RESUMEN
The dual-purpose wheat stands out as a complementary alternative for forage supply during the winter period. Therefore, this work had the objective of evaluate the performance characteristics in five genotypes of dual-purpose wheat submitted to different sowing densities and different clipping managements. The experiment was carried out during the 2016 and 2017 harvests. The experimental design was a randomized block design, organized in a factorial scheme, with five dual-purpose wheat genotypes (BRS Tarumã, BRS Umbu, BRS Figueira, BRS Guatambu and BRS 277) x five sowing densities (75, 150, 225, 300 and 375 seeds m²) x four clipping operations (zero, one, two and three clippings), arranged in three replicates. The measuring of characters were number of fertile tillers, seeds yield, angle of flag leaf, chlorophyll content and flowering. The genotype BRS Tarumâ is superior in number of fertile tillers and chlorophyll index for all the sowing densities, as well, the flowering is influenced direct by clipping managements. The sowing density of 75 seeds m-2 is not indicated for dual-purpose wheat independent of the clipping management. The seeds yield is amplified thought the increase in sowing density, however, advancing in clipping levels there is a decrease in forage yield.
O trigo de duplo propósito se destaca como uma alternativa complementar para o fornecimento de forragem durante o período de inverno. Portanto, este trabalho teve como objetivo avaliar as características de desempenho de cinco genótipos de trigo de duplo propósito submetidos a diferentes densidades de semeadura e diferentes manejos de corte. O experimento foi realizado durante as safras de 2016 e 2017. O delineamento experimental foi em blocos ao acaso, organizado em esquema fatorial, com cinco genótipos de trigo de duplo propósito (BRS Tarumã, BRS Umbu, BRS Figueira, BRS Guatambu e BRS 277) x cinco densidades de semeadura (75, 150, 225, 300 e 375 m² de sementes) x quatro operações de clipagem (zero, um, dois e três recortes), dispostos em três repetições. As medidas dos caracteres foram número de perfilhos férteis, rendimento de sementes, ângulo de folha de bandeira, teor de clorofila e floração. O genótipo BRS Tarumâ é superior em número de perfilhos férteis e índice de clorofila para todas as densidades de semeadura, assim como o florescimento é influenciado diretamente pelos manejos de corte. A densidade de semeadura de 75 sementes m-2 não é indicada para trigo de dupla finalidade independente do manejo de corte. O rendimento das sementes é amplificado pelo aumento da densidade de semeadura, entretanto, avançando nos níveis de recorte, há uma diminuição no rendimento de forragem.
Asunto(s)
Triticum , Adaptación FisiológicaRESUMEN
In cases of asymmetric competition, larger individuals of many animal species have a greater probability of acquiring territory, gaining initial access to resources and finding a mate in comparison to smaller individuals. The competition among larvae of the antlion Myrmeleon brasiliensis (Neuroptera, Myrmeleontidae) is observed in the search for space for the construction of traps, in the forage for prey, and in the occurrence of cannibalism. The body size of the larvae is proportional to the size of the traps and the success of predation. Thus, larger specimens are better competitors in terms of capturing preys (asymmetric competition). The aim of the present study was to determine the effects of asymmetric competition in M. brasiliensis regarding the distance among these larvae. The study was developed in a permanent reserve area, located in the municipality of Aquidauana, from the Mato Grosso do Sul state, Brazil. For the laboratory experiments, we collected M. brasiliensis larvae and placed two larvae in plastic pots. The observations occurred by the visual search of traps, when a larva was seen in the diameter of its trap and the trap of its closest neighbor. Next, the trap size and the distance between them were measured for a period of 15 days. The results of the present study demonstrate that the largest M. brasiliensis larvae were outside the clusters. Within these clusters, the larvae moved away from each other because of the size of their traps, as the larger the neighboring larvae the greater the distance between them. Thus, the asymmetric competition between M. brasiliensis (larger larvae are better competitors) suggests a spatial arrangement among the larvae that is guided by the variable size of the trap.