Alleviating phosphorus stress of Chile ancho pepper (Capsicum annuum L. 'San Luis') by arbuscular mycorrhizal inoculation

Chile ancho pepper (Capsicum annuum L. 'San Luis') is a primary source of vitamin C in the Mexican diet. It is important to select indigenous mycorrhizal fungi from Mexico that will utilize nutrients and water more efficiently in the production of this commercially valuable, native crop. In a greenhouse study, Chile ancho pepper plants were either non-inoculated (NonAMF), or inoculated with arbuscular mycorrhiza (AMF): Glomus fasciculatum, or a mixed species inoculum from Mexico (ZAC-19) containing Glomus albidum, Glomus claroides and Glomus diaphanum. Under reduced phosphorus (P) conditions, AMF enhanced plant vegetative and reproductive growth. Growth of AMF plants at low P was comparable with NonAMF plants at moderate P. At low P, only plants inoculated with ZAC-19 had greater leaf tissue P than NonAMF plants, while both groups of inoculated plants had greater leaf tissue P at moderate P fertility. AMF plants generally had greater Fe, Mn, Zn and Cn, but lower N and K (ZAC-19) than NonAMF chile ancho plants. Formation of extraradical hyphae was greatest in ZAC-19 at low P, and was reduced at higher P levels. This corresponded with a 2.9 fold reduction in spores recoverable in soil by ZAC-19 at high P; however spore production and development of extraradical hyphae by Glomus fasciculatum was not affected by P fertility. At low P, C. fasciculatum had greater arbuscule and vesicle formation than ZAC-19. While both AMF isolates enhanced vegetative and reproductive growth of chile ancho under reduced P conditions, G. fasciculatum was generally more effective than ZAG-19.