Analysis on Variation of Growth and Development in Erianthus Population

Erianthus, a perennial C4 grass, is gathering attention as a raw material for cellulosic bioethanol, mainly because it has high potential for biomass production based on its large canopy. During the annual regeneration of the population, differences arise among stocks of the population including disappearance in some cases. In the present study, we investigated the variation in growth and development of stocks in the Erianthus population year by year from the view-point of population ecology. Regardless of the year after planting, stocks with small numbers of stems were frequently observed, while those with large numbers of stems were seldom observed. Such a tendency became more pronounced year by year. In addition, the trend in annual changes after transplanting indicated that the growth variation increased with the canopy development of the population. The relationship between the growth variation and the competitive effect showed that the less the number of stems per stock, the larger the competitive effect. Cultivation of Erianthus over several years suggested that the law of constant final yield may hold. Thinning at an early stage of cultivation may increase the yield and inhibit the increase of growth variation of the stocks in the canopy.