Elite selections of rambutan (Nephelium lappaceum L.) for different economic attributes from Kerala, India

From a large population of natural variability of rambutan (Nephelium lappaceum L.), growing in the homesteads of entire Kerala state (India), a preliminary selection for desirable economic traits was done. Ten elite types from the selection were characterized to serve as a basis for specific locations and thereby promote cultivation of this exotic fruit in Kerala. Fruits were harvested from the different growing tracts from May to September 2015, coinciding with the ripening stage, and they were assessed for all morphological and biochemical characters in addition to sensory evaluation. Elite types were characterized on the basis of size, aril thickness and weight, attachment of aril to seed, juiciness, sweetness and texture of aril. Among the ten collections, six belonged to the shape oblong (Col. 016, Col. 020, Col. 052, Col. 053, Col. 061 and Col. 096), three to the shape globose (Col. 015, Col. 023, Col. 042) and one to the shape ovoid (Col. 021). Five collections (Col. 020, Col. 021, Col. 023, Col. 052 and Col. 053) were weighed above 40 g. The attachment of aril to seed was very weak in four collections (Col. 021, Col. 023, Col. 042, and Col. 052), medium in two collections (Col. 061 and Col. 096) and strong in four collections (Col. 015, Col. 016, Col. 020 and Col. 053). Juicy types were also identified in Col. 015, Col. 020 and Col. 061. TSS of seven collections were ranged above 20 degrees Brix (Col. 015, Col. 016, Col. 021, Col. 023, Col. 042, Col. 053 and Col. 061). Total sugar ranged from 13 to 18.4%, ascorbic acid from 26.2 to 45.45 mg 100 g-1 and acidity ranged from 0.51 to 1.4%. Fruits from Col. 021 and Col. 023 were more accepted by panellists because of their better fruit weight, TSS and easy detachment of aril from the seed. This study has immense practical relevance in terms of identifying very promising elite selections which can be turned into promising cultivars in near future.