The Effects of indigenous arbuscular mycorrhizal fungi on growth of selected Carica papaya L. hybrids in Kenya

Abstract

Arbuscular Mycorrhizal Fungi (AMF) are naturally occurring root symbionts and are known to improve the uptake of essential nutrients to host plants, due to their extra-radical hyphae. However, the latent effect of indigenous AMF inoculation on the growth rate of JKUAT and Malkia hybrids, papaya varieties has not been evaluated. The objective of this research was to evaluate the effect of AMF inoculation on the growth rate of papaya varieties, JKUAT and Malkia hybrids, at vegetative stage of growth. The spores were multiplied in a trap culture crop, Sorghum bicolor, for 4 months to obtain the inoculum. Three different treatments were used; AMF inoculum, compost manure and a combination of AMF inoculum and compost manure. The seedlings were replicated 6 times for every treatment and variety and completely randomized design was used. Data was obtained for a period of 20 weeks. The collected data was subjected to one way analysis of variance (ANOVA) Genstat statistical package 15^th edition. Plants that were treated with a combination of compost manure and AMF inoculum were significantly different, p≤0.05, as opposed to other treatments. The Malkia hybrid treated with a combination of compost manure and AMF inoculum (MIC) had the overall better performance. The height of MIC was 39.60 cm and 53.2 cm at 16 and 20 weeks respectively while that of JKUAT hybrid with a combination of compost manure and AMF inoculum (JKIC) was 35.2 cm and 49.3 cm at 16 and 20 weeks respectively. Malkia hybrid with AMF inoculum treatment (MI) was significantly different, p≤0.05, from JKUAT hybrid with AMF inoculum treatment (JKI). The stem girth of MI and JKI was 4.633cm and 4.233cm respectively at 14 weeks. Boosting the soil media with AMF inoculum should be recommended as a routine practice to promote the overall growth of papaya seedlings.