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Açaí (Euterpe oleracea Mart., Arecaceae), a palm tree native to the Amazon basin, faces problems associated with its initial development, such as uneven germination and slow growth. The objective of this study was to evaluate the initial biometric development of açaí palm seedlings as a function of inoculation, or co-inoculation, with plant growth-promoting microorganisms. The experiment was carried out in a nursery and the treatments consisted of inoculation, or co-inoculation, of seedlings with arbuscular mycorrhizal fungi (Glomus sp. and Gigaspora sp.), diazotrophic bacteria (Azospirillum brasilense) and beneficial microorganisms©, applied in the rhizosphere of the seedlings. At 90 days after sowing, there were no statistical differences between treatments for any of the individual variables. However, hierarchical cluster analysis revealed the existence of four clusters. Shoot height (25.0 cm), leaf insertion height (12.0 cm) and root length (12.1 cm) tended to be slightly lower in non-inoculated seedlings (cluster 1). Inoculation of mycorrhizal fungi tended to promote the best development of seedlings, especially verified through root length (18.3 cm), but forming a cluster with diazotrophic bacteria (cluster 4). On the other hand, co-inoculation of mycorrhizae and diazotrophic bacteria tended to result in the lowest means, especially for shoot dry mass (0.20 mg) (cluster 3). The mix of beneficial microorganisms©, alone or co-inoculated, always formed a single cluster (cluster 2). Inoculation of açaí palm seedlings affects their initial development, but does not promote significant growth and development in a period of 90 days. [ABSTRACT FROM AUTHOR]

The arbuscular mycorrhizal fungi (AMF) are keyorganisms for maintenance of plant biodiversity in agroecosystems. There is an increasing interest in changes of the microbiological properties in the rhizosphere by its practical and environmental relevance. This research aimed to evaluate the occurrence of AMF in the establishment of fruits under organic management, and to compare them with an area of native vegetation in semiarid Ceará. Soil samples were collected from 0-10cm layer in June, September and December 2010 in different areas. Number of spores, and diversity of AMF were quantified. The dominance of Glomus spores was confirmed in all the areas. [ABSTRACT FROM AUTHOR]

Guava culture stands for an important fruit-growing business in Brazil, with a greater and greater market. But, since 1989 severe damages to the culture caused by the nematode Meloidogyne enterolobii, have been reported. One the alternatives to solve this problem is the use of rootstocks with resistance to this nematode. This research aimed at the molecular characterization, with RAPD markers, of Psidium accessions susceptible to be utilized as rootstocks for the commercial guava trees. 30 primers were tested, from which 19 supplied distinct results for the amplification. The primers generated 163 polymorphic marks, resulting into a mean of 8,6 polymorphic bands per primer. The cluster analysis was performed per species, the accessions of Psidium sp presented the formation of two groups, one formed by A-UFLA accession and the other subdivided into four subgroups, that is, the accession with increased genetic distances, A-Ufla, resistant to M. enterolobii, A-Ufla4 and A-Ufla5, both susceptible to the nematode in issue, all collected in Lavras-MG with a similarity of about 66%. In the cluster analysis of the thirteen accessions of P.cattleyanum, it was possible to found the formation of two great groups. One made up by three accessions susceptible to M. enterolobii (A-20.2, A-10.1 and A-9.2) and the other group formed by ten accessions. The accessions grouped together according to the region of origin in six groups, the most divergent being that native to region of Lavras - MG, with 0.65 of similarity, where the genetic distances ranged from 0.88 to 0.65. The thirteen accessions of P. guineense, all susceptible to M. enterolobii, namely, 12 coming from Recife and one proceeding from Pelotas (A-14.1), grouped themselves together and two groups with similarity ranging from 0.59 to 0.83. As to the diversity study among the guava tree accessions, the greatest genetic distances were detected between the accessions G.P.S and G-Ufla with 0,71 Lavras-MG. [ABSTRACT FROM AUTHOR]