Theme 09: Forage Quality

Description

Palenque Plus and Ceres Torpedo are tall fescue (Festuca arundinacea Schreb.) cultivars available to the animal production systems in the humid Pampean Region of Argentina. They differ in growth cycle and morphological characteristics. At vegetative stage, Torpedo leaves are fine and tender, which suggests that their percentages of slowly digestible and indigestible tissues (SDIT) should be low. In this study we 1) explored the effects of phenological stage and nitrogen fertilization on leaf blade tissue percentages of both cultivars, using an ordination multivariate technique, and 2) evaluated the effects of these factors on the percentage of SDIT. Our results indicate that the analyzed cultivars have different histological responses to fertilization, and maturity. In vegetative stage, Torpedo responds to the fertilization increasing the percentages of live and suberizated tissues, and in reproductive stage increasing the percentage of a dead tissue which cells could be lignified. Palenque responds to both factors, maturity and fertilization increasing the percentage of sclerenchyma, but these responses interact. These different behaviours suggest that the percentage of SDIT would not be a good predictor of the quality in these cultivars in different development stages and fertilization levels.

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Maturity and Fertilization Effects on Leaf Blade Tissue Percentages of Contrasting Fescue Cultivars

Palenque Plus and Ceres Torpedo are tall fescue (Festuca arundinacea Schreb.) cultivars available to the animal production systems in the humid Pampean Region of Argentina. They differ in growth cycle and morphological characteristics. At vegetative stage, Torpedo leaves are fine and tender, which suggests that their percentages of slowly digestible and indigestible tissues (SDIT) should be low. In this study we 1) explored the effects of phenological stage and nitrogen fertilization on leaf blade tissue percentages of both cultivars, using an ordination multivariate technique, and 2) evaluated the effects of these factors on the percentage of SDIT. Our results indicate that the analyzed cultivars have different histological responses to fertilization, and maturity. In vegetative stage, Torpedo responds to the fertilization increasing the percentages of live and suberizated tissues, and in reproductive stage increasing the percentage of a dead tissue which cells could be lignified. Palenque responds to both factors, maturity and fertilization increasing the percentage of sclerenchyma, but these responses interact. These different behaviours suggest that the percentage of SDIT would not be a good predictor of the quality in these cultivars in different development stages and fertilization levels.