Growth And Yield Response Of Tomato (lycopersicon Esculentum Mill.) Cultivars To Exogenously Applied Calcium Carbide

Presently many chemicals have been identified that produce ethylene in the air of soil. Calcium carbide (CaC2) is one of them and is being considered well known source of ethylene (C2H4). The C2H4 released from CaC2 is not thoroughly investigated particularly for production of vegetables with improved quality.Laboratory, pot and field studies were conducted to evaluate the effectiveness of calcium carbide on tomato seed germination, growth, yield, photosynthesis and quality parameters.The first experiment was conducted under laboratory conditions to assess the best rate of calcium carbide for seed germination, root and shoot growth rate of five different tomato cultivars. It was found that application of CaC2 @ 15 mg per Petri plate was the best among all rates that improved seed germination, root and shoot growth.Tomato cultivars performed better were selected for the next experiment.The three selected cultivars were grown in compost medium containing three different rates of calcium carbide with different five coatings in growth room under controlled conditions.Results showed that CaC2 at the rate of 200 mg cup-1 with polyethylene, paint and paraffin coatings performed relatively better. In the 3rd experiment best selected calcium carbide based formulations in three different rates were further compared in the presence of recommended fertilizers in a pot study.Thus comparison included their effect on tomato growth, yield, photosynthetic activity and quality parameters. Data on plant height, number of flower per plant and proportion to fruit drop, yield of tomato fruit, root and shoot dry weight, and nitrogen uptake clearly showed positive effect of CaC2 in the presence of fertilizer on all stages of growth of tomato compared to control (fertilizer only). One further pot experiment was conducted to know the best rate and time of application of formulated calcium carbide in the presence of recommended fertilizer.Results obtained were compared with those obtained from control treatment (containing fertilizer only). It is evident from the results that CaC2 applied 2 weeks after transplanting performed better among all rates and times of application in improving almost all growth and yield parameters of tomato.Based upon the results from laboratory and pot trials, field experiment was conducted to verify the results obtained from previous experiments.In this field experiment, effect of different rates of coated CaC2 was investigated on two best performing cultivars selected from previous experiment.The results showed that application of CaC2 at the rate of 200 mg plant-1 not only improved growth and yield parameters of both tomato cultivars but also enhanced N uptake by different plant parts and improved nitrogen use efficiency. Overall results suggest that addition of calcium carbide along with recommended doses of fertilizers improved fruit yield more than 40 % by improving yield contributing parameters and N use efficiency. Furthermore, quality parameters related to physical appearance and chemical composition of tomato fruits were also improved by the application of CaC2.These parameters are very much required for improvement in shelf life and processing of tomato products.In the nutshell, results confirm the growth regulator role of CaC2 in improving the growth, yield and quality of tomato.