Abstract:

【Objective】 This study aimed at establishing and optimizing S-SAP system of apple, exploring the possibility of using S-SAP system to distinguish apple bud sports, lay a foundation for distinguishing and utilizing of apple bud sports at DNA molecular level. 【Method】 The primary S-SAP system was established using Fuji, Hanfu and Gala. Thirty-two primer combinations were screened according to band number variability and polymorphism. The effects of DNA restriction enzyme digestion, PCR amplification and silver stained method on S-SAP analysis of apple were studied. Eight Delicious bud sports were analyzed by S-SAP with six primer combinations. The SIMQUAL program of NTsys-pc2 software was adopted to calculate similarity coefficient. The cluster analysis was performed using UPGAM method, and the dendrogram was generated by Treeplot program. 【Result】 The optimum S-SAP for apple was as follows: Total DNA extracted with modified CTAB method. The total genome DNA was cut using MseⅠ/PstⅠdouble digests. The Taq DNA polymerase from Fermentas was used to perform PCR amplification. The selective PCR products were separated by 6% denatured polyacrylamide gel and the different fragments were detected by modified mild alkali method. Six S-SAP primer combinations that are suitable for apple cultivar were screened, and the LTRP1/Mtcc primer combination presented polymorphic bands in Red Spur Delicious, Starking Delicious and Xinyuanshuai. The similarity coefficient of the analyzed materials ranged from 0.88 to 0.98. Eight Delicious bud sports could be grouped into four distinct families based on similarity of 0.93. 【Conclusion】 Ty1-copia-based S-SAP system was established and six S-SAP primer combinations that are suitable for apple cultivar were screened, and the Delicious bud sports could be differentiated by LTRP1/Mtcc primer combination.

Key words: Malus domestica, S-SAP, Delicious bud sports