Dr. M. J. Williams
Dr. Roy Pittman
Dr. Esteban A. Pizarro
Ing. Agr. Pedro Juan Caballero
Trip Objectives:1. Taxa to be collected: Arachis spp.
2. Specific or general characteristics sought: seed production, compatibility in mixtures, grazing tolerance, flooding tolerance, drought tolerance, cold tolerance, and photo period insensitivity.
3. Use to be made of germplasm collected: cooperative development of improved annual and perennial Arachis cultivars for forage, turf, and erosion control in U.S. and international markets; and serve as a model in studies dealing with the physiological mechanism(s) for photoperiod insensitivity of vegetative growth in plants.
Sixty-five accessions of wild and domesticated Arachis, which are thought to represent six known species, were collected. Over 5000 km was covered in portions of nine departments in the central and south central portion of the country. Although some seed were found with many of the wild species, most of the material was immature. This suggests that future trips need to be undertaken later in the year if significant seed is to be collected. Much of the perennial material appeared to show great potential as ornamental or low maintenance turf species.
In particular, the A. lignosa collected in Concepción Department and the A. glabrata collected Paraguarí and Misiones Departments may hold potential as forage material for wetter sites in the tropical and subtropical areas of the world. This fieldwork also represents the first widely reported occurrence of extensive (>200 ha) areas of both A. glabrata and A. lignosa in single contiguous naturally occurring populations under grazing. We also observed, that as with any rapidly developing country, considerable evidence that conversion of native vegetation to pasture and farmland were impacting Arachis populations in this region of the country. Additionally, concerted efforts by the Paraguayan government to improve the transportation infrastructure in the countryside appeared to be altering the distribution of many of the wild populations.
This appears to have potentially beneficial effects as a significant portion of the wild material collected, particularly A. glabrata, was found on road verges or shoulders having been moved from their original source sites. Unfortunately, this also suggests that populations of less robust species might suffer due to burial or increased competition from aggressive pasture grass species. As a consequence, the team members would like to commend to the foresightedness of the Paraguayan government for allowing this joint germplasm collection effort at this time in order to catalogue and preserve this valuable component of the Paraguayan ecosystem.
The collection was divided, and a portion of the material will remain in Paraguay under the control the host country collaborator, Pedro Juan Caballero, MAG. All the collection numbers and herbarium identification should be preceded with these intials: CbWlPmPz.
International team members met in S. Paulo, and then proceeded on to Asuncion, Paraguay. Pedro Juan Caballero and Enrique Robledo of the Paraguayan Ministerio of Agricultura y Ganadería (MAG) met the team at the airport. Later on, Victor Santander also of the MAG met us at the hotel.
Our initial time in Asunción was spent consulting the GIS predicted climate and species distribution prepared by Andy Jarvis of International Plant Genetic Resources Institute (IPGRI), Cali, Colombia, and the floristic maps and spread sheet listing previous herbarium and collection sites supplied by the USDA, ARS, Plant Exploration Office (PEO); developing a collection route; securing detailed topographical maps from Servicio Geográfico Militar as well as maps for each of the Departments we were going to travel through; and finalizing the details for the collection permit.
Our plans were try to use as many secondary roads as possible and to systematically stop and look for Arachis material. At each stop we were going to record GPS data and generalized comments on vegetation.
Traveled extensively through the western and central portions of the department of Caaguazú and the northern portions of Guairá and Caazapá.
Although this region was predicted to be a priority area for material that had adaptation characteristics of particular interest (e.g., adaptation to cold temperatures and species richness), extensive areas of the native vegetation of the eastern portions of these Departments have been cleared for row crop production and dairy pastures. As a consequence we did not find any Arachis material. We did find a few wild Arachis spp. (901,902, and 907) in western portion of Caaguazú Department. The land use in this area was mainly small farm holdings interspersed with large estancias (ranches) that were often planted to brachiaria.
