عنوان مقاله [English]
Introduction: Eggplant (Solanum melongena) is a diploid plant (2n= 24). Eggplant cultivated as perennial in the tropics regions and grown as an annual in temperate areas According to the statistics of FAO, the area under eggplant cultivation in Iran were about to 21.3 thousand hectares, with an average yield of 31.4 tons per hectare. Eggplants grow into large plants that causes too much plant canopy, so pruning the plant is a good way to reduce the number of branches, leaves and to increase fruit set. Normally, pruning is not done on the eggplant plant and only 2 plants per square meter could be grown in the field and also greenhouse conditions. However, pruning operations should be performed in greenhouse conditions and plants might be kept with 2 to 4 branches. A study was conducted to evaluate the best method of eggplant pruning in greenhouse conditions in the Netherlands and the plants were pruned into one or two branches. Plants were pruned again from the second branch in different cases including the first, third, sixth and ninth nodes. The results showed that severe pruning had a positive effect on plant conditions and fruitset was better in heavily pruned plants.
Material and Methods: This experiment was conducted in 2018 and 2019 in greenhouse conditions in Varamin city. This area located 40 km from Tehran with an altitude of 1000 meters above sea level, an area of approximately 1500 square kilometers, longitude 50 degrees and 51 minutes, latitude 19 degrees and 35 minutes and the amount of first and second-degree agricultural lands 75 thousand Hectares. The average long-term annual rainfall is 120 mm, and the prevailing wind direction is southeast to northwest. The combined analysis based on a randomized complete block design experiment with three replications conducted and the treatments included three methods of plant pruning (two-branch, three-branch and four-branch). The seeds of Bellen variety planted in culture trays containing enriched peat moss and placed in an environment with a temperature of approximately 27 °C and relative humidity of 80%. After germination of seeds, the ambient temperature decreased to 24 °C during the day and 18 °C during the night. After the seedlings reached 3-4 leaves, they transferred to the main greenhouse. Pruning and guiding the plant on the scaffolding began with the first flower appearing on the meristem axis. All the male branches removed before the mentioned flower and the sub-branches branching from the main axis were allowed to grow above the first flower position. After data collection, data analyzed by SAS software and the means compared by Duncan test.
Results and Discussion: The effect of year on yield and yield components of eggplant were not statistically significant (Duncan 5%). Effect of pruning treatments on yield components, number of fruits in the first cut and early maturity index at 5% level and on total yield, the total number of fruits and number of fruits per plant were also statistically significant at 1% level. Two-branch and four-branch pruning treatments were statistically superior to three-branch pruning treatments, but considering the yield in the first four harvests, two-branch pruning treatment with the production of 5.33 t ha-1, compared to two three-pruning treatments and four branches showed a significant increase. Earliness index of plants that pruning in two, three and four plant branches were 12.21, 9.5 and 8.83%, respectively. The total yield in three pruning treatments of two, three and four branches were 44.45, 46.67 and 49.87 t ha-1, respectively. The results showed that branch pruning had positive effects on eggplant yield and based on the purpose of the research, including early crop production or higher total performance, the type of pruning will be different. Examination of the correlation coefficients of the traits measured in the experiment also showed that the relationship between pruning (branch removal) and yield in both totals (0.69*) and the first four harvests (0.80**) was significant. The correlation between the number of branches and eggplant yield has reported in some other studies nevertheless in some studies has not the different relationship between performance and number of plant branches. In reviewing the performance and diversity of morphological traits of some local varieties of Iranian eggplant relationship between fruit yield and number of fruits per plant were positive and significant.