Effectiveness of recurrent selection in Akebia trifoliata (Lardizabalaceae) breeding

Akebia trifoliata is perennial and deciduous vines, its fruit, seed, stem and root have been used in Chinese herbalism for at least 2000 years. As a high-value medicinal, the A. trifoliata should be exploited and domestication is underway as edible fruit crop. In the present study, a wild seedlings population and a three-generation selected population have been evaluated and characterized for a set of morphological traits in order to evaluate the effectiveness of recurrent selection method in achieving selection progress, maintaining genetic variability, and increasing the potential for selection of superior genotypes in A. trifoliata. The result showed that the fruit weight increased 33.16% which ranged from 237.67 to 598.54 g with an average of 310.86 g in the selected population. The leaf of A. trifoliata in the selected population became much larger range from 91.24 to 170.43 min with an average of 117.33 mm, the leaf length, leaf width and petiole length increased 15.72%, 7.91% and 9.33%, respectively. Correlation analysis showed most of the measured characters are highly correlated each other. The principal component analysis (PCA) indicated that the first five components can explain 83.90% of the total variance. Cluster analysis revealed two distinct clusters among the selected population. The present study showed the effectiveness of the recurrent selection method when applied in A. trifoliata breeding, although some refinements in the selection program could further improve its efficiency.