View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Brage INN REVIEW published: 25 August 2017 doi: 10.3389/fpls.2017.01484 World Vegetable Center Eggplant Collection: Origin, Composition, Seed Dissemination and Utilization in Breeding Dalia Taher 1, 2, Svein Ø. Solberg 1, 3*, Jaime Prohens 4, Yu-yu Chou 1, Mohamed Rakha 1, 5 and Tien-hor Wu 1 1 World Vegetable Center, Tainan, Taiwan, 2 Vegetable Crops Research Department, Agriculture Research Center, Horticulture Research Institute, Giza, Egypt, 3 Faculty of Applied Ecology and Agricultural Sciences, Inland Norway University of Applied Sciences, Elverum, Norway, 4 Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, Valencia, Spain, 5 Horticulture Department, Faculty of Agriculture, University of Kafrelsheikh, Kafr El-Sheikh, Egypt Eggplant is the fifth most economically important solanaceous crop after potato, tomato, pepper, and tobacco. Apart from the well-known brinjal eggplant (Solanum melongena Edited by: L.), two other under-utilized eggplant species, the scarlet eggplant (S. aethiopicum L.) Petr Smýkal, Palacký University, Olomouc, Czechia and the gboma eggplant (S. macrocarpon L.) are also cultivated. The taxonomy and Reviewed by: identification of eggplant wild relatives is challenging for breeders due to the large number Daniela Romano, of related species, but recent phenotypic and genetic data and classification in primary, University of Catania, Italy Rangan Parimalan, secondary, and tertiary genepools, as well as information on the domestication process Indian Council of Agricultural Research and wild progenitors, facilitates their utilization in breeding. The World Vegetable Center (ICAR), India (WorldVeg) holds a large public germplasm collection of eggplant, which includes the *Correspondence: three cultivated species and more than 30 eggplant wild relatives, with more than 3,200 Svein Ø. Solberg [email protected] accessions collected from 90 countries. Over the last 15 years, more than 10,000 seed samples from the Center’s eggplant collection have been shared with public and Specialty section: private sector entities, including other genebanks. An analysis of the global occurrences This article was submitted to Crop Science and Horticulture, and genebank holdings of cultivated eggplants and their wild relatives reveals that the a section of the journal WorldVeg genebank holds the world’s largest public collection of the three cultivated Frontiers in Plant Science eggplant species. The composition, seed dissemination and utilization of germplasm Received: 10 May 2017 from the Center’s collection are highlighted. In recent years more than 1,300 accessions Accepted: 10 August 2017 Published: 25 August 2017 of eggplant have been characterized for yield and fruit quality parameters. Further Citation: screening for biotic and abiotic stresses in eggplant wild relatives is a priority, as is the Taher D, Solberg SØ, Prohens J, need to amass more comprehensive knowledge regarding wild relatives’ potential for Chou Y, Rakha M and Wu T (2017) World Vegetable Center Eggplant use in breeding. However, as is the case for many other crops, wild relatives are highly Collection: Origin, Composition, Seed under-represented in the global conservation system of eggplant genetic resources. Dissemination and Utilization in Breeding. Front. Plant Sci. 8:1484. Keywords: conservation, crop wild relatives, diversity, plant genetic resources, Solanum melongena, Solanum doi: 10.3389/fpls.2017.01484 aethiopicum, Solanum macrocarpon Frontiers in Plant Science | www.frontiersin.org 1 August 2017 | Volume 8 | Article 1484 Taher et al. World Vegetable Center Eggplant Collection INTRODUCTION are incompletely understood (Levin et al., 2006; Meyer et al., 2012). Here, we limit ourselves to identify global occurrences Brinjal eggplant (Solanum melongena L.) is a warm-weather and regions of diversity. A key section is the overview of crop mostly cultivated in tropical and subtropical regions of the global genebank holdings of cultivated eggplant and their wild world. Two other cultivated eggplant species, the scarlet eggplant relatives. As we shall demonstrate, for such plants the collection (S. aethiopicum L.) and the gboma eggplants (S. macrocarpon at the WorldVeg is of paramount importance. Composition, seed L.), are less known but have local importance in sub-Saharan dissemination and utilization of germplasm from this collection Africa (Schippers, 2000; Daunay and Hazra, 2012). Based on are presented and discussed. The importance of safeguarding data from 2014, the global production of eggplant is around and evaluating wild relatives is highlighted, as crop wild relatives 50 million tons annually, with a net value of more than