Pineapple is one of the most important fruits, with large production in tropical and subtropical regions and great appreciation by consumers all over the world. The pineapple plant has many specific morphological, anatomical and physiological characteristics that determine crucial aspects of pineapple crop management, such as flower induction, water use and vegetative methods of propagation. The use of sexual reproduction of pineapple is restricted to breeding purposes carried out by research institutes looking for new hybrids with improved agronomic characteristics. Seeds are only produced if cross pollination among varieties occurs. Commercially pineapple has to be propagated by vegetative material, an asexual reproduction, without new combinations of genes. Some types of propagules are naturally produced by the plants and called conventional planting material. Its availability and quality depend on many factors, especially cultivar and environment. Management techniques of this material have been continuously developed and will be addressed. In addition to the conventional planting material, which in many situations is not sufficient to assure expansion or at least maintenance of the cultivated area, several other methods of vegetative propagation of pineapple have been studied and made available along the last decades and will also be discussed, involving techniques of stem sectioning, apical growing point gouging and chemical treatment for transformation of flowers into plantlets. Stem sectioning has been especially interesting, as it is mostly done using plant residues available at low cost, and is a rather simple method suited for multiplication and production of disease-free planting material in nurseries. Gouging and chemical treatment are less practiced, but can be applied in ratoon crops, thereby avoiding the loss of the first cycle fruit. Chemical treatment usually results in rather small plantlets, that must be further grown in nurseries before planting them in the field. And finally micropropagation will also be focused, as in vitro production of plantlets is a very important method of multiplication of new pineapple varieties, but this method yet has not been transformed into a common commercial way of pineapple propagation due to the final high cost and to the still high risks of incidence of somaclonal variations among the plantlets produced.

ARTICLES-Molecular characterization of Cassava (Manihot esculenta Crantz) with yellow-orange roots for beta-carotene improvement

Cinco genótipos de abacaxi (Gold, Pérola, Smooth Cayenne, BRS Vitória, BRS Imperial) e quatro novos híbridos (SC x PRI-21, SC48 x PRI-02, PE x SC-73 e PA x PE-01) foram avaliados quanto às suas características físico-químicas. A cultivar 'Gold' apresentou os maiores teores de carotenoides totais (7,82µg g-1) e vitamina C (51,0mg 100g-1), enquanto que a cultivar 'BRS' Imperial destacou-se pelos elevados teores de açúcares redutores (5,12%), açúcares totais (15,23%), sólidos solúveis (18,41°Brix), pH (3,96) e ratio (35,28). Os híbridos SC 48 x PRI-02, PE x SC-73 e PA x PE-01 apresentaram teores de sólidos solúveis, açúcares totais e redutores superiores aos das cultivares Smooth Cayenne, Pérola e BRS Vitória, destacando-se o híbrido PE x SC-73 por apresentar polpa amarela mais intensa, doçura elevada, elevado teor de carotenoides totais e vitamina C, sendo, portanto, um híbrido promissor para substituição de cultivares comerciais.

Avaliou-se a resistência das espécies de Eucalyptus globulus e Eucalyptus nitens inoculadas com um isolado uredinospórico monopustular de Puccinia psidii origininário de plantio de Eucalypstus grandis (UFV-2) em Itapetininga, SP. A avaliação foi realizada aos 12 dias após a inoculação, e quantificou-se a doença por meio de uma escala de notas com quatro classes de severidade da doença (S0, S1, S2 e S3). Em média, aproximadamente 60% das plantas de E. globulus e 50% de E. nitens foram resistentes a P. psidii. A variabilidade intra-específica nos materiais estudados indica ser possível a clonagem de genótipos resistentes para plantio comercial ou para uso em programas de melhoramento genético.