Variation analysis on chlorophyll fluorescence and growth traits of Catalpa bungei clones

To find the variation characteristics of chlorophyll fluorescence and growth traits of Catalpa bungei clones, 29 clones of C. bungei were taken in the research and 11 profiles of the clones were measured and analyzed, including tree height (H), basic diameter (BD), diameter of breast height (DBH), space between burls(SBB), leaf length (LL), leaf width(LW), leaf area(LA), stipe length (SL), fresh leaf mass per area(Flma), leaf mass per area(Lma), and parameters of chlorophyll fluorescence(Fv/Fm). The results showed that the curve of diurnal variation of Fv/Fm shaped “V”, reflecting the selfprotection mechanisms and variation of solar energy utilization efficiency of C.bungei clones. The average of H, BD, DBH, Flma, Lma and Fv/Fm of C. bungei clones were 4.58 m, 50.98 cm, 39.31 cm, 0.042 g/cm2, 0.014 g/cm2 and 0.836 respectively. The averages of LL, LW and SL all exceeded 20.00 cm, indicating that the leaves of C. bungei clones were much bigger. The analysis of variance showed that there was a remarkable difference in 11 characteristics among the clones (sig＜0.001). Seven coefficients of variation of phenotype were more than 10%, coefficient of genetic variation was closely to that of phenotype variation. The repeatability of 10 in 11 indices was higher than 0.800, indicating that C. bungei clone variation was strongly controlled by genetic factors. The results of phenotypic correlation showed that there were significant correlations among the growth target. Principal component analysis showed that the cumulative contribution rate of initial three principal components of the 11 characteristics in C. bungei clones was 71.23%. The contribution rate of the first principal components Y1 were the highest (35.92%), including H, BD, DBH, etc.; the second ones Y2 were the trait such as Flma, Lma and Fv/Fm, and the third ones Y3 were about LL and LW, etc. Based on the analysis of colligate evaluated, 2-2, 008-1, 2-8, 9-1, 1-1 and 4001 were selected as excellent clones when the selection rate was 20%. The genetic gains of three clones on H, DBH were 11.23% and 9.58%. Remarkable difference in characteristics of biomass and chlorophyll fluorescence can provide basis for future research in C. bungei.