Description and Cytology of a Form of Signal Grass (Brachiaria brizantha Stapf.) and its Agronomic Behavior Compared to Guinea Grass (Panicum maximum Jack.)

Abstract

The somatic chromosome number of a form of Signal grass (Brachiaria brizantha Stapf.), Puerto Rico P.I. No. 1525, introduced from Ceylon, was found to be 36. Only 15 percent of the florets studied developed karyopses. The meiotic behavior of chromosomes at microsporogenesis was irregular. Frequent lagging univalents at anaphase 1 and micronuclei in the spore quartets may account for the low seed-set of this form. More improvement of this character is expected in Signal grass through further research in genetics and by the introduction of more forms and varieties. A field description of Signal grass is given. Signal grass was compared to Guinea grass (Panicum maximum Jack.) as to agronomic behavior. It showed desirable characteristics, besides yielding the same as Guinea grass, one of our best forage grasses, when both grasses were tested at the Gurabo Substation for a period of 530 days. The mineral content of the grasses under this experiment was comparable, but calcium and magnesium were definitely higher in Guinea grass. The lignin content of Signal grass was lower than that of Guinea grass; this difference, although small in favor of Signal grass, may have more importance in terms of animal digestibility than the chemical analyses indicate. The results obtained in relation to yielding ability and drought-resistance of this form of Signal grass are very encouraging. As the palatability of this grass has been found to be comparable to that of Napier grass, which is the standard grass used for palatability tests at this Station, it may be expected to occupy in due time a very important place as a forage crop throughout the Island of Puerto Rico, especially in the drought areas.