Adaptability and Multi-trait Evaluation and Selection of Castanopsis hystrix Families in Yong'an

The progeny of superior trees of Castanopsis hystrix was determined in Yong'an，which is located in the central subtropical climate zone. The adaptability，cold tolerance，growth traits and shape of the 9-year-old C. hystrix families experimental forest were investigated，analyzed，comprehensive evaluated and selected in 2022. The results showed that the C. hystrix families could better adapt to the environmental conditions in the experimental area. The young forest could withstand the short-term extreme low temperature of -5 ℃. The preservation rate was high and the growth was well. The nine indexes，tree height，diameter at breast height，volume，clear bole height，trunk straightness，trunk bifurcation，lateral branch thickness，lateral branch density and lateral branch angle，among the families tested showed very significant differences，and had great variation and high heritability. The coefficient of variation of 9 indexes reached 18. 22%～36. 67%，and the heritability reached 73. 82%～87. 90%. 13 excellent families including GW36、HX5、A312、HS12、HX2、GW31、GW33、A318、HC23、PX03、A309、HS16、HS11 were selected through joint screening of multiple traits. The average genetic gains of tree height，DBH，single tree volume，height under branches，trunk straightness，trunk bifurcation，lateral branch thickness，lateral branch density and lateral branch angle reached 11. 41%，10. 90%，30. 33%，20. 31%，3. 80%，3. 22%，8. 64%，6. 57% and 5. 15% respectively，compared to the group average. The results provided a basis for expanding the cultivation range of C. hystrix and the popularization of improved varieties.