US$10 are highly under-represented in the global conservation system billion a year, which makes it the fifth most economically of plant genetic resources and may harbor important genes for important solanaceous crop after potato, tomato, pepper, and resistance or tolerance to biotic and abiotic stresses. tobacco (FAO, 2014). The top five producing countries are China (28.4 million tons; 57% of world’s total), India (13.4 million tons; 27% of world’s total), Egypt (1.2 million tons), Turkey TAXONOMY, WILD RELATIVES, AND (0.82 million tons), and Iran (0.75 million tons). In Asia and DOMESTICATION OF EGGPLANT the Mediterranean, eggplant ranks among the top five most important vegetable crops (Frary et al., 2007). Eggplants are berry-producing vegetables belonging to the large Regarding nutritional value, eggplant has a very low caloric Solanaceae family (nightshade family), which contains ∼3,000 value and is considered among the healthiest vegetables for its species distributed in some 90 genera (Vorontsova and Knapp, high content of vitamins, minerals and bioactive compounds 2012). Out of these Solanum L. is the largest one, with around for human health (Raigón et al., 2008; Plazas et al., 2014b; 1,500 species (Frodin, 2004) including globally important crops Docimo et al., 2016). In this respect, eggplant is ranked among such as potato (Solanum tuberosum L.) and tomato (Solanum the top 10 vegetables in terms of oxygen radical absorbance lycopersicum L.), as well as many other minor crops. Most taxa capacity (Cao et al., 1996). The bioactive properties of eggplant of Solanum genus have a basic chromosome number of n = 12 are mostly associated with high content in phenolic compounds (Chiarini et al., 2010). (Plazas et al., 2013), which are mostly phenolic acids, particularly The Solanum genus is mega-diverse and can be divided chlorogenic acid in the fruit flesh (Stommel et al., 2015) into 13 clades, where eggplant is the member of the large and anthocyanins in the fruit skin (Mennella et al., 2012). and taxonomically challenging Leptostemonum clade (subgenus Both phenolic acids and anthocyanins have multiple properties Leptostemonum Bitter; Knapp et al., 2013), which is commonly beneficial for human health (Plazas et al., 2013; Braga et al., 2016). known as the “spiny Solanum” group due to the presence of sharp Farmers need improved eggplant varieties for sustainable epidermal prickles on stems and leaves (Vorontsova et al., 2013). production and adaptation to climate change challenges. Because The subgenus Leptostemonum contains around 450 currently eggplant has a relatively long growth period, it is more exposed recognized species distributed worldwide (Knapp et al., 2013), than other vegetable crops to a broad range of plant diseases, many of which originated in the New World (Vorontsova and pests, nematodes, and weeds. The most common diseases include Knapp, 2012). All three cultivated eggplant species have the Old bacterial wilt, verticillium wilt, fusarium wilt, anthracnose fruit World in origin (Figure 1). The Old World (Africa and Eurasia) rot, alternaria rot, damping off, Phytophthora blight, phomopsis and Australia, are home to more than 300 Solanum species (Levin blight and fruit rot, leaf spot, little leaf of brinjal, and et al., 2006; Vorontsova and Knapp, 2016). Solanum melongena mosaic (Rotino et al., 1997). Eggplant is also subject to attack and S. macrocarpon are usually included in section Melongena by numerous insect pests including mites, whiteflies, aphids, Dunal (Lester and Daunay, 2003; Lester et al., 2011), whereas eggplant fruit, and shoot borer, leafhopper, thrips, spotted beetles, S. aethiopicum is assigned to section Oliganthes (Dunal) Bitter leaf roller, stem borer, and blister beetle (Rotino et al., 1997; (Lester, 1986). Medakker and Vijayaraghavan, 2007). Unpredictable weather Solanum melongena is characterized by large morphological with extreme temperatures, drought or flooding can reduce yield diversity, and frequently it has been considered as the same and fruit quality. In general, eggplant breeding programs aim to taxonomic species than its wild ancestor S. insanum L. (Ranil develop high-yielding varieties, mostly F1 hybrids, with high fruit et al., 2017). Four taxonomically informal groups, labeled E– quality, shelf-life and resistance to major disease and insect pests, H, were considered by Lester and Hasan (1991) to describe and with broad adaptation to environmental stress (Daunay and the different types of wild and weedy eggplant as well as their Hazra, 2012). distribution (Table 1). However, these four groups are presently Access to genetic diversity is fundamental for any breeding considered as representing two different species: the