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 v itamin C in the Mexican diet. It is important to select indigenous mycorrhi zal fungi from Mexico that will utilize nutrients and water more efficientl y in the production of this commercially valuable, native crop. In a greenh ouse study, Chile ancho pepper plants were either non-inoculated (NonAMF), or inoculated with arbuscular mycorrhiza (AMF): Glomus fasciculatum, or a m ixed species inoculum from Mexico (ZAC-19) containing Glomus albidum, Glomu s 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 p lants inoculated with ZAC-19 had greater leaf tissue P than NonAMF plants, while both groups of inoculated plants had greater leaf tissue P at moderat e P fertility. AMF plants generally had greater Fe, Mn, Zn and Cn, but lowe r N and K (ZAC-19) than NonAMF chile ancho plants. Formation of extraradica l hyphae was greatest in ZAC-19 at low P, and was reduced at higher P level s. This corresponded with a 2.9 fold reduction in spores recoverable in soi l by ZAC-19 at high P; however spore production and development of extrarad ical 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 chi le ancho under reduced P conditions, G. fasciculatum was generally more eff ective than ZAG-19.