HORTSCIENCE 44(7):2017–2019. 2009.

‘H15’, an Almagro-type PicklingEggplant with High Yield andReduced PricklinessJaime Prohens1, Julio E. Munoz-Falcon,and Adrian Rodrıguez-BurruezoInstituto de Conservacion y Mejora de la Agrodiversidad Valenciana,Universidad Politecnica de Valencia, Camino de Vera 14, 46022 Valencia,Spain

Francisco RibasCentro Agrario ‘‘El Chaparrillo,’’ Carretera de Porzuna s/n, 13071 CiudadReal, Spain

Angel CastroAsociacion para la Promocion de la IGP ‘‘Berenjena de Almagro,’’C/Toledillo 59, 13260 Bolanos de Calatrava, Spain

Fernando NuezInstituto de Conservacion y Mejora de la Agrodiversidad Valenciana,Universidad Politecnica de Valencia, Camino de Vera 14, 46022 Valencia,Spain

Additional index words. Solanum melongena, Protected Geographical Indication, locallandraces, participatory breeding, processing quality

Pickling eggplants (Solanum melongenaL.) are locally important in some areas of theMediterranean region, Middle East, China,Korea, Japan, India, and southeastern Asia(Inden et al., 1999; Munoz-Falcon et al.,2009). However, the breeding efforts devotedto the improvement of pickling eggplantshave been limited, and these types of cropshave been largely overlooked by the publicand private breeding programs. This ismainly the consequence of the smaller acre-age devoted to the production of picklingeggplants when compared with that of egg-plants for the fresh vegetable markets or forthe industrial preparation of frozen foods ordehydrated products. Also, the value of theharvest per individual plant is much lowerthan that of other varietal types of eggplants,like the hybrids for greenhouse production.

Consequently, the plant materials used forelaborating pickling eggplants usually con-sist of local landraces, which have beenselected and conserved by the farmers(Munoz-Falcon et al., 2009).

In Spain, pickling eggplants are producedin several areas in the center and south of thecountry. The most important area for the pro-duction of this type of eggplants is the region ofthe Campo de Calatrava, situated in the prov-ince of Ciudad Real, in the center of Spain.This region is home of the so-called Almagro(in reference to the city of Almagro, capital ofthe region of Campo de Calatrava) picklingeggplant, which is the only eggplant produceofficially recognized in Europe with a ProtectedGeographical Indication (PGI) status, whichwas granted in 1994 (Castro, 2005). Theacreage devoted to Almagro eggplant produc-tion is �60 ha and the total annual productionoscillates between 1500 and 2000 tons. Thefinal value of the Almagro eggplant produce inthe market is �$6 U.S. per 106.

The Almagro pickling eggplant is grownin the open field during the summer growingseason in fields that normally have been infallow during the winter season after a pre-vious winter or spring cereals crop. Becauseof the ample availability of land, farmerstypically do not repeat the eggplant crop inthe same land for 10 or 15 years, and most ofthe Almagro eggplant fields are isolated fromother eggplant or vegetable crops fields,which results in a very low incidence of pestsand diseases. Almagro eggplant fruits areharvested when very young, aged only �2weeks after pollination, and are characterizedby having fruits covered by a large and edible

acrescent calyx. After the pickling process,which involves fruit (including the berry,calyx, and part of the fruit pedicel) boiling,natural fermentation for several days, andcanning in a brine solution (Ballesteros et al.,1999; Sesena and Palop, 2007), Almagroeggplant fruits have a green or golden colorand a firm texture of the flesh, the latter beingone of the most remarkable characteristicfeatures of this variety (Sesena et al., 2001)and which differentiates it from other pick-ling varieties of Spain, like those of theneighboring region of Andalusia (Andalusianpickling eggplant), which have a softer in-ternal texture after the pickling process.

One of the most important deficiencies ofthe Almagro eggplant landrace is the prickli-ness of the fruit calyx, which hampers theharvesting of the fruits, damages the fruitsduring the postharvest processing as a result ofthe pricks to the berries, and also makes themanual removal of the calyx prickles neces-sary before the pickling process. Prickliness ofthe calyx not only involves a greater demandof labor for removing the prickles, but, occa-sionally, some fruits for which the prickleshave not been completely removed may gothrough the industrial process, which affectsnegatively the appearance of the final produce.Finally, prickliness increases the risk of injuryby pricks of the workers during the harvestingand removal of prickles. Because of this,Andalusian pickling eggplants, which havea lower prickliness, although they give a lowerquality of the pickles, have been introduced bysome farmers in the Almagro region.

