Weed competitiveness and productivity of interplanted wheat cultivars under varying water management

Growing two or more cultivars of the same crop species in mixture reduces intra-specific competition for growth resources by inducing variation in spatial and temporal patterns of crop growth, increases competitive ability of crops against weeds and thus enhances crop yield. This study was conducted to evaluate the potentiality of wheat cultivar mixtures to reduce weed growth and increase the wheat yield under different irrigation regimes, and determine the best row mixture ratio of two wheat cultivars for better weed suppression and higher productivity of wheat. Factors included seven cultivar mixture ratios viz. sole BARI Gom 25, sole BARI Gom 30, 1:2, 2:1, 2:3, 3:2 and 1:1 of BARI Gom 25 to BARI Gom 30, and three water management practices viz. no irrigation, one irrigation at crown root initiation (CRI) stage, and two irrigation at CRI and flowering stages arranged in a split-plot design with three replications. Results clearly indicated that cultivar mixture can improve the competitive ability of wheat plants against weeds and can increase wheat productivity. Both cultivars showed better growth, higher weed suppression and increased yield when grown in mixture irrespective of ratios compared to their monoculture. Based on the combined grain yield, different mixture ratios performed in the order 1:1, 2:3, 1:2 and 2:1 BARI Gom 25 to BARI Gom 30 under two irrigation regimes. BARI Gom 25 and BARI Gom 30 inter-planted in 1:1 row ratio under two irrigation appeared as the best practice resulting 9% and 5.83% yield advantages over sole culture of BARI Gom 25 and BARI Gom 30, respectively; while mixture ratio of 3:2 resulted in 6.43% and 3.36% weed dry matter reduction over sole culture of BARI Gom 25 and BARI Gom 30, respectively. In conclusion, cultivar mixture strategy can be adopted as an effective tool for better weed management and increased yield of wheat.