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DIVERSITY STUDIES AND UTILIZATION OF INDIGENOUS
VESICULAR- ARBUSCULAR MYCORRHIZAL FUNGI
ISOLATED FROM CITRUS PLANTATIONS 1
J I. Yago, JM Sison, SG Mateo, KB Rivera,
MP Gonzales, EI Bustamante 2
ABSTRACT
The study was conducted to collect and taxonomically identify existing mycorrhizae in citrus
plantations in Kongkong, Muta and Malabing Valley in Kasibu, Nueva Vizcaya. It aims to analyze the
diversity of indigenous Vesicular Arbuscular Mycorrhizal (VAM) fungi, to investigate the in-vivo compatibility
and colonization of each VAM species in citrus root system; to study the nutrient uptake of citrus seedlings
inoculated with indigenous VAM; and to determine the growth characteristics of citrus seedlings inoculated
with indigenous VAM.
The sieving pan method was used for the isolation process. Taxonomic identification revealed that
four (4) genus of indigenous VAM fungi were isolated namely Gigaspora, Scutellospora, Acaulospora and
Glomus. VAM fungi isolated from Kongkong Valley showed the most diverse population of mycorrhizal fungi
revealing 11 known species and three (3) unknown species presumed to be of the genus Glomus, Gigaspora
and Scutellospora. Five (5) known species and one (1) unknown species of the genus Gigaspora, were
observed in Muta Valley. Four (4) known species were observed to be present in Malabing Valley and the
most dominant was Gigaspora gigante.
Diversity analysis found that diversity index value in Kongkong Valley was the highest (0.92) compared
to Muta (0.53) and Malabing Valley (0.26). Species richness value was higher in Kongkong (7.85) which
is located in lower elevation/areas. S value in Muta Valley recorded with a value of 5.54 while in Malabing
Valley was 2.53. Repetition index in Kongkong Valley recorded with a value of 0.56 followed by Muta Valley
with a value of 0.69 and 0.63 for Malabing Valley.
Macronutrients were significantly enhanced when citrus seedlings were inoculated with VAM fungi
compared to non-inoculated citrus plants. Results show that mycorrhizal fungi’s penetration to the root
system is evident for symbiotic association. Thus, citrus growth characteristics were significantly affected.
Keywords: Fungi, Citrus, Diversity
The potential of vesicular-arbuscular
mycorrhizal (VAM) fungi to enhance plant
growth is well documented. VAM fungi can also
facilitate plant uptake of phosphorus (Graham,
1982). There is increasing evidence that VAM
fungi affect citrus root growth independent of
phosphorus nutrition (Peng et al., 1993). VAM
fungal stimulation of citrus root growth may be
beneficial for nursery or stock for out planting
since their limited root system makes seedlings
vulnerable to desiccation (Davies and Albrigo,
1994.) Alternately, increased below ground
carbon allocation of VAM inoculated plants can
also result in plant growth depression if not
compensated by increased carbon acquisition.
Much of the research documenting
the effects of VAM fungi on citrus growth and
physiology is based on differences between
plants inoculated with a single isolate of VAM
fungi (usually Glomus intraradices Schenck
& Smith) and non-VAM inoculants. However,
citrus orchard soils contain communities of
VAM fungi rather than a single species (Nemec
et al., 1982) and several or all of these species
might colonize citrus roots at the same time.
1
1st Place, Best Paper-Research Category, 21st CVARRD RSRDEH Symposium
2
Faculty-researchers, Nueva Vizcaya State University
1