Farmers growing the Almagro eggplantusually produce their own seeds, whichmakes the Almagro eggplant a diverse land-race amenable to selection (Munoz-Falconet al., 2009). The goal of this research was totake advantage of this diversity to developa selection of Almagro eggplant that, com-pared with the Almagro eggplant landrace,maintains the typical plant and fruit charac-teristics, has reduced prickliness, higheryield, and maintains the high-quality stan-dards of the original landrace. The result ofthis selection program has been line ‘H15’.

Origin

The participatory selection program thatled to the development of ‘H15’ began in2004. A team formed by breeders, farmers,local industrialists, and staff from the Almagroeggplant PGI Council visually screened forprickliness and fruit characteristics thousandsof individual plants growing in the fields ofdifferent farmers in the Campo de Calatravaregion. Twenty-seven selected individualplants displaying low prickliness werepruned, uprooted, and carried to Valencia,where each of them was transplanted intoa 25-L pot and grown in a greenhouse. Self-pollinated offspring of the selected plantswere grown during the following season infarmers’ fields in the Campo de Calatravaregion. Most offsprings were homogeneous,and the few heterogeneous offsprings werediscarded. In this respect, although the

Received for publication 26 June 2009. Acceptedfor publication 6 Oct. 2009.This contribution was financed by the ‘‘Consejerıade Agricultura de la Junta de Comunidades deCastilla La Mancha’’ and by the ‘‘Ministerio deCiencia e Innovacion’’ grants AGL2006-04878/AGR, AGL2009-07257, and RF2008-00008-00-00.We acknowledge the participation of the followingfarmers and Almagro eggplant PGI staff in theparticipatory breeding program and in the field trials:Heriberto Alanon, Vicente Alanon, Jose AntonioAlbertos, Cipriano Barba, Juan Antonio Calzado,Jose Marıa Castro, Francisco Hita, Vicente Malagon,Antonio Pardo, and Luis Villanueva. We are alsograteful to Pablo Peco for his help in the dataacquisition and in the evaluation of the materials.1To whom reprint requests should be addressed;e-mail jprohens@btc.upv.es.

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eggplant is mostly autogamous, a variablerate of cross-pollination occurs, especiallyunder open-field conditions (Daunay, 2008;Pessarakli and Dris, 2004). A participatoryselection among homogeneous offspringoriginating from different individual plantswas performed for low prickliness, highyield, and plant and fruit characteristicstypical of the Almagro landrace. This led tothe selection of several promising lines thatwere subsequently characterized, tested foragronomic performance in more extensiveplots in farmers’ fields, and evaluated forpickling quality. Seed increase of the lineswas always performed by self-pollinationunder greenhouse conditions in Valencia.‘H15’ is the final selection of this processand originates from the selfing of an individ-ual plant selected in 2005 in one of theAlmagro eggplant farmers’ fields.

Description

The plant of ‘H15’ has a semierect habitwith purple stems and a strong anthocyaninintensity in the shoot tip (Fig. 1). The stemand leaves are not prickly and have purpleveins. The inflorescences have from one tofive flowers with a mean number of 2.7flowers per inflorescence. Flowers havea white and pale blue corolla, and all flowersare functionally hermaphroditic. Contrarilyto what occurs with many large-fruited egg-plants, fruit setting of the basal flower of theinflorescence does not inhibit the setting ofthe distal brevistyled flowers from the in-florescence, which behave as functionally

hermaphroditic, and infrutescences with mul-tiple fruits are common (Fig. 1).

The berry of ‘H15’ is oblong with a length/width ratio of�1:5 (Table 1), and although itcan grow to more than 25 cm long when lefton the plant until reaching its full size, to beused for pickling, it should be harvested whenit has a length of 4 to 9 cm and a fruit weightof 40 to 60 g (Fig. 2). At this stage, the pedicellength varies between 9.5 and 12 cm long andit is slender and smooth in the proximal part(Table 1; Fig. 3). This trait clearly distin-guishes the ‘H15’ eggplant from other mor-phologically similar pickling eggplants nativeto other regions of Spain, like those ofAndalusia, which display a wider and rougherproximal part of the fruit pedicel. At the stageof harvesting, the acrescent calyx covers all ormost of the berry (Table 1), a trait required forthe elaboration of Almagro pickling eggplant.The calyx is purple and green in color andpresents reduced prickliness when comparedwith the original Almagro landrace (Table 1;Fig. 4). The berry is green in color in the areacovered by the calyx and purple in the areaexposed to the sun, indicating that, like theAlmagro landrace, ‘H15’ is homozygous forthe dominant alleles of the A (fruit anthocy-anin presence) and G (fruit chlorophyllspresence) genes as well as for the recessivealleles of the Gv (reticulated pattern of chlo-rophyll) and Puc (purple under calyx) genes(Daunay et al., 2004; Tigchelaar et al., 1968).

