Plant Exploration in Northern Chile to Collect Wild Tomato Species,

With Emphasis on Coastal Populations of Lycopersicon chilense

FINAL REPORT

Roger Chetelat and Ricardo Pertuze

8/15/2005

Summary

A total of 23 accessions were collected of L. chilense, L. peruvianum, S. lycopersicoides, and S. sitiens.  Although weather along the coast of Chile was exceedingly arid during 2004/2005, which reduced the abundance of L. chilense in this region, several interesting populations were found on the southern margins of this species’ distribution, and at several locations in the Andes.  The L. peruvianum collections include a morphologically distinctive race from the Camarones valley, and good samples were taken from the large populations found in river drainages near the coast.     Additional populations of S. sitiens and S. lycopersicoides were collected from underrepresented geographic regions.  Evidence of continued loss of native populations of all four species was observed at several locations, of which two have been negatively impacted since our visit in 2001.  An agreement between the TGRC and INIA-Chile governing maintenance and distribution of these seed collections is attached.

I.  Narrative

Objectives and Rationale

                                                                The objectives of this trip were to collect additional populations of L. chilense from the coast ranges and the Andes of Chile, as well as to fill in gaps in existing collections of L. peruvianum, S. lycopersicoides, and S. sitiens.  A recent study of genetic diversity in L. chilense (E.B. Graham, 2005, Ph.D. thesis, UC-Davis) showed that the coastal populations at the N and S ends of the distribution are genetically diverged and reproductively isolated from populations in other regions.  The TGRC currently has relatively few accessions of L. chilense collected from the coast ranges.  Using herbarium records and plant lists from various sources, we identified several sites along the coast where L. chilense had been found in the past.  Maps of currently held accessions also revealed some gaps in our existing collections for the other three species, notably in certain drainages of the Andes.

                                                                The rationale for collecting additional populations of these wild tomato species is that each possesses potentially unique phenotypic traits that are of potential interest to plant breeders, geneticists, and other researchers.  L. chilense and L. peruvianum have each been used by breeders as sources disease resistance and other traits for improvement of cultivated tomato.  S. lycopersicoides and S. sitiens possess other potentially unique characteristics not found among the Lycopersicon species.  While more difficult to hybridize with cultivated tomato (L. esculentum), recent research in our group has demonstrated the feasibility of producing various types of genetic stocks representing the chromosomes of these nightshades in a tomato nuclear background.  In addition, our previous trip in 2001 raised concerns about the viability of some populations, which are threatened by mining, overgrazing, and other human activities.   In this context, it was desirable to improve representation of these species in ex situ germplasm collections such as the TGRC.

Notes on the Collections

                                                                We collected seed from 23 wild populations, including 14 of L. chilense (however, seed from one were immature at time of collection), 4 of L. peruvianum, 4 of S. lycopersicoides, and 1 of S. sitiens.  The new L. chilense populations include several interesting items.  LA4324 (Estacion Puquio) is the northernmost population ever collected from Chile, and grows in an extremely arid, desolate, and inaccessible area near the border with Peru.  This population was previously known only from an herbarium specimen collected in the 1950’s along the railroad tracks between Arica and La Paz.  Thanks to the details on the herbarium label, which included a distance (in Km) along the railroad, we were able to find this population, still growing at the same precise location after over 50 years.  The border region between Peru and Chile probably contains other tomato populations, but has not been well explored because of its general inaccessibility and heavy military presence (a local soldier warned us not to stray too far off the road because there are landmines in the area). 

We also collected several new L. chilense populations (LA4329, LA4330, LA4332) in the Andes between Calama and San Pedro de Atacama, an area from which we previously had only one accession.  The new material represents a ‘link’, at least geographically, between populations to the Southeast, a distinctive race which some taxonomists had recognized as a separate species (L. atacamense), and populations to the North, which is the central portion of the distribution (most of our existing collections are from this region).  Along the coast, we collected a population (LA4339) of L. chilense at Quebrada los Zanjones, notable because it is located about 15 Km further South than any of our existing collections, in a different drainage system, and possibly unique environmental conditions.

