Drought Tolerance of Several Tomato Genotypes Under Greenhouse Conditions

Growth and production of agricultural crops are greatly affected by water shortage. Thus, yield enhancement under drought conditions is a major goal of plant breeding. Four commercial tomato cultivars (Imperial, Pakmore VF, Strain-B and Tnshet Star), a drought-tolerant breeding line (L 03306) and their hybrid combinations were selected in this study to evaluate drought tolerance and to develop initial material for a drought tolerance breeding program. Four-weeks-old seedlings were transplanted into soil under greenhouse conditions. Six irrigation treatments (T = 20, T = 40, T = 60, T = 80, T (control) = 100 and T = 120% of the 1 2 3 4 5 6 estimated evapotranspiration, ET ) were imposed during a 140-day growing period through a drip irrigation c system. Vegetative growth, flowering and yield traits were measured while water use efficiency (WUE) was determined. All vegetative and fruit traits decreased significantly as deficit irrigation levels increased. For T1 and T , yield was reduced by 46.7 and 33.5%, respectively, compared with T . WUE was increased significantly 2 5 as the amount of irrigation water decreased. The relationship between production and water amount was a second-degree polynomial. Significant differences among genotypes were found for all traits, suggesting that they could be taken into account when selecting for drought tolerance. Pakmore VF and the breeding line L 03306 had good yield performance under different deficit irrigation treatments. These genotypes could be selected for in a breeding program as recurrent (female) and donor (male) parents, respectively.