Vegetative development rootstocks grapewine in subtropical conditions

O trabalho teve como objetivo avaliar o desempenho vegetativo de diferentes porta-enxertos na fase de formacao a campo e o desenvolvimento inicial do enxerto, bem como o emprego de tecnicas auxiliares para o incremento do potencial rizogenico de estacas do porta-enxerto âVR 043-43â em condicoes de viveiro. Estacas caulinares lenhosas de 20 cm comprimento do porta-enxerto de videira âVR 043-43â, estratificadas por 48 h (sob temperatura de 4 oC) ou nÃo (ambiente de 25o ?} 5 oC), foram tratadas em solucao de acido indolbutirico (AIB) nas concentracoes de 0, 1.000, 2.000 e 3.000 mg L-1, associado ou nao com acido borico a 150 μg L-1, por 10 seg. As estacas foram plantadas em saco plastico de polietileno (capacidade de 2,5 L), contendo solo com textura argilosa como substrato e mantidas sob viveiro constituido de tela de sombreamento de 50% de luminosidade, sendo avaliadas apos 120 dias. Em novembro, mudas oriundas de estacas enraizadas de 17 porta-enxertos de videira (âSO4â, âTeleki 8Bâ, âHarmonyâ, âGoliaâ, âRiparia de Traviuâ, âPaulsenâ, â420 Aâ, â99Râ, â5Câ, âRR101-14â, âKober 5BBâ, âRupestris Du Lotâ, âIAC 313 Tropicalâ, âIAC 766 Campinasâ, âIAC 572 Jalesâ, âVR 043-43â e âIAC 571-6 Jundiaiâ) foram levadas a campo, em condicoes subtropicais (24o33â40â S e 54o04â12â W, altitude de 420 m e clima Cfa Koppen, com temperatura media maxima anual de 28,5 oC e minima de 17,5 oC). Passados quatro meses, avaliou-se a severidade da antracnose e ferrugem da videira nas folhas das brotacoes dos porta-enxertos e mais cinco meses o vigor dos mesmos (numero total de ramos, diametro medio, comprimento do maior ramo e massa fresca total media dos ramos). Em seguida, realizou-se a enxertia invernal com garfos da videira âBRS Violetaâ e avaliou-se apos 60 dias a porcentagem de pegamento, o diametro e o comprimento medio do enxerto. Concluiu-se que a estratificacao das estacas nao e fundamental para que haja maior eficiencia do processo de enraizamento do porta-enxerto âVR 043-43â, devendo as estacas apenas serem tratadas com 3.000 mg L-1 de AIB, associada ao acido borico. Os porta-enxertos âIAC 572 Jalesâ e âIAC 313 Tropicalâ foram resistentes a antracnose e a ferrugem. O porta-enxerto âIAC 572 Jalesâ foi o que promoveu maior desempenho a campo, previamente a operacao de enxertia. Os porta-enxertos SO4â, âHarmonyâ, âPaulsenâ e âIAC 766 Campinasâ promoveram maior vigor ao desenvolvimento do enxerto de âBRS VioletaâThe aim of the work was to evaluate the phytotechnical performance of different rootstocks in the formation level on field conditions and the initial development of the graft, as well as the application of auxiliaries technicians to the root potential increment of the rootstocks cuttings of âVR 043-43â in nursery conditions. Ligneous cuttings from grapevine âVR 043-43â, measuring 20 cm, were stratified for 48h (under the temperature of 4 oC), part of the cuttings were kept under environment temperature (25 ?} 5 oC). All the cuttings were treated with indolbutyric acid (IBA) in different concentrations of 0, 1.000, 2.000 and 3.000 mgL-1, associated and not associated to boric acid at concentration of 150 μg L-1 for 10sec. The cuttings were planted into polyethylene plastic bags (capacity of 2,5L), filled with clay soil. They were kept in nursery made of shading screen providing 50% of luminosity. The evaluations occurred 120 days after the experiment deployment. In November, the seedlings originated from the rooted cuttings of 17 grapevine rootstocks (âSO4â, âTeleki 8Bâ, âHarmonyâ, âGoliaâ, âRiparia de Traviuâ, âPaulsenâ, â420 Aâ, â99Râ, â5Câ, âRR101-14â, âKober 5BBâ, âRupestris Du Lotâ, âIAC 313 Tropicalâ, âIAC 766 Campinasâ, âIAC 572 Jalesâ, âVR 043-43â and âIAC 571-6 Jundiaiâ) were taken to the field under subtropical conditions (24o33â40â S and 54o04â12â W, 420 m height and Cfa Koppen climate, with annual maximum average temperature of 28,5 oC and minimum of 17,5 oC). After four months, it was evaluated the anthracnose and rust severity on the grapevine leaf sprouting from the rootstocks and more five months of vigor (total branch number, average diameter, biggest branch length and total leaf area fresh mass). In the sequence, it was performed winter graft using âBRS Violetaâ. The evaluated characteristics for this part of the experiment were percentage of tissue union, diameter and graft average length, which happened after 60 days of grafting. It was concluded that the stratification of the cutting is not fundamental to increase the efficiency of the rooting process of the rootstock âVR 043-43â. The cuttings should only be treated with IBA at 3.000 mg L-1 in association to boric acid. The rootstocks âIAC 572 Jalesâ and âIAC 313 Tropicalâ were resistant to the anthracnose and rust. The rootstock âIAC 572 Jalesâ was the one that showed greater performance on field, before grafting. The rootstocks SO4â, âHarmonyâ, âPaulsenâ and âIAC 766 Campinasâ showed greater vigor to the development of the graft âBRS Violeta