EFFECTS OF DRIP IRRIGATION REGIMES, VELUM PRIME RATE AND NEEM PRODUCTS ON GROWTH AND YIELD OF TOMATO (SOLANUM LYCOPERSICUM L.) IN ROOT-KNOT NEMATODES (MELOIDOGYNE SPP.) INFESTED SOIL IN NORTHERN GHANA

Abstract

One of the most important vegetable crops widely cultivated and consumed in the world is tomato (Solanum lycopersicum L). However, tomato production has been decreasing at at the various irrigation sites in Ghana due to the devastating effects of root-knot nematodes (Meloidogyne spp.). In this study, the impact of drip irrigation regime, Velum Prime and neem extract on root-knot nematodes and yield of tomato were investigated. The experiment was carried out in a greenhouse (from May to August 2022, at the Council for Scientific and Industrial Research-Savanna Agricultural Research Institute (CSIR-SARI), Nyankpala, near Tamale, Ghana. A 3 x 2 x 3 factorial experiment laid out in a Randomized Complete Block Design (RCBD) with three replications was conducted. The treatments consisted of irrigation regimes (50% ETc, 75% ETc and 100% ETc), Velum Prime rate (0.625 and 1.25 L/ha) and neem leaf extract, neem seed extract, and neem cake, each at 5 t/ha. Each experimental pot was filled with 5 kg soil and infested with 159 ml of nematode-infected water. Results of the CROPWAT model showed that the seasonal water needs for tomato ranged from 254 mm at 50% ETc to 508 mm at 100% ETc. The soil textural class was clay loam and field capacity of the topsoil and subsoil were 31.70% and 31.90%, respectively. Application of 100% ETc with 1.25 L/ha Velum Prime plus of either 5 t/ha neem seed extract or 5 t/ha neem leaf extract increased crop growth indices such as plant height. Irrigation at 75% ETc plus Velum Prime (1.25 L/ha) and neem seed extract (5t/ha) increased number of leave per plant, whilst 100% ETc irrigation with 5 t/ha neem seed extract, 1.25 L/ha Velum Prime and neem leaf extract and 1.25 L/ha Velum Prime with neem seed extract (5 t/ha) gave the highest leaf chlorophyll content. The 75% ETc irrigation and 5 t/ha neem seed extract promoted flowering. Moreover, irrigation with 75% ETc and 1.25 L/ha Velum Prime with 5 t/ha neem seed extract gave the highest fruit set. Irrigation with 75% ETc combined with 5 t/ha neem seed extract increased number of fruits per plant. However, the greatest fruit yield of 1.7 t/ha was obtained by the application of 75% ETc irrigation with 5 t/ha neem seed extract. Fruit yield correlated positively with plant growth and reproductive indices of the plants (plant height, number of leaves, leaf chlorophyll, flower and fruit counts) showing coefficient of correlations as: r = 0.78, 0.67, 0.96, 0.85, 0.95, respectively. The study therefore revealed integration of drip irrigation, Velum Prime rate and neem extract exhibited greater potential in increasing the ???? of tomato in root-knot nematodes infestation soils at irrigation sites.