Abstract:

【Objective】Camellia chekiangoleosa is a high-quality woody edible oil tree species found in the mountains of southern China. To provide a reference for the genetic evaluation of germplasm resources and selection breeding of C. chekiangoleosa, we analyzed the genetic variability of the seed and fruit traits of C. chekiangoleosa in the main distribution areas and its correlation with geographical and ecological factors. 【Method】Eight traits of C. chekiangoleosa seed and fruit from six representative producing regions in Jiangxi Province, Zhejiang Province and Fujian Province were measured. Multiple methods, such as Duncan’s multiple comparison, Shannon-Wiener diversity index (H'), phenotypic differentiation coefficient (V_ST), and correlation analysis were used for statistical analysis. 【Result】The peel thickness of C. chekiangoleosa was 0.31-2.43 mm, with an average of 1.19 mm, and the fresh seed yield was 3.02%-48.63%, with an average of 20.54%. The degree of variation of the traits of C. chekiangoleosa was in the following order: seeds per fruit > weight per fruit > thousand seed weight > fresh seed rate > peel thickness > fruit height > fruit diameter > fruit shape index, and all the traits were significantly different among and within the producing regions (P < 0.01). In the Wuyishan region, the weight per fruit was the largest (average 106.50 g) and the peel thickness was the thickest (1.46 cm), while the fresh seed yield was the lowest (only 16.53%). Xiapu had the highest fresh seed yield (average 23.68%) and the smallest thousand seed weight. The fruit shape index and thousand seed weight were the largest in Leping. The largest variation coefficient of weight per fruit was in the Dexing production region, reaching 39.82%, while the smallest was in the Wuyishan region (only 26.66%). The largest variation coefficient of fresh seed yield was in the Wuyishan region (31.42%), while the smallest was in the Kaihua region (22.54%). The largest coefficient of variation of thousand seed weight was of Dexing origin (30.55%), while the smallest was of Xiapu origin (24.03%). The largest coefficient of variation of single fruit number was in the Leping region (43.74%), while the smallest was in the Kaihua region (23.63%). The traits with a small degree of variation are fruit shape index, fruit diameter and fruit height, and the coefficients of variability of their traits were mostly concentrated between 10% and 15%. In general, the coefficients of variations of seed and fruit traits of C. chekiangoleosa in the six producing regions were in the following order: Dexing > Leping > Wuyuan > Wuyishan > Xiapu > Kaihua. The average Shannon-Wiener diversity index of seed and fruit traits was 1.885 0. Fruits and seeds had high phenotypic diversity in the Dexing and Leping regions areas, and their diversity indexes were 1.949 7 and 1.948 7, respectively. The Shannon-Wiener index of each trait was 1.627 6-1.949 2, among which the highest was seeds per fruit and fresh seed yield, with diversity indexes of 1.949 2 and 1.944 1, respectively. The average phenotypic differentiation coefficient of the eight traits was 35.31%, indicating that the individual variation in the different regions was the main source of the overall variation in seed and fruit traits. The genetic clustering results of various producing regions reflected the kinship of the producing regions, and the fruit and seeds from the Wuyishan area, with a high altitude, were grouped separately, showing the differentiation of seed and fruit traits in high-altitude environments. There was a significant positive correlation between peel thickness and altitude and thousand seed weight and precipitation, indicating the adaptability of C. chekiangoleosa to the environment. 【Conclusion】This study comprehensively analyzed the variation in seed and fruit traits of C. chekiangoleosa in six producing areas. The eight seed and fruit traits were rich in variation among and within the producing areas; among them, the economic traits such as weight per fruit, fruit diameter, fresh seed yield and peel thickness varied greatly. The Dexing and Leping production regions had higher genetic diversity among the six production regions. The variation within populations is the main source of overall variation in the seed and fruit traits. The genetic clustering was consistent with the origin. The Wuyishan area at high altitude was grouped separately, owing to the significant positive correlation between peel thickness and altitude and between thousand seed weight and precipitation, indicating the effect of environment on the seed and fruit traits of C. chekiangoleosa. This study provides a reference for the breeding of specific traits of C. chekiangoleosa in different production regions.

Key words: Camellia chekiangoleosa, seed and fruit traits, different producing regions, variation