Study On Early Comprehensive Evaluation Of Acacia Melanoxylon Clones

Early selection is the most important method to clonal selection. The study used11Acaciamelanoxylon clones as research materials, on the basis of identifying and analyzing the differencesof growth traits, their photosynthesis, water physiology and biochemistry, and then studiedcorrelation between the indicators, which was used to evaluation comprehensively of11Acaciamelanoxylon clones. The superior clones with fast growth and high photosynthetic ability andstrong resistance are suggested. The main results were as follows.1. By analyzing growth traits in11Acacia Melanoxylon Clones, we found that these indicesamong different Acacia Melanoxylon Clones were extremely significantly or significant different（sig<0.01）. The average tree height （H） was2.953m, the range was between2.271m and3.98m;The average ground diameter was3.874cm, the range was from2.972cm to5.57cm; the averagecrown diameter was1.834m, the range was between1.49m and2.257m. The repeatabilities ofeach factor were between75.32%and81.23%, showing that the variation of growth traits inAcacia Melanoxylon Clones was highly controlled by genes, as for the result can provide basis forclone selection.2. Eleven Acacia melanoxylon clones leaf traits the results showed: leaf characters hadsignificant difference among clones. Eleven Acacia melanoxylon clones of leaf area range was4.6cm2¹5.20cm2, the maximum value was3.3times of the minimum; specific leaf area thebiggest clones was number32,15.2cm2, was3.3times the minimum value. Leaf index maximumclone was the smallest clone leaf index4.86times. The leaf traits and growth through thecorrelation analysis, in addition to leaf area and crown width had a significantly positivecorrelation, the leaf index and tree height, ground diameter showed no correlation with the crown,there was a positive correlation, but had not reached the significant level.3. The result Chlorophyll indices of11Acacia Melanoxylon Clones showed that Chlorophylla contents, Chlorophyll b contents, Chlorophyll（a+b） contents were extremely significantlydifferent （sig<0.01）, except Chlorophyll a/b. That showed preliminary growth of the differencesbase on physiological differences. Chlorophyll a contents of the range was between1.0325mg·g^-1and2.0865mg·g^-1, Chlorophyll b contents of the range was from0.3134mg·g^-1to0.7903mg·g^-1,Chlorophyll（a+b） contents was between1.4481mg·g^-1and2.8767mg·g^-1. Rank of11AcaciaMelanoxylon Clones were made by Chlorophyll a contents, Chlorophyll b contents, andChlorophyll（a+b） contents, which were general consistent. It preliminarily indicated that threecomponents of Chlorophyll had strong relevance. Combined with the growth, contents ofChlorophyll of clones34，33，36，32，35were high, which were good situation.4. There were highly significant differences in Chlorophyll fluorescence parameters, except for Fm. It further showed that the difference in growth based on the photosynthetic efficiency. Thevalue of Chlorophyll fluorescence parameters F0range from29.27to37.17, PSⅡFv/Fm was from0.844to0.868, PSⅡFv/F0was between5.424and6.584. The value of Chlorophyll fluorescenceparameters PSⅡFv/Fm or PSⅡFv/F0was high in the clones of34,33and36, as far as thechlorophyll content and the growth,which was high chlorophyll content and amount of growth.5. By analyzing the rates of leaf water losing in11Acacia Melanoxylon Clone, it showed thatthere were differences between each other with the advance of the dehydration process. Water lossrate and the time for curve fitting showed that correlation coefficient were above0.8, in part to0.9,which were good. Drought resistance of clones was evaluated by the rates of leaf water losing, theresult showed that clone28,26,34,29,25were superior clones to drought resistanceperformance.6. There were highly significant difference （sig<0.01） in the contents of soluble sugar andsoluble protein. The range of contents of soluble sugar was from0.7628mg·g^-1to12.925mg·g^-1,and contents of soluble protein was between0.0047mg·g^-1and0.0112mg·g^-1.Clones ofbiochemical differences further provided for clonal selection. The content of soluble protein washigh36,28,33,34clones, which were growth amount.7. By the calculation of the physiological and biochemical index of broad sense heritability,in addition to the maximum fluorescence Fm genetic force was small, the remaining charactersheritability were above0.6. It was displayed that the selected indicators could become theevaluation and selection of Acacia Melanoxylon superior clones indications, which were stablyinherited between clones. The correlation coefficient, between the growth, physiological andbiochemical index, showed that the initial fluorescence F0, PSII original efficiency of light energyconversion of Fv/Fm and PSII Fv/F0potential activity significant or highly significant correlatedwith growth traits. Chlorophyll content and biochemical substances both related to fluorescenceparameters, which could be used early evaluation index.8. We used principal component analysis to comprehensively evaluate11AcaciaMelanoxylon clones. The result of principal component analysis displayed that component valuesY1of clones34,33,36,28were positive and high, and it indicated that such as height, crowndiameter, ground diameter, chlorophyll content, PS II original efficiency of light energyconversion and PS II potential activity were high; The second was drought resistance ability, whileprincipal component values Y2of clones28,36and26were high, showing that drought resistanceability was strong; principal component values Y3of clones were34,26,28,29,24and25,revealing that the few clones had high growth potential physiological basis, in addition, showingstrong pre resistance. Basing on the comprehensive score ranking, clones of34,33,36and28were selected excellent clones.