Desempenho de populações de alfafa sob desfolhação

Abstract

RESUMO -Neste trabalho, objetivou-se verificar a resposta de populações de alfafa à desfolhação. Avaliaram-se duas populações de alfafa Crioula (tipo-feno), selecionada em estádio de plântula de acordo com o comprimento do segundo entrenó (EC = 1,5 cm; EL = 2,5 cm) e uma do cultivar Alfagraze (tipo-pastejo). As plantas foram cultivadas em vasos nos meses de março a agosto de 2005 e submetidas a uma combinação de altura (2 e 8 cm) e freqüência de corte (semanal, quinzenal e mensal) durante 141 dias. Não houve diferença quanto à produção da matéria seca (MS) aérea sob cortes semanais e quinzenais. Com cortes mensais, a população Crioula-EL, com maior altura e quantidade de hastes, superou as demais. Os cultivares Alfagraze e Crioula-EC foram similares quanto à quantidade de MS subterrânea. As populações de alfafa diferiram na resposta ao manejo de corte e apresentaram declínio gradual na MS quando submetidas a cortes mais freqüentes, com maior sobrevivência do cultivar Alfagraze em comparação aos cultivares Crioula-EC e Crioula-EL. O cultivar Alfagraze diferiu das populações do cultivar Crioula e apresentou menor altura, maior diâmetro, maior proporção de hastes da coroa e maior alocação de MS na parte subterrânea, portanto, estas características estão relacionadas ao tipopastejo. O comprimento do entrenó da plântula poderia ser utilizado complementarmente para selecionar populações de alfafa com maior aptidão ao pastejo, o que torna possível obter populações com variabilidade de produção de matéria seca e sobrevivência.Palavras-chave: cortes, persistência, tipo-feno, tipo-pastejo Performance of alfalfa populations under defoliationABSTRACT -This work aimed to evaluate the performance of alfalfa populations in response to defoliation. Two populations of alfalfa cv. Crioula (hay-type) and one population of alfalfa cv. Alfagraze (grazing-type) were evaluated, being selected at seedling stage according to the length of the second internode (EC=1.5 cm; EL=2.5 cm). The trial was performed in pots, between February and August/2005. The populations were harvest at two cutting intensities (2 and 8 cm) and three cutting frequencies (weekly, fortnightly and monthly) during 141 days. There was no difference on shoot dry matter (DM) yield between weekly and fortnightly cuttings; the Crioula-EL, under monthly cuttings was the tallest and had higher amount of stems, surpassing the others. There was similarity between the cultivar Alfagraze and Crioula-SI regarding underground DM biomass. Alfalfa populations responded differently to defoliation management, with a gradual decline on DM yield under more frequent cuttings and a higher survival of plants from Alfagraze compared to Crioula-EC and Crioula-EC. Alfagraze cultivar differed from the Crioula populations, presenting shorter plants, higher proportion of stems originate from the crown and a higher allocation of DM to the underground parts, indicating that these characteristics belong to a grazing-type alfalfa. The length of seedling internodes could be used as a complementary...

Production of alfalfa hay under different drying methods

“…In Brazil, alfalfa is produced and traded mainly as hay and Crioula is the main cultivar used (Favero et al, 2008), its entire drying process is done under the sun. However, since it is a leguminous, an excessive drying under the sun might occur and the turnings are likely to cause fall of the leaves, consequently, decreasing its nutritional value.…”

Morphological development of Alfagraze cultivar and Crioula alfalfa populations selected at the seedling stage

“…The Crioula-SI cultivar population, which resembled that of the Alfagraze cultivar at the seedling stage, was basically smaller and less productive. On the other hand, in the study undertaken by Favero et al (2008), this same population, when submitted to intense (2 cm) and frequent (weekly) clippings, revealed a 50% persistence rate, whereas the Crioula-LI cultivar did not survive. In the same study, the Alfagraze cultivar survived remarkably well, exhibiting the highest tolerance for this clipping management.…”

“…Crioula-LI populations, which stood out in this study for their larger stem number at the flowering stage and for their greater average height, also showed the same behavior under clipping management. Favero et al (2008) mentioned that this population benefited more from less frequent clippings, every 30 days, outperforming Crioula-SI and Alfagraze cultivars in terms of dry matter yield.…”