Effect of Shading on Incidence of Black Rot Disease and Yield Quality of Broccoli in Humid Tropical Regions of Thailand.

ABSTRACT

The study was carried out in the experimental location of Department of Plant Science, Faculty of Natural Resources, Prince of Songkla University, Thailand, from April to June, 2012. Split-plot in randomized complete block design was used in this experiment with four replications. The broccoli plants under the shading had the lowest incidence of black rot disease (14.48%) which was significantly lower than the full sunlight (76.91%). There was a positive impact of the shading on yield quality of the broccoli. The Yok Kheo had the highest head length and diameter (39.13 cm and 12.11 cm, respectively) when planting under the shading. These results consistent with broccoli total yield, the highest total yield was obtained from the Yok Kheo under the both shading and full sunlight (10.92 t.ha-1 and 8.29 t.ha-1, respectively), followed by the Green Queen under the shading (6.21 t.ha-1). Therefore, the appropriate variety for planting during dry season in humid tropical regions of Thailand was the Yok Kheo and Green Queen because its total yield per hectare was higher than of the Top Green and they also had higher quality of head.