Effect of different planting dates on growth and yield of three broccoli hybrids. (Brassica oleracea var.italica).

Abstract

The present study was conducted during the 2024/2025 growing season in the agricultural fields of Kalar Horticultural Station in Sulaymaniyah province to evaluate three hybrids grown at different planting dates and their effects on some growth and yield of broccoli )Brassica oleracea var. Italica (on some growth and yield of broccoli plant. This study identifies optimal planting dates and hybrids to boost broccoli yield and quality. It promotes sustainable practices, supports food security, and enhances farmer incomes. Despite challenges in broccoli cultivation due to suboptimal planting practices and limited research, farmers lack guidance on optimal planting times and hybrids. This study examines planting dates and hybrid effects to offer practical solutions for improved yield and quality in Sulaymaniyah Governorate/Iraq. Thereby, this research seeks to establish the ideal planting period and select the most appropriate broccoli hybrid for effective cultivation under the agroclimatic conditions. In this experiment, a complete randomized design (CRD) with three replicates was used. The first factor included Three broccoli hybrids, V₁: Wisdom, V₂: Hana, V₃: Hapa were grown at three planting dates, D₁: 1_st September, D₂: 15_th September and D₃: 30_th September, The findings demonstrated notable disparities, with first date (1_st September) exhibiting superior performance, giving a plant height of (40.48 cm), leaves per plant (17.06 leaves plant^-1), Leaf area (409.71 cm²), Chlorophyll content in leaves (72.26  SPAD), Flower disc diameter (17.22 mm), flower disc weight per plant (512.93 g plant^-1), and the total yield of tubers (61.46 tons. ha^-1). The combined effect of two factors, namely planting dates and hybrids, and it is worth noting that the interaction between the first date and hybrid wisdom, had a significant effect on all vegetative growth and yield parameters, resulting in the highest plant height (cm), number of leaves (leaves per plant^-1), leaf area, chlorophyll percentage, flower disc weight and total yield (t ha^-1). Interaction. Based on these results, it can be concluded that the planting date (1_st September) and broccoli hybrid Wisdom (V₁) can be successfully grown in the agro-climatic conditions of Iraq. The results show that planting date significantly impacts broccoli yield, while hybrid choice does not. The interaction between hybrids and planting dates is also insignificant. Thus, selecting the optimal planting date is more crucial for maximizing yield than choosing a specific hybrid variety. Future research may investigate additional hybrids, environmental factors, and multi-season data to optimize planting schedules and broccoli yield, with climate modeling enhancing strategies.