Cluster Analysis to Tiller Age Categories in Marandu Palisadegrass Under Continuous Stocking Management and Nitrogen Fertilization.

Combination of morphological traits and multivariate analysis techniques has been widely used as a means of determining similarities between groups of interest in forage plant studies. In grazed swards, tiller age interfere with plant responses to modifications in environmental conditions and defoliation management altering morphogenetic responses. In this context, the response variables leaf appearance (LAR) and elongation rate (LER) and leaf life span (LLS) were used to evaluate the relationship between tiller age and plant morphogenetic responses of continuously stocked marandu palisadegrass swards maintained at 30 cm, fertilised (150, 300, 450 kg/ha) or not (control) with nitrogen, using a multivariate procedure of data analysis; Cluster Analysis. It was used the mean distance method, calculated based on the pooled means of the response variables studied, as a means of identifying tiller age groups. LAR, LER and LLS were effective in allowing discrimination between three tiller age groups or categories: young (0 to 60 days of age), mature (60 to 120 days of age) and old tillers (more than 120 days of age); indicating base values for planning future studies on ecophysiology of marandu palisadegrass.