RESEARCH WORK

Collection of forage legumes in three Eastern provinces of Cuba

Yuseika Olivera, R. Machado y Carmen Fung

Estación Experimental de Pastos y Forrajes "Indio Hatuey". Central España Republicana, CP 44280, Matanzas, Cuba

E-mail: yuseika@indio.atenas.inf.cu

ABSTRACT

A prospecting and collection work was carried out in the eastern zone of the country with the objective of collecting germplasm of herbaceous, shrubby and tree multipurpose legumes to be used in the livestock production sector. The trip included the northern and southern coast of the Guantanamo province, the northern and central coast of the Holguín province, as well as the central-eastern part of the Granma province. An individual sampling system was used in small populations, with repetitiveness of species in different sites, and sometimes random sampling was performed in abundant populations. The information was gathered through the descriptors related to location, natural habitat, vegetation, soil and damage caused by insects and diseases, etc. Ninety-five accessions belonging to 24 species were collected, among which stood out those of herbaceous type (10 genera). Herbaceous as well as shrubby and tree species used with different purposes were found (animal feed, cover, green manure, living fences, etc.). It is recommended to clean the samples obtained; proceed to their fast reproduction, morphobotanical characterization and agronomic evaluation (stage I); use this material for different purposes, among them conservation and exchange; as well as to continue the collection in other zones of the country.

Key words: Plant collection, legumes

According to the FAO (1996) in the World Action Plan for the conservation and sustainable utilization of plant genetic resources for food and agriculture, the support that must be given to the planned and selective collection of plant genetic resources is evident; for that purpose it is established that local species, ecotypes and varieties must be collected, as well as the genetic diversity of the existing collections must be completed, by means of a selective collection with defined priorities.

In Cuba there are about 430 species of the family Leguminosae, represented by 239 corresponding to the subfamily Faboideae, 113 to the subfamily Caesalpinioideae and 81 to the subfamily Mimosoideae (Barreto, 1990). This allows to state, according to Anon (2006), that this country is remarkably biodiverse in taxa of this family, taking into consideration its small extension (1 250 km) and its total gross area (114 525 km²).

Among the existing taxa are those that have remarkable usefulness for the livestock production systems, aspect that contributed to develop a systematic collection work since the 70's (Menéndez and Machado, 1978), which is maintained and increased at present (Fontes, Hernández, Cruz, Seguí and Cubillas, 2000; Machado, Navarro, Fung and Reino, 2005) and has been motivated by the rescue of these plant genetic resources in natural ecosystems, with the objective of avoiding their genetic erosion, and by the need of enriching the forage germplasm with new and promising acquisitions.

In the eastern provinces of the country a large part of that biodiversity is concentrated; hence it is considered important to continue the collection of legumes in that zone, because it constitutes a promising stock of important resources for the livestock production sector and the opportunity to collect and preserve them for future generations.

The objective of this work was the collection of forage legumes in a trip that included the northern and southern coast of the Guantánamo province, the northern and central coast of the Holguín province, as well as the central-eastern part of the Granma province.

MATERIALS AND METHODS

Period, itinerary and characteristics of the collection zones

The collection work was carried out between February 20 and 25, 2006. In the trip itinerary soil samples of the following groups were collected: Brown, Humic, Calcimorphic, Hydromorphic, Vertisol, Fersiallitic, Ferritic and Little Evolved. Except the last three, the others are of medium to high fertility and have an organic matter content that varies between 3,0 and 9,0%.

The trip comprised uncultivated lands and paddocks close to highways and roads, of the Guantánamo, Holguín and Granma provinces (fig. 1). In the sampling work preference was given to the sites located in marginal areas, with predominance of plain, undulated and mountainous terrains, and the presence of deep ditches with thicket vegetation (soil covered by diverse types of weeds and natural pastures), in addition to ravines, clearings and limiting fences of naturalized or non naturalized pastures and other crops, hills and perimeter areas of forests as well as bushes and disturbed stands. For that purpose a map with scale 1:1 000 000 (ACC, 1989) was taken as reference, in which the populations and soil groupings were indicated.

Many coastal sites of the Guantánamo and Holguín provinces where sampling was performed were characterized by the presence of abrasive, fault, dentate, abrasive- and erosive-tectonic coasts, as well as tectonic-erosive bay coasts.

The collection zone in the Guantánamo province, where coastal plains with insufficient humidity, high evaporation and high temperatures prevail, shows an annual mean rainfall lower than 600 mm, a mean evaporation of 2 200-2 500 mm, a mean annual temperature of 26-30ºC and a prevailing wind speed of 0,30-0,50 m/seg. Another zone of this province where mountains with high and stable humidity, low evaporation and fresh temperatures prevail, is remarkable for its mean annual rainfall of 1 900-2 500 mm, evaporation by day of 1 200-1 600, mean annual temperature of 16-23ºC and a wind speed of 3,6-4,2 m/seg.

