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The growing demand for organic products and the need to plant onions (Allium cepa L.) in the town of Pinhais, Brazil at different times of the year generated this study in the Organic Horticulture Experimental Station of Canguiri-Federal University of Parana, Pinhais, Brazil. The objective was to evaluate the agronomic performance of seven cultivars of open-pollinated onion in an organic system in two planting seasons (January and September) different than traditional times (April and June). The experimental design was completely randomized in a 7x2 factorial scheme with three replicates: Franciscana IPA-10, Vale Ouro IPA-11, Brisa IPA-12, Alfa São Francisco (Cycle VIII), Alfa São Francisco -RT (Thrips tabaci-resistant genotype assessment - Embrapa Semiarid) and BR-29. The results were evaluated for homogeneity by Bartlett’s test and treatment means were compared by Tukey’s test at a significance level of 5%. The variables assessed at the start of bulb formation and harvest were stem height, fresh and dry leaf weight, leaf number and scape diameter. At harvest we measured dry and fresh mass of the bulb, bulb type according to the diameter and productivity. The cultivars Alfa São Francisco and Alfa São Francisco-RT produced higher values of dry mass and productivity in January.

Biofertilizers based on seaweed extract are a source of nutrients that can replace conventional synthetic fertilizers, allowing their use in organic agriculture. The objective of this research was to evaluate the effect of Ascophyllum nodosum (L.) Le Jolis seaweed extract on tomato (Lycopersicon esculentum) yield and vegetative development. The experiment was carried out under protected cultivation and in the field, using the Piccolo F1 cultivar. The experimental design was completely randomized in 5 × 2 × 5 factorial arrangement (five combinations of doses and frequency of seaweed extract application; two environments: greenhouse and field, with five assessment dates) for the variables: stem diameter, average number of leaves and relative chlorophyll content. For the other variables, a 5 × 2 factorial design was used (five combinations of doses and frequency of seaweed extract application; two environments); the following variables were evaluated: stem diameter, leaf relative chlorophyll content, number of leaves, average fruit weight, number of fruits, longitudinal and transverse fruit diameter, rachis length and average yield. It was possible to verify that the 0.3% seaweed extract dose under protected cultivation and in the field, applied every two weeks, increased the tomato yield, without altering the characteristics of fruits and vegetative growth.

Thrips tabaci Lindeman is the main pest of onion crops, and chemical control is the main method adopted by farmers. Alternative control methods should be prioritised to reduce the amount of insecticides used. Resistant cultivars are one efficient way to control thrips in the field. Our aim was to assess the influence of morphological and chemical characteristics of seven onion cultivars and their resistance to T. tabaci. The number of thrips and the morphological and chemical characteristics of the plants were assessed. Among the evaluated cultivars, Alfa Sao Francisco RT, BR 29 and Sirius showed resistance to T. tabaci, as indicated by the lower number of thrips observed during the cycle (64, 87, and 74 thrips, respectively). Morphological and chemical characteristics were associated with onion's resistance to T. tabaci. For the cultivar Alfa Sao Francisco RT, a wider central angle (16.4°), a thinner cuticle, a larger amount of epicuticular waxes, and stomata on the surface of leaves accounted for resistance. For the cultivars BR 29 and Sirius, the resistance was likely due to the presence of resistance-conferring substances or high amounts of some component in the chemical composition of plants.