Agronomic potential of stylo [Stylosanthes guianensis (Aubl.) Sw.] in Puerto Rico

Abstract

Forty stylo accessions [Stylosanthes guianensis (Aubl.) Sw.] were evaluated in 1989-90 at the USDA-ARS Isabela farm for growth vigor and plant height at 90 and 120 d during the establishment period, and for dry matter yield (DMY), crude protein (CP) concentration, and in vitro dry matter digestibility (IVDMD) at one 120-d and four 60-d harvests. No significant differences were observed among the 20 and 32 accessions having a growth vigor index (GVI) of 4.0 to 5.0 at the 90- and 120-d harvests, respectively. Plant height (PHt) and GVI were highly correlated. Most of the accessions were classified as short-day plants. No DMY differences were observed among the 14 higher yielding accessions at the 120-d harvest nor among 17, 14, 2 and 11 higher yielding accessions at the first, second, third and fourth 60-d harvests, respectively. Across the 60-d harvests, the mean DMY of the 40 accessions was 1,563 kg/ha. CIAT 1102 had the highest value (2,710 kg/ ha). Mean CP concentrations for the 120-d and four 60-d harvests were 17.3, 15.8, 16.2, 16.9 and 16.8%, respectively. For all harvests, the IVDMD of the accessions averaged 52.4%. Accession 1102 has good potential as a forage crop for protein banks, hay or grass-legume combinations and theoretically could produce 16 t/ha of DMY annually when harvested every 60 d.