Genetic diversity of indigenous carambola (Averrhoa carambola L.) accessions based on fruit morphometric and biochemical traits.

Genetic variability study is an initial step aiming to the germplasm characterization and conservation of the precious fruit trees for future breeding programs. North-East India is endowed with unique physiography and rich plant genetic diversity, and is blessed with nature’s unique gift for flora and fauna. The present investigation was focused to assess the genetic variability of 25 carambola accessions and to identify the elite types based on fruit morphometric and biochemical parameters from Mizoram, north-east India. The findings underscored a remarkable range of diversity among the accessions viz., fruit weight (29.92–73.25 g), fruit length (66.95–94.35 mm), fruit diameter (38.57–56.27 mm), percent edible portion (84.33–93.33%), seed number (1.67–4.67), juice (33.40-72.32%), TSS (5.10–8.63 °Brix), titratable acidity (0.56–0.78%), reducing sugars (4.09–8.96%), total sugars (7.85–14.23%), ascorbic acid (37.30–48.20 mg 100 g− 1) and sugar: acid ratio (10.90-25.43). Principal component analysis (PCA) showed significant genetic diversity with 82.61% of the total variation by the first four principal components with eigenvalues ≥ 1. Cluster analysis revealed significant diversity and divided the accessions into three clusters A, B, and C. From the results of the present investigation, accessions CS-7, CS-11, CS-9, CS-2, CS-1, and CS-22 have overall superiority in morpho-biochemical characteristics and these may be considered as elite types for use in future breeding programmes. Conservation efforts are urgently required to safeguard the existing genetic diversity for posterity and utilization in improvement programmes.