Analysis of genetic diversity in pear germplasm using morphological traits and DNA markers

Variability among 47 pear genotypes was evaluated for characters like vegetative, reproductive and fruit traits. Among three pear groups, hard pear group was found earliest in flowering, semi-soft pear strains were observed with maximum fruit length, breadth and weight, whereas soft pear had the maximum number of fruits per spur. The fruit characters showed significant variation among three groups with maximum TSS in semi-soft pear strains and highest acid content in hard pear strains. Genetic divergence among these genotypes was also estimated using simple sequence repeats (SSR) marker. Thirteen SSR primer pairs amplified 733 bands in 47 genotypes with the average of 15.7 bands per genotype. On the basis of SSR data, the 47 genotypes clustered into four major groups with similarity coefficient of 65 per cent. The dendrogram based on five morphological markers showed 10 per cent similarity coefficient. The set of microsatellite markers used in the present study provided a positive assessment of the ability of SSR markers in producing unique DNA profiles and established discrete identity of pear genotypes, which, otherwise was not possible using only morphological traits.