ABSTRACT Accurate identification of species is fundamental to every biological research. While morphological identification is a time-consuming and skilled technique, straightforward molecular techniques require the availability of a database of previously sequenced and identified specimens. For most countries of South America, species of noctuids with available sequences are scarce, mostly restricted to species of economic importance, making molecular identification untenable. Here we sequenced the mitochondrial DNA ‘barcode’ region of the cytochrome c oxidase subunit I gene of 34 specimens pertaining to 26 species of South American noctuids, 20 of these for the first time. For all species, genetic distances were higher for interspecific than for intraspecific relations, supporting the utility of DNA ‘barcodes’ to identify species. Larger intraspecific divergences occurred in species of Agrotis and Anicla, and interspecific divergences lower than 2% occurred in about one fifth of the species, all in species of Agrotis, Feltia, and Anicla. These results will allow identifying these species using DNA ‘barcodes’, either for pest management or general biological studies. Furthermore, we carried out phylogenetic analyses with those sequences and 158 other sequences of 85 species of noctuids mined from GenBank. These analyses, in every case, grouped species of the same genus suggesting that the DNA ‘barcodes’ region alone can be useful for lower level phylogeny in this group, recovering as monophyletic groups such as Copitarsia, Agrotis and Austrandesiita. Conversely, groups such as Mythimna (Mythimna) and the subgenera of Feltia were not recovered as monophyletic, suggesting the need for further taxonomic studies in these groups.

In Argentina, lettuce (Lactuca sativa L.) is the most common vegetable used in salads, while amaranth (Amaranthus mantegazzianus Pass.) is characterized by its high production of green matter, with high protein and mineral levels; both species are considered accumulators of nitrate, so in order to avoid health problems for the consumer, the European Commission regulates the levels of nitrate in lettuce. In order to assess the accumulation of nitrates in both species and evaluate the protein levels and dry matter content, a trial was conducted at the Faculty of Agronomy, UNLPam, Santa Rosa, La Pampa, Argentina. On December 28, 2009, crisp lettuce was transplanted and amaranth was sown. Four levels of fertilization were added for both species: 1) Compost base: 10 dm³·m-2 moderately composted manure, 2) Double Compost: 20 dm³·m-2 moderately composted manure, 3) Compost base + 30 kg·ha¹ urea and 4) Compost base + 60 kg·ha¹ urea. An experimental design of randomized complete blocks with five replications was employed; significant differences in nitrate levels between species and levels of fertilization were obtained. The values in lettuce were 2.9 % dry basis and 2,634 mg·kg-1 fresh-1 and in amaranth 4.1 and 4,764, respectively. In the case of fertilization levels, compost base with 10 dm³m-2 manure differed from other treatments, for both species studied. Under evaluation conditions, amaranth exceeded the thresholds stipulated by the European Commission. Protein levels showed significant differences between species (20.2 % in lettuce and 24.8 % in amaranth).

La lechuga (Lactuca sativa L.) es la hortaliza más utilizada en ensaladas en Argentina. El amaranto (Amaranthus mantegazzianus Pass.) se caracteriza por su gran producción de materia verde y buen contenido proteínico y mineral. Ambas especies son consideradas acumuladoras de nitratos. Para evitar problemas de salud del consumidor, la Comisión Europea regula la cantidad de nitratos en lechuga. Con el objetivo de evaluar la acumulación de nitratos en ambas especies así como el contenido de proteínas y de materia seca, se realizó un ensayo en la Facultad de Agronomía de la UNLPam., en Santa Rosa, La Pampa, Argentina. Se trasplantó lechuga del tipo crespa y se sembró amaranto el 28 de diciembre de 2009. Se aplicaron cuatro niveles de fertilización para ambas especies: 1) Abono base: 10 dm³·m-2 de estiércol medianamente compostado, 2) Abono doble: 20 dm³·m-2de estiércol medianamente compostado, 3) Abono base + 30 kg·ha-1 de urea y 4) Abono base + 60 kg·ha-1 de urea. Se utilizó un diseño de bloques completos al azar con cinco repeticiones. Se obtuvieron diferencias significativas en el contenido de nitratos entre especies y niveles de fertilización. Los valores en lechuga fueron 2.9 % base seca y 2,634 mg·kg-1fresco-1 y en amaranto 4.1 y 4,764, respectivamente. Para niveles de fertilización, el abono base con 10 dm³·m-2 difirió del resto de los tratamientos, para ambas especies. El amaranto superó los valores máximos establecidos por la Comisión Europea. En contenido de proteína hubo diferencias significativas entre especies (20.2 % en lechuga y 24.8 % en amaranto)