Table of Contents
ISRN Agronomy
Volume 2012, Article ID 148042, 7 pages
http://dx.doi.org/10.5402/2012/148042
Research Article

Differences in Arbuscular Mycorrhizal Fungi among Three Coffee Cultivars in Puerto Rico

1Departamento de Biología, Pontificia Universidad Católica de Puerto Rico, 2250 Boulevard Luis A. Ferré, Ponce, PR 00717-9997, USA
2Departamento de Biología, Universidad de Puerto Rico, Río Piedras, P.O. Box 23360, San Juan, PR 00931-3360, USA
3Center for Forest Mycology Research, Northern Research Station, USDA Forest Service, P.O. Box 1377 Luquillo, PR 00773-1377, USA

Received 30 April 2012; Accepted 4 July 2012

Academic Editors: D. Chikoye and H. P. Singh

Copyright © 2012 Ligia Lebrón et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Mycorrhizal symbiosis is important for growth of coffee (Coffea arabica), but differences among coffee cultivars in response to mycorrhizal interactions have not been studied. We compared arbuscular mycorrhizal (AM) extraradical hyphae in the soil and diversity of AM fungi among three coffee cultivars, Caturra, Pacas, and Borbón, at three farms in Puerto Rico. Caturra had significantly lower total extraradical AM hyphal length than Pacas and Borbón at all locations. P content did not differ among cultivars. Extraradical hyphal lengths differed significantly among locations. Although the same morphotypes of mycorrhizal fungal spores were present in the rhizosphere of the three cultivars and total spore density did not differ significantly, frequencies of spore morphotypes differed significantly among cultivars. Spore morphotypes were typical of Glomus and Sclerocystis. Levels of soil nutrients did not explain differences in AM colonzation among cultivars. The cultivar Caturra is a mutant of Borbón and has apparently lost Borbón’s capacity to support and benefit from an extensive network of AM hyphae in the soil. Widespread planting of Caturra, which matures earlier and has higher yield if fertilized, may increase dependence on fertilizers.