Population characteristics of Poa pratensis cv. Qinghai

Abstract： Poa pratensis cv. Qinghai is palatable forage with strongly cold resistance and drought resistance due to strong root system. An experiment was conducted to determine the dormiens module, root biomass, reproduction and intraspecific competition of population characteristics of Poa.pratensis cv. Qinghai. This study showed the root biomass increased with the increase of growing years, and peaked at the fourth year with 1 014 g/m2 and then subsequently decreased as the growing year increased. The dormiens seedlings and buds was the highest with the number of 185.825.34 and 137.6728.97, and then decreased as the growing year prolonged. The maximum of parent strains was 672.337.74 at the fourth year, indicating that the parent strain firstly increased and then decreased with the increase of growing year. The root biomass could be simulated by y=e7.355-1.939/t（P0.01）and showed a S curve, in which the first year was adaptive period, and the second year was logarithmic, and the periods from third year to fifth year were stable, and the sixth year was recessive. The asexual reproduction of P. pratensis cv. Qinghai was observed at the first and second year, and the sexual reproduction was observed at the third and fourth year. However, reproductive ability of asexual and sexual reproduction reduced when the growing years were over 5 due to pasture degradation.