Variation in seed and kernel oil characteristics of wild Litsea cubeba influenced by major ecological factors across southern China
摘要
Litsea cubeba is an important industrial plant valued for its pericarp essential oil and kernel oil. However, variation in seed traits and kernel oil characteristics among wild populations and their relationships with ecological factors remain insufficiently understood. Wild germplam from 21 provenances across eight provinces in southern China was evaluated for seed traits, kernel oil content, and fatty acid composition, and variance analysis, correlation and path analysis, and multivariate ecological analyses were used to characterize phenotypic diversity and examine its associations with environmental variables.
ResultsAnalysis of variance showed that the investigated provenances differed significantly in seed traits and kernel oil characteristics (P < 0.05). Provenances ZJ-LY and SC-KJ exhibited relatively high kernel oil content (≥ 35%), whereas YN-XC, GZ-ZY, and SC-KJ showed higher seed yields (SY, ≥ 1000 g.tree−1). In addition, kernel oil from Yunnan provenances was characterized by relatively high lauric acid content (C12:0, ≥ 60%). Variance partitioning analysis revealed that provenance effects accounted for the majority of variation in seed and kernel oil characteristics. Seed and its kernel oil yield showed greater diversity than its oil content and components. Based on the RDA analyses, annual average relative humidity, annual average rainfall, soil pH, soil maximum water-holding capacity, soil total potassium, soil water content, and longitude were identified as the main environmental correlates of seed and kernel oil characteristics. Greater kernel oil accumulation was associated with higher annual minimum temperature, higher soil total potassium, and higher latitude, whereas less favorable fatty acid composition was associated with higher soil water content and longitude; in addition, greater C12:0 accumulation was associated with higher annual maximum temperature and higher soil water content.
ConclusionsThese findings reveal substantial variation in seed traits and kernel oil characteristics among wild L. cubeba populations in southern China. Provenances ZJ-LY and SC-KJ are promising candidates for breeding programs targeting high kernel oil content. Moreover, the identified associations of kernel oil accumulation and fatty acid composition with annual minimum temperature, soil water status, and soil nutrients provide useful guidance for germplasm selection and cultivation management.