Abstract:

【Objective】 The aim of the experiment is to investigate the genetic diversity and genetic basis of main sesame cultivars in China. 【Method】 SRAP (Sequence-related amplified polymorphism) was used for the analysis of 67 sesame cultivars widely used in China’s sesame major production areas from 1950 to 2007. 【Result】 A total of 561 bands were amplified using 21 SRAP random primer pairs, with 265 of them were polymorphic, resulting a polymorphism ratio of 47.2%. The total bands and polymorphism amplified by each primer pair averaged 26.7 and 12.6, respectively. The average genetic similarity coefficient and genetic distance of the 67 cultivars were 0.9104 and 0.0706, respectively, indicating limited genetic diversity and narrow genetic basis. Comparative analysis on genetic similarity and genetic distance of different classified cultivars showed that the difference of average genetic similarity coefficient and genetic distance between the landraces and cultivars bred through crosses reached a significant level (P=0.01), with the genetic basis of landraces wider than that bred cultivars. The genetic basis of cultivars used in 1990-2007 was more narrow than that of cultivars from 1950 to 1969 and from 1970 to 1989, with the differences of average genetic similarity coefficient and genetic distance reached a very significant level. 【Conclusion】 The genetic basis of main sesame cultivars in China is relatively narrow, and the genetic basis of cultivars developed through crosses in recent years is more narrow than history cultivars.

Key words: Sesamum indicum L., cultivars, SRAP, genetic diversity, genetic basis