Evaluation of bio-efficacy and selectivity of herbicides for weed control in tuberose (Polianthes tubrosa) cv. Prajwal.
A field experiment was conducted to study the bio-efficacy on weeds and selectivity of herbicides on growth, flowering and bulb yield of tuberose (Polianthes tuberosa Linn.) cv. Prajwal at the Division of Floriculture and Landscaping, Indian Agricultural Research Institute, New Delhi, during 2012-13. Ten different combinations of herbicides, particularly pre-emergence tank-mix herbicides application treatments were laid out in a randomized block design with three replications. The herbicidal treatments significantly reduced the density, and fresh and weight of weeds compared to the unweeded control. Maximum bulb sprouting (98.15%), and highest plant density (35.33) were observed with Pendimethalin (1 kg /ha)+rice residue (5t/ha). Maximum average plant height (70.50 cm), spike length (30.75 cm), number of florets (29.56), and number of flowers (8.79) opened at a time were associated with the combination of atrazine (1.0 kg /ha)+rice residue (5t/ha). Lowest weed fresh (12.52 g/m2) and dry weight (5.76 g/m2), weed density/m2 (37.32) and weed control index (98.15%) were also observed with atrazine (1.0 kg/ha)+rice residue (5t/ha). Maximum bulb yield/m2 (268.77 g) was observed with atrazine (1.0 kg /ha)+one handweeding 30 days after planting, but atrazine (1.0 kg /ha)+rice residue (5t/ha) was at par. However, effect of herbicides was not significant on bulblet yield/plant, bulb weight and diameter. Thus, application of atrazine (1.0 kg/ha)+rice residue (5t/ha) resulted in better weed control, higher growth, flowering and bulb yield.