EVALUATION OF THE GROWTH AND YIELD OF SOLANUM LYCOPERSICUM L. PECTOMECH GRAFTS IN ROOTKNOT NEMATODE INFESTED SOILS

ABSTRACT This study evaluated the resistance, agronomic performance, yield, fruit quality and shelf life of Solanum lycopersicum “Pectomech” grafted (cleft method) onto four Solanum spp. rootstocks (Solanum macrocarpon, Solanum aethiopicum, Solanum lycopersicum “Mongal”, and Solanum lycopersicum “Samrudhi”) under four root knot nematode densities (0, 500, 1000 and 5000). It consisted of a greenhouse pot experiment, field pot experiment, and open field experiment. The experimental design used was a 4x4, 2x3 factorial experiment in a split plot design and a randomized complete block design with three replicates respectively. The interaction effect between the Solanum rootstocks and the nematode densities had no significant effect on gall score index and the nematode reproductive factor (GI ≤ 2, RF ≤ 1). However, screening of the rootstocks using Mi gene specific primers (PMIR3/F3 and C2D1/C2S4) revealed that the rootstocks Solanum lycopersicum “Samrudhi and Solanum lycopersicum “Mongal possessed the Mi gene with double PCR band sizes of 300 bp and 500 bp and a single band size of 800 bp for the primer pair of PMIR3/F3 and C2D1/C2S4 respectively whilst Solanum macrocarpon and Solanum aethiopicum bands did not possess the Mi gene. The grafting success of Pectomech grafted onto Solanum macrocarpon and aethiopicum on the average were higher (93% and 94%) compared to the grafting success of Solanum lycopersicum “Mongal (0%). There was no significant interaction between rootstocks and the nematode densities on, fruit quality and shelf life of tomatoes, however, in the open field experiment the grafted rootstock effect significantly increased the yield in Pectomech grafted onto Solanum aethiopicum (461g/plant) compared to the un-grafted Pectomech (152 g/plant). The grafted rootstocks also offered resistance to the spread of Fusarium oxysporum f.s. lycopercici which is host specific to tomato compared to the non-grafted Pectomech an indication that grafting has multiple functions in crop protection