RESEARCH WORK

Seed quality of accessions collected in the western, eastern and central regions 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

Two collection missions were conducted during 2007 (western and eastern regions) and 2009 (central region) in Cuba, which comprised certain zones of the provinces Granma, Guantánamo, Holguín, Las Tunas, Camagüey, Pinar del Rio, Matanzas, Sancti Spiritus and Villa Clara. Seeds from 88 accessions (52 tree and 36 herbaceous accessions) were collected. Afterwards, all of them went through a germination test in Petri dishes with river sand, with a previous coat cut, to know their quality. The number of used seeds was variable in each accession, in correspondence with the sample size and only one replication was used. The germination counts were made according to international rules. High quality was obtained in the seeds of tree and shrub species (70-100%), which did not happen in Swietenia sp. from Granma (0 and 8%) or in Jatropha curcas collected in Pinar del Río, Guantánamo (0%) and Banao (8%), or in Albizia lebbeck from Guantánamo or Guazuma ulmifolia (24%) collected in Villa Clara. For the herbaceous legumes germination varied between 80 and 100%, except in Macroptilium atropurpureum (60%) and in Teramnus (12%) from Granma, in Neonotonia wightii (20%) collected in Matanzas, in Calopogonium sp. (52%) from Banao and in Glycine sp. (50%) from Sancti Spiritus. Seed quality was concluded to depend on the time they were in the field after pod maturation. To continue the collection in other zones of the country is recommended, which will allow higher diversity in livestock production systems.

Key words: Legumes, plant collection, quality, seed.

INTRODUCTION

The search for new species and/or varieties that increase the existing germplasm at the Experimental Station «Indio Hatuey», has always been a permanent task as a warrant of food security for the present and future generations in Cuba. Hence the collection and study of endemic and/or naturalized resources through prospection and collection in different national scenarios is a way used (Toral et al., 2006). During its development seeds are generally collected, but there are few studies about their quality (Reino et al., 2010; González et al., 2011), aspect which knowledge is important per se, and its relation to later plant development.

With this purpose, several researchers used the germination test as the main indicator to estimate seed quality, according to the report 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 included this technique in seeds from L. leucocephala cv. Peru and Teramnus labialis cv. Semilla Clara. Muñoz et al. (2009) also evaluated the quality of 20 legume accessions stored under unfavorable conditions.

Taking into consideration these premises when the collections were conducted, the objective of this study was to know the seed quality through their germinative performance.

MATERIALS AND METHODS

The seeds of 88 legume accessions, from them 52 trees and 36 herbaceous plants, were studied. The collections were made in 2007 for the western and eastern regions, and in 2009 for the central region.

The quality test was conducted for each accession; for that purpose Petri dishes were used and river sand was the substratum. The number of seeds was variable, in correspondence with the size of the collected sample; only one replication was used and the germination counts were made according to international rules (ISTA, 1999).

Procedure

The pods were sun-dried, thrashed and then cleaned. For the quality tests it was necessary to eliminate the dormancy present in the seeds with impermeable coats, because a germination test would not estimate their real quality (Gómez-Campo, 2006), for which a seed coat cut was performed as anti-dormancy treatment and thus their viability was estimated.

RESULTS AND DISCUSSION

High quality was detected in the collected tree and shrub seeds (tables 1 and 2), which germination values generally valued between 70 and 100%, in correspondence with the report by Schmidt (2000) for the seeds from newly-harvested trees and shrubs. Some species, such as mahoganies (Swietenia sp.) collected in the Granma province showed germination values between 0 and 8%, which could have occurred due to the immaturity of the seeds (they showed soft endosperm), but it can be improved during storage in cold chamber. Something similar occurred in Jatropha curcas with 0% germination for the ones collected in Pinar del Río and Guantánamo, unlike those from Granma, which showed higher maturity and reached 100% germination. Some Albizia lebbeck seeds also showed low germination (12%), due to the attack of borers which affected their quality (table 1).

In the 2009 collection (table 2) the best quality seeds corresponded to the species L. leucocephala and A. lebbeck (100 and 96% of germination, respectively); however, those from J. curcas and Guazuma ulmifolia possibly did not express their true quality, because the coat cut did not eliminate dormancy and for these seeds the immersion in concentrated sulfuric acid during 60 minutes is indicated (Muñoz et al., 2004).

The seeds from the herbaceous species collected in 2007 (table 3) showed homogeneous quality and germination values varied between 80 and 100%, except in Macroptilium atropurpureum with 60% (Granma), which could have been due to the heterogeneous maturation of its seeds and to the stressing environmental conditions (Heydecker, 1977); similar performance was observed in Teramnus (12%) from Granma and in Neonotonia wightii (20%) from Matanzas. For the seeds collected in 2009 (table 4) the quality was also similar and the values fluctuated between 96 and 100%, with the exceptions of Calopogonium sp. (52%), from Banao, and Glycine sp. (50%) collected in Sancti Spiritus.

Seed quality depended on the time they remained in the field after the pod maturation stage; similar results were reported by Reino et al. (2010) and González et al. (2011) for accessions of similar species collected in other Cuban regions. Most of them were observed to achieve high survival, although some species showed low germination, which could have been caused by pod deterioration after the maturation stage in the field where they remained until the harvest moment (Heydecker, 1977).

Through these collection missions, the germplasm of the Experimental Station «Indio Hatuey» was increased with 83 accessions. Seed quality was concluded to depend on the time the seeds remained in the field after pod maturation. To continue the collection in other zones of the country is recommended, which will allow higher diversity in livestock production systems.