Deficit Irrigation Effects on Yield, Yield Components and Seed Production of Three Cultivas of Watermelon (Citrullus lanatus (Thunb) Matsum and Nakai)

A two-year study (2005 - 2006) was carried out to explore the effect of deficit irrigation treatments according to evaporation from a class A basin، including ET= 1 (T1)، ET = 0. 75 (T2)، and ET = 0. 5 (T3)، on yield، yield components and seed yield of three varieties of watermelon (Charleston Gray، Sugar Baby and Crimson Suite) in the Varamin Agricultural Research Center of Iran. A randomized complete block design with a split plot arrangement with four replications was used. The results showed that fruit yield، yield components and seed yield were not significantly different in T1 and T2 treatments in contrary to T3 treatment. Among the yield components، number of fruits per plant most suffered from the negative impact of severe water stress (T3) (1. 20 fruit per plant). Rind thickness، percent soluble solids in fruit and seed yield were not affected by water stress. According to phenotypic traits، and correlation coefficients، a significant positive correlation (1% probability level) was observed between the weighted average، and the number of fruit with the fruit yield. Crimson Suite cultivar produced the highest yield (2533 kg ha-1) compared to the cultivars Charleston Gray and Sugar Baby. Sugar Baby and Crimson Suite cultivars، with 311. 7 and 298. 2 kg ha-1، respectively، produced the highest amount of seed. Crimson Suite cultiavr had the highest percentage of soluble solids in fruit (1. 35). Rind thickness in Crimson Suites، Charleston Gray and Sugar Baby cultivars were 1. 35، 1. 13 and 1. 10 cm، respectively. The results of this study showed that under a moderate moisture stress condition (ET = 0. 75)، fruit and seed yield could be similar to the no-water stress conditions.