Agromorphological Characterisation of Gboma Eggplant, an Indigenous Fruit and Leafy Vegetable in Ghana Abstract Résum
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African Crop Science Journal, Vol. 22, No. 4, pp. 281 - 289 ISSN 1021-9730/2014 $4.00 Printed in Uganda. All rights reserved © 2014, African Crop Science Society AGROMORPHOLOGICAL CHARACTERISATION OF GBOMA EGGPLANT, AN INDIGENOUS FRUIT AND LEAFY VEGETABLE IN GHANA D. NYADANU1, 2, L.M. ABOAGYE2, R. AKROMAH1, M.K. OSEI3 and M.B. DORDOE2 1Department of Crop and Soil Sciences, Faculty of Agriculture, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana 2Faculty of Agriculture Education, University of Education, Winneba. P. O. Box 40, Asante Mampong, Ghana 3Crops Research Institute, Kumasi, Council for Scientific and Industrial Research, Ghana Corresponding author: [email protected] (Received 25 September, 2014; accepted 24 November, 2014) ABSTRACT Gboma (Solanum macrocarpon L.) is an important leafy and fruit vegetable in Ghana. Despite its nutritional and medicinal properties, and consumption by many ethnic groups in the country, the crop is underdeveloped. The objective of this study was to characterise diversity among local landraces of Solanum macrocarpon in Ghana using agro-morphological descriptors in order to identify outstanding accessions which could be involved in further breeding programmes. A total of 23 accessions collected from different agro-ecological zones in Ghana were characterised using morphological descriptors. The accessions varied significantly in days to 50% flowering, days to fruiting, stem girth, fruit weight, number of seeds per fruit, weight of leaves per plant and plant height. Principal components analysis based on the morphological traits showed that PC1 for 99% of the total variation was mainly defined by number of leaves, number of branches, plant height, stem girth and number of leaves per plant. The accessions evaluated were grouped under five clusters. The clustering pattern indicated that inter- cluster distance was higher than intra-cluster, indicating wide genetic diversity among the accessions. Correlation analyses between morphological traits revealed positive and negative relationships, indicating predictable success for eventual breeding activities. Accessions CAGRICW3, CAGRICW4, CAGRICN2 and CAGRICA4 had more leaves and fruits, and could be used as potential donors for hybridisation programme to develop variety with higher yield potential. Key Words: Inter-cluster distance, Solanum macrocarpon RÉSUMÉ L’aubergine Gboma (Solanum macrocarpon L.) est un important légume feuille et fruit au Ghana. En dépit de ses propriétés nutritionnelle et médicinale, et de sa consommation par plusieurs ethnies du pays, cette culture est sous développée. L’objectif de cette étude était d’évaluer la diversité entre les cultivars traditionnels de Solanum macrocarpon au Ghana en se servant des descripteurs agro morphologiques, dans le but d’identifier des cultivars à bonne performances agro-morphologiques pouvant être introduits dans des programmes ultérieurs d’amélioration variétale. Au total 23 cultivars traditionnels collectés dans différentes zones agro-écologiques au Ghana ont été caractérisés. Les cultivars ont montré une différence significative en ce qui concerne la date de floraison, la date de fructification, la circonférence de la tige, le poids du fruit, le nombre de pépin par fruit, le poids des feuilles par plante et la hauteur des plantes. L’analyse en composantes principales basée sur les traits morphologiques montre que le premier axe PC1 comportant 99% de la variation totale était essentiellement défini par le nombre de feuilles par plante, le nombre de branches, la hauteur des plantes et la circonférence de la tige. Les accessions évaluées ont été groupées en cinq typologies. La répartition typologique a montré que la distance intergroupes était plus importante que la distante au sein des groupes, cela suggère une grande diversité génétique entre les accessions. L’analyse des corrélations entre traits morphologiques révèle des corrélations positives et négatives, 282 D. NYADANU et al. ceci indique qu’on peut aboutir à de bons résultats en amélioration variétale. Les cultivars CAGRICW3, CAGRICW4, CAGRICN2 et CAGRICA4 avaient plus de feuilles et de fruits, et de ce fait pourraient être utilisés comme potentiel parents dans des programmes d’amélioration variétale pour développer des variétés à haut rendement. Mots Clés: distance intergroupes, Solanum macrocarpon INTRODUCTION The objective of this study was to characterise diversity among local landraces of Gboma (Solanum macrocarpon L.), of the family Solanum macrocarpon in Ghana, using agro- Solanaceae, is one of the horticulturally important morphological descriptors, in order to identify eggplant species with an African ancestry. It is