Genetic Variation and Clonal Diversity of the Two Divergent Types of Clonal Populations of Leymus chinensis Tzvel on the Song Liao Steppe in the West of Northeastern China

Abstract

Abstract:The genetic variation and clonal diversity of two divergent types (grey-green and yellow-green) of clonal populations of Leymus chinensis Tzvel at 14 loci were compared. Total gene diversity (H T ) and the coefficient of genetic differentiation (G ST ) were all higher for the yellow-green type (H T = 0.270; G ST = 0.186) than for the grey-green type (H T = 0.250; G ST = 0.157) of L. chinensis. Rare alleles usually occurred as heterozygotes rather than homozygotes and significant deviations from Hardy-Weinberg equilibrium were found only at a few loci. This indicated that these two types of populations were mainly out-crossing. Clonal diversity, evenness of clones, and mean clone size were not significantly different between the two types. We found that differences between the clone size and genetic variation of the yellow-green type of populations occurred with different climate and habitat population groups. However, for the grey-green type of populations, these genetic variations decreased under conditions of different climate and habitat population groups.

The genetic diversity of perennial Leymus chinensis originating from China

“…In this study it was also found that the grey-green accessions had more variation than the yellow-green accessions, as indicated by a wider scattering of the grey-green group in the PCO analysis ( Figure 2). This was supported by the results of Cui et al (2000) but not those of Wang et al (2005). This discrepancy was most likely related to limited number of loci, with nineteen putative loci in ten enzyme systems in the work of Wang et al (2005).…”

“…Cui et al. (2000) and Wang et al. (2005), however, demonstrated that there was a stable genetic difference between the two types and indicated that the result of Zhang et al.…”

“…(2005). This discrepancy was most likely related to limited number of loci, with nineteen putative loci in ten enzyme systems in the work of Wang et al. (2005).…”

“…Zhang et al (1992) reported that L. chinensis populations in the Songnen Steppe of north-eastern China had two divergent types based on colour, and concluded these two types of L. chinensis were due to morphological traits instead of genetic discrepancy by undertaking an analysis with peroxidase and esterase. Cui et al (2000) and Wang et al (2005), however, demonstrated that there was a stable genetic difference between the two types and indicated that the result of Zhang et al (1992) was imprecise owing to the limited number of isoenzymes used. Based on the characterization in this study, a clear and significant difference (P < 0AE05) between the grey-green type and yellowgreen type was observed.…”

“…Cui et al (2002) investigated nine natural populations of L. chinensis, collected from the Songnen Plain, using fifteen RAPD primers, showed that the yellow-green populations possessed fewer amplified fragments and had a lower proportion of polymorphic loci than the grey-green populations, indicating that the level of genetic diversity in the yellow-green type was lower than that in the grey-green type. However, Wang et al (2005), who surveyed forty grey-green populations and twenty yellow-green populations of L. chinensis with an analysis of fourteen loci from ten allozymes, concluded that the total gene diversity and the coefficient of genetic differentiation were higher for the yellow-green type than for the grey-green type. Liu et al (2004), using thirty-one RAPD primers from five accessions, discovered a significant positive correlation between genetic differentiation and geographical distance, although a few populations with a close geographical distance were not aggregated together because of a small-scale ecological difference in their habitats.…”