Agronomic Comparison and In Vitro Dry Matter Digestibility of Eight Sorghums at Two Locations in Puerto Rico

Abstract

Eight sorghum (Sorghum bicolor L. Moench) genotypes were evaluated during four consecutive 60-day cuttings at two locations in Puerto Rico. Differences between genotypes and cuttings were significant for the eight traits studied (green forage yield, content and yield of dry matter and crude protein, in vitro dry matter digestibility, plant height and leaf area). The location x genotype interaction was significant for most traits except dry matter content and in vitro dry matter digestibility (IVDMD). At both locations the best dry forage producers over the 240-day period were ATx623 x Rio and ATx623 x TMTx430 with 34 and 30 t/ha, respectively, al Isabela; and 20 and 19 t/ha, respectively at Mayagüez. Average IVDMD and crude protein values of hybrids were 58 and 10.2%, respectively. Rio was lowest in dry forage yield but highest in IVDMD value: 62%. Leaf area had a high positive correlation with the three yield criteria. A rough estimate of net profit from growing forage sorghum in Puerto Rico for milk production is $1,211/ha.