outstanding accessions which could be involved found throughout the warmer and non-arid parts in further breeding programmes to develop of Africa, where it is an important fruit or leafy improved varieties for farmers and consumers. vegetable (Schippers, 2000). Gboma eggplant is rich in protein, fibre, calcium, iron, potassium, MATERIALS AND METHODS magnesium, phosphorus and sodium (Agoreyo et al., 2012; Nyadanu and Lowor, 2014). The The experiment was carried out at the research quality of protein in Gboma leaf and fruit is of station of the College of Agriculture Education, high quality and, therefore, represents affordable University of Education, Winneba, Ashanti but quality nutrition for many families (Adeyeye Mapong campus, located within longitudes 0.05 and Adanlawo, 2011). It is used in traditional degrees and 1.30 degrees west and latitudes 6.55 medicine for treatment of various ailments, degrees and 7.30 degrees north in Ghana. ranging from weight reduction, asthma, skin Twenty three accessions (Table 1) of local infections, rheumatic disease, gastro- landraces of Gboma egg plant were collected from oesophageal reflux diseases, to constipation and Volta, Ashanti, Eastern, Brong Ahafo, Western diabetes (Nwodo et al., 2011). The fruits are said and Northern regions of Ghana. Seeds extracted to represent blessings and fruitfulness and are from the fruits were first nursed at the research offered as tokens of goodwill during visits, station of College of Agriculture Education, marriages and other social events in Ghana and University of Education, Winneba, Mampong Nigeria (Schippers, 2000). Campus, Ghana. Seedlings were transplanted at Despite the importance of Gboma eggplant, four-leaf stage to 3 m x 2 m beds, in a randomised in most African countries, the crop is neglected complete block design, with four replicates, at a and underutilised. Virtually, no research has been spacing of 40 cm between rows and 30 cm within done to enhance the germplasm potential or to rows. study its agronomic requirements. Consequently, Quantitative and qualitative characters of cultivated varieties are still landraces and their vegetative development, leaf, floral and seed cultivation is in drastic decline due to pest and production were studied using descriptors for disease pressures, poor yield and small fruit sizes. eggplant (IBPGR, 1990). These parameters Breeding for improved varieties is no longer an included number of leaves, number of branches option, but a dire need to meet the requirements per stem, days to 50% flowering, number of of both farmers and consumers in Africa. The flowers per plant, plant height, petal colour, fruit knowledge of diversity and characteristics of colour, leaf blade width, leaf length, sepal colour, existing landraces, and farmers’ selection criterion number of leaf lobes, fruit shape, fruit apex shape, are a pre-requisite for designing a concrete number of flowers per inflorescence, leaf blade breeding programme (Adoukonou-Sagbadja et shape, leaf apex shape, leaf base shape, girth of al., 2006). Lack of this information places Gboma stem, fruit length, fruit width, fruit colour at eggplant in danger of continued genetic erosion physiological maturity, measured using a colour and disappearance. Agromorphological characterisation of Gboma eggplant 283 TABLE 1. Status, collection sites and regions of Gboma egg- based on Euclidean Distance Coefficient and plant accessions collected in Ghana UPGMA clustering method (Fig. 1), clearly showed phenotypic diversity among S. Accessions Status Collection Region macrocarpon accessions. The phenogram sites separated the 23 accessions studied into five CAGRIC V1 Cultivated Keta Volta distinct clusters by grouping accessions sharing CAGRIC V2 Cultivated Keta Volta close phenotypic similarities into distinct CAGRIC V3 Cultivated Anloga Volta clusters. The clustering pattern indicated that the CAGRIC V4 Cultivated Anloga Volta inter-cluster distance is higher than intra-cluster CAGRIC V5 Cultivated Denu Volta distance. CAGRIC V6 Cultivated Denu Volta Colours of fruits, sepals and collora were CAGRIC W1 Wild Wiawso Western variable, clearly revealing diversity among the CAGRIC W2 Wild Wiawso Western accessions (Plates 1a-d; 2a-d). The most CAGRIC W3 Cultivated Wiawso Western characteristic fruit shapes were round, oval or CAGRIC W4 Cultivated Wiawso Western CAGRIC A1 Cultivated Ejura Ashanti egg and oblong shaped. Fruit colour ranged from CAGRIC A2 Cultivated Ejura Ashanti white, pale green to dark green. Some accessions CAGRIC A3 Wild Ejura Ashanti produced fruits with shiny green fruits with dark CAGRIC A4 Wild Mampong Ashanti green stripes; while others were uniformly green CAGRIC E1 Wild Begoro Eastern without stripes. The sepal colour ranged from CAGRIC E2 Cultivated Konongo Eastern pale green, green to purple black. Inflorescence