In the case of S. lycopersicoides, we collected two small populations (LA4320 and LA4326) at elevations (1200 - 1400m) which are far lower than any other known populations.  This species was previously thought to grow only at high elevations (at over 3,600m, the highest of any tomato relative).  The new material is therefore interesting because it is likely to be genetically distinct, assuming local adaptation at lower elevation.  The newly extended elevational range may indicate the species was once more widespread than it is now.  S. lycopersicoides     is especially vulnerable to human-associated activities, such as farming and overgrazing, due to its low reproductive output, extended seed maturation time, and narrow ecological requirements.  The relative scarcity of the low elevation populations of S. lycopersicoides     may be due to more intense human pressures (e.g. land suitable for farming is more abundant at lower elevations), or perhaps because it is marginally adapted to these conditions to begin with.

For L. peruvianum, we collected two populations (LA4317 and LA4325) growing in abandoned agricultural fields near the coast.  At both locations, but especially the first, large ‘metapopulations’ were found growing from sea level up to mid elevations in the river drainages.  As expected for large populations of an obligate outcrosser, we observed much morphological variation from plant to plant, indicating a relatively high level of genetic diversity in this material.  In Chile, the coastal populations of L. peruvianum  tend to be  relatively large and diverse compared to the other wild tomatoes.  We also made new collections from the upper Rio Lluta and Rio Camarones drainages (LA4318 and LA4328).  The latter population, of which we could find only one plant, was unique in its morphology.  Its leaves are thick and leathery, with a glossy surface and highly dentate leaves.  This may represent a new race of L. peruvianum, as it did not resemble any of our existing accessions of this species.  This river drainage is another inaccessible area, even by Chilean standards.  Although we have other collections of L. peruvianum  from lower elevations in the Rio Camarones, the new material represents the upper limits of this species distribution in this particular valley.

Finally, for S. sitiens we made only one new collection, however it is of particular interest to us because of its location.  This accession, from Cerro Quimal (LA4331), is the easternmost population of this species in our collection (or in herbarium records).  It grows on slopes and along a mining road in an exceedingly arid situation – we found no other plant species growing in association with it – on a mountain (cerro) that borders the Salar de Atacama.  It is also unusual for growing at relatively high elevation (3,060m), near the upper limit for this species, and in an area that is exposed to strong winds, and low, probably freezing temperatures.

As mentionned above, we used site information from herbarium records to locate many of the new collections.  This information came from various sources.  Prior to the trip, we consulted plant lists available online, the most useful of which turned out to be the ‘LomaFlor’ database (http://www.sacha.org/) which includes lists of plant species from the coast ranges of Chile and Peru.  We also consulted with local botanists (Luis Faundez and Raquel Pinto), and visited the national herbarium in Santiago (Quinta Normal).  Finally, Sandra Knapp at the Natural History Museum in London kindly shared her database of herbarium records, compiled from herbaria around during preparation of a monograph on tomato and related species.  Some of the recent herbarium records included latitude and longitude coordinates, which enabled us to find even the relatively isolated populations using a hand held GPS unit.

                                                                Besides the plant material, we also collected samples of insects seen visiting flowers of wild L. chilense and L. peruvianum in order to gather information on the natural pollinators.  Captured insects were dried and later identified to the genus level by Dr. Lynn Kimsey, entomologist with the UC-Davis Bohart Museum of Entomology.  We observed pollinators at two locations.  The first was along the coast, at the site of L. peruvianum  LA4325 (Caleta Vitor).  Here we found two species of bees actively buzzing flowers for pollen: a fairly small bee identified as a species of Exomalopsis (family Apidae), and a much larger bee identified as a species of Caupolicana (family Colletidae).  The second site was in the Andes at over 3,100m elevation, at the location of L. chilense LA4330 (Caspana).  Here we observed one species of reddish brown, relatively large bee, later identified as a species of Centris (family Apidae).  No insects were observed visiting flowers of S. lycopersicoides or S. sitiens.

Threats to Genetic Resources

                                                                This trip afforded an opportunity to revisit some populations collected in 2001 and assess any changes or threats which may have occurred in the intervening 4 years.  At two locations we saw evidence of habitat destruction and loss of plants.  The most worrisome to us was a population of S. sitiens growing near Mina Escondida (LA4105).  This population is interesting because it represents the southernmost population for S. sitiens, is geographically isolated from the others, and is morphologically distinctive.  This population grows on the slopes above the main road to two of the world’s largest copper mines (Escondida and Zaldivar).  Since our last visit, the road was enlarged to accommodate a pipeline, which has obliterated the plants that grew there. From our vehicle we could see only one plant still growing, however we did not have time to conduct a thorough census.  Still, there is ample reason to believe this population is threatened by the pipeline construction and associated activities.  We intend to contact the mining company about this situation and express our concerns. 

