Soil management systems directly interfere in the soil–plant relationship. However, there are still few studies evaluating the influence of long-term management systems on the physiological quality of soybean seeds. Another little-known topic is the influence of pre-harvest desiccation on the physiological quality of soybean seeds, especially on seed longevity. Thus, the aim of this research was to evaluate the physiological quality of soybean seeds cultivated under conventional tillage and no-tillage systems with and without desiccant use. The experiment was carried out in design is a split plot in a randomized complete block design. The treatments consisted of soil management systems (conventional tillage and no-tillage), with and without pre-harvest desiccation. In the treatment with desiccation, the herbicide Paraquat was applied, when the plants were at the R7.3 phenological stage (most of the seeds had a yellowish coat, with a shiny surface and were already detached from the pod). Seed germination, vigor (first germination count, seedling dry mass, seedling length, time to reach 50% germination (T50), seedling emergence and emergence speed index) and longevity (P50) were evaluated. Seeds cultivated under conventional tillage showed greater vigor for most traits evaluated, with values of T50 and seedling length higher by 24.39% and 24.77%, respectively, compared to NT. In addition, non-desiccation increased the seedling length and dry mass, in 15.45% and 21.59%, respectively. The use of desiccant aiming at seed vigor is dependent on the soil management system. Soybean seed longevity was superior in the no-tillage system, but desiccant application reduced seed longevity.

O objetivo do trabalho foi avaliar o efeito de doses de 2,4-D (ácido 2,4-diclorofenoxiacético) na produção de frutos de abóbora japonesa em Gurupi -TO. O delineamento experimental utilizado foi de blocos casualizados com oito tratamentos e quatro repetições. Foram testadas sete doses do regulador vegetal em baixa concentração aplicado na forma de 2,4-D, nas seguintes concentrações 187,5; 200; 212,5; 225; 237,5; 250 e 262,5 mg.L -1 e mais a testemunha (polinização com pólen) feita de forma manual. Avaliou-se peso médio de fruto, produtividade média de frutos, formato de fruto e textura da casca. Os dados foram submetidos à análise de variância e ajustado equações de regressão. O tratamento com pólen foi comparado aos demais por contraste. O uso de 2,4-D promoveu uma boa taxa de frutificação, com produtividade média de 24,35 ton ha -1 , não diferindo estatisticamente da testemunha, pelo teste de Dunnett. O uso de 2,4D na dose 225,0 mg.L-1 resultou em aumento no peso médio dos frutos colhidos. Não houve incremento de produtividade, de acordo com as diferentes concentrações de 2,4D, e o formato e espessura da casca não foram alterados.

Com esse trabalho, objetivou-se verificar através da inoculação artificial, a reação fenotípica de plantas de abóbora cv. ‘Caserta’ a isolados de ZYMV e ZYMV+SqMV e também verificar a reação fenotípica em quatro genótipos de melão de um isolado misto (ZYMV+SqMV), ambos oriundos de regiões produtoras de melancia no Estado do Tocantins. O trabalho foi realizado em casa de vegetação com telados a prova de afídeo. O delineamentoexperimental utilizado foi o inteiramente casualizado com cinco plantas por parcela e três repetições. As plantas inoculadas foram observadas quanto ao aparecimento de sintomas aos 28, 33 e 38 dias após a primeira inoculação. Nas plantas de abóbora, inoculadas com o isolado simples, os sintomas predominantes exibidos foram mosaico e nervuras paralelas. Nas infecções mistas houve maior agressividade dos sintomas, evoluindo para deformações e estreitamentos foliares, além de bolhosidade, nervuras paralelas e esporão, comprometendo grande parte da área foliar das plantas avaliadas. Nos genótipos de melão, os sintomas observados foram mais agressivos nos genótipos Sunshine e Amarelo. No genótipo Eldorado observou-se apenas mosaico e no melão Valenciano não foram observados sintomas.

The sowing system, as well as the species used as covercrops, may interfere with the production of straw and the development of further crops. The objective of this research was to evaluate sowing systems for black oat (Avena strigosaSchreb) and white lupine (Lupinus albus) as cover crops, the dry matter production of these plants and their influence on Americana and Curly lettuces yield. Two experiments were performed, one for each lettuce cultivar. The experimental design was composed of 8 treatments (factorial 4x2), evaluated in randomized blocks, with five replications. The first factor is related to four soil coverages (black oat, white lupine, black oat + white lupine and weed) and the second one is the sowing system (handand mechanized in line). The cover plants drying was performed 47 days after planting and the amount of dry matter produced in the area (straw) was then measured. After 30 days from drying, varieties of Curly and Americana lettuce were planted under straw. The lettuce cultivars were evaluated for fresh mass, shoot height and head diameter. For both lettuces, the benefit ofgreen manure was higher using black oat only or combinedwith white lupine, either handor mechanized sowed.

Papaya ringspot virus, watermelon type (Pappaya ringspot virus-PRSV-W) is the main watermelon viral disease in Brazil. The work intended to evaluate the genetic divergence of watermelon lines type Crimson Sweet obtained from the cross of the resistant accession PI 595201 with Crimson Sweet and selected for to PRSV-W. Thirteen characteristics in 23 lines of the cross PI 595201 with Crimson Sweet and two control cultivars were evaluated. The genetic divergence was evaluated by multivariate procedures such as the Mahalanobis distance and by the Tocher's optimization grouping and nearest neighbor methods. The characteristics which contributed the most to the genetic divergence of the watermelon genotype were pulp coloration, total soluble solids, pH and titratable acidity. The Mahalanobis distance by the Tocher optimization grouping and nearest neighbor methods separated the lines into two distinct groups. The line WMX-001G-09-04-58-07pl#08 of group II was the most dissimilar in relation to the others of group I, which are