Cultivo do girassol na época da safrinha no Rio Grande do Sul.

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Responses of Solanum tuberosum L. to Water Deficit by Matric or Osmotic Induction.

Toselectpotatogenotypestoleranttowaterdeficit,systemstosimulatethisstresshavebeen used. Polyethylene glycol (PEG) is the main osmotic agent used for this purpose, but it causes an excessively severe stress. However, it is difficult to carry out an experiment that aims to compare plant responses under water deficit by osmotic or matric induction, and, thus,fewstudiescomparethesestress-inducingmechanisms.Therefore,theobjectiveofthis studywas to compare the responses of Agata, BRS Clara,C2406-03andCota genotypes to water deficit in both induction methods (matric or osmotic). The tests were carried out in a greenhouse, one using hydroponics (osmotic induction) and the other in pots with soil (matric induction). In both tests, the application of stressful conditions occurred at the beginning of tuberization. Assessments of gas exchange and shoot temperature were made throughout the exposure to stress. Also, samples were collected from leaves for analysis of osmotic potential and leaves and tubers for analysis of metabolite content. At the end of the potatoplantcycle,thenumberandweightoftuberswereevaluated.Inbothstressconditions, there were significant reductions in photosynthesis and transpiration rate compared to the respective normal hydration conditions. In addition, indicators such as metabolite levels (proline and soluble sugars) were significantly altered in plants exposed to different stress inductions. These data, together with the significant limitations in the growth of stressed plants, indicate that the experimental models induce similar responses. However, the water deficit by osmotic induction was more severe for the potato plants when compared to stress due to matric induction, mainly affecting tuber production. Therefore, the water deficit osmotic induction model can be recommended for phenotyping tolerance to this stress, due to the hydroponic system inducing greater tuber production per plant under optimal cultivation conditions

Molecular characterization of Corynebacterium pseudotuberculosis, C. silvaticum, and C. auriscanis by ERIC-PCR.

The aims of the present study were (i) to genotype Corynebacterium pseudotuberculosis, C. silvaticum, and C. auriscanis strains using enterobacterial repetitive intergenic consensus (ERIC-PCR), and (ii) to analyze the epidemiological relationships among isolates according to biovar (Equi and Ovis), species, host, and geographical origin of the C. pseudotuberculosis strains. Sixty-eight C. pseudotuberculosis, nine C. silvaticum, and one C. auriscanis, C. pseudotuberculosis ATCC® 19410? strain and the attenuated C. pseudotuberculosis 1002 vaccinal strain were fingerprinted by ERIC 1+2-PCR. Field strains were isolated from various hosts (cattle, buffaloes, sheep, goats, horses, dogs, and pigs) in six countries (Mexico, Portugal, Brazil, Equatorial Guinea, Egypt, and Israel). High genetic diversity was found among the studied Corynebacterium spp. isolates, clustering in 24 genotypes with a Hunter & Gaston diversity index (HGDI) of 0.937. The minimal spanning tree of Corynebacterium spp. revealed three clonal complexes, each associated with one bacterial species. Twenty-two genotypes were observed among C. pseudotuberculosis isolates, with an HGDI of 0.934. Three major clonal complexes were formed at the minimal spanning tree, grouped around the geographic origin of C. pseudotuberculosis isolates. These results reinforce the high typeability, epidemiological concordance, and discriminatory power of ERIC-PCR as a consistent genotyping method for C. pseudotuberculosis, which could be useful as an epidemiological tool to control caseous lymphadenitis. Moreover, our results also indicate the potential of ERIC 1+2-PCR for the genotyping of other species of Corynebacterium other than C. pseudotuberculosis

Cultivo do girassol no Rio Grande do Sul: plantio janeiro a fevereiro.

A demanda por esta oleaginosa está aumentando no RS, de forma que os produtores estão expandindo a área e a época de plantio, com isso surge um interesse especial no período de plantio janeiro/fevereiro (safrinha). Visando atender esta demanda, foram realizados ensaios com quatro datas de semeadura e em seis locais, a fim de determinar a viabilidade técnica deste cultivo no período da safrinha 2007 no RS. Os ensaios foram instalados nos seguintes locais / instituições do RS: Pelotas (Embrapa Clima Temperado); Passo Fundo (Embrapa Trigo); Bagé (Embrapa Pecuária Sul); Fortaleza dos Valos (COTRIMAIO); Santa Rosa (COOPERMIL); Rio Pardo (AFUBRA).bitstream/item/96068/1/ID-30191.pd