Growth, fruit yield and quality of tomato (Lycopersicon esculentum Mill.) as affected by deficit irrigation regulated on phenological basis

A field experiment was conducted for two years (2013-15) to evaluate the response of tomato (Lycopersicon esculentum Mill.) to deficit irrigation (DI) with drippers. The options tried were either the regulated DI on the basis of climatological approach i.e. irrigation water equalling 0.6, 0.8 and 1.0 times the evapotranspiration (ET) or DI0.6(FT) at phenological stages (vegetative, flowering, fruiting, vegetative cum-flowering, vegetative-cum-fruiting and flowering-cum-fruiting stages) and disrupting irrigation (15 days) at either of vegetative, flowering and fruiting stage. Compared with the full irrigation (Ft; 78.0 Mg ha(-1)) the regulated deficit irrigation though did not affect the marketable fruit yield (MFY) at RDI0.8, there was loss of about one-fourth MFY with RDI0.6. Nevertheless the water productivity (19.2 kg m(-3)) was the maximum under RDI0.8. When the deficit irrigation was applied at different growth stages, MFY was rather improved by 4% with Dio.s(vs) while DI0.6(FL) showed little effect and a decline of 7% was monitored with D10.6(Fr). The DI applied at either of two stages (DI0.6(vsa); Di(0.6)(FL+ Fr); Dlogvs+ Fr)) resulted in 14-18% decline in MFY. The crop was able to tolerate interruptions of irrigation for 15 days at the above phenological stages i.e. simulating canal closures and the decline in yield was only 3-7%, the highest being at fruiting stages (IlFr). The major advantage of DI was improvement in quality in terms of total soluble solid, ascorbic acid, acidity and colour index (lycopene) though the fruit size was affected. It was concluded that benefits of deficit irrigation in terms of improved quality and water productivity while sustaining fruit yield could be achieved with regulated DI at 0.8xET and DI at 0.6xET during vegetative stage followed by flowering. (C) 2016 Elsevier B.V. All rights reserved.