We speculated that the intense human activity along even the secondary roads had impacted local Arachis populations. We were informed in a conversation with a local farmer that populations of Arachis did still exist in the campo (countryside). This indicated to us that if further collections were to be made in the area, more effort needed to be made making contacts with local farmers to gain access to areas in private holdings. In addition to the wild material found, we purchased four A. hypogaea accessions, a large red (903), a small red (904), a small black (905), and a very small red (906), at the local market in the city of Caaguazú before heading south.
During this time frame, we traveled west through eastern Cordillera Department and then south through the department of Paraguarí and into northern Misiones and western Guairá Departments. En route we purchased two more accessions of A. hypogaea, a large black (908) and a small black (909). On the northern portion of this trip, we found four A. glabrata populations (910, 912, 913, and 914).
In addition to vegetative material, we were able to collect some seed from accession 910. At the site we collected 913, the landowner informed us that she used leaves of this Arachis in a tea as a treatment for a sore throat. During this portion of the trip, we also collected a non-flowering population of A. repens from a yard (911).
The homeowner said he had transplanted the material from Maringa, Parana, Brazil about 1.5 years previously. We also observed an ornamental planting of A. glabrata in the median in downtown Paraguarí but did not collect it. South of the city of Paraguarí, we headed west to Lago Ypoá because of the wet nature of that area. We were interested in finding Arachis material, particularly A. glabrata that was adapted to wetter sites.
The majority of area leading over to the lake is a rolling alluvial plain that has fairly high water table. We did find three A. glabrata (915, 916, and 919) in this area. Accession 915 had unusually large fleshy rhizomes (3-mm diameter). Throughout this area and up the rocky slope of the range of hills you have to cross before reaching the lake, we made several collections (917, 918, and 920) of plants that had a taproot and pubescent leaf margins that we tentatively classified as A. lignosa. Accession 920 consisted of two old plants that had extremely large and robust taproots, each about 2 cm diameter and about 12 cm long.
We did not make it to Lago Ypoá because of time concerns and the deteriorating condition of the road. In northwestern Misiones Department, we also found three accessions of A. glabrata (921, 923, and 924), only one of which was associated with wet soil. In the wet area we also found another population of what we were calling A. lingosa (922). On the way north through eastern Paraguarí and western Guairá Departments we visited a Barrerito Experiment Station - MAG and were directed to their forage plots where we found an older planting of A. pintoi material that were labeled with what Pizarro recognized as CIAT numbers.
Since this was not new material, we decided not to sample them, but we did record the numbers we could find and rated them for weediness, cover, and general appearance. Of the eight accessions present, we positively identified six:
CIAT 18744 - poor coverage, weedy, and irregular yellow patches
CIAT 18745 - good cover, few weeds, and only minor yellow patches
CIAT 18746 - good cover but not vigorous, weedy
CIAT 18747 - good cover, few weed, and only minor yellow patches
CIAT 18751 - poor coverage, weedy, and irregular yellow patches
CIAT 18752 - good cover, few yellow patches
Our opinion was that CIAT 18745 looked the best of the labeled plots. Continuing east and then north, we found three additional populations of A. glabrata (925, 926, and 929), two of which were extensive (926 and 929) and heavily grazed in associated brachiaria pastures and extending down the side of a road cut. Mixed in with 926, we found two plants that were very pillose and had tap roots, which were tentatively identified as Erectoides section (927).
Additionally on the edge of the travel path of the dirt road, we found a third Arachis that may also be in the Erectoides section (928) but this one was not pillose. On way into San Salvador in Guairí Department, crossing the cobbled causeway we found an as yet unidentified Arachis (930) with very round leaflets that both Pizarro and Roy thought was similar to what Valls had identified as the "butterfly" Arachis. This plant was possibly rhizomatous.
The population was quite extensive, extending over 100 m down one shoulder of the causeway, but was not native to this exact site, apparently being brought in with fill dirt when the causeway was built. The last collections made on this portion of the trip were two A. glabrata (931 and 932). Accession 932 was particularly healthy and extended right up to the pavement.
