The recent exploration of yacon demands scientific information for improving the crop production technology. This study aimed to set a leaf area estimate model for yacon plants, using non-destructive measurements of leaf length (L) and/or width (W). Sixty-four representative yacon plants were randomly selected in an experimental field during the full vegetative growth. One thousand leaves of various sizes were taken from those plants for setting and validating a model. The logarithmic model best fitted this purpose, the result of multiplying length by width being used as independent variable. Yacon leaf area can be determined with high precision and accuracy by LALW = (-27.7418 + (3.9812LW / ln LW ) , disregarding the leaf size.

O objetivo deste trabalho foi formular substratos, a partir do caroço de açaí triturado fermentado, para produção de mudas de quiabo e tomate. Os experimentos foram conduzidos em delineamento inteiramentecasualizado, e os tratamentos constituídos por cinco substratos (1: 100% de caroço de açaí triturado fermentado; 2: 75% de caroço de açaí triturado fermentado e 25% de substrato comercial Basaplant v/v; 3: 50% de caroçode açaí triturado fermentado e 50% de substrato comercial Basaplant v/v; 4: 25% de caroço de açaí triturado fermentado e 75% de substrato comercial Basaplant v/v; 5: 100% de substrato comercial Basaplant). As formulaçõesforam testadas com a cultivar: Santa Cruz-47 de quiabo (Abelmoschus esculentus), e a cultivar: Santa Clara de tomate (Lycopersicon esculentum). Ao final do experimento foram avaliados: número de folhas e área foliar, altura, massa fresca e seca da parte aérea, da raiz e total. De maneira geral, observaram-se melhores resultados nas mudas produzidas em substrato contendo 75% de caroço de açaí triturado fermentando com 25% de substrato comercial Basaplant. O uso do substrato formulado com 75% de caroço de açaí triturado fermentando e com 25% de substrato comercial Basaplant, promoveu maior crescimento das mudas de quiabo e tomate.

Yacon is a functional food with great potential for horticultural exploitation and its cultivation demands the generation of agronomic information. To address these needs, this study was performed to evaluate the production of yacon planted in different planting seasons under two growing conditions in Brazil. The experiments were conducted in two different locations, one in the mountain region (tropical microclimate at altitude with milder temperatures) and the other in the lowland region (warm tropical microclimate with higher temperatures). At both sites, yacon was planted in four seasons: autumn (April), winter (July), spring (September) and summer (December). At harvest, the tuberous roots were evaluated for leaf area index and the variables of vegetative development and productivity of plants (for total and standard commercial roots). It was concluded that yacon cultivation in mountain conditions (tropical climate with milder temperature) promotes the development and production of yacon. Additionally, planting in the autumn for both growing conditions (mountain or lowland) promotes the development and production of yacon, including increased production of roots of better commercial grade, allowing greater economic profitability. These results indicate that temperature has an influence on the growth and yield of the tuberous roots of yacon, and milder temperatures were more favourable.

This research aimed to catalog insects that cause injury to the yacon (Smallanthus sonchifolius, família Asteraceae) crop, in order to identify those who may cause damage. The study was carried out in Alegre, Espírito Santo State, Brazil. Cultivation began in May 2013 and the harvest was done 180 days later. Three species from the Coleoptera order: Lagria villosa (Coleoptera: Lagriidae); Cerotoma arcuata and Diabrotica speciosa (Coleoptera: Chrysomelidae) and two species from the Lepidoptera order: Spodoptera eridania (Lepidoptera: Noctuidae) and Chlosyne lacinia saundersii (Lepidoptera: Nymphalidae) were observed causing damage to the yacon crop. The caterpillar C. lacinia saundersii, known as sunflower caterpillar, was the most important species, being observed throughout the yacon cycle.

No abstract