Genotypic Diversity Affects Age Structure of Tiller and Rhizome of Leymus chinensis Population, But Not Age Structure of Bud

The effect of genotypic diversity on the age structure and bud bank of the Leymus chinensis population has not yet been demonstrated. This experiment was designed to study the age structure of the tiller, rhizome, and bud of L. chinensis at genotypic diversity levels of 1, 2, 4, 8, and 12. A total of 64 communities were established in this experiment, following the principle of randomized block experimental design. The results indicated that genotypic diversity had a significant or obviously significant effect on the cumulative length of rhizomes of 2a and 4a, dry matter accumulation of rhizomes of 1a and 2a, tiller number of 1a, tiller productivity of 3a, but had no significant effect age structure of buds. As the levels of genotypic diversity increased, the proportion of the cumulative length of rhizomes with 4a decreased and then increased, and dry matter accumulation of rhizomes with 1a and 2a gradually increased while the number of tillers with 1a gradually decreased, when the gradient of genotypic diversity increased. At the 1, 2, 4, 8, and 12 genotype diversity levels, the number of tillers, the cumulative length of rhizomes, and dry matter accumulation in rhizomes and buds were all age structures of expanding type. However, tiller productivity was an expanding or stable age structure at levels of 1, 2, 4, 8 genotypic diversity, while it was a declining age structure at the 12 genotype diversity gradient. An appropriate genotypic diversity is conducive to maintaining the growth and stability of the age structure of L. chinensis population, but too high a gradient of genotypic diversity can have a negative impact on the population age structure. This study provided that an appropriate number of genotypic diversity contributes to the stability of the population.