Objective In order to provide theoretical basis and data support for improving the yield and quality of Pinus koraiensis cones, this paper studies the variation and correlation of seed, cone traits and nutritional components of P. koraiensis at different developmental stages.

Method In this study, P. koraiensis cones were used as materials, and the samples from different developmental stages were used to observe the morphological changes, meanwhile, determine phenotypic traits and the nutrients during the developmental cones. By analyzing the variation and correlation among the indicators, this study aimed to find the key development period of nutrient accumulation.

Result (1) The whole developmental cycle of P. koraiensis cones was 15 months, the rapid growth period of cone development was from mid-May to early July of the second year, and the rapid growth period of seed development was from June 20 to early July of the second year. Seed kernel showed a rapid growth period after July 20 of the second year. (2) The shape of cones was long oval in the first year and oval in the second year. The seed kernels were colorless and transparent at the early stage, and pale yellow and triangular with cones mature. (3) When the P. koraiensis kernel was mature, the moisture content, oil content, protein content and total polysaccharide content were 20.46%, 70.96%, 104.71 mg/g and 3.48 mg/g, respectively. (4) Correlation analysis showed that cone length, cone width, cone mass, seed length, seed width and 100-seed mass were significantly positively correlated (P < 0.01), oil content and moisture content of kernel were negatively correlated (P < 0.01), and it was positively correlated with total polysaccharide content (P < 0.01).

Conclusion The growth and development of Pinus koraiensis fruit, as well as the dynamic changes in nutritional components provide a scientific basis for the selection of excellent clones for P. koraiensis cones, which is of great significance for improving the quality of P. koraiensis nuts and ensuring their high and stable yield.