The region explored in Holguín was represented by plains and heights with stable seasonal humidity, high rainfall and high temperatures. In this zone the mean annual rainfall is 1 000-1 200 mm, the evaporation 1 800-2 000 mm, mean annual temperature 23-25ºC and wind speed 2,8-3,3 m/seg; while Granma, with plains and heights similar to those of Holguín, shows equal mean annual rainfall, slightly higher evaporation (1 800-2 200 mm) and mean annual temperature (25-27ºC) and higher wind speed (3,6-5,3 m/seg).

Sampling method

An individual sampling system was used, because generally the samples were taken from small populations; nevertheless, sampling was performed randomly when there was a high number of individuals of a certain species. Of each plant the highest number of seeds was collected, repeating these species in all the possible places, so that the highest variability was achieved. All the species considered useful were sampled, independently from their vigor, but those that showed severe damage caused by pests and/or diseases were avoided.

The seed from supposedly different ecotypes in the autogamous species was maintained separated, and in the particular case of trees it was collected in as many individuals as possible, with the objective of maximizing the heterosis of the material from allogamous plants.

Descriptors

In addition to the sample number other 27 descriptors were used related to general information, location, natural habitat and vegetation of the area, the specific site, soil and damage caused by insects and diseases (Machado, Roche, Toral and González, 1999).

The distance between one collection site and the next depended on the landscape and soil changes, and the simple visualization of the plants. The car speed was maintained below 40 km/hour, higher only in very homogeneous zones from the physiographical and vegetation point of view.

In each presumed collection sites an approximate area of 1,0 ha was visited, in all directions, if the natural obstacles allowed it.

The seed was maintained in conveniently identified, separated and closed envelopes, to avoid contamination among their contents. All the germplasm collected was carried to the Experimental Station of Pastures and Forages "Indio Hatuey" with the objective of carrying out their multiplication.

RESULTS AND DISCUSION

The results indicate that in the collection zones a high generic and specific diversity is concentrated, for the herbaceous accessions, of which 10 genera with 16 species were found, as well as the tree and shrubby types, of which seven genera were found with eight species (table 1), totaling 17 genera, 24 species and 95 accessions.

In the collected material there was a higher representation, in terms of accession number, in the herbaceous genera, mainly in Centrosema, Teramnus and Galactia. Among the tree and shrubby genera Leucaena, Desmanthus and Albizia stood out. This finding is considered extremely important, because the germplasm of those species that are more utilized in Cuban livestock production systems or have proven high potential in commercial livestock production is consistently enlarged (Paretas, Suárez and Valdés, 1989; Simón, Lamela, Esperance and Reyes, 1998; Hernández, 2000), specially if the specificity character of this material is considered, carrying genes with adaptation to the collection zones, many of which coincide with those where a wide livestock production activity is developed.

It is important to emphasize the tree species found, because the date chosen, favorable to collect herbaceous species, did not coincide with the most appropriate moment for finding trees with seeds, aspect mentioned in the methodology for the collection of germplasm useful for livestock production (Machado et al., 1999). It indicates that for certain environments and species seed can be found, although the dates are anticipated or delayed with regards to the normal phenological patterns that regulate the reproductive period of the species with different habits.

On the other hand, it must be noticed that the diversity found did not only correspond to the number of genera and species, but it also transcended to the intra-specific level, because in very few species only one accession could be collected, as in the case of Alysicarpus vaginalis, Macroptilium lathyroides, Cajanus cajan and Peltophorum ferrugianum. In the other species (table 1) two or more accessions were collected, which showed in situ a higher or lower degree of morphological differentiation.

Tables 2 and 3 indicate the type of vegetation, the specific habitat, the damage due to insects/diseases, the soil cover and the degree of shade existing in the collection spots, indicators in which there was high heterogeneity. Thus, most of the species were collected in undulated or plain terrains, with predominance of thicket, bush or grassland vegetation. Only some samples of Leucaena and Peltophorum were found in the forest. This shows the high probabilities of finding material in marginal areas, which is very important from the adaptation point of view, because the preference for undulated habitats has been described for all these species and those of the rest of the genera collected (Menéndez and Machado, 1978; Albert, Morán, Valdespino and Álvarez, 2000).

In this study it was observed that most of the species were found mixed, in a higher or lesser degree, with the thicket vegetation, natural or naturalized pastures and shrubs (tables 2 and 3), which presupposes a high level of associative capacity, particularly in the herbaceous ones.

The results presented above reveal that all the accessions, independently from their growth habit found a better adaptation domain in soils with good or regular drainage, specially in those with higher fertility; unlike the soils of high fertility but with strong limitations of permeability, as in the case of Hydromorphic soils.

There was not great damage because of pests and diseases, which shows the natural resistance of these accessions in these environments.

The results of prospecting and collection are concluded to be encouraging, because they provide a material with excellent perspectives of multiuse in the livestock production sector, and at the same time they contribute to the increase of the germplasm of naturalized ecotypes, which sometimes is not taken into consideration, and in it, precisely, high potential promising types are found (Flores and Shultze-Kraft, 1994; Toral, Machado, Navarro, Fung and Reino, 2006). For such reason it is recommended to clean the samples obtained; proceed to their fast reproduction, morphobotanical characterization and agronomic evaluation (stage I); use this material for diverse objectives, among them conservation and exchange; as well as to continue the collection in other zones of the country, although non prospected zones of these provinces could be included.