ABSTRACT. Mangabeira (Hancornia speciosa Gomes) is a fruit tree of the Apocynaceae family, which is native to Brazil and is a very important food resource for human populations in its areas of occurrence. Mangabeira fruit is collected as an extractive activity, and no domesticated varieties or breeding programs exist. Due to a reduction in the area of ecosystems where it occurs, mangabeira is threatened by genetic erosion in Brazil. The objective of this study was to characterize and evaluate the genetic diversity of 38 mangabeira individuals collected from natural populations in Pernambuco State using inter-simple sequence repeat (ISSR) molecular markers. The ISSR methodology generated a total of 93 loci; 10 were monomorphic and 83 were polymorphic. The average number of loci per (2015) primer was 15.5, ranging from 9 (#UBC 866) to 21 (#UBC 834). The results showed a high level of genetic diversity (0.30), and found that only around 30% of genetic variability is distributed among populations (G ST = 0.29, Ф ST = 0.30), with the remainder (Ф CT = 70%) found within each population, as expected for forest outcrossing species. Estimates for historic gene flow (1.18) indicate that there is some isolation of these populations, and some degree of genetic differentiation.

ABSTRACT

The present work aimed to study the phenotypic and pathogenic diversity of 40 Colletotrichum isolates obtained from mango trees in the Northeast of Brazil and to identify different species of this pathogen, incitant of anthracnose, through the analysis of the ITS sequence of the ribosomal DNA. As for the morphologic and cultural characterization, the colonies of the isolates presented diversity in relation to color and aspec t, being more common the color wh i t e -a s h , c h a ra c t e r i s t i c of C . g l o e o s p o r i o i d e s . E x p re s s i v e variations were not observed in the morphology of the 40 isolates. The conidia were predominantly hyaline and unicellular varying in shape from rod to cylindrical. All isolates produced appressoria of di fferen t s ha pes a nd i n di fferent a mou nt s, a nd 1 0 i sola tes showed setae. In relation to mycelial growth and growth rate the i solat es were cla ss i fi ed i n s even grou p s. gloeosporioides species. The isolates were pathogenic to detached leaves of mango, inducing anthracnose symptoms such as dark l e s i o n s s li g h t l y d e p r e s s e d , a n d p r e s e n t i n g v a ri a t i o n s o f aggressiveness. In the specific identification based on the analysis of the ITS sequence of the ribosomal DNA, 36 isolates amplified with the primer CgInt, specific for C. gloeosporioides and with the primer ITS4. Isolates CM1, CM4, CM5 and CM10 did not amplify product s for non e of the spec ific prim ers, bei ng id enti fied as Colletotrichum spp. The results of this work demonstrate that Colletotrichum isolates obtained from mango trees present large morphophysiologic and pathogenic variability, and also that, possibly exi sts more tha n on e sp ecies of Co llet otr ichu m t hat caus es anthracnose in mango trees in the Northeast of Brazil.exibiram taxa de crescimento >10mm/dia, considerada típica da espécie C. gloeosporioides. Os isolados foram patogênicos em folhas destacadas de mangueira, induzindo sintomas de antracnose, na forma de manchas escuras levemente deprimidas, e apresentando variações quanto à agressividade. Na identificação específica, baseada na análise da seqüência ITS do DNA rib oss omal, 36 is olad os a mpli fic aram com o oligonucleotídeos CgInt, específico para C. gloeosporioides e o ITS4, Os isolados CM1, CM4, CM5 e CM10, não amplificaram produtos para nenhum dos oligonucleotídeos específicos, sendo identificados como Colletotrichum spp. Os resultados desse trabalho demonstraram que isolados de Colletotrichum, obtidos de mangueira, apresentam am pla vari abilida de m orfofisi ológica e p atogêni ca. E qu e, possivelmente, existe mais de uma espécie de Colletotrichum que causa antracnose em mangueira no Nordeste do Brasil.

Malpighia emarginata is cultivated in almost all Brazil and is considered an important agricultural crop. The root-knot nematode Meloidogyne enterolobii has been described as a major threat to this crop, causing great production losses. Due to the scarcity of information about the severity of this parasite in M. emarginata plants in Brazil, this study investigated M. enterolobii resistance of ten M. emarginata genotypes from the active germplasm bank of Universidade Federal Rural de Pernambuco. The experiment was conducted adopting a completely randomized design in a factorial arrangement of 11 x 2 x 5, where M. emarginata cuttings were inoculated with 10,000 eggs in a greenhouse. After 150 days, plants were evaluated for the following parameters: gall index, egg mass index, number of eggs per root system, number of eggs per gram of root, and reproduction factor. The accessions showed different responses depending on host x pathogen interaction, from susceptibility to moderate tolerance. Accessions 027-CMF and 031-CMF were considered tolerant to the nematode and could be of great value in new breeding programs for resistance to M. enterolobii infection.

ABSTRACT. The Neotropical Heliconia genus contains highly diversified plants and up to 220 species have been reported from the north of Mexico to the South of Brazil. Heliconia are cultivated as ornamental garden plants and as cut flowers. All species can be propagated by seeds or vegetatively, through rhizomes. Depending on the species, an individual plant can spread and form large clonal populations. H. bihai L., H. chartacea Lane ex Barreiros, and H. wagneriana Petersen are among the most cultivated Heliconia species. However, they still have undesirable characteristics that could be improved for the international market. This study aimed to characterize 15 half-sib families originating from commercial cultivations, by morphological and molecular markers. The genetic diversity (Ĥ E ), considering all individuals of the three species was 0.103. For H. bihai half-sib families, the value of Ĥ E was 0.242, showing high genetic diversity. The Ĥ E value for H. chartacea was 0.068, indicating low genetic diversity. All individuals of H. wagneriana showed the same band patterns, suggesting that the two parental plants were propagated vegetatively from the same plant and may have undergone some endogamic crossings. These results showed that molecular characterization can differentiate individuals closely related as half-siblings for H. bihai and H. chartacea, despite the low variation observed with morphological descriptors. The high genetic diversity observed in H. bihai half-sibling genotypes can provide valuable resources for breeding programs.