RESEARCH WORK

Seed quality of legume accessions collected in the eastern region of Cuba (Technical note)

Yolanda González, J. Reino y Odalys Toral

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

E-mail: yolanda.gonzalez@indio.atenas.inf.cu

ABSTRACT

A collection mission was conducted during 2006 in the eastern region of Cuba, which comprised zones of the provinces Granma, Guantánamo, Holguín, Bayamo, Las Tunas and Camagüey. Seeds from 95 legume accessions, 68 herbaceous ones and 27 trees, were collected. Afterwards, a germination test was conducted, to know their quality (with seed coat cut). For that purpose, Petri dishes were used on river sand. The number of seeds used was variable in each accession (according to the collected amount) and only one replication was used (without statistical design). The germination counts were made according to international rules. The best quality seeds corresponded to the tree species, although low germination was shown by Cajanus cajan, Cassia siamea, Peltophorum ferrugianum and Leucaena leucocephala, from the Floro-Pérez zone in the Holguín province. They all showed 100% survival. Seed quality depended on the time the seeds stayed in the field after the pod maturation stage. Through this collection mission the germplasm of the EEPF «Indio Hatuey» increased with 64 new accessions. To continue collecting germplasm in other zones of the country is recommended, with emphasis on trees, which would allow achieving higher diversity from their use in livestock production systems, as well as to conduct the corresponding quality tests.

Key words: Quality, seed collection.

INTRODUCTION

The search for new species and/or varieties to increase the existing germplasm at the Experimental Station of Pastures and Forages «Indio Hatuey» has constituted a permanent objective. One of the ways to achieve it is the collection and study of the endemic and/or naturalized resources through prospection and collection in different national scenarios (Toral et al., 2006).

During prospection seeds are generally collected, but few times information is sought about their quality, important aspect per se and because of its relationship to later plant development.

With this purpose, several researchers used the germination test as the main indicator for estimating seed quality, according to the reports made by Lezcano et al. (2007) in Leucaena leucocephala cv. Peru when its seeds were stored under ambient conditions, as well as by González and Mendoza (2008) and González et al. (2007), who also used it in seeds from Leucaena leucocephala cv. Peru and Teramnus labialis cv. Semilla Clara.

Taking into consideration such premises, the objective of this study was to learn the quality of legume seeds collected in the eastern region of Cuba, through their germination performance, as well as the survival in bags of the plants obtained before the multiplication stage.

MATERIALS AND METHODS

Seeds from 95 accessions, 27 tree and 68 herbaceous legumes, were collected. The quality test was conducted in Petri dishes on river sand. The seed number was variable in each accession (according to the collected quantity) and only one replication was used (without statistical design); the germination counts were made according to international rules (ISTA, 1999).

Procedure

The pods were dried under sunlight and then cleaned. For the quality tests it was necessary to eliminate the dormancy present in the impermeable coat seeds, because a germination test would not estimate their real quality (Gómez-Campo, 2006); for that purpose the seed coat cut was made as anti-dormancy treatment and thus their viability was estimated. The accessions that showed germination were seeded in black polyethylene bags, before their multiplication on a soil substratum plus 30% of organic matter and survival was determined.

RESULTS AND DISCUSSION

Seed quality depends on the time lapse they spend in the field after the pod maturation stage and afterwards they can start becoming deteriorated (Schmidt, 2000).

Table 1 shows the seed quality of the tree species and table 2a y b shows that of the herbaceous species.

The tree seeds showed high quality, which could have been due to the fact that the collection was made at the optimum moment of their fructification (Schmidt, 2000); however, some of them showed low germination, such as Cajanus cajan, Cassia siamea, Peltophorum ferrugianum and L. leucocephala, from the Floro-Pérez zone in the Holguín province. They all showed 100% survival.

In the case of the herbaceous species (table 2a y b), their seeds showed irregular germination and the presence of impermeable seed coats has been reported in all of them (González and Mendoza, 2008; Muñoz et al., 2009). It is necessary to state that when applying the seed coat cut, the newly harvested seeds should have shown high germination, but deterioration in the field begins since they reach the optimum maturation stage (Heydecker, 1972), which could have influenced these results.

In general, the seed quality depended on the time lapse they spent in the field after the pod maturation stage; similar results were reported by Reino et al. (2010) for the ones from the collection made in 2005 in the central-eastern region of Cuba.

Most accessions were observed to achieve a high survival rate, although some species did not show germination or it was very low; for example, in C. cajan the seeds show permeable coats and in the field where they remained until the collection time deterioration was faster (Heydecker, 1977). In the case of herbaceous legumes there could have been depletion of the seed reserves, which prevented them from showing viability (Bewley and Black, 1982). All seems to indicate that the collection was made after a critical port-maturation time period for many of the herbaceous species and for such reason their seeds died.

The discussed results prove the importance of knowing the seed quality and the relationship between this indicator and seed deterioration at the moment of collection; this was shown in the large variability shown by the germination percentages (viability) of the seeds when the tree and herbaceous legumes were collected in the same time lapse, which caused that only 64 accessions (67% of the collected accessions) became part of the germplasm of the EEPF "Indio Hatuey".

To continue collecting germplasm in other zones of these and other provinces of the country is recommended, with emphasis on trees, which would allow achieving higher diversity from their use in livestock production systems, as well as to conduct the corresponding quality tests in the collected seed.