Qualidade fisiológica de sementes de milho tratadas com inseticidas e armazenadas em diferentes temperaturas

The objective of this work was to evaluate the effect of the industrial treatment with insecticides on the physiological quality of corn (Zea mays) seeds during storage at different temperatures. Seeds of the BM 950 PRO3 and BM 709 PRO2 hybrids were subjected to industrial treatment with insecticides based on chlorantraniliprole, cyantraniliprole, and clothianidin, as well as to a control, and stored at different temperatures (10, 20, and 30°C) for 0, 90, 180, 270, and 360 days, in a 4x3x5 factorial arrangement for each hybrid, in a completely randomized design. To evaluate the quality of the seeds, tests of moisture content, germination, seedling emergence, accelerated aging, and cold were performed. For the seeds of both hybrids, germination is preserved at minimum commercialization standards for up to 360 days of storage, regardless of the insecticide or storage temperature. The temperature of 10°C preserves seed vigor and minimizes the negative effects caused by the insecticides during storage. At 20 and 30°C, vigor is cumulatively impaired as storage is extended, mainly at 30°C. Chlorantraniliprole results in a greater preservation of seed vigor regardless of storage temperature, whereas clothianidin provides a greater loss of vigor in industrially treated corn seeds, especially when stored at 30°C.O objetivo deste trabalho foi avaliar o efeito do tratamento industrial com inseticidas sobre a qualidade fisiológica de sementes de milho (Zea mays) ao longo do armazenamento, em diferentes temperaturas. Sementes dos híbridos BM 950 PRO3 e BM 709 PRO2 foram submetidas ao tratamento industrial com inseticidas à base de clorantraniliprole, ciantraniliprole e clotianidina, além de a um controle, e armazenadas em diferentes temperaturas (10, 20 e 30°C) por 0, 90, 180, 270 e 360 dias, em arranjo fatorial 4x3x5 para cada híbrido, em delineamento inteiramente casualizado. Para avaliar a qualidade das sementes, foram realizados testes de grau de umidade, germinação, emergência de plântulas, envelhecimento acelerado e de frio. Para as sementes dos dois híbridos, a germinação é preservada nos padrões mínimos de comercialização por até 360 dias de armazenamento, independentemente do inseticida ou da temperatura de armazenamento. A temperatura de 10°C preserva o vigor das sementes e minimiza os efeitos negativos causados pelos inseticidas durante o armazenamento. A 20 e 30°C, o vigor é cumulativamente prejudicado à medida que o armazenamento é prolongado, principalmente a 30°C. O clorantraniliprole resulta em maior preservação do vigor da semente, independentemente da temperatura de armazenamento, enquanto a clotianidina proporciona maior perda de vigor em sementes de milho tratadas industrialmente, especialmente quando armazenadas a 30°C

AGRONOMIC PERFORMANCE OF ERECT AND SEMI-ERECT COWPEA GENOTYPES IN THE NORTH OF MINAS GERAIS, BRAZIL

The objective of this work was to evaluate the agronomic performance of elite-strains of cowpea cultivars under the conditions of the north of Minas Gerais (MG), Brazil. Fifteen elite-strains and five erect and semi-erect cultivars of cowpea were evaluated in the 2014 and 2015 summer-fall crop seasons in Janaúba MG. A randomized block experimental design was used with four replications. Plant size, lodging and value of cultivation, pod length and grain yield were evaluated. The data of the two crops were subjected to individual and joint analysis of variance. The genotype-crop interactions significantly affected all studied variables. The strains MNC04-792F-146 and MNC04-792F-144 stood out as the most productive genotypes in both crops. The cultivars BRS Itaim and BRS Novaera presented adequate size and lodging characteristics for cultivation, and values of cultivation that meet commercial standards, thus representing good alternatives for the genotypes cultivated in the north of Minas Gerais