Abstract:

In order to compare the performance difference of young stand of half-sib families of Catalpa bungei in Enshi, the seedlings bred with natural Catalpa bungei seeds collected in Enshi were used as materials for afforestation. By measuring the growth, chlorophyll content, and photosynthetic characteristics of different half-sib families, the fuzzy function was used to comprehensively evaluate the difference among these half-sib families. The results showed that the difference in diameter at breast height (DBH) among different families did not reach a significant level (P>0.05), while the difference in tree height reached a significant level (P<0.05), which was mainly related to the excessive planting density. The difference in leaf chlorophyll content among different families reached a highly significant level (P<0.01). Different families showed different light intensity adaptability. The light saturation point of ‘No. 7’ and ‘No. 54’ families both exceeded 1700 μmol/(m²·s), and they had good adaptability to strong light; the maximum net photosynthetic rate of ‘No. 8’ family reached 23.24 μmol/(m²·s), with great photosynthetic potential; ‘No. 11’ and ‘No. 8’ families had relatively good low light adaptability; and ‘No. 7’ and ‘No. 8’ families had relatively high dark respiration rate and active metabolism. Tree height, leaf chlorophyll content, light saturation point, the maximum net photosynthetic rate, light compensation point and dark respiration rate were all positively correlated with DBH. The comprehensive evaluation ranking of the families was ‘No. 8’> ‘No. 54’> ‘No. 9’>‘No. 7’ > ‘No. 12’>‘No. 11’, and ‘No. 8’family had a great potential for breeding.

Key words: Enshi, Catalpa bungei, family, evaluation