Production systems influence crops differently, mainly in terms of yield. However, there are few studies that have evaluated different bushing snap bean genotypes in different systems. Thus, this study aimed to evaluate the production components and yield of bushing snap beans in conventional and organic production systems. The experimental design was a randomized complete block, in a factorial 6 × 2 arrangement, corresponding to six genotypes and two production systems, with three replications. The genotypes Isla Manteiga Baixo ®

RESUMO -O presente trabalho objetivou avaliar o efeito de subdoses de glifosato sobre o processo germinativo e o desenvolvimento de plântulas de cultivares convencionais de milho em condições de laboratório. O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial 2 x 6, com quatro repetições. Os tratamentos consistiram da interação de dois genótipos convencionais de milho (Sintético UEL e AG 9010 PRO) submetidos a seis subdoses de glifosato (0; 3,5; 7,0; 10,5; 14,0 e 17,5 g e.a. ha -1 ). As avaliações consistiram da germinação de sementes (plântulas normais, anormais e sementes mortas), comprimento e massa seca de plântulas (parte aérea, raiz e total). O desempenho germinativo e o crescimento inicial das plântulas de milho são alterados pelas subdoses de glifosato. Existe efeito de hormese para germinação e massa seca de parte aérea nas subdoses de 0,084 e 7 g e.a. ha -1 respectivamente para o genótipo AG9010 e para massa seca da parte aérea na subdose de 8,16 g e.a. ha -1 para o genótipo Sintético UEL.O incremento das subdoses de glifosato favorece a anormalidade de plântulas e a mortalidade de sementes, além de diminuir o comprimento e a massa seca das radículas e de plântulas.Palavras-chave: hormese, germinação, Zea mays. LOW RATES OF GLYPHOSATE ON THE PROCESS GERMINATION AND CORN SEEDLING DEVELOPMENTABSTRACT -This work aimed to evaluate, in the laboratory, the effect of low rates of glyphosate on the germination and seedling development of conventional corn cultivars. The experimental design was completely randomized in a factorial 2 x 6, with four replications. The treatments consisted of the interaction of two conventional corn genotypes (Synthetic UEL and AG 9010 PRO) submitted to six low rates of glyphosate (0, 3.5, 7.0, 10.5, 14.0 and 17.5 g a.e. ha -1 ).Evaluations consisted of seed germination (normal seedlings, abnormal and dead seeds), seedling length (shoot, root and total) and seedling dry weight (shoot, root and total). Low rates of glyphosate change germination performance and early growth of corn seedlings . There hormesis effect for the germination and dry mass of shoots in rates of 0.084 and 7 g e.a. ha -1 respectively for the AG9010 genotype and dry weight of shoot in doses of 8.16 g e.a. ha -1 for Synthetic UEL genotype. The increase of the low rates of glyphosate promotes abnormal seedlings and seed mortality, and reduce the length and dry mass of radicles and seedlings.

O experimento foi conduzido no laboratório de Tecnologia e Produção de Sementes da Universidade Estadual de Londrina-PR. Objetivou-se avaliar o efeito do estresse hídrico e salino no vigor e germinação de sementes de feijão-vagem. Os gradientes de potenciais osmóticos foram obtidos por meio de diluições de solução salina estoque de NaCl PA, de potencial -2,1 MPa, preparada previamente. Os tratamentos corresponderam aos seguintes potenciais osmóticos: 0,0: -0,4; -0,8; -1,2; -1,6; -2,0 MPa. A semeadura foi realizada em rolos de papel tipo germitest, constituídos de três folhas cada, umedecidas com volume de solução equivalente a duas vezes e meia a sua massa seca e, posteriormente, mantidos em germinador a temperatura constante de 25ºC. Os efeitos do estresse hídrico e salino foram avaliados pelos seguintes parâmetros: primeira contagem de germinação (PCG), porcentagem de germinação (PG), comprimento do sistema radicular (CSR), comprimento da parte aérea (CPA), comprimento total (CT), massa seca do sistema radicular (MSSR), massa seca da parte aérea (MSPA) e massa seca total (MST). As variáveis PCG e PG não foram influenciadas pelos estresses hídrico e salino, apresentando o mesmo comportamento da testemunha. Para as variáveis CSR, CPA e CT, o potencial osmótico de -1,2 MPa mostrou-se como o limiar de salinidade para o desenvolvimento da parte aérea. Em relação ao sistema radicular, tal limiar foi observado a -1,6 MPa. Quanto à MSSR, MSPA e MST, a partir do potencial -0,4 MPa constatou-se redução no acúmulo de massa seca total das plântulas.

The plants synthetize a big quantity of chemically diverse compounds, which discharged into the environment influence in a decisive manner in the species dynamics that form the agroecosystems, phenomenon denominated allelopathy. The study had the aim of the evaluation of allelopathic effects of turnip aqueous extract under beans and corn seeds. The experimental design was completely randomized with five treatments (concentrations of 0%, 25%, 50%, 75% and 100% of raw extract) and four repetitions. The gross extract was prepared through the mixture of 50 g of turnips aerial part fresh mass in 450 mL of cold distilled water and then blended in a blender. The mixture was kept in rest in absence of light for 24 hours at 25˚C for posterior filtration and dilution of concentrations. They were evaluated the percentage of germination and the germination velocity index in Germitest paper rolls dampened with the extract or distilled water, according to the treatments and each roll was distributed 50 seeds, kept in germination chamber at 25˚C ± 3˚C and 12 hours of photoperiod. At the end of seven (corn) and nine (beans) days, the root length (RL) and the aerial part (APL) were evaluated, and after drying in a hothouse (50˚C), the dry mass of root system (DMR) and aerial part (DMAP) was determined, by the measure of 20 plantlets of each treatment. The results were submitted to an analysis of variance by F test and, when there was statistical significance, it was made the regression analysis test. For the realization of the statistical analysis, the ASSISTAT software was used. The turnip aqueous extract affected negatively the germination and initial development of bean and corn plantlets.

Snap bean is a variety of common bean (Phaseolus vulgaris L.) that is cultivated and consumed as a vegetable worldwide. In order to optimize the crop's production, germination tests are used to ensure that seeds are high in quality. However, because these tests possess inherent limitations, vigor tests, such as the electrical conductivity test, may be used instead to assess seed quality. The goal of the present study was to develop a standardized methodology for measuring electrical conductivity in snap bean seed that could reliably assess the physiological quality of seed batches. Groups of seeds (n = 50) from each of seven snap bean genotypes (UEL 1, UEL 2, HAV 21, HAV 22, HAV 34, HAV 35, and HAV 42) were immersed in distilled water (75 or 150 mL) for various immersion periods (2, 4, 8, 12, 16, 20, or 24 h), using a completely randomized 7 × 2 × 7 factorial design, with eight replicates per treatment. After immersion, the electrical conductivity of seeds from each treatment group was measured in μS cm-1 using a conductivity meter. The group means were subjected to ANOVA and the Scott-Knott test (p ≤ 0.05). The optimal conditions for the electrical conductivity test in snap bean seeds were a 16-h immersion in 75 mL of water. Under these conditions, genotypes could be clearly differentiated based on their seed vigor, optimizing the measurement of seed quality.