Influence of soil moisture on yield and quality of tomato on a heavy clay soil

The effect of three soil moisture regimes [deficit: 22-26mm H2O per 100 mm soil depth, field capacity (FC): 34-43 mm and saturation: 44-48 mm] on growth, yield and quality of a tomato (Lycopersicon esculentum L. Mill) cultivar ‘Improved Apollo’ was examined on a heavy clay soil. Leaf area and plant height were reduced in deficit and saturation, whereas stem diameter increased with increasing soil moisture. Fruit yield declined by 31 and 24% in deficit and saturation respectively compared with the FC. Maximum attainable fruit yield would be achieved with 35 mm H2O per 100 mm soil depth. Total titratable acidity (TTA), ascorbic acid (AA) and firmness decreased and pH increased with increasing soil moisture. Dry matter, total soluble solids (TSS), TSS: TTA and blossom end rot (BER) were highest for deficit, followed by saturation and lowest at FC. Although yield increased and BER decreased at FC, other quality improved with water stress compared to FC.