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ABSTRACT. Capsicum species are frequently described in terms of genetic divergence, considering morphological, agronomic, and molecular databases. However, descriptions of genetic differences based on anatomical characters are rare. We examined the anatomy and the micromorphology of vegetative and reproductive organs of several Capsicum species. Four Capsicum accessions representing the species C. annuum var. annuum, C. baccatum var. pendulum, C. chinense, and C. frutescens were cultivated in a greenhouse; leaves, fruits and seeds were sampled and their organ structure analyzed by light and scanning electronic microscopy. Molecular accession characterization was made using ISSR markers. Polymorphism was observed among tector trichomes and also in fruit color and shape. High variability among accessions was detected by ISSR markers. Although the species studied Characterization of Capsicum species present a wide morphological and molecular variability, this variability was not reflected in anatomical features.

Determination of Optimal Conditions for PCR-RAPD Analyses in Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae) ABSTRACT-PCR-RAPD has been widely used for genetic analysis in several organisms. However, due to complex interactions among the components of the PCR reaction it is unlikely that a single amplification condition can be suitable for all situations. In order to determine the optimum conditions for using PCR-RAPD in taxonomical analyses of the genus Atta, the following factors were tested: concentrations of MgCl 2 , DNA, BSA, cycling programs and methods of DNA extraction, using Fractional Factorial Design and Central Composite Design. DNA extraction methods had little influence on PCR-RAPD reactions, while the cycling programs showed the largest effect. The MgCl 2 concentration was less important than the amount of DNA used in the reaction. Using cycling program P 2 , a significant improvement in the number of DNA fragments was achieved when MgCl 2 concentration was increased to 3.0 mM and the BSA and DNA concentrations were reduced from 0.1% to 0.05% and from 2 to 1 ng/ µl, respectively. The optimum conditions for PCR-RAPD with Atta specimens obtained in this study were: 25 µl reaction with 10 mM Tris-HCl (pH 9.0), 3.0 mM MgCl 2 , 50 mM KCl, 100 µM of each dNTP, 0.2 µM of primer, 1.0 U of Taq polymerase, 25 ng template DNA (extracted by Cheung's method) and BSA 0.05%, using the amplification program which consisted of 3 min at 94ºC, 3 min at 35ºC, followed by 40 cycles of 1 min at 94ºC, 1 min at 36ºC and 2 min at 72ºC, and a 5 m final extension at 72ºC.

-This work was carried out in order to identify Bemisia tabaci (Genn.) biotypes present in the state of Paraná and to determine their geographical distribution and host plants. About 50 adults were collected in several host crops, weeds and ornamental plants in North, Northwest, Northeast, West and Central areas of the state, from January to May, 1998 and 1999. The species were identified by means of RAPD-PCR, using the primer Operon H-16. Whitefly populations were detected mainly from February on, in both years, seldom achieving more than one adult per leaf. The insect was found in only 66% of the sampled areas. Bean golden mosaic was almost never observed during the pe-

High quality DNA for molecular studies can be easily extracted from fresh specimens. However, live samples are difficult to keep for long periods thus making their preservation a serious problem, specially when they are collected and transported from remote locations. In order to establish an efficient method to preserve Atta spp. (leaf-cutting ants) for RAPD analysis, six different storage methods were examined: 1) -70°C; 2) 95% ethanol at -20°C; 3) 95% ethanol at 4°C; 4) 95% ethanol at room temperature; 5) silica gel at room temperature; and 6) buffer (0.25 M EDTA, 2.5% SDS, 0.5 M Tris-HCl, pH 9.2) at room temperature. DNA was extracted (Cheung et al., 1993 - modified) and examined after 90, 210 and 360 days of storage. Freshly killed specimens were used as control. DNA yield was measured with a minifluorometer. DNA quality was determined by scanning photographs with a densitometer and the integral of the scan was calculated for DNA of size > 9.4 kb. Data were analyzed using a completely randomized split-plot design with four replicates. All methods were efficient to preserve Atta spp. DNA up to 210 days. At 360 days, DNA was degraded only in 95% ethanol at room temperature, which resulted in RAPD profiles with missing bands. Although preservation at low temperatures is recommended for long periods, methods using silica gel and buffer can be considered satisfactory alternatives when refrigeration and transportation are limiting factors.

Páginani-0 em Euealyptu-0 u4ophylla, Salto, SP

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