Effect of weed species on drought tolerant rice genotypes at Sundarbazar, Lamjung, Nepal

Abstract

Weeds compete with rice for water, nutrients, space and light. The effect of weeds on productivity of rice genotypes were studied at research field of Institute of Agriculture and Animal Science, Lamjung Campus, Lamjung, Nepal in 2016. Eight rice genotypes (IR-87684- 18-1-2-3, IR-83388-3-3-140-4, IR-8839-39-1-6-4, IR-87759-7- 1-2-3, IR-88966-22-1-1-1, IR-88839-3-1-2-2, IR-88869-2-2-2-2, and Sukhadhan-3) and two weed management practices (Weeded condition and non weeded condition) were studied in randomized complete block design (RCBD) with three replications. Results showed that weeding operation significantly increased the growth traits and final yield of rice genotypes. Non-significant results among tested genotypes were obtained for grain yield and straw yield however the maximum grain yield (3.68 t ha-1) and straw yield (5.99 t ha-1) were found in IR-88839- 39-1-6-4 which might be due to highest test grain weight (30.64 g), tallest plant height (105.7m) and lower sterility percentage (21.84%). Similarly, the relative grain yield loss due to weed infestation was 41.8%. The highest grain yield (3.99 t ha-1) and straw yield (6.90 t ha-1) was found in weeded plots compared to non-weeded plots (2.321 t ha-1 and 6.43 t ha-1, respectively). Among weed species, Rotala indica was found most dominant (1091 m-2) and proportion 18%) followed by Eriocaulon cinereum (245.83 m-2 and 12%). Interaction effect between variety and weed population showed non-significant results for all growth and yield attributes. The plots having highest number of weed population showed greater loss of rice yield. Thus this study suggests that weeding should be carried out to achieve higher rice production.

Keywords

• rice genotypes
• grain yield
• harvest index
• weed population
• competition