Dry matter yield of rhizoma perennial peanut (Arachis glabrata) harvested at six, nine and 12 weeks at two semiarid sites

Rhizoma perennial peanut (RPP) is a forage legume of excellent adaptability and persistence under subtropical and tropical conditions. Four accessions (USDA-TARS 17033, 17050, 17052, and 17097, with PI nos. 276233, 262826, 26 2833, and 262839, respectively) and two cultivars (Arbrook and Florigraze) of rhizoma perennial peanut (RPP) in Lajas, and two of the accessions (1703 3 and 17097) and cultivar Florigraze in Juana Diaz, Puerto Rico, were evalu ated for dry matter yield (DMY) under irrigation during a full year. The RP Ps were evaluated at six-, nine- and 12-wk harvest intervals (HI) in each o f the four seasons of the year. At both sites, yield of accession 17033 was highest (P < 0.01) and averaged 35,779 kg DM/ha/yr. In Lajas, yield of acc ession 17097 was second best with an average of 30,151 kg DM/ha/yr, yields of the other four RPPs were similar, averaging 25,374 kg DM/ha/yr. Cultivar Florigraze, which produced 16% less than accession 17097 in Lajas, had sim ilar productivity in Juana Diaz. On average, the total yields of accessions 17033 and 17097 and cultivar Florigraze declined (P < 0.01) by about 35 an d 27% at the two locations, respectively, as HI increased from six to 12 we eks. Season of harvest had a strong influence on the DMY of RPP. At both lo cations, 69 and 64% of total yields were produced during spring and summer, respectively. Differences in height among RPPs were significant (P < 0.01) at both locations. Height averaged 26.0, 17.6, and 18.5 cm for accessions 17033 and 17097 and cultivar Florigraze, respectively. The great adaptabili ty of RPP to the tropical environment, and its high yield when harvested fo r hay, make it a crop with the potential of becoming one of the most import ant forages in the tropics.