Establishment of rhizoma perennial peanut (Arachis glabrata) under irrigation at two semiarid sites in the Caribbean

Two experiments were conducted to determine time for full establishment of rhizoma perennial peanut (RPP) under irrigation. Experiment one (E1) and ex periment two (E2) were conducted, respectively, at the Lajas and Fortuna Su bstations of the Agricultural Experiment Station of the University of Puert o Rico. At Lajas, rhizomes of accessions USDA-ARS no. 17033, 17050, 17052, 17097 (PI no. 276233, 262826, 262833, 262839, respectively) and cultivars F lorigraze and Arbrook, planted at 0.76 and 1.5 m apart in rows, were compar ed for rate of establishment at 60, 120, 180 and 240 days postplanting. At Fortuna, rhizomes of accessions 17033 and 17097, and cv. Florigraze were co mpared at 80, 160, and 240 days postplanting. In E2, plots were subjected t o the following weed control methods: (1) manual, (2) mowing, and (3) chemi cal. Time to full establishment in E1 increased from about six months to ei ght with an increase in planting distance from 0.76 to 1.5 m. Accessions 17 033 and, 17097 and cv. Florigraze showed a tendency for faster lateral spre ad prior to 120 days postplanting than the other RPPs. However, peanut geno types achieved full cover at about the same time. The use of herbicide in E 2 was the most effective method for promoting faster cover of RPP plants. E stablishment of the stand was achieved prior to 240 days in plots receiving weed control treatments 1 and 3, whereas those receiving treatment 2 achie ved only 62.5% cover. Compared to a tropical grass, RPP exhibits a slower p attern of lateral spread and requires a longer time for full establishment when planted under similar conditions. However, reducing planting distance and using herbicides to control weeds are management strategies that can re duce time for full establishment of the RPP stand.