Produção de batata-semente por brotos, multiplicação e desempenho a campo de cultivares para sistema orgânico

Abstract

Organic farming requires the production or use of certified seeds from the same cultivation system and, the information of potato cultivars adapted to organic production system is important. The objective of this work was to study the feasibility of utilizing sprouts of different potato cultivars, seed multiplication and yield potential in field conditions without using agrochemicals. Three experiments were conducted: the first experiment using sprouts as seed under protected cultivation in Guarapuava, Paraná State, Brazil, from November 2011 to February 2012; the second experiment was field conducted in Candói, Paraná State, from May to September 2012 and the third experiment was field conducted in Guarapuava, Paraná State, from February to May 2013. The experimental design was a randomized block design with 3 replications in all 3 experiments. In the 2 first experiments the following cultivars were evaluated: BRS Ana, BRS Clara, BRS Eliza, Crystal and Catucha, and in the last experiment Agata, Bintje, Baronesa and BRSIPR Bel were included. The traits analyzed were length of main stem, number of stems, number of leaves, fresh weight and number of tubers, percentage of infection by viruses and in the second experiment the incidence of late blight on leaves. In the third experiment, leaf area index (LAI), tuber, leaves and stem dry weights and late blight severity were also analyzed. In the first experiment, the cultivars showed differences in plant height and minituber production, the highest value was observed in cultivars BRS Clara and BRS Ana for plant height and cultivar BRS Clara for minituber production. In the second experiment, there was difference only in plant height, the tallest cultivars were BRS Ana and BRS Clara. There was low spread of viruses and, it did not directly reflect in tuber yield. In the third experiment the cultivars with lower disease severity were those recommended to organic farming, especially BRS Clara and Catucha; this second cultivar had the higher LAI and tuber yield, as well as resistance to late blight, factors that might have contributed to the recorded highest total tuber yield (13.8 t/ha).