PROCEEDINGS of the 33Rd ANNUAL MEETING
Total Page：16
File Type：pdf, Size：1020Kb
PROCEEDINGS OF THE 33rd ANNUAL MEETING 6-12 July 1997 Proceedings Edited by Nelson Semidey and Lucas N. Aviles Published by the Caribbean Food Crops Society Proceedings oithe Caribbean Food Crops Society. 33:171-177. 1997 POTENTIAL OF FORAGE PEANUT IN THE TROPICS A. Sotomayorf, E. Valencia \ A. Quiles T. Ruiz 3 and S. Torres 'USDA, ARS;-Tropical Agriculture Research Station, Mayaguez, Puerto Rico, 2Department of Agronomy, University of Florida, Gainesville, Florida, 3 Department of Animal Industry, University of Puerto Rico, Mayaguez, Puerto Rico. ABSTRACT. Two of the most important perennial forage species of the genus Arachis (A. glabrata Benth . and A. pintoj Krap. & Greg) have been evaluated by TARS in preliminary trials. Desirable qualities of these forage legumes are (1) high biomass of excellent quality, (2) insect resistance and low disease susceptibility, (3) drought tolerance, and (4) long-term persistence. A. Glabrata is propagated by rhizome and A. pintoj by seed or stolon. Two new A. glabrata cultivars released by the University of Florida, "Arblick" and "Ecoturf', were among those evaluated. Rate of establishment using different management techniques and dry matter yield were determined. A. glabrata accessions 17097 and 17033 had 90% ground cover after 120 days on a Mollisol at the Fortuna Substation of the University of Puerto Rico (UPR). These accession 17097 has the ability to produce 25,000 and 21,000 Kg/ha/yr at the 6-and 12-wk CI. These yields, plus its high crude protein concentration (19 and 16% at the two CI), make it an ideal forage legume for use in animal-feeling systems in the tropics. INTRODUCTION Perennial peanut is native to South America. Its center of origin is the Jequitinhonha Valley, Sao Francisco, and the Tocantins River in Brazil (Vails, 1992). Two important forage species are Arachis glabrata Benth and A. pintoi Krap. & Greg. The main difference between the-two species is that the former is propagated by rhizomes and the latter by seed. This legume has wide, ovate, and lanceolate leaves. It produces a papilionaceous flower that is generally self-pollinated but it may be cross pollinated by various species of bees. Although Arachis flowers can be yellow, pastel, orange, reddish orange, cream-white, or white, they are generally yellow. The forage peanut Arachis has received little attention in Puerto Rico although considerable research on this legume has been conducted in Central and South America, Mexico, Asia, Africa, and the Pacific (Argel, 1993; Pizarro and Rincon, 1993; Stür and Ndikumana, 1993). In the United States, rhizoma perennial peanut (RPP) (A. glabrata Benth.) has been planted in Florida, Louisiana, and Texas. Current rhizoma peanut area in Florida is over 10,000 ha, most of it planted to "Florigraze"a cv developed by the University of Florida (Prine et al., 1981,1986). Arachis peanut can be used for forage or hay and as ornamental and a cover crop. In agricultural enterprises with a high gross return per unit area, such as hay production, and dairying, and for plantation crops needing ground coverage, it will most likely find quick adoption. Arachis as a cover crop can contribute to decreasing the cost of coffee production due to less need for nitrogen fertilizer and weed control and improvement of the surrounding plants by increasing soil tilth arid porosity and decreasing erosion and loss of vital minerals. The objectives of this paper are to summarize the main research activities that have been conducted in Puerto Rico on forage Arachis by the Tropical Agriculture Research Station 171 (TARS) of the USDA-ARS, and the University of Puerto Rico, College of Agricultural Sciences, and to summarize the research and development and constraints of this crop in the tropics in general. MATERIALS AND METHODS The Arachis spp. collection: On February 8, 1990, 70 rhizoma peanut accessions (vegetative material) of five of A. repens, and commercial cvs Arbrook and Florigraze were planted on an Oxisol (Typic Hapludox) at the USDA-ARS Isabela farm in Northwestern Puerto Rico. 18 7' N, 67 W. The accessions and cultivars were maintained in replicated plots and lateral spread measurements taken February 7, 1991. Between May and July, 1991, the plots were divided and maintained with distinct boundaries measuring 4 χ 4 m. All the Arachis spp of the collection were evaluated for plant spread, plant height, and vigor. Cultivars Arbrook and Florigraze and the best 10 were selected for agronomic field evaluations. The/4, repens accessions were not