Root morphology and root characters of different cocoa (Theobroma cacao L) types at 100 and 50 percent field capacity under water deficit condition

Abstract

The main aim of this study was to screen the root morphology and root characters of different cocoa types at 100 and 50 percent field capacity under water deficit condition at seedling stage. A survey was conducted at Idukki region of Kerala, India and twenty seven plus trees were identified. These twenty seven plus trees were screened for water stress tolerance under glasshouse condition by gravimetric method. With respect to the performance of plus trees, root length under 50% field capacity got increased to 21.15 cm as against 20.51 cm in 100 per cent field capacity. Fresh root weight and dry root weight substantially got increased under water stress. The average root girth of 27 plus trees got increased in stressed condition from 3.70 cm to 3.88 cm. The root volume also followed the same trend (47.28 as against 45.96). The percent of nitrogen is 1.37 in 50 per cent field capacity as against 1.63 in 100 per cent field capacity. The percentage of phosphorous decreased to 0.16 under 50 per cent field capacity as against 0.37 in 100 per cent field capacity. Similarly the percentage of potassium also showed a decreasing trend (1.27 % under 100 % field capacity to 1.06 % under 50 % field capacity). In the present investigation, under water stress condition the root length, number of roots, fresh weight of root and dry weight of root tends to increase compared to the 100 per cent field capacity, indicating the morphological adaptations of roots to survive under water stress condition. Furthermore, under water stress condition, root nutrients tend to get depleted.