Tamil Nadu Agricultural University, India
P. Jeyakumar has completed his M.Sc (Ag) in Crop Physiology from Tamil Nadu Agricultural University (TNAU), Coimbatore and PhD from Forest Research Institute (FRI), Dehradun, India. He has undergone postdoctoral training in postharvest physiology at McGill University, Canada and ARO Volcani Centre, Israel. He has received the Best Researcher Award from Tamil Nadu Agricultural University, Coimbatore and Eminent Scientist Award from National Environmental Science Academy, New Delhi. He has published more than 60 papers in reputed journals and presented many papers in International Conferences across the globe. Prof. P. Jeyakumar is serving as the Technical Editor of The Madras Agricultural Journal and as Research Coordinator, Department of Crop Physiology, TNAU, Coimbatore, India.
A strobilurin class fungicide, Trifloxystrobin has been found to have influence on postharvest quality characters in tomato fruits. The compound is widely used for disease management in many cereals, fruit and vegetable crops. Physiological alterations in plants resulting in longer retention of green leaf tissue, inhibition of ethylene biosynthesis, increase in cytokinins and auxins, better N assimilation, increase in CO2 assimilation, water use efficiency and harvest index have been reported in many crops. Trifloxystrobin alone or in combination with Tebuconazole imparts biotic and abiotic stress tolerance in few crops. However, there are no studies on the influence of Trifloxystrobin on postharvest quality of any commercial fruit or vegetable. Hence, an experiment was done during 2013 at Department of Crop Physiology, TNAU, Coimbatore, to assess the impact of Nativo 75 WG (Trifloxystrobin+ Tebuconazole), in tomato hybrid Vijaya. There were six treatments in the experiment consisting of foliar spray of Nativo at four different concentrations i.e., 200, 300, 400, 600gha-1, Mancozeb at a single concentration of 1000gha-1 and unsprayed control. The tomato fruits were observed for weight loss at three days interval and quality characters were assessed on twelfth day after storage at ambient temperature (~32°C). A gradual decline in fruit weight over the time was observed irrespective of the treatments. The minimal loss in weight was observed in fruits harvested from plants treated with Mancozeb @ 1000gha-1 and Nativo @ 300gha-1 by recording 27.96 and 29.05 per cent. The unsprayed control registered the maximum loss of 39.01 per cent after 12 days of storage. The plants treated with Nativo @400gha-1 had higher fruit moisture content (86.6 %), fruit firmness (1.39 kg) and total soluble solids (7.8 °brix). The same treatment also had lower respiratory rate of fruits (17.8 mg CO2 kg-1h-1) favouring extended shelf life. The quality characters such as pulp pH, lycopene, ascorbic acid and titrable acidity were found not influenced by any of the treatments. However, the measurements on chromacity indicated that Mancozeb had positive influence on colour (redness) of the fruit by recording the highest ‘a’ value of 24.2. Nativo treatments also resulted in ‘a’ value of >20 while unsprayed control registered only 18.1.