In situ characterization of tamarind (Tamarindus indica L.) fruit and spotting sweet tamarind types in Palakkad gap of Kerala

Kerala, a humid tropical southern state, is the third largest producer of Tamarind (Tamarindus indica L.) in India. This tree spice is an important livelihood option for the rural society, especially in Palakkad district which is the lead producer of tamarind in the state with a few accepted primitive cultivars, viz. 'valanpuli', 'madhurapuli' and 'thenpuli'. A survey was conducted to identify the fruit variability and document the sweet tamarind types of Palakkad. This study revealed the variability and weight of 30 fruits was seen to be the most indicative variable of tamarind in Kerala. The pod length varied from 5.28 to 23.41 cm and fruit weight from 4.83 to 43.40 g. Hierarchical clustering on principal component analysis resulted in six clusters. The clusters I, IV and V represented collections with fruit weight more than 20 g. Box plot diagrams revealed the high real pulp value in sample KTJ 162 (9.57) and high fruit length in KTJ 44 (21.68 cm). Among 113 collections, 18 samples were collected as perceived sweet types based on local enquiry. In the scatter plot between total soluble solids and ratio between total soluble solids and total titrable acidity, two samples were spotted as sweet types with acidity below 8%. Further molecular characterization and systematic crop improvement programmes are required for conserving the eroding gene pool of tamarind in Kerala and to develop sweet types for commercial production.