Characterization data using primary de-scriptors from EGGNET (Eggplant GeneticResources Network; EGGNET, 2005; Prohenset al., 2005; van der Weerden and Barendse,2007) shows that ‘H15’ is morphologicallyvery similar to the Almagro landrace used bythe farmers, except for a lower prickliness ofboth the leaves and fruit calyx (Table 1).Morphologically, ‘H15’ can also be distin-guished from other Spanish pickling eggplantsfrom the neighboring region of Andalusia forhaving smaller leaves (shorter leaf petiole, leafblade length, and width) and smaller corolla,and also for some fruit traits, it has lower calyxanthocyanin pigmentation, shorter fruit pedi-cel length, smaller fruit pedicel width at theproximal end, and with a higher length/widthratio (Table 1).

The fruit of ‘H15’ had a soluble solidscontent of 5.5% to 6.3%, a pH of 5.4 to 5.8,and an ascorbic acid content of 15 to 23mg�kg–1. Values for these traits do not differ

significantly from those of the Almagro andAndalusian landraces. As is general with theAlmagro eggplant landrace, ‘H15’ presentsa high content in antioxidant phenolic com-pounds (0.7 to 0.9 g�kg–1 of fresh weight), andbecause of this, it represents a source ofvariation for breeding programs aimed atincreasing the phenolic acid content of egg-plant (Prohens et al., 2007; Stommel andWhitaker, 2003).

Molecular characterization with 36 simplesequence repeats has shown that ‘H15’ clus-ters with other Almagro eggplant materialsand also that it is genetically differentiatedfrom the Andalusian pickling eggplant land-race. ‘H15’ is homozygous for the allele 206for the EM127 marker and the allele 360 forthe EM145 marker. These alleles are specificto the Almagro eggplant landrace and are usedas diagnostic markers to distinguish Almagroeggplants from other Spanish pickling egg-plants (Munoz-Falcon et al., 2009).

Performance

Fruit production of ‘H15 was comparedwith those of the local Almagro landracematerials used by the farmers and with highyield and low prickliness (but low quality)Andalusian pickling eggplant landrace mate-rials for 3 years (2006 to 2008) in multi-location replicated trials in fields of farmersassociated with the PGI Almagro eggplant.Results consistently have shown that ‘H15’had a high yield with an average yield acrossthe 3 years of trials of one-third higher than theoriginal Almagro landrace and almost 20%higher that the Andalusian landrace (Table 2).

Regarding prickliness, ‘H15’ shows muchlower fruit calyx prickliness than the mate-rials of the local Almagro landrace used by thefarmers (Table 2; Fig. 4). In all the trials done,the average degree of prickliness of ‘H15’ranged between 1.2 and 1.4, whereas for theAlmagro eggplant it ranged between 1.8 and2.0. This represents an important advance,although the Andalusian landrace, with a de-gree of prickliness ranging between 0.4 and0.6, is less prickly than ‘H15’ (Table 2).

Fruit quality of the pickled fruits of ‘H15’was compared with those of the Almagrolandrace used by the farmers as well as withthe Andalusian pickling landrace. Samples ofeach of the materials were boiled, naturallyfermented, and pickled using the traditional

Fig. 1. Young plant (A) and older plants showinginflorescences of ‘H15’ (B) with abundantflowering and fruit setting. The rectangular plateof the T-label plate stake measures 9.4 · 5.4 cm.

Table 1. Mean and range for fruit morphological traits of ‘H15’ and of the Almagro and Andalusianlandraces obtained from five characterization trails performed in 3 years (2006 to 2008).