In this portion of the trip, we covered northern and central San Pedro Department and extreme southeastern Concepción Department. At San Estanislao, we purchased seed of a Brazilian A. hypogaea (933). Heading west on Rt. 10 toward the town of Villa del Rosario, prior to reaching the town of Gen. Aquino, we only found one A. glabrata (934). Although this was an unpaved road, it has received extensive road work in recent years which may have impacted local Arachis populations. On a secondary road south of Gen. Aquino, we purchased the only A. hypogaea material (935) we got from the actual grower during our whole trip. Accession 935 was a small seeded black-skinned valencia type that was locally grown in the area. The farmer said it was a 120-day maturity type.
We headed north from Villa del Rosario to Colonia Volendam, which turned out to be another area of brachiaria pastures and soybean, corn, and wheat fields. We did not find any Arachis spp. in this area. From Colonia Volendam, we headed back southeast to Rt. 10 intersecting it at Gen. Aquino. Just east of Gen. Aquino, we collected two adjacent populations of unidentified Arachis sp. that had taproots and some immature seed (936 and 937). There is a strong possibility that 936 and 937 are the same, although we maintained the collections under separate numbers. On Rt. 3 north of Lima, we collected another A. glabrata (938) that was aggressively growing right up to the pavement. In the Mercado at Concepción we purchased two additional A. hypogaea accessions, another large red (939) and a small red (940) from local vendors.
East of Concepción on the road to Belén, we found a nice population of A. glabrata (941) that appeared to be heavily grazed. South of Belén toward Colonia San Juan and Puerto Ybapobó we found two unidentified Arachis sp. seedlings (942 possibly of 943) in the road margin and another population of plants with rather long narrow leaflets (943) in the cut over woodland area on the road shoulder. Roy thought the long narrow leafed material was in the section Erectoides, and we excavated several whole plants. At the next stop, also in a wooded area, Pedro spotted another patch of the long narrow leafed material (944), this one had a seedling with it. We drove about another 100 km south in the general direction of San Pedro de Ycuamandyyu before winding up on Rt. 11 east of Nueva Germania without seeing an additional Arachis.
Perhaps it was due to the area being greatly disturbed with the trees gone and the land planted to brachiaria pastures. Additionally, panicum dominating the shoulders. We proceeded east on Rt. 11, which was being extensively reworked and widened, to Santa Rosa on Rt. 3 then north and west back to Concepción on Rt. 5.
We went east on Rt. 5 toward the city of Pedro Juan Caballero to the Parque Nacional Cerro Corá. This park contains some of the largest contiguous area (approx. 5000 ha) of undisturbed natural vegetation in western Amambay department. The park ranger said that Arachis was present in the park, but that we needed a special collection permit. After leaving the park, headed back west to the Bella Vista road, a continuation of Rt. 3, and drove north until we reached the Arroyo Negla. The Bella Vista road is a prominent area in previous Arachis collection trips because it leads south from Brazil. We wanted to revisit the site at the Arroyo Negla because three previous collection trips had noted A. hoehnii at that site and Vanni et al. had found an A. glabrata. A few kilometers north of Rt. 5, we collected a nice specimen of A. glabrata (945).
This population was competing nicely with a thick stand of brachiaria growing on the roadside. Again, we felt that this population had been moved into the area due to roadwork. The whole road had been extensively altered by roadwork from fence line to fence line, a distance of over 50 m. Most of the shoulder area was grown up in either brachiaria or panicum, very little of the native vegetation remained. These grasses were escapes from the surrounding estancias. At Arroyo Negla, in addition to the panicum on the road shoulders, about 80 m either side of the roadway was cleared of trees. We thought this general level of fairly recent disturbance was not favorable for find Arachis in the immediate area, but since Krapovickas et al., Schinini et al., and Vanni et al. had all found A. hoehnii at this location, we started looking. We immediately found two Arachis on the road shoulder, one of which had a taproot and was probably in the Erectoides section (946).
