Superior Clones Of Populus Nigra Comparative Trial

Poplar is one popularly valueable plant in Henan Province. Undoubtedly, it is of great significance to make improvent in enriching its varieties and enhancing its yields, quality and resistance to various unfavorable natural forces.105 superior clones have been carefully selected form home and abroad, and were planted in typically different climatic areas in Henan Province so that a clone Experimental Forest war successfull created with reference to Zhonglin46(39).In the process of selecting and breeding,we attach much importance to those clones that grow fast, those that have strong resistance to and those with a higher rate of srrival. A synehetical evaluation on superior clones was made in this thesis in light of their heghts,diameters,volurnes,resistance and rate of survival reysectirely.By a careful contrast and comparison, four new findings are eventrally achieved in our present study.Firstly, Populus nigra 13 grows well everywhere in Henan Province,while Populus nigra 38 and Populus nigra 32 can live well only in the southern areas and Populus nigra 35 in the northern areas only.Secondly, Populus nigra 38 has the advantage of a high resistance to Tetranychus and Anoplophora glabripennis(Mostch).Thirdly, poplars height diameter and volume the job of predicting can be successfully carricd out according to its unit length.Fourthly, differences can be seen concerning their respective photosyntetic rate, transpiration rate, water fluctuating efficiency. The volatility of water efficiency is correlated to trees diameter. In good conditions the two are significantly positive correlated while in poor conditiors, Negative correlated.