selected due to their low spreading habit and minimal top-growth. Experiment 1: Agronomic evaluation of Arbrook and Florigraze and 10 RPP at the Isabela USDA-ARS farm harvested at 6-, and 12-wk cutting intervals (CI). Management practices utilized in this experiment are described in a previous paper (Valencia et al., 1997). Experiment 2: Agronomic evaluation of six A. pintoi accessions was conducted at the Isabela USDA-ARS farm. Seed of six A. pintoi accessions introduced from CI AT, Cali Colombia, were germinated in the greenhouse after being inoculated with rhizobium CIAT 3101. Three weeks after germination, the seedlings were planted at the Isabela USDA-ARS farm April 3, 1992. The design was a randomized complete block with three replications. Plots measured 2.0 χ 3.5 m. The plots were irrigated every three days during four weeks. Ground cover percentage (GCP) was measured 8, 12 and 16 weeks after planting. Management practices utilized in the experiment and a description of the measurements taken and chemical analyses conducted are described in a previous paper (Valencia et al. 1997). Experiment 3: Agronomic evaluation of six RPP selections was conducted during the establishment and harvesting periods at the Lajas Substation (Southwest region) of the College of Agricultural Sciences of the University of Puerto Rico. Rhizoma perennial peanut selections USDA 17033, 17050, 17052, 17097-and cv Florigraze and Arbrook were planted on a Vertisol February 15, 1995. Plots measured 3.65 χ 6.08 m arranged in a randomized complete block design with four replications. Plots were irrigated about once a week during the establishment and harvesting periods. The peanut was fertilized twice each year with approximately 625 kg/ha of 0-10-20 with the same amount of S and Mg as phosphorus (10%), applied two times per year. Once established , the plots were harvested in two locations every 6-, 9-, and 12 weeks for a full year. RESULTS AND DISCUSSION Experiment 1: The mean annual dry matter yield (DMY) of cv Arbrook and Florigraze and 172 the 10 RPP accessions at the 6-, and 12-week CI was 18,262 and 16,056 kg/ha/year, respectively. At the 6-week CI, accessions 17097 and 17095 were significantly the highest yielders among the RPP studied (24,846 and 24,090 kg/ha/year). The DMY of accession 17097 was 25% higher than that of Florigraze. At the 12-week CI, no significant differences (P=0.05) were observed among the highest producers (accessions 17097 and 17095 and Florigraze) (Fig. 1). The mean crude protein content (CPC) of the 1.2 RPP accessions and cultivars at the 6-, and 12-weèk CI were 18.4 and 15.1%, respectively. No significant differences were observed among the six accessions having a high CPC at the 6-week CI (17052, Arbrook, 17050, 17097, 17102 and Florigraze). At the 12-week CI, accession 17044 had the highest CPC (16.1%), however, it was not different from that of Arbrook and five other RPP (Fig.2). The mean in vitro dry matter digestibility (IVDMD) of the 12 RPP accessions at the 6-, and 12-week CI was 58.8 and 54.0%, respectively. There were no differences among the seven RPP accessions with high IVDMD at the 6-week CI. At the 12-week CI, the IVDMD of 17039 and 17044 (58.5 and 56.8) was higher than that of the remaining RPP (Fig. 3). Accession 17097 has the potential to produce about 25,000 kg/ha/yr of dry matter when harvested every 6 weeks. At the 12-week CI, no significant differences were observed among accessions 17097, 17095 and cv Florigraze. The highest yielder, accession 17097, has the potential at the 12-week CI to produce 21,000 kg/ha/yr. Apparently, it is more profitable to harvest the RPP plant at a 6-week than at a 12-week CI. Table 1. Percentage of ground cover (PGC) at eight, 12 and 16 weeks of growth, and dry matter yield (DMY), crude protein concentration (CPC) and in vitro dry matter digestibility (IVDMD) of six Arachis pintoi accessions harvested at 16 weeks after planting in 1992 at Isabela, P. R. CIAT Accesion PGC iWeeks) DMY CPC IVDMD Number 8 12 16 (Kg/ha) - %- 18748 38 67.7 92.9 1371 16.4 67.7 18744 33.7 59.3 89.7 2,180 15.2 58.0 18747 42.0 59.6 80.5 950 25.6 65.0 18751 29.3 47.7 75.5 1,006 15.9 60.2 18746 36.6 51.3 75.1 508 15.7 58.8 18745 19.0 42.6 70.5 659 15.6 55.7 Mean 33.1 54.7 80.7 1,112 15.7 60.7 CV 16.2 11.3 24.2 387 4.8 5.4 LSD=0.05 NS 16.2 16.6 780 NS 5.9 Experiment 2: Accessions CIAT 18748, 18744 and 18747 had greater PGC, over 55 percent, at 12 week of growth and no differences were observed among them. At the 16 173 week of growth there were no significant differences in the percent ground cover of the six accessions.