Resistência ao mosaico dos "seedlings" de cana de açúcar obtidos em 1950

[摘要] Inoculation of sugar cane seedlings by rubbing with the help of carborundum gave better results than needle inoculation. The extract obtained from the leaves of corn plants infected with the sugar cane mosaic virus was found to be slightly more infectious than extract from leaves of infected sugar cane field plants. Additional advantages are offered by corn plants as a source of mosaic virus for seedling inoculation in sugar cane breeding projects : the leaves are easier to ground and give more jiüce than sugar cane leaves; corn plants grow rapidly in greenhouses and can supply large amounts of inoculum within a short time; they permit multiplication of the desired virus strains; inoculum from corn minimizes the risk of carrying pathogenic bacteria or fungi as it might be the case when it is obtained from sugar cane leaves. More than 20,000 seedlings, obtained in 1950, were tested for resistance to mosaic by rubbing with inoculum from corn, with the help of carborundum. The results were very satisfactory. Out of 21,673 inoculated seedlings from various crosses, 9,512 became infected, thus giving an average percentage of transmission of 43.9. Varieties of the CP group conferred more mosaic resistance to the hybrid seedlings than Co's.