Elementos de produção de milho doce em diferentes densidades populacionais

The objective of the present study was to evaluate the population density effect upon yieldcomponents of sweet corn during two crop years. The experimental design used was the randomizedcomplete blocks with four replications. The treatments were based on combination among sweetcorn hybrids (Tropical Plus and RB-6324) and plant populations (40,000; 55,000; 70,000; 85,000 and100,000 plants ha-1), in the factorial scheme 2 x 5, evaluated in two “Summer” crop years (2009 and2010). The characteristics evaluated were number of rows per ear, number of grains per ear row,plant prolificacy and total husked ear yield, whose average values were submitted to the jointanalysis of variance. In the year of 2009 for Tropical Plus and in the year of 2010 for RB-6324, theprolificacy decreased linearly until the maximum population of plants used, which presented valuesof 1.04 ear plant-1 and of 1.02 ear plant-1, respectively. A minimum value of prolificacy (1.08 earplant-1) was observed for RB-6324 in 2009 with 92,935 plants ha-1. In 2009, the highest yields of huskedears for Tropical Plus (8.43 t ha-1) and for RB-6324 (9.88 t ha-1) were achieved with a density of 100,000plants ha-1. On the other hand, in the second crop year, the yields increased quadratically from51,848 plants ha-1 (7.78 t ha-1), for Tropical Plus, and from 57,648 plants ha-1 (9.32 t ha-1), for RB-6324,until the maximum population of plants evaluated, whereupon presented their respective maximumvalues of 12.04 t ha-1 and 12.31 t ha-1. In general, the increase in population was unfavorable to theprolificacy of plants, but did not impair the husked ear yield, for which it was noted better answerswith a population of 100,000 plants ha-1, in both crop years and hybrids used.O objetivo do presente estudo foi avaliar o efeito da densidade populacional sobre componentes de produção de milho doce durante dois anos agrícolas. O delineamento experimental utilizado foi o de blocos completos casualizados com quatro repetições. Os tratamentos constituíram-se da combinação entre híbridos de milho doce (Tropical Plus e RB-6324) e populações de plantas (40.000, 55.000, 70.000, 85.000 e 100.000 plantas ha-1), no esquema fatorial 2 x 5, avaliados em dois anos agrícolas de “Verão” (2009 e 2010). Foram analisadas as características número de fileiras por espiga, número de grãos por fileira de espiga, prolificidade de plantas e produtividade média total de espigas despalhadas, cujos valores médios foram submetidos à análise de variância conjunta. No ano de 2009 para Tropical Plus e no de 2010 para RB-6324, a prolificidade reduziu linearmente até a máxima população de plantas utilizada, na qual apresentaram os valores de 1,04 espiga planta-1 e 1,02 espiga planta-1, respectivamente. Um mínimo valor de prolificidade (1,08 espiga planta-1) foi observado para RB-6324 no ano de 2009 com 92.935 plantas ha-1. Em 2009, as maiores produtividades de espigas despalhadas de Tropical Plus (8,43 t ha-1) e RB-6324 (9,88 t ha-1) foram atingidas com a densidade de 100.000 plantas ha-1. Por sua vez, no segundo ano agrícola, as produtividades aumentaram quadraticamente de 51.848 plantas ha-1 (7,78 t ha-1), para Tropical Plus, e de 57.648 plantas ha-1 (9,32 t ha-1), para RB-6324, até a máxima população de plantas avaliada, em que apresentaram seus respectivos máximos valores de 12,04 t ha-1 e 12,31 t ha-1. De maneira geral, o incremento populacional foi desfavorável à prolificidade de plantas, porém não prejudicou a produtividade de espigas despalhadas, para a qual se notou melhores respostas com a população de 100.000 plantas ha-1, em ambos os anos agrícolas e híbridos utilizados. Yield elements of sweet corn in different population densitiesAbstractThe objective of the present study was to evaluate the population density effect upon yieldcomponents of sweet corn during two crop years. The experimental design used was the randomizedcomplete blocks with four replications. The treatments were based on combination among sweetcorn hybrids (Tropical Plus and RB-6324) and plant populations (40,000; 55,000; 70,000; 85,000 and100,000 plants ha-1), in the factorial scheme 2 x 5, evaluated in two “Summer” crop years (2009 and2010). The characteristics evaluated were number of rows per ear, number of grains per ear row,plant prolificacy and total husked ear yield, whose average values were submitted to the jointanalysis of variance. In the year of 2009 for Tropical Plus and in the year of 2010 for RB-6324, theprolificacy decreased linearly until the maximum population of plants used, which presented valuesof 1.04 ear plant-1 and of 1.02 ear plant-1, respectively. A minimum value of prolificacy (1.08 earplant-1) was observed for RB-6324 in 2009 with 92,935 plants ha-1. In 2009, the highest yields of huskedears for Tropical Plus (8.43 t ha-1) and for RB-6324 (9.88 t ha-1) were achieved with a density of 100,000plants ha-1. On the other hand, in the second crop year, the yields increased quadratically from51,848 plants ha-1 (7.78 t ha-1), for Tropical Plus, and from 57,648 plants ha-1 (9.32 t ha-1), for RB-6324,until the maximum population of plants evaluated, whereupon presented their respective maximumvalues of 12.04 t ha-1 and 12.31 t ha-1. In general, the increase in population was unfavorable to theprolificacy of plants, but did not impair the husked ear yield, for which it was noted better answerswith a population of 100,000 plants ha-1, in both crop years and hybrids used