Morphological and Microsatellite Marker Analysis of Fruit Size and Shape in Selected Accessions and Commercial Cultivars of Capsicum Species in Sri Lanka

Abstract

Chili pepper (Capsicum spp.)is a vegetable crop with medical and ornamental uses. In Sri Lanka, 56% of dried chili is imported annually making it a huge burden to the economy. To improve the chili pepper industry, breeding could be suggested as one of the strategies. With the advancement of Molecular Biology,
breeding is now practiced with marker assisted selection. According to the present knowledge, no such breeding programs are taking place in Sri Lanka. Therefore the objectives of the present study were to characterize the morphology and validate fruit size and shape linked microsatellite markers using an ex situ Capsicum collection in comparison to the commercial cultivars. The accessions and cultivars were established in a greenhouse at Peradeniya, Sri Lanka. Leaf and fruit morphological data were recorded at flowering and fruit maturity respectively. Five microsatellite markers (HpmsE045, CAeMS010, GPMS178, CAMS451 and CAMS493) were used to genotype all 49 accessions using PCR and bands were size separated using polyacrylamide gel electrophoresis. According to the fruit shape, six groups were identified namely Triangular, Elongated long, Elongated short, Spherical sharp-end, Spherical blunt-end and Rectangular. The plant height had a negative correlation with the number of fruits of the plant at first harvest. Number of seeds per fruit and the fruit diameter were significantly associated with the fruit weight (P<0.05). Microsatellite marker analysis revealed 44 alleles explaining very high level of genetic diversity (in the range of 62% to 87%). Out of the 44 alleles, 15 alleles were found to be significantly affecting on fruit size traits and 23 alleles were associated with fruit shape. This validated marker information could be used to plan future breeding programs and genetic studies for chili pepper.

KEYWORDS: QTL, genetic diversity, morphological diversity, chili pepper, Capsicum.