Effects of planting dates and varieties on growth and yield of broccoli during rainy season

Abstract

Broccoli (Brassica oleracea var. italica) is one of the most popular vegetable crops in many countries of the world as its nutritional importance. It has the most exacting climatic and cultural requirements, which limit its commercial production to a few favored locations. In Thailand, broccoli has been expending in recent years and amount of increasing production. It is best planted in the North where the weather is cool or in the Northeast during winter season. The South has tropical climates and raining all year round, but farmers can produce broccoli during early summer by using the heat-tolerant varieties. Although the broccoli is highly priced and still wanted by consumers in the rainy season, the farmers might not choose to grow as the problems with low productivity. Thus, the selection of suitable planting dates and varieties is crucial for successful cultivation during rainy season in the South. The experiment was performed to evaluate the effects of planting dates and broccoli varieties on their growth and yield responses during rainy season. Four broccoli varieties: 'Top Green', 'Green Queen', 'Yok Kheo' and 'Special' were plated for six planting dates: July, August, September, October, November and December at Prince of Songkla University, Thailand, between July, 2011 and January, 2012. Split-plot in a randomized complete block design was used in this experiment with four replications. This study showed that four broccoli varieties had highly seedling survival rates of 70.31-99.22% when planting in July-December except 'Special' of 54.68% when planting in August. 'Yok Kheo' had plant diameter of 67.54-75.24 cm when planting in July and December, not significantly different from 'Top Green' planting in July, August and November of 69.15-71.24 cm and 'Green Queen' in July and September of 68.69-68.88 cm. The highest total yield was obtained by 'Yok Kheo' when planting in July and December of 7.73-7.87 t.ha-1. It is anew interesting hybrid variety producing higher yields than'Top Green' which is popular variety planted in southern Thailand. Therefore, 'Yok Kheo' is the suitable variety for production during rainy season in southern Thailand because it provides high growths and yields, especially in July and December. © 2013 Science Publication.