Along the coast, we revisited a population of L. chilense which we had collected in 2001 (LA4107) growing near the coast highway.  Since our earlier visit, this important road has been renovated and enlarged, and in this particular spot an entirely new roadbed has been built.  As above, we did not have time to count plants, but the obvious paving over of former habitat could only have reduced plant numbers.  Unless conservation measures are implemented, it seems inevitable that the increased mining, road building, agriculture and other activities will adversely affect the native tomatoes of Chile.

Seed Regeneration Plans

Seed of our new collections were extracted and dried upon our return to Santiago.  Most collections, particularly of the Solanum spp., yielded only modest quantities of seed.  Nonetheless, we obtained adequate seed amounts for the purposes of future seed regeneration, and we were able to leave subsamples of each accession with INIA prior to our departure for backup storage and other uses.  After regeneration at Davis, we will provide them with larger samples, as they become available.   Prior to our departure from Chile, we had our seed samples inspected by the authorities at SAG (their agricultural inspection service), who issued a phytosanitary certificate for importation into the US.  From our port of entry, seed were sent to USDA Plant Quarantine in Beltsville, as per the USDA guidelines for plant collecting expeditions.

Regeneration of these collections by the TGRC will take several years to accomplish due to limitations in available greenhouse space.   We are starting with accessions we judge to be the most unique and/or interesting.  For each species, we plan to regeneration 2-3 populations per year.  

Collecting Agreement

                                                                Following negotiations between the TGRC and INIA (with input from USDA), an agreement governing the conditions for maintenance and distribution of seed from these collections was worked out. (A copy of the signed agreement is attached). The new agreement is quite similar to the one negotiated in 2001, and is intended to be consistent with existing USDA/NPGS policy regarding germplasm distribution.  While placing no restrictions on eventual use of this material, the agreement requires the TGRC to notify recipients that they may not claim ownership over the supplied material (see item #8). 

Benefit Sharing Plans

Our collecting proposal included some ‘benefit sharing’ funds to promote germplasm conservation and utilization programs in the host country. These funds will be used to improve the scientific collaboration between UC-Davis and University of Chile on several Solanaceae-related projects, as well as to stimulate University of Chile’s own research capabilities.     Funds will be used for improving computer capabilities (hardware and software). The funds will also be used to enable University of Chile scientists to visit UC Davis to collaborate on research projects and publications originating from the collecting trips of 2001 and 2005.  This visit(s) will also provide the opportunity for training in tomato breeding, genetics, and germplasm conservation.  The knowledge and experience gained by this scientific exchange will benefit several ongoing research projects at University of Chile.  These include a study of the physiological responses to drought stress in Chilean accessions of L. chilense and S. sitiens, an analysis of fruit phenolic content in native tomatoes, and in situ conservation of S. sitiens.  Other project may be developed in the future. The benefit sharing funds will also be used, as needed, to purchase technical reference books.  Ricardo Pertuzé will be responsible for final determination of how these funds are used by the University of Chile.   

In addition, the host country will benefit from this project by receiving seed samples of each accession following their     regeneration at UC Davis.  The TGRC will provide, in cooperation with the USDA, long term maintenance and storage of these collections.  Any material maintained at the TGRC will be available to potential users from Chile.  In this way, the TGRC will preserve and distribute populations of tomatoes that are threatened in the native region, thereby benefiting research and development of the cultivated tomato in Chile.

Participants

                                                                The four participants in this collecting expedition each provided unique expertise and knowledge.  Ricardo Pertuzé coordinated all aspects of the project in Chile, including negotiations with INIA regarding the collecting agreement.  Luis Faúndez provided botanical knowledge and familiarity with the plants of the Atacama region.  Carl Jones was our trip photographer, and gave a presentation at the Univ. of Chile on his dissertation research.  Roger Chetelat was responsible for pretrip planning and choosing daily exploration objectives, and will oversee maintenance and distribution of the newly collected accessions by the TGRC staff.

