Evaluation of the initial growth of Shorea platyclados wildlings through the application of mycorrhizal biofertilizer under different levels of shading

Abstract

Abstract The obstacles to the propagation of Shorea platyclados involve the uncertain flowering and fruiting seasons, the recalcitrant nature of the seeds, and the dependence on shade for growth. Furthermore, a mutualistic symbiosis, called mycorrhizae, usually exists between the roots and fungi, similar to other species of Dipterocarpaceae. This consequently hinders the regeneration process, which in turn may threaten the sustainability of this species in the wild. Ex-situ conservation using wildings is one of the measures that can be taken to overcome this issue. This study aimed to assess the initial growth of S. platyclados seedlings by administering different amountsof mycorrhizal biofertilizers under varying shade conditions at four and eight weeks of age in the nursery. A randomised complete block design was employed with the dose of biofertilizer as the treatment (0, 2.5, 5, 7 and 9 g/polybag) and shade as the group (0, 50, 60 and 70%). Observations were taken in the nursery at four and eight weeks of age. The observation parameters included the survival percentage, height growth, diameter growth, and vigour of the seedlings. There were significant differences in percentage of survival. Still, significant differences in height growth were observed with different doses of biofertilizer and shading at both four and eight weeks of age. Significant differences in diameter growth were observed with different doses of biofertilizer at both four and eight weeks of age, but not with different shades. No significant differences were observed for seedling vigour with different doses of biofertilizer and shade at both four and eight weeks of age. The optimal amount of biofertilizer was 5 g/polybag, resulting in maximum growth. This was achieved in a shade of 60%.