A Note on the Effect of Heat Stress on Growth and Fruiting of Three Tomato (Solanum lyc opersicum) Landraces from Sudan

Abstract

Two experiments were carried out to study the effect of high temperature on growth of three tomato landraces. The experiments were carried out during the summer of 2007 and 2008 in the nursery of the Department of Horticulture, Faculty of Agriculture, University of Khartoum, using a Randomized Complete Block Design (RCB) with three replicates. The landraces were HSD 0977, Tuktuk and Abu Zarif traditionally grown in summer under irrigation or rain-fed conditions, compared to Strain B, an imported commercial cultivar normally grown in winter. During the experimental period, the Temperature varied between 36- 38°C and 23-250C day and night respectively, measured with a maximumminimum temperature thermometer. Significant genotypic differences in plant height, time to 50% flowering, time to physiological maturity, fruit size and fruit weight were observed. Plant height was shortest for Strain B and highest for HSD0977 (61.0 and 59,8cm and91.0 and99.9cm for the first and second seasons respectively). Days to 50% flowering were shortest for HSD0977 and longest for Abu Zarif (50.7 and 51.3 days and 63.0 and 62.3 days for the first and second seasons respectively). Days to physiological maturity were shortest for HSD0977 and longest for Tuktuk (83.0 and 83.0 days and 108.0 and 111.3 days for the first and second seasons respectively). Fruit size was largest for Abu Zarif and Tuktuk and smallest for HSD 0977 while fruit weight ranged from 6.0 to 64.9 gm and from 5.7 to 49.6 gm in the first and second seasons respectively. HSD 0977 had the lowest fruit weight during both seasons but the highest weight was recorded for Abu Zarif in the first season.