Leaf and Fruit Trait Diversity of Rambuttan at Field Genebank of Fruit Research and Development Institute, Horana, Sri Lanka

Abstract

Rambutan (Nephelium lappaceum Z.) is on the commercially import tropical fruit crops grown in Wet and Intermediate Zone in Sri Lanka. Malavana Special is the only locally selected officially released variety by the Department of Agriculture. Hence present study was carried out to find the fruit and leaf trait diversity of selected 30 diverse accessions with 3 recommended varieties (AC11-Malayan Yellow), 56 (Malayan Yellow), AC62,AC64,AC65, AC66, AC99,AC 1 00, AC 1 03, AC1 05, AC1 08, AC1 1 0, AC 1 1 4 (Malayn Red) AC I 1 5, AC 1 2 1, AC724,AC 1 32(Javan), AC 1 3 5(Javan), AC 1 39, ACr44, AC149, AC300, AC301, AC74(RV6), AC80, RV1, RV10, RV11, RVl3, RV9) at field gene bank of FRDI, Horana. Sri Lanka. Rambutan accessions were characterized using 18 fruit traits and 11 leaf traits to identifr distinguishing characteristics of accessions from recommended varieties ('Malwana Special,' 'Malayan Yellow,' 'Malayan Red') and to identiff promising accessions in breeding program. Descriptive statistics were used to explain general diversity of germplasm and Principal Component Analysis (PCA) (Minitab 17, 2010) and cluster analysis was done to identiff the clustering pattern of accessions in different heterotic groups. Evaluation of 33 accessions revealed significant genetic variability, especially in fruit haii and rachis length. The studied accessions were clustered in 5 clusters based on fruit traits. Cluster 2 consisted with accessions with the highest Brix value (sweethess) and flesh thickness. Accessions were grouped in to 3 clusters based on leaf traits. Cluster 2 consisted of accessions with leaf structures better suited for efficient light capture. Importantly, two accessions, RV6 and RV11, showed distinct characteristics compared to the 'Malwana' reference variety. RV6 was unique with its obovate leaf shape, dark red rind, and acidsweet taste. RV11 featured a reddish-orange rind, thicker/fleshier arils, high Brix value, and fewer leaflets. These unique and desirable traits position RV6 and RV11 as strong candidates for future breeding programs and potential commercrahzalton.