Author(s): Karuna Phular, Rajesh Sharma, HS Ginwal and VK Varshney

Abstract: In recent years, trends in plasticity of sex expression in conifers, particularly in gymnosperms has become a very intriguing subject for research. However, due to the limited research on this subject, the mechanisms underlying unpredictable gender expression remain unknown. Cedrus deodara, predominantly characterized as monoecious and occasionally dioecious, exhibits irregular intervals in cone production, with certain populations yielding seeds after three to four years. This unpredictable reproductive behavior is influenced not only by climatic factors but also by physiological factors, the specifics of which are yet to be elucidated. The present study aims to unravel the role of biochemical factors affecting periodic cone production in Cedrus deodara. Three distinct sites namely, Cheog forest in Theog, and HFRI Campus forest in Shimla, Himachal Pradesh and Chakrata range, Uttarakhand, each representing a pure stand of the species were selected and 300 trees at each site were marked for recording reproductive behaviour of the species. Selection criteria were based on the reproductive age of Cedrus deodara, as it attains maturity when it reaches a height of 19 to 20 meters. Our findings revealed that Cedrus deodara exhibits subdioecious behaviour, characterized by the occurrence of four basic sex forms such as male trees, female trees, monoecious trees, and neutral trees. Additionally it was also found that individual trees demonstrated change in their expression of sex during each reproductive cycle. Samples from trees showing uncertainity in their expression of gender were collected for exploring the effect of total carbohydrate content and total protein content on this pattern. We found that the allocation of energy resources like carbohydrates and proteins were directly proportional to the production of seeds, the previous year.

DOI: 10.33545/26174693.2024.v8.i3b.693