Evaluation of transplanting effect on growth and yield in some broccoli (Brassica Oleracea L.) cultivars as second crop after rice havesting under Guilan climatic condition

Broccoli (Brassica Oleracea L.) is a winter season vegetable crop grown in many countries. Broccoli contains all the essential vitamins, mineral nutrients, amino acids and it has antioxidant and anticancer activity. Vegetables play a major role in daily human diet and they are required for maintaining of good health. Broccoli is one of the leading vegetables in the world. The selection of suitable planting dates and varieties is crucial for successful cultivation during rainy season. Fore this reasone, this experiment was performed to evaluate the effects of transplanting dates and broccoli varieties on their growth and yield.

This experiment carried out in 2017 - 2019 cropping seasons as split plot based on randomized complete block design with three replications in Rasht (Guilan province) climatic condition, Iran. Three transplanting dates (August 29, October 7 and November 15), four broccoli cultivars (Agassi RZ, Heraklion, Aquiles and Romanesco) comprised experimental treatments, as main and sub plot, respectively.

In this experiment, the effect of variety, transplanting date and the interaction effect between transplanting dates and variety was significant for all measured characteristics such as cordon weight, cordon yield, cordon diameter, plant height, leaf number per plant, leaf length and diameter and stem diameter. Results of this study showed that the highest cordon weight (800.82 g), cordon yield (33.36 t/ha), cordon diameter (31.42 cm), leaf length (57.06 cm) and diameter (26/69 cm) and stem diameter (6.30 cm) were obtained in Heraklion cultivar in response to August 29 transplanting date. But, greatest plant height (47.70 cm) and leaf number per plant (27.41) were observed in Aquiles cultivar and August 29 transplanting date. In addition, Romanesco broccoli after Heraklion cultivar showed superiority to other cultivars for all studied agronomic traits. There were positive and significant correlation between cordon yield and all measured characteristics including cordon weight, cordon yield, cordon diameter, plant height, leaf number per plant, leaf length and diameter and stem diameter.

In this experiment, delayed transplanting date, related to broccoli variety caused to a sever decrease in cordon yield. It seems that, delayed transplanting date could reduce cordon yield due to the decrease of plant photosynthesis capacity in broccoli plants. Hence, based on results of this experiment, early transplanting (August 29) after harvesting of rice crop and land preparation (second cropping) and Heraklion broccoli cultivar could be recommendable in order to enhance cordon yield per unit area under Guilan climatic condition.