Contact information

Roger Chetelat Dept. of Plant Sciences University of California Davis, CA  95616, USA tel. 1-530-752-6726 fax. 1-530-752-9659 trchetelat@ucdavis.edu		Ricardo Pertuzé Depto. Produccion Agricola Universidad de Chile Casilla 1004 Santiago, CHILE tel. 56-2- 978-5728 fax: 56-2-978-5729 rpertuze@uchile.cl
Carl Jones Dept. of Plant Sciences University of California Davis, CA  95616, USA tel. 1-530-754-8647 fax. 1-530-752-9659 cmjones@ucdavis.edu		Luis Faúndez Depto. Produccion Agricola Universidad de Chile Santa Rosa 11315, La Pintana Santiago, CHILE tel. 56-2- 978-5727 fax: 56-2-978-5700 lfaundez@abello.dic.uchile.cl

II.  Catalog of collections.  For more detailed passport information, see http://tgrc.ucdavis.edu.

Accession Number	Collection Number	Taxon	Collection Site	Date	Latitude	Longitude	Elevation	# Plants Sampled
LA4317	SAL8001	L. peruvianum	Rio Lluta, desembocadura	4/12/2005	S 18°24'59"	W 070°18'52"	25m	10
LA4318	SAL8002	L. peruvianum	Sora - Molinos, Rio Lluta	4/13/2005	S 18°21'04"	W 069°52'37"	1154m	12
LA4319	SAL8003	L. chilense	Alto Rio Lluta	4/13/2005	S 18°19'07"	W 069°48'59"	1440m	13
LA4320	SAL8004	S. lycopersicoides	Alto Rio Lluta	4/13/2005	S 18°19'04"	W 069°48'18"	1490m	7
LA4321	SAL8005	L. chilense	Quebrada Cardones	4/13/2005	S 18°28'45"	W 069°45'34"	1822m	19
LA4322	SAL8006	S. lycopersicoides	Quebrada Cardones	4/13/2005	S 18°25'51"	W 069°45'39"	2815m	11
LA4323	SAL8007	S. lycopersicoides	Putre	4/14/2005	S 18°12'29"	W 069°32'33"	3690m	14
LA4324	SAL8008	L. chilense	Estacion Puquio	4/14/2005	S 18°13'05"	W 069°46'27"	3530m	18
LA4325	SAL8009	L. peruvianum	Caleta Vitor	4/15/2005	S 18°45'16"	W 070°19'49"	5m	14
LA4326	SAL8010	S. lycopersicoides	Cochiza, Rio Camarones	4/15/2005	S 18°58'06"	W 070°41'45"	1210m	1
LA4327	SAL8011	L. chilense	Pachica, Rio Camarones	4/15/2005	S 18°56'06"	W 069°39'17"	1944m	12
LA4328	SAL8012	L. peruvianum	Pachica, Rio Camarones	4/15/2005	S 18°55'12"	W 069°36'50"	2275m	1
LA4329	SAL8013	L. chilense	Puente del Diablo, Rio Salado	4/18/2005	S 22°18'32"	W 068°28'50"	2657m	<20
LA4330	SAL8014	L. chilense	Caspana	4/19/2005	S 22°21'03"	W 068°19'11"	3126m	16
LA4331	SAL8015	S. sitiens	Cerro Quimal	4/19/2005	S 22°58'10"	W 068°49'15"	3060m	9
LA4332	SAL8016	L. chilense	Rio Grande	4/20/2005	S 22°36'32"	W 068°31'19"	2968m	25
LA4333	SAL8017	L. chilense	Talabre	4/20/2005	S 23°17'46"	W 067°56'29"	2914m	6
LA4334	SAL8018	L. chilense	Quebrada Sicipo	4/21/2005	S 23°37'48"	W 068°02'40"	2435m	21
LA4335	SAL8019	L. chilense	Quebrada Tucuraro	4/21/2005	S 23°48'13"	W 068°16'31"	2495m	4
LA4336	SAL8020	L. chilense	Quebrada Cascabeles	4/22/2005	S 25°16'09"	W 070°26'14"	54m	12
LA4337	SAL8021	L. chilense	Quebrada Paposo	4/22/2005	S 25°01'37"	W 070°27'44"	200-400m	14
LA4338	SAL8022	L. chilense	Quebrada Taltal, Estacion Breas	4/23/2005	S 25°30'08"	W 070°24'41"	568m	8
LA4339	SAL8023	L. chilense	Quebrada Los Zanjones	4/23/2005	S 25°32'15"	W 070°28'20"	514m	13

III.  Itinerary 

                          The map on the next page shows the route traveled (highlighted in pink) and the approximate location of collection sites.  The individual collections are numbered as follows: #1=SAL8001, #2=SAL8002, etc).