Determinations of total nitrogen, phosphorus, potassium, calcium, magnesium, and boron were made on leaves of ten grape varieties on different rootstocks, growing in experimental plots under comparable soil, cultural, and climatic conditions. The youngest fully matured leaf was sampled at booming time. The influence of rootstock and scion on the principal nutrient elements in grape leaves could be summarized as follows: a) Rootstocks induced larger variations in the concentrations of nutrient elements in the leaves than did the scion varieties, b) Some of the rootstock differences were similar from one scion variety to another. This is illustrated for the highest levels of nitrogen and phosphorus on nearly all scion over the rootstock Rupestris du Lot, and for high calcium increases in leaves for most varieties grafted on the Riparia x Rupestris 101-14 rootstock. c) At least for potassium, the scion does have some influence on the composition of the leaves. The varieties Diamante Negro, Itália e Moscatel de Hamburgo had more potassium present in their leaves, regardless of the rootstock. d) Some characteristics are peculiar to some rootstock-scion combinations only, e) The range in leaf content of the various nutrient elements showed that potassium had the least variation and calcium had most variation among the macro-nutrient elements. Boron had more variation between samples than all macro-nutrient elements. f) The results suggested the need for different "optimum" values for certain mineral constituents when rootstocks and varieties are considered. | No presente trabalho é feito um estudo comparativo do porta-enxêrto e da variedade através de seus efeitos na composição das fôlhas de videira, cultivada em canteiros sob condições comparáveis de solo, tratamento cultural e clima da Estação Experimental de São Roque, do Instituto Agronômico. Amostras de fôlhas de idade definida (a primeira madura, a contar da ponta) foram colhidas à época do florescimento, e analisadas para nitrogênio total, fósforo total, potássio, cálcio, magnésio e boro. Os dados obtidos permitem distinguir as variações de composição das fôlhas determinadas pela variedade-enxêrto e variedade-cavalo e o uso desta informação como base nos pesquisas para o estabelecimento dos índices de nutrição para a videira, pela análise foliar. A diferença encontrada nos teores dos elementos nutritivos nas fôlhas foi maior entre porta-enxertos do que entre variedades.

Termohlen proved that corky root was caused by a fungus, which was readily isolated and cultivated. The fungus did not sporulate but several isolates made sclerotia on agar. Its features on nutrient medium were described. The fungus had not been named. Isolates varied greatly in pathogenicity. The pathogen remained in the soil as myceliurn in root debris and possibly also as sclerotia.Besides the tomato several other Solanaceae were susceptible to corky root. From Physochlaena orientalis and cucumber the pathogen could be isolated; these plants, however, did not show any symptoms and were thus carriers. Rotation experiments with cucumber and some other crops alternating with tomato had but little effect on the inoculum potential of the soilControl was by steaming the soil or disinfecting it with chloropicrin. DD had no effect.All cultivated varieties of tomato so far tested were susceptible. Lycopersicum glandulosum, L. peruvianum and L. hirsutum were highly resistant. Crosses to obtain resistant tomato varieties were made. The first filial generation of the crossing L. esculentum with L . hirsutum was resistant and suitable as a root stock for the tomato but it was susceptible to eelworm infestation.

Termohlen proved that corky root was caused by a fungus, which was readily isolated and cultivated. The fungus did not sporulate but several isolates made sclerotia on agar. Its features on nutrient medium were described. The fungus had not been named. Isolates varied greatly in pathogenicity. The pathogen remained in the soil as myceliurn in root debris and possibly also as sclerotia.Besides the tomato several other Solanaceae were susceptible to corky root. From Physochlaena orientalis and cucumber the pathogen could be isolated; these plants, however, did not show any symptoms and were thus carriers. Rotation experiments with cucumber and some other crops alternating with tomato had but little effect on the inoculum potential of the soilControl was by steaming the soil or disinfecting it with chloropicrin. DD had no effect.All cultivated varieties of tomato so far tested were susceptible. Lycopersicum glandulosum, L. peruvianum and L. hirsutum were highly resistant. Crosses to obtain resistant tomato varieties were made. The first filial generation of the crossing L. esculentum with L . hirsutum was resistant and suitable as a root stock for the tomato but it was susceptible to eelworm infestation.