Proceedings
of The World Avocado Congress III, 1995 91 - 95
PROGRESS
OF THE STUDY ON THE AVOCADO GENETIC RESOURCES
I.
CURRENT STATUS OF AVOCADO GERMPLASM BANKS IN THE MEXICO STATE
L.López-López
M.Rubi-Arriaga
Fund.
Salvador Sánchez Colin,
CICTAMEX,Coatepec
Harinas,
Estado
de México.C.P.51700.
A.F.Barrientos-Priego
Depto.de
Fitotecnia
Universidad
Autónoma
Chapingo,
Texcoco,
México
C.P. 56230.
A.Ben
Ya'acov
Volcani
Center
Bet-Dagan
P.O.box 6.
Tel-aviv
Israel
Abstract
The different
collects of the Persea genus and their wild relatives established in two
germplasm banks, in the State of Mexico, were classified to determine its current
status. The natural patrimony about genetic diversity preserved is about 180
collections belonging to the Persea and Beilschmiedia genus.
Apart the Persea genus in addition to the three races and the local
selections considered as hybrids are present the following species:
Persea steyermarkii, Persea schiedeana, Persea nubigena, Persea
lingue, Persea indica, Persea floccosa, Persea cinnerascens, Persea gigantea and
others classified as Persea spp. Among other genus regarding to Persea
is found Beilschmidia with the following species: Beilschmieidia
anay, Beilschmiedia miersii, Beilschmiedia towa, and Beilschmiedia taraire.
Keywords:
Persea
genus, genetic resources, avocado
1. Introduction
The reserve of
germplasm in special plots, is due the labor of explorers who had traveled for
many years trough all the world carrying on the collection of vegetative
material than will be used to preserve the source of genetic variation, that
could help to preserve species economically important how is happening with the
Persea genus and its relative wilds.
In Mexico thanks
to the support of Institutions as GIARA, HAIGUD, UACH, The University of
Hohenheim of Germany and the Fundación Salvador Sánchez Colin CICTAMEX, S.C.,
the genetic resources of the Persea genus have been preserving in two
germplasm banks whose accesions are found with different degree of development
and growth at the moment.
In
this way, the scientific community is able to watch with optimism the expansion
of the different materials collected in a sustainable way, leaded toward a
genetic improvement of rootstocks and varieties, of the genotypes which
production will be more efficient and may shows tolerance to stress conditions,
and furthermore, those that gather the new requirements of quality of the
market. (Brooks and Borton, 1977, Thompson, 1981).
Therefore the aim of this
work is to show the current situation of the germplasm banks of avocado
preserved in the state of Mexico.
2. Materials
and Methods
It is evident
that the conservation of the populations in its natural habitat can be one of
the most adequate approaches, however, when exist certain limitations as is
shown in the present case, is recommended to try to establish collections under
similar environmental conditions to its ecological environment. In this way
were established the two germplasm banks called high elevation and low
elevation.
a) High Elevation: Is located
in "El Potrero", Coatepec Harinas, State of Mexico, with 2240 masl,
the soil is sandy clay loam, deep, with pH about 6.5. In this place are kept
Mexican race and Guatemalan materials and some relative wilds.
b) Low Elevation: is located
in "El Salitre", Ixtapan de la Sal, State of Mexico, with 1920 masl,
the soil is a little deep with a pH between 7.2 to 7.8, classified as slightly
alkaline, the sodium level in the irrigation water is about 375 mg/l, and the
electrical conductivity is 761.5 mmhos, In this place have been established
materials of the west Indian race and relatives wilds like Beilsmedia anay and
Persea schiedeana among.
Within each germplasm bank
has been carried out the data record according to the Germplasm Collection
IBPGR Directory (1992) and the Avocado Descriptor. (Barrientos et al. 1991).
3.
Results
The number of collections is near
to 180, in spite of the fact that actually is conserved just a small
reservation of diversity, the Persea genus and its relatives wilds requires the
continuation of the total rescue of the germplasm of local selections which continue under the threats of the
increase of the performance varieties.
In table 1 is
possible watch the materials preserved with different development stages and
among them are also presented the wild species whose diversity is astonishing,
on the other hand in table 1 is presented the classification according to Persea
and Beilschmiedia genus.
The material
described is product
of several explorations and
collections trips around regions and ecological niches from Mexico, Guatemala,
Honduras, Costa Rica, Ecuador, Chile and New Zealand (Barrientos-Priego, et
al.1991;Ben Ya’acov,
1991;López and Ben Ya’acov, 1992, López and Rubi, 1993)
some of these subjects are plants very closed to the modern avocado cultivars
other plants have not been domesticated yet but are considered descending of
those that were used to domesticate cultivars from the three races known (Kopp.
1966).
Respect Bielschmiedia
anay this comes from the Veracruz State in Mexico, Beilschmiedia miersii
proceeds from Chile, while, Beilschmiedia towa and B. taraire proceed
from New Zealand.
4.
Conclusion
The genetic material with which is counted in the
germplasm banks cited constitute an important reservation for future genetic
improvement projects in this genus, same that remains within reach of al researchers.
5.
References
Barrientos, P. A.F., A.D.Ben
Yalacov, E.De La Cruz T. L. L6pez L., G. Bufler y M.W. Borys. 1991.
Descriptores para aguacate. descriptors for avocado. Fundación Salvador Sánchez
Colin CICTAMEX S.C. Folleto 1 69p.
Barrientos, P.A.F.,M.W.
Borys, A.D.Ben Ya’acov, E.De La Cruz T., L. López L. 1991. El germoplasma de
aguacate en Yucatán, México. En: Memoria Fundación Salvador Sánchez Colin CICTAMEX S.C pp 97-104
Brooks,H.J., and D.W. Barton.
1977. A plan for national fruit and nut germplasm repositories. Hort.Science
12:298-300
IBPGR, 1992.Directory of
germplasm collection. International Board for Plant Genetic Resources, Rome
Italy. pp. 19-40.
Kopp, L. 1966. A taxonomic of
the genus Persea in the western hemisphere (Persea -Lauracea) New York Bot Garden pp. 15-20.
López L.L. y A.D. Ben
Ya'acov, 1992. Participación del CICTAMEX en la preservación y utilización del
germoplasma de aguacate. Primer encuentro de Ciencia y Tecnologia del
Sector Agropecuario y Forestal del
Estado de México. SARH p.98.
López, L.L. y Rubi, A.M. 1993.La biodiversidad del aguacate antillano (Persea americana var. americana) en el estado de Nayarit. En: Memoria Fundación Salvador Sánchez Colin CICTAMEX S.C. Coatepec Harinas, México. pp. 61-70.
Thompson, M.M. 1981.
Utilization of fruit and nut germplasm bank. Hort. Science 16(2): 132-135.
