There is controversy about the benefits of silicon (Si) on tomato plants. This element has structural and metabolic functions in the physiology of plants, generating benefits that may result in increased productivity of various plant species. Thus, the aim of this study was to evaluate the phytotechnical characteristics and the productivity of tomato plants according to the rates and sources of Si. The design was established in randomized blocks with factorial 3x5, corresponding to three sources of silicate (calcium silicate, potassium silicate and sodium silicate) and five doses of Si (equivalent to 0, 100, 200, 400 and 800 kg ha-1 of SiO2). The fertilization with Si increased the commercial productivity of tomato plants and reduced the occurrence of cracked fruits. Calcium and potassium silicates increased the Si levels on the leaves linearly with the increase of the doses, while sodium silicate reduced the levels in larger doses. Silicon fertilization increases the productivity of tomato plants with possible economic return on the use of this input.

This study aimed to investigate the effect of silicon (Si) sources and doses on the physicochemical quality as well as post-harvest conservation of tomato fruits. Treatments were arranged in a 3 x 5 factorial scheme corresponding to sources [calcium silicate, potassium silicate and sodium silicate] and five doses of Si (equivalent to 0, 100, 200, 400 and 800 kg/ha SiO 2 ). Randomized blocks were the experimental design, with four replications. Soluble solids, vitamin C, lycopene, titratable acidity, mature fruit firmness, initial firmness, firmness half-life, time until reaching firmness equivalent to 3.0 x 10 4 N/m 2 and 2.0 x 10 4 N/m 2 and Si content in fruits were evaluated. Soluble solids, vitamin C and lycopene of fruits increased with increasing doses of Si, except for the highest dose. Calcium and sodium silicate provided the highest lycopene concentration in fruits. An increase in initial firmness, number of days until reaching firmness half-life and firmness equivalent to 3.0 and 2.0 x 10 4 N/m 2 were observed along with increasing doses of Si. Tomato fertilization with calcium silicate, potassium silicate and sodium silicate, used as sources of Si, increased the post-harvest conservation as well as the physicochemical quality of tomato.

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).

ABSTRACT. Breeding different strawberry genotypes and plant selection in Brazil could result in new cultivars with better environmental adaptations. The aim was to develop and select new F 1 strawberry plants with higher potential yields. Twelve hybrid populations were obtained from breeding the cultivars Aromas, Camarosa, Dover, Festival, Oso Grande, Sweet Charlie and Tudla, and 42 F 1 hybrids were obtained from each population. An augmented randomized block design was used. Productive traits were measured and heterosis was calculated for all traits. The breedings Dover x Aromas and Camarosa x Aromas both showed 28.6% of their hybrids with a total fruit mass that was higher than that of cv. Aromas, and 9.5 and 14.3% were higher than that of cv. Camarosa, respectively. The breeding of Camarosa x Aromas produced hybrids with high potential yields and a large average fruit mass that reached the commercial standard. Hybrids MCA12-93, MFA12-443 and MCA12-89 showed high potential yields and can be used as parents in strawberry breeding programs.

RESUMO O trabalho teve como objetivo avaliar a produtividade, características físico-químicas e perdas pós-colheita de cultivares de cebola produzidas em sistemas de cultivo convencional e orgânico. Foram avaliadas a produção total e a massa média dos bulbos, o teor de sólidos solúveis, a acidez titulável, a massa seca e o pH. Além destas características, foram avaliadas perdas pós-colheita, com observação da perda de massa. Os bulbos foram armazenados em câmara fria à temperatura de 3ºC ± 1ºC e umidade relativa de 75% ± 5% durante 90 dias. O sistema orgânico foi superior ao convencional em produtividade, não diferindo significativamente nas demais características. A produtividade do híbrido Baia F 1 foi mais expressiva, nos dois sistemas de cultivo, assim como as maiores massas médias de bulbos. Dentre as cultivares, a Red Creole proporcionou elevados valores de sólidos solúveis e massa seca de bulbos, nos dois sistemas de cultivo. Essas características indicam que a cultivar Red Creole possui bom desempenho para industrialização. Nas avaliações pós-colheita, na cultivar Red Creole observou-se a maior redução na massa de bulbos, tanto no sistema orgânico quanto no convencional. Estes dados revelam que não existe influência do sistema de cultivo na conservação pós-colheita dos bulbos.Palavras-chave: Allium cepa L., rendimento, ácido pirúvico, pungência. ABSTRACT YIELD AND POSTHARVEST QUALITY OF ONION CULTIVARS IN THE ORGANIC AND CONVENTIONAL CROPPING SYSTEMSThe study aimed to evaluate yield, physical-chemical features and post-harvest losses of onion cultivars grown in organic and conventional cropping systems. Total yield and average weight of bulbs, content of soluble solids, titratable acidity, dry weight and pH. Were evaluated Besides these characteristics, post-harvest losses were also evaluated, with observation of mass loss. The bulbs were stored in cold chamber at a temperature of 3 ° C ± 1 º C and relative humidity of 75% ± 5% for 90 days. The organic system had higher yield than the conventional system, but did not differ significantly in other evaluated characteristics. The hybrid Baia F 1 showed the greatest yield and the highest average masses of bulbs in both cropping systems. The Red Creole cultivar showed higher values of soluble solids content and bulbs dry mass than other cultivars in the two cropping systems. These characteristics indicate that Red Creole cultivar is an excellent material for industrialization. Post-harvest evaluations showed that Red Creole cultivar had the highest reduction in the weight of bulbs in conventional and organic systems. This data show that there is no influence of the cropping systems in the bulbs post-harvest conservation.

