiments and regression fitting methods were used to study the difference in biological characteristics, analyze the competitive effects, yield characteristics and economical threshold of Phalaris paradoxa L. and Phalaris minor Retz. in greenhouse. 【Result】 Plant height, leaf length, leaf width and growth from sowing to each periods of duration of the tested wheat were greater than Phalaris paradoxa L., Phalaris minor Retz. in the vegetative period, but the growth of Phalaris paradoxa L. and Phalaris minor Retz. was faster than the wheat in reproductive period. The growing period was in the order of Phalaris minor Retz. (129.33 d)＞Yunxuan 2 (128.78 d)＞Phalaris paradoxa L. (124.78 d). The competitive power of Phalaris paradoxa L. and Phalaris minor Retz. was positively correlated with density which gradually increased to tested wheat with the increasing plant density, but the competitive power of Phalaris minor Retz. was stronger than Phalaris paradoxa L. Yield characteristics of tested wheat were affected because of the competitive effects. The regression method of y=96.5687×(1-e-[(x+2.1672)/54.5604]^0.8220) and y=96.3346×(1-e-[(x+2.5306)/46.7132]^0.7918) were the best for describing the relationship between Phalaris paradoxa L., Phalaris minor Retz. and yield lose of wheat. In wheat field, the economical thresholds of Phalaris paradoxa L. and Phalaris minor Retz. were 3.07 and 2.63 plant/m2 for manual weeding and 1.71 and 1.61 plant/m2 for fenoxaprop-ethyl chemical control. 【Conclusion】 Difference in biological characteristics of Phalaris paradoxa L., Phalaris minor Retz. and tested wheat is existed under the same planting condition in greenhouse. The competitive power of Phalaris paradoxa L. and Phalaris minor Retz. is strong to tested wheat which can affect yield of wheat significantly.

Key words: Phalaris paradoxa L.')">Phalaris paradoxa L., Phalaris minor Retz., competitive effects, economical threshold