Genetic Diversity of 30 Cai-xins (<em>Brassica rapa var. parachinensis</em>) Evaluated Based on AFLP Molecular Data

Abstract

Cai-xin is common Chinese name for Brassica rapa var. parachinensis that is one of very important leafage vegetables in South China. The objectives of this research were to detect genetic diversities of the selected 30 Cai-xins based on AFLP makers as well as to evaluate the feasibilities of AFLP approach for biodiverse study . In this paper, the 25 pairs of AFLP primers were employed to generate 1160 amplified bands, of which 876 bands account for 76% were polymorphic bands The average polymorphism of tested 25 primer combinations reached 80%, the mean of polymorphism information content (PIC) was about 0.0239 and the amount of polymorphic loci was about 85.33%. The parameters of genetic diversity were calculated by the aid of GenAlEx 6.4 software including the number of different alleles (Na) 1.754, the number of effective alleles (Ne) 1.544, Shannon's Information Index (I) 0.472 and He 0.363. The values of genetic distance (GD) and genetic similarity (GS) were 0.112 and 0.895, respectively. Statistic analysis revealed that almost 100 percentage of variation existed within Cai-xins based on AMOVA data. The tested Caixins can classified into four groups at the 0.17 threshold of Nei’s genetic distances by clustering analysis based on UPGMA approach . The present results indicated that the genetic diversity of the tested Cai-xins should be quite low and the genetic variations of Caixins be mostly attributed to within varieties. Whereas we confidentially have conclusions that AFLP approach might be useful, efficiency and accuracy to detect genetic diversity among varieties, landraces and lines of Caixin, especially for those which have close relationship.