Os trabalhos experimentais foram realizados nos anos agrícolas de 2007-2008, 2008-2009 e 2009-2010, com o objetivo de conhecer a produtividade agroeconômica dos clones de taro Chinês e Macaquinho, propagados usando rizomas-filhos graúdos, extras, grandes, médios, pequenos e muito pequenos. A colheita foi realizada em média aos 202 dias após o plantio, nos três anos agrícolas. Com base nas análises de vari ância conjuntas realizadas, observou-se que os clones de taro apresentaram diferenças significativas quanto à produtividade de massas frescas e secas de folhas, rizomas-mãe, rizomas-filho comerciais e rizomas-filho não-comerciais; que existiam diferenças significativas de produtividade de um ano agrícola para o outro; e o tamanho das mudas induziu diferenças significativas na produtividade. Nas condições em que foram conduzidos os experimentos e considerando a maior produtividade média de massa fresca de rizomas-filho comerciais (28,69 t.ha-1) e a maior renda líquida (US $14,741.14) correspondente aos três anos agrícolas recomenda-se cultivar o clone Macaquinho, utilizando mudas pequenas na propagação.

The experimental studies were conducted in 2007-2008, 2008-2009 and 2009-2010 crop seasons, in order to know the agro-economic yield of 'Chinês' and "Macaquinho" taro clones, propagated using huge, extra, large, medium, small and tiny cormels. The harvest was done on average on 202 days after planting, in three crop seasons. Based on the joint analysis of variance carried out, it was observed that taro clones showed significant differences in the yield of fresh and dry weight of leaves, cormels, and commercial and non-commercial comels; besides, there were significant differences in yield of a crop season to another and the size of the cuttings induced significant differences in yield. In the conditions that the experiments were conducted, and considering the highest average yield of fresh weight of commercial cormels (28.69 t.ha-1) and highest net income (US $14,741.14) correspondent to the three crop seasons, it is recommended to cultivate 'Macaquinho' clone using small cuttings in propagation.

The screening of Bacillus thuringiensis (Bt) Cry proteins with high potential to control insect pests has been the goal of numerous research groups. In this study, we evaluated six monogenic Bt strains (Bt dendrolimus HD-37, Bt kurstaki HD-1, Bt kurstaki HD-73, Bt thuringiensis 4412, Bt kurstaki NRD-12 and Bt entomocidus 60.5, which codify the cry1Aa, cry1Ab, cry1Ac, cry1Ba, cry1C, cry2A genes respectively) as potential insecticides for the most important insect pests of irrigated rice: Spodoptera frugiperda, Diatraea saccharalis, Oryzophagus oryzae, Oebalus poecilus and Tibraca limbativentris. We also analyzed their compatibility with chemical insecticides (thiamethoxam, labdacyhalothrin, malathion and fipronil), which are extensively used in rice crops. The bioassay results showed that Bt thuringiensis 4412 and Bt entomocidus 60.5 were the most toxic for the lepidopterans, with a 93% and 82% mortality rate for S. frugiperda and D. saccharalis, respectively. For O. oryzae, the Bt kurstaki NRD-12 (64%) and Bt dendrolimus HD-37 (62%) strains were the most toxic. The Bt dendrolimus HD-37 strain also caused high mortality (82%) to O. poecilus, however the strains assessed to T. limbativentris caused a maximum rate of 5%. The assays for the Bt strains interaction with insecticides revealed the compatibility of the six strains with the four insecticides tested. The results from this study showed the high potential of cry1Aa and cry1Ba genes for genetic engineering of rice plants or the strains to biopesticide formulations.