Search

A propagação da amoreira-preta e da framboeseira dá-se principalmente por meio de estacas de raiz e mesmo de hastes novas, contudo, já é crescente o interesse pelo uso da micropropagação como um método alternativo de propagação . O enraizamento é uma das etapas mais difícieis, onde a definição do meio de cultivo, da concentração ótima de AIB para o enraizamento, constitui um passo importante, por isso objetivou-se com este experimento determinar o melhor meio de cultivo, melhor tipo de cultivo e a melhor concentração de AIB no meio de cultura para o enraizamento in vitro da amoreira-preta 'Xavante' e de framboeseira 'Batum' e 'Heritage'. O material vegetal utilizado foram microestacas apicais com duas folhas, com cerca de 1 cm de comprimento, oriundas do cultivo in vitro. Os fatores estudados foram o tipo de meio de cultura MS e WPM - Wood Plant Media, a concentração de AIB no meio de cultura e o tempo de cultivo das microestacas em meio com AIB. O meio WPM, em concentrações baixas, menores de 3 µM de AIB, induziram maiores médias de enraizamento e comprimento. Concentrações altas de AIB induziram a formação de calo, para amoreira-preta, 'Xavante'. Para a framboeseira o meio WPM, com menores concentrações de AIB (0 e 3 µM), mostrou as melhores médias no número de raízes, comprimento de raízes e pequena intensidade de calo; com as maiores concentrações de AIB, ocorreu maior aparecimento de calo.The propagation of blackberry and raspberry occur mainly through root cutting and even of softwoods stem; however, it is already increasing the interest for the use of the micropropagation as an alternative technique of vegetative propagation of fruit plants, since the rooting is one of the most difficult stages, in which the definition of both the culture environment and the best concentration of AIB for the rooting, is an important stage. For that purpose, the aim of this research was to determine the best cultivation type and the best concentration of IBA in the culture environment for the in vitro rooting of the blackberry 'Xavante' and the raspberry 'Batum' and 'Heritage'. The vegetable material used was atex microcutting with two leaves, measuring about 1 cm of length, originated from the in vitro cultivation. The studied factors were the kinds of culture (MS and WPM), the IBA concentration in the culture environment and the time of cultivation of the microcutting in an environment with IBA. The WPM environment, in low concentrations, less than 3 µM of IBA, together with T1, induced larger rooting averages and length. High concentrations of AIB induced the callus formation for blackberry 'Xavante'. For raspberry, using WPM environment with smaller concentrations of AIB (0 and 3 , µM), it was shown the best average in the number of roots, length of roots and small callus intensity, with the largest concentrations of IBA it happened larger callus emergence.

The effects of the combinations of leaf rust inoculation at different growth stages and initial inoculum levels on leaf rust development and yield of winter wheat cultivars, McNair 1003 and Coker 762 were evaluated. Disease onset stage and initial inoculum level affected the rate of leaf rust development and shape of the disease progress curves in both cultivars. Epidemics with common onset stages and different initial inoculum levels differed in area under the disease progress curve (AUDPC). Leaf rust epidemics initiated at Feeke's growth stages 5, 7, and 10 reduced yield in both cultivars. Leaf rust epidemics initiated early with high inoculum levels had the greatest deleterious effect on yield. Maximum losses due to leaf rust were 30—40 %. Yield loss was directly related to AUDPC when the AUDPC varied from 500 to 1700 in McNair 1003 and from 250 to 1700 in Coker 762. Yield reduction was mainly due to reduction in grain weight. [ABSTRACT FROM AUTHOR]