Genetic divergence among inbred lines in Cucurbita moschata from China

Knowledge of genetic divergence among inbred lines is essential for cross breeding. The objectives of this study were to (1) analyze the level and character of genetic diversity in C. moschata accessions, and (2) classify the genetic divergence among inbred lines in C. moschata to assist in selection of parent genotypes for genetic improvement. Twenty agronomic characters were investigated and rich diversities were demonstrated among 39 inbred lines of C. moschata from China. Various degree correlations among these characters made it possible to summarize the diversities of the twenty characters into 3 major principal components: leaf, fruit and flesh quality factor. Forty-one inbred lines of pumpkin were clustered into four groups based on principal component data, which is more distinct for classification that based on the original data of the 20 characters. However, parent inbred lines whose hybrids displayed significant heterosis in fruit weight, soluble solid and fruit shape were located in different clusters or sub-clusters based on standardized original data. It was suggested that genotypes in the same clusters may represent members of one heterotic group.

Research highlights▶ The investigated data showed a large range of variability of morphological characters among the 39 inbred lines of C. moschata. ▶ There were various degree correlations among morphological characters, making it possible to summarize the diversities of the 20 characters into 3 major principal components: leaf, fruit and flesh quality factor. ▶ The classification based on principal component data was more distinct than that based on standardized original data, because it extracted the major information of genetic divergence among inbred lines and ignored the minor information. ▶ However, the cluster based on standardized original data was more valuable than that based on principle component data in cross breeding for classifying heterotic group, because parent inbred lines whose hybrids displayed significant heterosis in fruit weight, soluble solid and fruit shape were generally located in different clusters or sub-clusters based on standardized original data.