Arbuscular Mycorrhizal Fungi Increase Growth of Cocoa Seedlings Applied with Papuan Crandallite Phosphate Rock

Abstract

The mycorrhizal inoculation, consisting of none mycorrhizal, indigenous mycorrhizal from cocoa rhizosphere in Manokwari, and Mycofer from Bogor Agriculture Institute. Papuan Crandallite Phospahte Rock was five consisting of 0, 0.5, 1.0, 1.5 and 2.0 g P2O5.seedling-1. Cocoa seeds of F-1 Upper Amazone Hibrid were collected from the Indonesian Coffee and Cocoa Research Institute. The seedlings were grown in polybags with Ultisol acid soil obtained from Jasinga, Bogor. The seedlings were grown for four months under 60 % shading net. The results showed that increasing phosphate rock dosages in the mycorrhizal inoculated seedlings resulted in linear increase of shoot dry weight and P uptake by 50.14% and 64.88%, respectively; and this was lower than the indigenous mycorrhizal inoculation which increased shoot dry-weight by 66.30% and P uptake by 65.45%. Whereas shoot dryweight and P uptake of the non-mycorrhizal seedlings increased by 73.56% and 121.94%, respectively. Mycofer inoculants were found to be much more effective in increasing shoot dry-weight by 127.55% and P uptake by 45.16% than that of the indigenous mycorrhizal, which increased by 96.97% and 21.29% in shoot dry-weight and P uptake, respectively at phosphate rock dosage of 2.0 g P2O5.seedling-1 as compared to the non-inoculated seedlings.