Evaluation of excellent individual plant traits and cold tolerance of Camellia osmantha in Guilin area

In order to screen out the excellent single plant of Camellia osmantha with strong cold resistance suitable for planting in Guilin area of Guangxi, the excellent plants were selected in Lingchuan County of Guilin, and the fruit economic characters and cold resistance of the excellent plants were evaluated.After natural low temperature ( below 0℃ ) stress, the relative conductivity ( REC ), malondialdehyde ( MDA ) content, peroxidase ( POD ) activity, catalase ( CAT ) activity, soluble sugar ( SS ) content, chlorophyll content, chlorophyll b content, comprehensive chlorophyll content and free proline ( PRO ) content of the selected superior individuals were determined. Based on principal component analysis and cluster analysis, the phenotypic characteristics and cold tolerance of superior plants were comprehensively evaluated. The results showed that there were significant differences in phenotype and cold tolerance among superior plants, and there were significant differences in single fruit weight, seed number, fresh seed rate, thousand seed weight and fruit shape index among single plants, among which MJ2206 was a large seed type. The difference of POD activity, CAT activity and PRO content among individual plants was extremely significant, and the difference of REC was significant. The difference of malondialdehyde ( MDA ) content, soluble sugar ( SS ) content, chlorophyll content, chlorophyll b content and comprehensive chlorophyll content was not significant. According to the results, the superior plants MJ2205, MJ2207 and MJ2216 with better fruit economic traits and strong cold tolerance were selected.