关键词: 崇州枇杷茶, 野生大茶树, 染色体, 核型

Abstract: [Objective] The purpose of the article was to understand the evolution and variability of six different types of Chongzhou loquat tea plants and provide some cytological basis for its origin, evolution and genetic relationship by karyotype analysis. [Method] Six different types of wild loquat tea from Sichuan Chongzhou, named as class A, B, C, D, E, F, respectively, were used in karyotype analysis. We used shoots primordia of loquat tea by the wall degradation hypotonic method. [Results] Chromosomes of six types of loquat tea were small chromosomes and varied morphologically. The karyotype formulas of them are 2n=2x=30=22m+8sm. It was the original type 2A according to the Stebbins standard. [Conclusion] According to symmetry of karyotype, average arm ratio, and karyotype asymmetry index, it is concluded that the class F and class A tea are the original types, while the E-class tea are newly evolved. The present cytological evidence supported that the Sichuan Chongzhou loquat tea since both they appeared original symmetry of their karyotype, but also contained more asymmetry and evolutionarily derived karyotypes, showing a gradual evolutionary trend.

Key words: Chongzhou loquat tea, wild tea plants, chromosome, karyotype