Sex ratio and spatial distribution of <i>Cycas panzhihuaensis</i> in <scp>Sichuan Panzhihua</scp> cycad <scp>National Nature Reserve</scp>

Abstract The sex ratio of the endemic gymnosperm Cycas panzhihuaensis was investigated within a 1 ha permanent plot in the Sichuan Panzhihua Cycad National Nature Reserve, with a total of 1034 individuals. The study was based on the potential sex‐determining gene MADS‐Y. The research analyzed the sex dimorphism and spatial distribution of male and female individuals. The findings revealed the following: (1) The coning sex ratio of C. panzhihuaensis in the study plot varied across different years. The genotypic sex ratio was 1:1 ( p &gt; 0.05), indicating no significant gender bias in the population. (2) Female individuals exhibited larger stem diameter and nutrient leaf length compared with male individuals ( p &lt; 0.05), while there was no significant difference in stem height and number of nutrient leaves between female and male populations ( p &gt; 0.05). (3) The spatial distribution of male and female individuals within the plot revealed a clear clustering pattern at a smaller scale and a random or uniform distribution at a larger scale. The spatial association between male and female populations was positively correlated on smaller scales and uncorrelated on larger scales. These results suggest that the genotypic sex ratio of the C. panzhihuaensis population in the study plot is balanced. Additionally, there is a significant clustering effect in spatial pattern, which may be associated with its spatially limited pollination mechanism and seed dispersal primarily influenced by gravity.