Weedy rice species exhibit differential competitive ability and cause significant losses to rice yield. The present study was conducted to evaluate the competing ability of weedy rice accessions collected from foothills of eastern Himalayas and coastal Odisha grown in the presence of cultivated indica rice var. Swarna. The competitive ability of Swarna and weedy rices were estimated on the basis of (i) Swarna yield reduction under different durations of competition with weedy rice; and (ii) nutrient uptake by Swarna and weedy rice in competitive environment. There was significant yield reduction (18%) when competition was allowed until 6 weeks after emergence (WAE) compared to competition until 2 WAE, which was due to vigorous growth of weedy rice at early vegetative stage. The biomass accumulation and tiller number of weedy rice were significantly higher compared to Swarna. Odisha weedy rice accession recorded about 18, 57 and 24% higher N, P and K uptake, respectively, than Swarna. The highest yield reduction (22%) in Swarna was recorded when grown with OA1 and the lowest impact (7.7%) was recorded with AA2. As conclusion, management practices should be implemented within 2–4 weeks of emergence considering 5–10% acceptable yield loss of Swarna, and grain yield of cultivated rice was reduced significantly by high N and K uptake by weedy rice under a competitive environment.

中文翻译：

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杂草稻对栽培籼稻 (Oryza Sativa L.) 的影响

杂草稻品种表现出差异化的竞争能力，对水稻产量造成重大损失。本研究旨在评估从喜马拉雅东部山麓和奥里萨邦沿海地区收集的杂草稻种质在栽培籼稻变种存在下的竞争能力。斯瓦纳。Swarna 和杂草稻的竞争能力是根据 (i) Swarna 在与杂草稻竞争的不同持续时间下减产的基础上估计的；(ii) Swarna 和杂草稻在竞争环境中的养分吸收。与直到 2 WAE 的竞争相比，在出苗后 6 周（WAE）允许竞争时产量显着降低（18%），这是由于早期营养阶段杂草稻的旺盛生长。杂草稻的生物量积累和分蘖数显着高于Swarna。奥里萨邦杂草稻的 N、P 和 K 吸收率分别比 Swarna 高 18%、57% 和 24%。与 OA1 一起种植时，Swarna 的减产幅度最大 (22%)，而与 AA2 一起记录的影响最低 (7.7%)。总之，考虑到 Swarna 可接受的 5-10% 的产量损失，应在出苗后 2-4 周内实施管理措施，并且在竞争环境下杂草稻吸收高 N 和 K 会显着降低栽培稻的谷物产量。7%) 用 AA2 记录。总之，考虑到 Swarna 可接受的 5-10% 的产量损失，应在出苗后 2-4 周内实施管理措施，并且在竞争环境下杂草稻吸收高 N 和 K 会显着降低栽培稻的谷物产量。7%) 用 AA2 记录。总之，考虑到 Swarna 可接受的 5-10% 的产量损失，应在出苗后 2-4 周内实施管理措施，并且在竞争环境下杂草稻吸收高 N 和 K 会显着降低栽培稻的谷物产量。