ABSTRACT. The wild tomato, Solanum pennellii, is an important source of resistance genes against tomato pests. This resistance is due to the presence of acyl sugars (AS), which are allelochemicals that have negative effects on arthropod pests. There are no commercially available tomato cultivars that exhibit significant levels of resistance to arthropod pests. Therefore, this study evaluated resistance to whitefly (Bemisia tabaci) in F 2 and F 2 RC 1 tomato genotypes with high AS levels from a cross between Solanum lycopersicum 'Redenção' and the S. pennellii accession, LA-716. Plants were exposed to B. tabaci biotype B at the pre-flowering stage. In both generations, there were significant, negative correlations between AS content and oviposition preference and nymph development. Whitefly exhibited a lower preference for oviposition and produced fewer nymphs in genotypes with high AS levels and the wild parent S. pennellii than in the low AS-level genotypes and Redenção cultivar, demonstrating that the breeding program was effective in transferring resistance to the F 2 and F 2 RC 1 generations. RVTA-2010-pl#31 and RVTA-2010-pl#94 are promising genotypes that produced materials with high AS levels in the F 2 RC 1 generation (RVTA-2010-31-pl#177 and RVTA-2010-94-pl#381).

The two-spotted spider mite (TSSM) Tetranychus urticae is a polyphagous pest which infests several wild and cultivated species of plants worldwide. To date, this mite is the most deleterious pest attacking the strawberry plant under a protected environment. Exogenously applied salicylic acid (SA) has been found to induce resistance to biotic and abiotic stresses. Morpho-anatomical changes in strawberry leaflets and TSSM preference tests were investigated in response to SA treatment. Plants grown in a greenhouse were foliar sprayed with different concentrations of SA (0 mg · L−1, 25 mg · L−1, 50 mg · L−1, 75 mg · L−1 and 100 mg · L−1). After the third application, certain parameters including the number of glandular and non-glandular trichomes, thickness of leaflet, abaxial cell wall, adaxial cell wall, palisade and lacunous parenchyma and mesophyll were measured using scanning electronic microscopy (SEM). Two-choice and non-choice assays were employed to verify the TSSM preference. Exogenous treatment with SA promoted morpho-anatomical changes in the following parameters, namely: thickness of the leaflets, mesophyll, lacunous and palisade parenchyma, cell wall (abaxial and adaxial) and the number of glandular and non-glandular trichomes in strawberry leaflets. In general, TSSM preferred less leaflets treated with SA compared with the control in a two-choice assay. A lesser number of TSSM eggs and live females were also recorded in leaflets treated with SA compared with the control plants in no-choice assays. The values of the number of eggs and live females correlated negatively with those obtained for the morpho-anatomical traits induced by exogenous SA.

Brazil’s low garlic productivity is attributed, mainly to the lateral shoot growth, a physiological anomaly characterized by early lateral shoot growth of cloves in noble group garlic cultivars. Considering the aforementioned information, the aim was to evaluate the occurrence of lateral shoot growth and productivity characteristics in garlic plants, cv. Chonan, subject to herbicide chemical stress. In order to do so, an experiment was conducted in outlining randomized blocks in a 3x5 factorial scheme, constituted by three herbicides (paraquat 500 g ha-1; ammonium gluphosinate 400 g ha-1 and glyphosate 720 g ha-1) and five subdoses (0, 5, 10, 15 and 20% of the minimum recommended dose of each herbicide). The electron transport rates (ETR) were evaluated after herbicide application, as well as the culture’s morphological and productive characteristics. The chemical stress caused by herbicides paraquat, ammonium gluphosinate and glyphosate in underdoses of 25, 40 and 36 i.a. ha-1, respectively, was efficient in reducing the electron transport rate and the lateral shoot growth of the Chonan garlic cultivar, and also technically viable in increasing the productivity of commercial bulbs.

Knowledge of the combining ability of genotypes, genetic diversity, and heterosis play the paramount role in obtaining double-cross hybrids with high productivity. This study was aimed at evaluating these parameters in tomato genotypes using partial diallel crosses among the commercial single-cross hybrids, which verified the possibility of using double-cross hybrids for commercial purposes. Tomato genotypes included 15 double-cross hybrids, their genitors, and two commercial genotypes as checks. Of the fifteen double-cross hybrids of tomato, two crosses exhibited superiority, such as Aguamiel × Compack and Dominador × Compack, mainly for the total and commercial fruit yields. The phenotypic expression of the trait is controlled by the genes with non-additive effects, whereas the genes with additive effects account for the genotypes of fruit mass, horizontal diameter, vertical diameter, and bunch insertion height. Regarding the genetic diversity, molecular analyses pointed out polymorphism for 79 percent of the evaluated loci evidencing a high genetic variability among the genitors. The heterosis values were low for most of the crosses, except for Forty × Plutão that represented 107 percent of heterosis for the total fruit yield. As compared with the commercial checks, the diallel cross generated superior quality hybrids, which inferred the possibility of obtaining double-cross hybrids of tomato with significant heterosis.

A Região Centro-Sul do Estado do Paraná apresenta características sócio-econômicas destacadamente relacionadas à agricultura, porém com pouco destaque para a produção de olerícolas. Este trabalho visou identificar quais são as principais olerícolas da região centro-sul do Paraná em relação ao estado e país mediante revisão bibliográfica e utilizando em parte dados oficiais da SEAB e IBGE e coleta de dados junto à órgãos municipais. Na comparação dos dados a nível estadual e nacional tem-se em comum a batata, cebola e tomate na região de Guarapuava e pouca ou nenhuma expressão para a cultura da mandioca. Outras olericolas são cultivadas com baixa expressão em termos de ocupação de área e geração de renda, porém são importantes para autoconsumo nas proprieades e complemento do abastecimento local. Concluiu-se que esta região apresenta um grande potencial para este tipo de produção devido as características das propriedades com expressiva participação da agricultura familiar. Entretanto, para que a produção de olericolas seja expressivamente aumentada de forma viável ao produtor, são necessárias mudanças e investimentos em aspectos que envolvem tanto o fomento e assistência técnica, como também a organização de produtores. Condições que contribuirão para melhor estruturação do sistema de comercialização, bem como da infraestrutura de classificação, processamento e embalagem dos produtos antes da destinação ao mercado consumidor final. Palavras-chave: Olericultura, região Centro-Sul do Paraná, agricultura familiar.