R E S U M ONeste trabalho se objetivou avaliar a aplicação foliar de aminoácidos associada à aplicação de nitrogênio em cobertura, no desempenho produtivo e nas características agronômicas da cultura do milho, cultivado no período da safrinha. O delineamento foi o de blocos ao acaso, em esquema fatorial 4 x 4, com 4 repetições. Foram utilizadas quatro doses de nitrogênio em cobertura (0, 60, 120 e 180 kg ha -1 ) na forma de ureia e quatro doses de aminoácido (0, 8, 16, e 24 L ha -1 ) aplicadas via foliar. A cultivar de milho utilizado foi o Pioneer 305 31H. As variáveis analisadas foram teor de nitrogênio foliar, altura de plantas, altura de espiga, diâmetro do colmo, comprimento de espiga, número de fileiras de grãos por espiga, número de grãos por fileira, número de grãos por espiga, massa de 100 grãos e produtividade de grãos. O aminoácido não alterou as variáveis analisadas. O nitrogênio incrementou linearmente as variáveis altura de plantas, altura de inserção de espiga, número de grãos por espiga e número de grãos por fileira. O comprimento de espiga, a massa de mil grãos e a produtividade de grãos obtiveram, respectivamente, máxima resposta ao nitrogênio nas doses de 135,3, 157 e 149,5 kg ha Aplicação foliar de aminoácidos e adubação nitrogenada de cobertura na cultura do milho safrinha

Tukey's test (p ≤ 0.01) were used. The interaction between cultivars and environments influence all yield components, GY and PC. The interaction management forms of N and environments affected the TKW, NEA, GY and PC. The results showed that in low-rainfall environments, nitrogen topdressing could be suppressed with no negative effects on GY or PC. Under ideal weather conditions, the GY of wheat cultivars was enhanced on application of 60 kg.ha-1 N of urea at the beginning of tillering as well 20 kg.ha-1 of N at booting. Matching the appropriate cultivars to the ideal growth environment is essential for achieving high GY values. The nitrogen forms on the topdressing do not influence the PC of cultivars in Pato Branco.

No abstract

ResumoA diversidade genética existente no milho permite seu cultivo nos mais diversos ambientes. Contudo, o excesso de chuva, em regiões úmidas e quentes, logo após a semeadura, pode prejudicar a germinação por restringir o oxigênio ou causar danos embrionários provocados pela embebição demasiadamente rápida. Deste modo, este trabalho teve por objetivo verificar os efeitos de períodos de hipoxia na germinação de sementes de diferentes cultivares de milho. Foram utilizados três tipos de cultivares, sendo dois híbridos (DKB 787 e AG 8088), uma variedade melhorada (IPR 114) e duas variedades crioulas (Asteca e Caiano) submetidos a 4; 8; 12; 24; 36; 48 e 96 horas de hipoxia, sob temperatura de 25 ºC, com quatro repetições de 50 sementes. A qualidade inicial das sementes foi caracterizada pelos testes de germinação, de emergência de plântulas no campo, de envelhecimento acelerado e de frio. Após os períodos de hipoxia, as sementes foram submetidas ao teste de germinação com avaliação das porcentagens de plântulas normais, anormais, sementes mortas e massa seca de plântulas. A hipoxia reduz a porcentagem de germinação das sementes e aumenta a porcentagem de plantas anormais em todas as cultivares. As cultivares Asteca e Caiano apresentam menor porcentagem de germinação. O incremento do período de hipoxia causa mortalidade de sementes para as cultivares IPR 114 e DKB 787. As cultivares DBK 787 e AG 8088 apresentam menor massa seca de plântulas e menor sensibilidade às condições de hipoxia que a variedade e as cultivares crioulas.Palavras-chave adicionais: alagamento; encharcamento do solo; tolerância; variedades crioulas; Zea mays. AbstractMaize genetic diversity permits its cultivation under most of the environmental conditions. Excessive rain in hot and humid regions soon after seed sowing may, though, hamper germination due to lack of oxygen or cause damage to the embryo axis due to a very rapid imbibition. So, this study had the objective of verifying the effects of periods of hypoxia on the germination of seeds of several maize cultivars. Three types of maize cultivars were used : two hybrids (DKB 787 and AG 8088), one improved variety (IPR 114),and two landrace varieties (Asteca and Calano) whose seeds were submitted to 4, 8, 12, 24, 48, and 96 hours of hypoxia under a temperature of 25 °C with four repetitions of 50 seeds. Seed initial quality was evaluated by means of germination, seedling emergence in the field, accelerated aging, and cold test. After the hypoxia treatments, the seeds were submitted to the germination test evaluating the percentage of normal seedlings, abnormal seedlings, dead seeds, and the seedlings dry matter content. Hypoxia reduced seeds germination percentage and increased the percentage of abnormal seedlings in all cultivars. Cultivars Asteca and Caiano presented the lowest germination percentage. Increasing hypoxia duration causes seed death in cultivars IPR 114 and DKB 787. Cultivars DKB 787 and AG 8088 seedlings were the ones with the lowest dry matter content in comparison with the ...

The quality of wheat is a pre-eminent factor in the criteria for commercialization of this cereal, and several parameters contribute to the evaluation of wheat quality. The objective of this study was to verify the effects of nitrogen fertilization on the cover and the environment for wheat cultivars and the effects on the industrial quality of the grain. Furthermore, we sought to identify correlations between the parameters of industrial quality. Experiments were conducted in Londrina for 2 years, in two distinct environments (A1 and A2). The experimental design was a randomized complete block design with four replications. The cultivars IPR Catuara TM, BRS Gaivota, Quartzo, and CD 120 were evaluated with different forms of nitrogen management: N1, without N in coverage; N2, 60 kg ha-1 of N in the form of urea at the beginning of tillering; N3, 80 kg ha-1 of N in urea formulation (60 kg ha-1 in tillering and 20 kg ha-1 in booting); N4, 100 kg ha-1 of N in the form of urea (60 kg ha-1 in tillering and 40 kg ha-1 in booting); N5, 80 kg ha-1 of N (60 kg ha-1 of N in the form of urea at the beginning of tillering, and 20 kg ha-1 of N in the form of ammonium sulfate in booting); N6, 100 kg ha-1 of N (60 kg ha-1 of N in the form of urea at the beginning of tillering, and 40 kg ha-1 of N in the form of ammonium sulfate in booting). Further, we evaluated grain yield, protein content, sedimentation volume with sodium dodecyl sulfate, and parameters of alveograph and farinograph. Nitrogen fertilization did not influence industrial quality parameters. The stability of the mass was influenced by the isolated effects of cultivars and the environment. The interaction of cultivars and environments influenced the parameters of alveograph and water absorption of the mass. The higher the protein content, the lower the stability of the mass, independent of the cultivar.