اثر نسبت‌های متفاوت آمونیوم به نیترات بر رشد و عملکرد چند رقم توت فرنگی (Fragaria xananassa Duch.)

Some strawberriy cultivars (Fragaria x ananassa Dutch. cv. Aliso, Selva, Gaviota and Camarosa) were grown hydroponically with five NH4:NO3 mM concentration ratios (0/6 (S1), 0.25/6 (S2), 0.5/6 (S3), 1/6 (S4), 2/6 (S5) and constant nitrate concentration in three replicates for two seasons: Summer and Winter, in greenhouses of Agriculture Faculty of Tehran University. The results are reported as Follows: In summer shoot dry weight and shoot/ root ratio were highest in 0.25 and 0.5 mM NH4-N and were constant in remaining solutions with higher ammonium concentration. Increasing ammonium concentration resulted in decreasing the root dry weight. Aliso and Selva had the highest shoot and root dry matter respectively. Gaviota had the highest runner. In winter, shoot dry matter was highest in plants grown in S5 solution. Increasing ammonium from 0 to 0.5 mM decreased fruit yield but more ammonium in S4 and S5 solution increased yield. Root and fruit dry matter were highest in Selva. Yield and Fruit fresh weight were highest in Gaviota. Camarosa had the highest shoot dry weight. In summer shoot dry weight was significantly higher than in winter. Due to the high yeild, commercial use of the S5 solution and the cv. Gaviota is recommended.