ROOT ZONE TEMPERATURE AFFECTS EMERGENCE AND GROWTH TRAITS OF SNAKE TOMATO (TRICHOSANTHES CUCUMERINA L.)
2009, 10 (3) p. 239-244
Two Nigerian morphological variants of Trichosanthes cucumerina L., (Cucurbitaceae) an under-exploited tropical leaf and fruit vegetable were evaluated for response to root zone temperature (RZT) in a climate controlled growth chamber at 20, 25 and 30 oC. The Green variant [V1] has long fruit with deep green background and white stripes at unripe stage while Light Green variant [V2] has light green coloured long fruit when at unripe stage. Results showed that the first emergence for seeds at RZT of 30 oC occurred at 7 days after planting (DAP) for both variants while those planted at RZT of 20 oC and 25 oC showed first emergence at 10 and 14 DAP, respectively. At RZT of 20 oC, 25 oC and 30 oC, days to 50% emergence were 18, 12 and 8 DAP while last emergence was registered at 24, 15 and 10 DAP, respectively. This work showed that under controlled growth chamber conditions, days to first emergence was reduced by 5 days compared to the 12 DAP recorded under tropical field conditions. Root zone temperatures (T) produced statistically significant (P ≤ 0.05) effects on the average number of tendrils, number of leaves, fresh leaf weight, stem length, fresh stem weight, root length, root weight and root volume while the main effect of T. cucumerina variants (V) and the interaction (V x T) produced no significant effects on all the parameters measured. The values recorded for each of the growth parameters were only numerically higher in the Green Variant (V1) compared to Light Green Variant (V2). The significantly highest value for each of the growth traits were recorded at 30 oC followed by 25 oC and 20 oC, in that order. Low root zone temperature of 20 oC produced adverse effects on both emergence and growth of T. cucumerina. This study established the need for providing soil warming facility for a successful cultivation of T. cucumerina in chilly (temperate) environment.