Diversity Analysis of Tomato Cultivars Based on Coefficient of Parentage and RAPD Molecular Markers

Genetic diversity analysis provides information on the genetic base of the gene pool of released genotypes. The objectives of this study were to assess the diversity of tomato cultivars and breeding lines released from North Carolina State University based on their coefficient of parentage (COP) and RAPD markers, and to estimate the contribution of ancestors to these tomato cultivars and breeding lines. The COP analysis revealed that a single ancestor Walter constituted 25.17% of the North Carolina tomato gene pool followed by Blazer (11.57%) and Fla. 2153 (6.29%). Walter was used in developing 30 lines, whereas Blazer and Fla. 2153 were used in developing 29 lines each. The highest COP value (0.828) was between Summit and Monte Verde, indicating that they were the most similar lines. Similarity coefficients based on the RAPD molecular markers ranged from 0.461 to 0.935, with an average of 0.77. The similarity coefficient of NC3Grape with NCEBR8 was the lowest (0.461), whereas it was the highest (0.935) between NC1CS and NC946. On the basis of molecular data, first and second principal components accounted for 78% and 3.3% of the total variation, respectively. A significant positive correlation (r = 0.19, p = 0.04) existed between two similarity matrices based on the RAPD and the pedigree. This information may be useful for selecting the parents in breeding programs, particularly to widen the genetic base for designing future breeding strategies.