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Improving food legumes for South American tropical areas
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Subject: Improving food legumes for South American tropical areas
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From: biotec@goliat.ugr.es
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Date: 26 Nov 1996 12:13:51 GMT
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Article: 16824 of alt.sustainable.agriculture
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Newsgroups: alt.sustainable.agriculture
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Organization: Centro Informatico Cientifico de Andalucia
Improving food legumes for South American tropical areas
Two projects entitled “Genetic improvement of the food legumes of
the genus Phaseolus for the lowland and highland tropical areas of
Colombia and Peru” lead by Prof. Jean-Pierre Baudoin of Faculté des
Sciences Agronomiques de Gembloux, Belgium, in partnership with
other scientific institutions in Colombia and Peru, and “Production
of interspecific hybrids of Phaseolus and their characterization”
lead by Prof. Otto J. Crocomo of the University of São Paulo,
Brasil, in partnership with other scientific institutions in Brasil
and Belgium were carried out under the European Union (D.G.XII)
STD2 scientific programme.
The lack of varieties of major legume crops well adapted to
particular environmental and agricultural conditions constitutes a
great constraint to human nutrition and agricultural development in
many areas of the world. The two research projects were set out in
order to obtain further progress in the breeding of either common
beans or related species.
The first project dealt with the improvement of food legumes for
both highlands and lowlands of tropical zones of Peru and Colombia.
In highlands disease resistance, rusticity and cold tolerance are
looked at as the most important adaptation features. In Peruvian
lowlands, which stand in the desert coast, the most valuable
adaptation characters are drought tolerance, earliness, disease and
pest resistance and non viviparous seed, while in Colombian
lowlands, located in the atlantic coast, selection mainly pursuits
a combination of both drought and heat tolerance, together with
pest and disease resistances, including several non identified
viruses.
Though common beans constitute the most important crop of the genus
Phaseolus, other species such as P. coccineus (Spanish bean), P.
polyanthus and P. lunatus (Lima bean) are traditionally cultivated
in Central and South America; in particular, both P. coccineus and
P. polyanthus are well adapted to highlands, while P. lunatus is
considered as a lowland species. Therefore, two major breeding
strategies may be envisaged: (i) intraspecific hybridization and
selection within each of the above mentioned species or (ii)
interspecific hybridization either between different cultivated
species or between cultivated species and their wild relatives, in
order to transfer useful traits into the cultivated species. The
research project that assembled the Faculté des Sciences
Agronomiques de Gembloux (Belgium), the Instituto Colombiano
Agropecuario (Colombia) and the Universidad Nacional Agraria La
Molina (Peru) faced several important questions regarding both
breeding strategies.
In order to achieve a better insight into the genetic diversity of
the genus Phaseolus, the electrophoretic patterns of molecular
markers, such as seed storage proteins and chloroplast restriction
fragments, were analized. At the interspecific level a more clear
picture of the phyletic relationships within the complex P.
vulgaris-P. coccineus-P. polyanthus was obtained. In particular, it
was possible to individuate three major groups of taxons: a single
species group including P. glabellus, a species originating from
the Sierra Madre Oriental in Mexico and known to be very well
adapted to humid highland forests; a second group including P.
vulgaris, P. polyanthus, P. costaricensis and the natural hybrids
P. vulgaris x P. polyanthus; and a third group including P.
coccineus and the natural hybrids P. coccineus x P. polyanthus. At
the intraspecific level, evidence has been given on the large and
unexplored genetic variability within P. coccineus, P. polyanthus
and P. lunatus.
Several interspecific hybrids within the complex P. vulgaris-P.
coccineus-P. polyanthus, including either cultivated or wild forms,
were produced and segregating populations derived from those
hybrids, as well as populations derived from intraspecific
hybridization within both P. coccineus and P. polyanthus, were
further evaluated for their adaptation to highland environments.
Several promising genotypes were identified, not only among the
interspecific hybrids between common bean and P. coccineus or P.
polyanthus, but within each of these last species as well, thus
confirming the great potential for breeding still available within
natural genetic diversity.
In order to overcome the poor or null seed setting in some
interspecific hybrids, new methods were developed for in vitro
culture of early (5 to 6 days old) embryos, immature embryos
germination and rooting of germinated embryos. The rate of success
for the rescue and transfer of early embryos averaged 90%, while
the mean germination rate of immature embryos was 60%; rooting of
germinated embryos was less successful, varying from 35 to 45%, but
further improvements were envisaged.
In what new material for lowlands was concerned, the most promising
results were achieved, in Peru, by the individuation of well
adapted genotypes of the two main cultigroups of P. lunatus - Big
Lima group (the andian group) and the Sieva or Potato group (the
meso-american group) -, the choice of complementary genotypes for
hybridization between the two groups and the evaluation and
selection of genotypes in their offsprings; in Colombia, selection
within the Sieva or Potato group proved to be the best approach for
the development of well adapted new varieties.
The second STD project, assembled the above mentioned group of
Gembloux with several institutions in Brazil: Campus of the
University of São Paulo, Foundation for Agricultural Research -
FEALQ, Center for Agricultural Biotechnology - CEBTEC and
Department of Chemistry and Department of Agriculture - ESALQ. It
aimed at the development of interspecific hybrids for both the
Southeast (Piracicaba) and Northeast (Recife) of Brazil. Besides
the hybrids within the complex P. vulgaris-P. coccineus-P.
polyanthus as in the previous project, interspecific hybrids
between common beans and P. acutifolius were also produced, as well
as between P. lunatus and seven wild species, mostly from its
secondary gene pool. Some interspecific hybrids showed very
interesting traits, particularly in what resistance to bean golden
mosaic virus was concerned. Moreover, some of the resistant plants
also showed other superior agronomic characteristics, such as bush
type, short life cycle, homogeneous ripening, small grains, low
requirements for soil fertility, high productivity and resistance
to other viruses. This was mainly the case of F3 plants obtained
>from the initial cross between P. vulgaris x P. coccineus.
Taken together, the above mentioned projects provided further
insights in the phyletic relationships between Phaseolus species,
the adaptation pattern of the single species and of several
interspecific hybrids as well, and allowed the improvement of the
breeding methods that can be applied to the development of new
varieties for specific tropical agro-ecological systems. It was
also possible to identify superior agronomic genotypes that can
soon develop into new varieties, that will surely contribute to the
improvement of food supply in the areas covered by the two
projects. The cooperation between EU countries and Central and
South American countries provided new oportunities for training,
further germplasm exchange between research centers of the two
continents and allowed technology transfer, mainly into Peru and
Colombia.
Within these projects several publications have been issued.
For further information please contact:
Prof. J.P. Baudoin
Faculté des Sciences Agronomiques de Gembloux (FSAGx)
Address: 2, Passage des Déportés
B-5030 Gembloux, Belgium
Phone: +32-81-62 25 11
Fax: +32-81-62 45 44
Prof. O.J. Crocomo
Campus of the University of São Paulo
Address: Av. Carlos Botelho, 1025
13.418-900-Piracicaba-SP-Brazil
Phone: +55-194-34 16 44/Ext. 4344
Fax: +55-194-3416 44
Contract numbers TS2-A-028 and TS2-A-105