S23 - Session P8 - Physico-chemical and postharvest quality characteristics of Intra and Interspecific grafted tomato fruits

Authors: Willis Owino *, Dianah Walubengo, Irene Orina, Yasutaka Kubo

Grafting onto robust rootstocks has been utilized as an optimal alternative to increase tolerance to bacterial wilt which is a challenge in tomato production that can lead to upto 100% postharvest losses. Grafting on different rootstocks has been reported to have varying results on the postharvest quality of tomato. The objective of this study was to evaluate the physico-chemical and postharvest quality characteristics of intra- and interspecific grafted tomato fruit. 'Anna F1', a commercial tomato variety was interspecifically (Tomato Scion and African eggplant rootstock ( Solanum aethiopicum) ) and intraspecifically (Tomato Scion and bacterial wilt resistant hybrid tomato rootstock) grafted. The tomatoes were grown in a greenhouse and harvested at mature green, turning and ripe stages respectively. The tomatoes were analyzed for size, weight, cumulative weight loss, color changes, texture, respiration and ethylene gas production rates, vitamin C and lycopene content. Interspecific grafting on 'Manyire', 'AB2', and intraspecific grafting on 'Armada', and 'B.B' rootstocks significantly improved physical, and physiological attributes. There was significant difference (p < 0.05) in size and weight of grafted tomatoes and control at all the three maturity stages. Intraspecific grafted tomato fruits on 'Armada' rootstocks had the best quality characteristics in terms of firmness, low weight loss, respiration and ethylene production rates which are associated with prolonging shelf-life. Intraspecific grafting reduced respiration and ethylene gas production rates with tomatoes grafted onto 'Armada' rootstocks attaining the least climacteric peaks of 20.20 mL CO 2 Kg -1 h -1 and 0.34 μL C 2 H 4 Kg -1 h -1 respectively at mature green stage, thus extending the postharvest life of these tomatoes. Tomatoes grafted onto 'B.B' rootstock had the highest vitamin C content (28.11 mg.100g -1 ). In general, intraspecific grafting recorded the best quality traits over the interspecific grafting. However interspecific grafting of tomato onto African eggplant 'Manyire' and 'AB2' rootstocks had lower but comparable fruit quality to intraspecific grafting.