Although the majority of horticultural crops are mycorrhiza-dependent, the role of arbuscular mycorrhizal (AM) inoculation in plant production has been neglected in high-input agriculture. Field application of a commercial inoculum mix of Glomus spp. was tested in spice pepper (Capsicum annuum L. var. longum), cv. Szegedi, cultivation. With polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP), differences in small subunit ribosomal RNA genes were used to characterize groups of arbuscular mycorrhizal fungi (AMF) with respect to effects of mycorrhizal inoculation on an indigenous AMF population. The AMF inoculant was able to establish in the rhizosphere of pepper plants and mycorrhizal inoculation increased yield of spice pepper by more than 65% compared with the non-treated control plants. Having relatively high root colonization in the control, non-inoculated treatment indicated high presence of indigenous populations of AMF in the field soil. Although the inoculation affected structure of the resident AM fungal community, it did not influence the composition of AMF associated with pepper roots significantly.
Ildikó Hernádi, Zita Sasvári, Jana Albrechtová, Miroslav Vosátka and Katalin Posta
Andrea Quintana, Jana Albrechtova, Tom Davis, Robert J. Griesbach and Rosanna Freyre
Wild Anagallis monelli has blue or orange flowers. Hybrids with red flowers were developed at the Univ. of New Hampshire. Orange is due to pelargonidin, but delphinidin and malvidin can also be present; red is due to delphinidin and malvidin; and blue is due to malvidin only. In this study, blue and orange wild diploid accessions were used to develop four F2 populations (n = 46 to 81). In three populations, segregation ratios supported a previously proposed three-gene model for flower color in this species (P> 0.01). In the fourth population, white flower color was obtained in addition to blue, orange, and red. Molecular studies of genes in the anthocyanin pathway using a candidate gene approach are in progress. In a separate F2 population, blue, violet, lilac, and red flower colors were obtained. One hybrid per color was studied on three replicate plants. Cells with vacuoles containing anthocyanins in upper and lower petal epidermis peels were counted in five flowers per clone using light microscopy (M = 200×). Blue and red hybrids had mostly blue and red cells, respectively, on both surfaces. Lilac and violet hybrids included cells that were blue and intermediate (containing both red and blue) on both surfaces, and also had red cells on the lower epidermis only. Violet hybrids had more blue cells on the upper epidermis than the lilac hybrids. Anthocyanins were determined by HPLC for each petal epidermis in the four flower colors. The blue hybrid had only malvidin in both upper and lower epidermis, and the red hybrid had mainly delphinidin in both surfaces. Lilac and violet hybrids had small amounts (2% and 2.5%, respectively) of delphinidin on upper surfaces, while lower surfaces had 25% to 33% delphinidin.