Synchronization of flowering and optimal clonal configuration in primary Schima superba seed orchard

To solve the issues of abundant flowering but low seed-setting rates, which has severely impacted the production of improved seeds and the supply of seedlings from the orchard. research on the synchronization of flowering periods (SFP) among clones in the S. superba seed orchard was conducted to provide reference value for optimizing the clone configuration and achieving abundant seed and fruit production in the orchard.

In 2023, a preliminary study was conducted on 10 representative S. superba clones with high flowering intensity and abundant fruiting. To enhance sample diversity and representativeness, 53 additional clones were included in 2024, resulting in a total of 63 clones. The flowering phenology and flowering synchronization of all tested clones were surveyed and analyzed.

1) The total flowering duration (TFD) for the clones of S. superba ranges from 9 to 19 days, with variations in flowering phenology among different clones; 2) The results of cluster analysis and ANOVA (Analysis of variance) indicated that based on the timing of the first flowering period (FFP), the clones can be divided into three categories. There are extremely significant differences (P<0.01) in flowering periods among different clones: The FFP of the early-flowering clone was on May 3rd, with a TFD of 14.63 days. The FFP of the mid-flowering clone was on May 14th, lasting for a TFD of 14.02 days. The FFP of the late-flowering clone was on May 21st, with a TFD of 13.00 days. 3) Within the seed orchard, approximately 36.9% of the clone combinations have a flowering synchronization index (C) greater than 0.6, while 29.44% of the clone combinations have a C value less than 0.1. Within the annual period, the coefficients of variation for the C value among clones ranged from 61.05% to 240.72% in 2023 and from 37.87% to 164.52% in 2024, respectively. Between years, there are some differences in the C value, but it remains relatively stable overall. The average C value is higher for combinations of clones of the same type compared to combinations of different types, and the average C value for mid-flowering clones is higher than that for early- and late-flowering clones.

Currently, C value of flowering among clones within the seed orchard is relatively low. Therefore, attention should be given to the differences in flowering phenology and flowering synchronization among S. superba clones. Select mid-flowering clones and combinations of similar clones, screen out compatible clones with different provenances and a high C value to plant adjacently, and introduce measures such as artificial pollination to facilitate pollination, thereby enhancing the seed and fruit production and quality in the seed orchard.