Abstract:

【Objective】 Sweetpotato varieties with high carotene content have higher value of healthy care to human. This paper aims to improve the breeding efficiency of special varieties with high carotene content by using the method of combining molecular markers and agronomic traits to evaluate and screen the parents. 【Method】 Cluster analysis was carried out to identify and screen the excellent parents by utilizing phenotypic results of the agronomic and characteristic traits, RAPD and ISSR markers of 15 parents and their descendants by group crossing. 【Result】 A great variation in two important characteristics of the carotene content and the storage root yield was observed among different parent materials. A negative correlation was found between the factor of the carotene content and both factors of fresh roots and dried root production. The most significant positive correlation between the carotene content of parents and that of their descendants was calculated, with the coefficient value of 0.7932 **. The phenotypic correlation calculated based on the agronomic characteristics of all the trial materials was not agreed with the known genealogy, while that based on the molecular markers data showed better result. ISSR markers could amplify 13.8 bands per primer on average, in which the rate of polymorphic loci was 89.6%. RAPD markers amplified 9.4 bands per primer, in which the rate of polymorphic bands was 74.46%. 【Conclusion】 A large genetic variation of carotene content was found among the parents. For analyzing the genetic diversity of sweetpotato, the method of molecular marker was found to be better than morphological traits. ISSR marker was thought to be more efficient than RAPD markers. The results from the molecular markers and agronomic traits analysis can supply a valuable theory reference for the selection of parents for breeding of new varieties with high carotene content.

Key words: sweetpotato, carotene, selection of parents, RAPD, ISSR, cluster analysis