Effect of shading on growth, development and reproductive biology of Phalaris minor Retz.

Abstract

Despite the advancement in weed management methods, weeds continue to dominate over crops due to their aggressive competitiveness. Hence, understanding the nature of underpinning crop-weed competition is central to develop weed management methods and their continuous improvements. Since, both crops and weeds compete for light by shading each other, an understanding of the different competitive potentials of crops and weeds under shade is critical to design suitable IWM strategies. All the above inferences and reasoning formed the basis for the present experiment. The present experiment was conducted in winter season 2017 to evaluate the effects of shading on growth, development and reproductive biology of Phalaris minor. The treatments included full sunlight, 55% shade and 75% shade. The total duration was delayed by more than two weeks under 55% shading while under 75% shading, it was delayed by as much as four weeks due to cumulative increases in vegetative and reproductive stages as well as time taken from flowering to maturity. Plant height increased significantly under both the levels of shading. Total aboveground dry matter accumulation decreased by more than 80% under shading and almost two-three fold proportion of dry matter was partitioned towards leaves. Concomitant variation in SLA, RGR, NAR and LAR indicated adaption to shade at whole plant level. Number of seeds per plant was reduced by 67% under shading as a consequence of proportional reduction in number of inflorescences.