Drought screening in cocoa (Theobroma cacao L.) based on root and shoot parameters
M Boomiga, V Jegadeeswari
Cocoa (Theobroma cacao L.) belongs to the family Malvaceae originated from Amazon forests and highly sensitive to drought or water deficit condition. This study was conducted with 35 cocoa single plant selections collected from Thondanuthur and Vedapatti regions of Coimbatore districts and the screening was done in Coconut nursery, Department of Spices and Plantation crops, Horticultural College and Research Institute, Tamilnadu Agricultural University, Coimbatore. The seedling of 3 months old were used for the screening with two different moisture conditions viz., 100 percent field capacity and 50 percent field capacity. After imposition of treatments, observations on root and shoot parameters were taken after 45 days. Among the 35 plus trees, under 50% FC Tc (Vedapatti) 48 recorded more number of roots, maximum fresh weight, maximum whole plant fresh weight and highest root volume. Tc (Vedapatti) 2 recorded increased fresh root weight and dry root weight under stress condition. Tc (Vedapatti) 86 recorded high dry shoot weight and whole plant dry weight under 50% FC when compared to control. Baby santhini (2017) also reported the same in case of root characters evaluated under different stress condition in cocoa. Similarly, the seedling of plus trees, Tc (Vedapatti) 2, Tc (Vedapatti) 48 and Tc (Vedapatti) 86 was also recorded less difference in root recorded under different irrigation regime (50 and 100 per cent respectively). Hence, these plus trees can be further evaluated in the field condition to screen for drought tolerance.