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Improving food legumes for South American tropical areas



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