The other one appeared to be an A. glabrata (947). We then jumped into the head high panicum and stomped our way down the embankment to the reach an adjacent pasture, which seemed to contain mostly heavily grazed native species. In that site we found a large stand of A. glabrata (948), which may have been the source of the material on the road verge. Other than these three accessions, we found no other Arachis. Since we did not spend much time checking up and down the stream banks, we cannot definitely say that the A. hoehnii doesn't still exist even though the level of disturbance was high. Northeast of Concepción on the Passo Barreto road, we found a series of populations (949 - 955) of both yellow and orange-flowered, tap rooted Arachis, which due to locality we assumed was A. lignosa, although the key does not indicated a yellow flowered phenotype. This material was of particular interest to us because it was found in both acidic (pH<5.0) and slightly alkaline sites (pH=8.0) and in sandy and wet, heavy clay soils.
There was also evidence that horses and cattle extensively grazed these plants. Northeast of Paso Barreto going toward Bella Vista, we collected one unidentified Arachis sp. (956) and two accessions of A. glabrata (957 and 958) that may represent a discontinuous related population, which extended a distance of about a kilometer. All of this material was heavily grazed. At the 957 sites, we also found two plants that were tentatively identified as A. pseudovillosa (959 and 960). North of Concepción on the road to Puerto Vallemi/San Carlos we relocated two major areas of Arachis that had been previously found on collection trips that Pizarro had made with Brazilian and Paraguayan cooperators. Both of these populations, an A. glabrata (961) and an A. lignosa (962), are major components of their respective ecosystems and occur, by conservative estimate, in areas in excess of several hundred hectares. The A. glabrata material is found on the top the small mountain range called Serrania de San Luis west of the Reserva Ecológica Serrania San Luis. We measured a distance of over 10 km were we easily observed A. glabrata associated with Aristida sp. and small trees.
The soil is very shallow heavy clay interspersed with large rocks and outcrops of boulders. It was not unusual to observe the A. glabrata material growing in the cracks in the boulder surfaces. The A. lignosa occurred in a natural wetland savanna north of the Río Aquidabán. The savanna appeared to periodically be flooded for short periods of time, but drained rather quickly in most spots due to a gravel layer underneath the top soil. The A. lignosa was being actively grazed by large herds of cattle and horses on this estancia. We had reports of additional large areas on other estancias in the region, but were unable to find the populations due to a lack of time and the wet road conditions. The final collection in the Concepción area was another A. lignosa (963) made on the south side of the eastern edge of the bridge crossing the Río Paraguay in Concepción. Pizarro had previously observed this material in 1997 in a pasture at that site, but it was now an industrial park area and only a remnant population remained.
Went back to Lago Ypoá to recollect 915 which had deteriorated badly while in storage. En route purchased two additional A. hypogaea, a very large red (964) and a large tan (965) that Roy thought resembled Bayo Grande from Peru.
Worked in Asunción repacking the germplasm. At this time, we also divided the samples that Pedro requested for his evaluation trials in Paraguay.
Additionally we processed the final soil samples for pH and texture, finished writing and translating the trip report, and awaited the export permit and phytosanitary certificate.
On Monday morning we met again with Victor Santander, Enrique Robledo, Pedro Juan Caballero at the MAG offices. At that time we summarized our work for Victor and Enrique and gave them a copy of the trip report and germplasm photos on CD.
Monday afternoon the international team members left Asunción for their respective home countries.
The collection team wishes to express its appreciation to the USDA, Plant Exploration Office for funding this project. Also, we would like to thank Victor Santander and Enrique Robledo of the Ministerio de Agricultura y Ganadería - MAG. In addition, we would like to thank Karen Williams for her considerable assistance in preparing for this collection trip.