The effect of tiller length and age on herbage quality of hybrid Pennisetum canopies.

Abstract

Whole plants were sampled every 10 or 11 days from field-grown P. americanum X P. purpureum canopies which were cut at intervals of 3 or 6 weeks. Tillers of varying lengths were analysed for in vitro dry matter digestibility (IVDMD). During the growing period, average whole tiller digestibility decreased, as did differences between tillers of different lengths. In 42-day-old herbage, no difference in IVDMD was found between 10 and 70 cm tillers. The decline in digestibility with time was attributed to (1) the appearance of tall tillers and (2) the detrimental effects of low light intensities on tillers growing deep in the canopy. Results suggested that it is doubtful whether tiller length or other morphological or physiological traits can be used to predict herbage digestibility, and that in breeding for better digestibility selection for stem digestibility per se should be more promising than selection for reduced stem growth. (Abstract retrieved from CAB Abstracts by CABI’s permission)