Abstract:
To increase production and improve quality of tomatoes grown under greenhouses, root zone volume restriction system is one method that could be adopted by farmers. However, this technique predisposes the plant to moderate water stress and water stress is associated with increased risk of physiological disorders especially blossom end rot (BER). The main objective of this study, therefore, was to evaluate performance of tomato fruits under different root volume restrictions. The experiment was carried out in JKUAT from July 2020-February 2021. Tomato cv. Anna F1 was grown in four pot volumes; 0.25L,0.5L,1L and 2L respectively in a greenhouse, fertigated using Hoagland solution under hydroponic system. Results showed that fruits had mean weight of 70g, 78.12g, 81.77g and 90.53g in the 0.25L, 0.5L, 1L and 2L pots respectively. Yield per
plant (1st- 7th truss) was significantly different with the lowest in 0.25L pots (4095g) and the highest (8232g) in the 2L pot. There was a significant difference in the marketable to non-marketable fruits ratio (2.33, 2.79, 4.36 and 9.07 in 0.25l, 0.5L, 1L, and 2L pots respectively) due to BER incidence. In terms of flavor, there was no significant difference in fruits grown in the four volumes. Fruits in the 0.25L pot had the highest sugar/acid ratio of 1.89 followed by 1.09, 1.06 and 1.02 in the 0.5L, 1L and 2L pots respectively. Mean lycopene concentration was highest in the 2l pot (443. 98μg.g-1) and lowest in the 0.25L pot (264. 71μg.g-1) and mean beta carotene concentration was highest in the 0.25L pot (1.861mg.100g-1) and lowest in the 2L pot (1.287 mg.100g-1) however the
differences in concentration were not significantly different at P=0.05. In conclusion, root volume restriction of between 0.25L and 2L can be recommended for quality production of tomatoes.
Keywords Tomato, quality, root volume restriction, fertigation, BER