The influence of different cover crops was evaluated over the agronomic performance of tomato hybrids for industrial processing, as well as its effect over soil chemical attributes. The experimental design was completely randomized, in a split plot scheme, with four replications. Main treatments (plots) were composed of winter cover crops (oat, hairy vetch, clover and radish) and of a fallow area (spontaneous vegetation). Subplots were composed of four processing tomato hybrids (AP529, AP533, Kátia and Sicílio). We evaluated the total production (TP), marketable production (CP), average mass of marketable fruits (AMCF) and number of marketable fruits (NCF). Chemical analysis of soil was done in two stages: one week preceding implantation of cover crops and in the phase of tomato implantation. Highest TPs were obtained in treatments in which cover crops were composed by hairy vetch and radish. However, although hairy vetch has caused an increase in TP, no difference between covers was obtained in relation to CP. Sicílio hybrid presented the greatest AMCF, however, its TP was lower than expected. This fact is related to lower NCF, which was half of the observed in AP529 and AP533 hybrids. Radish cover increased phosphorus, calcium and potassium in soil and this could be one of the factors responsible for the increase of TP provided by radish. On the other hand, oat has caused inverse effect, reducing availability of Ca and K. All covers have increased organic matter in soil, the major increment being presented by oat. Based on these results we conclude that hairy vetch and radish are the most indicated plants for cover preceding tomato cultivation.

Tomato is the most important vegetable species and has a strong bottleneck effect in its domestication and evolution. In exploring the existing genetic variability in commercial germplasm, germplasm has been proven to be an excellent alternative to obtain inbred lines in order to provide superior new hybrids in the future. In this sense, the objective of this study was to estimate the genetic distance among commercial processing tomato hybrids via agronomical and quality postharvest fruit traits with the aim of suggesting promising crosses for the formation of base populations for tomato breeding. Ten hybrids of processing tomato were evaluated in a complete randomized block design with three replicates. In total, eleven agronomic and postharvest fruit quality traits were evaluated. The genetic distances were estimated between the hybrids using the generalized Mahalanobis (

-The objective of the study was to determine the physiological and isozyme alterations in lettuce seeds submitted to different conditions and storage periods. We used a completely randomized design with four replications in a factorial arrangement with six lettuce cultivars (Everglades, Babá de Verão, Elisa, Grand Rapids, Hortência and Salinas 88) and four storage periods (30, 60, 90 and 120 days), on three storage rooms (15, 25 and 35 ° C). The physiological quality was evaluated by first and final germination count, emergence, and germination and emergence speed indexes. The isoenzyme expression of catalase (CAT), esterase (EST), alcohol dehydrogenase (ADH) and malate dehydrogenase (MDH) were determined. The physiological quality of lettuce seeds was preserved when stored at 15 ° C room temperature. The high room temperatures associated with higher storage periods cause a reduction in physiological quality and alterations in enzymatic patterns of CAT, EST, ADH and MDH. For seeds stored at 15 ° C, there were no physiological changes. The lettuce cultivars, especially Everglades, have different levels of tolerance to storage and isoenzyme expressions.Index terms: Lactuca sativa, enzymes, storability, thermotolerance.Alterações fisiológicas e isoenzimáticas em sementes de alface em diferentes condições e períodos de armazenamento Termos para indexação: Lactuca sativa, enzimas, potencial de armazenamento, termotolerância.