H15 Almagro landrace Andalusian landrace

Fruit pedicel length (cm) 10.3 (9.5–11.8) 9.6 (8.5–10.8) 9.2 (8.0–10.5)Fruit pedicel diameter at the

proximal end (mm)7.2 (6.9–7.6) 7.5 (7.0–8.0) 10.8 (10.3–11.3)

Fruit pedicel diameter at thedistal end (mm)

18.9 (18.4–19.4) 19.1 (18.4–19.9) 18.4 (17.7–18.8)

Calyx colorz 4.1 (3.8–4.5) 4.4 (4.0–4.7) 5.7 (5.4–5.8)Fruit area covered by the calyx (%) 75.3 (70.9–81.1) 73.4 (68.8–79.7) 89.1 (82.2–90.7)Fruit length (mm) 63.7 (62.4–65.1) 62.1 (57.6–64.5) 60.8 (56.4–62.7)Fruit width (mm) 41.8 (41.1–42.8) 41.3 (40.0–42.3) 44.6 (43.2–45.1)Fruit length/width ratio 1.53 (1.48–1.56) 1.50 (1.44–1.53) 1.36 (1.31–1.40)zMeasured on a 1 to 7 scale (1 = green; 7 = purple).

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method (Castro, 2005). They were scored forfive traits by a trained panel for sensorialquality using a standard score tasting card forthe Almagro eggplant, in which higher scoresare better. Traits scored were: 1) color (0 to20 points); 2) fruit conformation (1 to 5points); 3) harmonious appearance (1 to 10points); 4) firmness (1 to 10 points); and 5)texture (1 to 10 points). The organoleptic

tests showed that ‘H15’ does not differsignificantly in quality traits from the Alma-gro landrace materials used by the farmersfor any of the quality traits studied (Table 3).However, ‘H15’ had significantly betterscores for firmness and texture than theAndalusian landrace materials.

In summary, ‘H15’ had a higher yield andlower prickliness than the Almagro landraceand maintains the same levels of quality forthe processed pickled produce. Furthermore,‘H15’ had a higher yield and better qualitythan the Andalusian pickling eggplant land-race. Consequently, ‘H15’ represents sub-stantial improvement over the currentlyused plant materials.

Availability

Seeds of ‘H15’ for commercial use can beobtained through a concession agreementfrom the Asociacion para la Promocion dela IGP Berenjena de Almagro, C/ Toledillo59, 13260 Bolanos de Calatrava, Spain; e-mail: berenjenas@castillalamancha.es. Smallsamples of ‘H15’ seeds for research purposesare available from Jaime Prohens, COMAV,UPV, Camino de Vera 14, 46022 Valencia,Spain; e-mail: jprohens@btc.upv.es.

Literature Cited

Ballesteros, C., L. Palop, and I. Sanchez. 1999.Influence of sodium chloride concentration onthe controlled lactic acid fermentation of ‘Alma-gro’ eggplants. Intl. J. Food Microbiol. 53:13–20.

Castro, A. 2005. Berenjena de Almagro, algo unico.Asociacion para la Promocion de la IndicacionGeografica Protegida Berenjena de Almagro.Bolanos de Calatrava, Ciudad Real, Spain.

Daunay, M.C. 2008. Eggplant, p. 163–220. In: Prohens,J. and F. Nuez (eds.). Handbook of plant breed-ing: Vegetables II. Springer, New York, NY.

Daunay, M.C., S. Aubert, A. Frary, S. Doganlar,R.N. Lester, G. Barendse, G. van der Weerden,J.W. Hennart, J. Haanstra, F. Dauphin, and E.Jullian. 2004. Eggplant (Solanum melongena)fruit colour: Pigments, measurements and ge-

netics. Proc. XIIth EUCARPIA Mtg. Genet.Breeding Capsicum Eggplant. p. 108–116.

EGGNET. 2005. Eggplant Genetic Resources Net-work. 31 Mar. 2005. <http://www.bgard.science.ru.nl/eggnet/eggnet01.html >.

Inden, H., Y. Kawano, Y. Kodama, and K.Nakamura. 1999. Present status of vegetablepickling in Japan. Acta Hort. 483:421–428.

Munoz-Falcon, J.E., J. Prohens, S. Vilanova, F.Ribas, A. Castro, and F. Nuez. 2009. Distin-guishing a Protected Geographical Indicationvegetable (Almagro eggplant) from closelyrelated varieties with selected morphologicaltraits and molecular markers. J. Sci. Food Agr.89:320–328.

Pessarakli, M.M. and R. Dris. 2004. Pollination andbreeding of eggplant. J. Food Agr. Environ. 2:218–219.

Prohens, J., J.M. Blanca, and F. Nuez. 2005.Morphological and molecular variation in a col-lection of eggplants from a secondary center ofdiversity: Implications for conservation andbreeding. J. Amer. Soc. Hort. Sci. 130:54–63.

Prohens, J., A. Rodrıguez-Burruezo, M.D. Raigon,and F. Nuez. 2007. Total phenolics concentra-tion and browning susceptibility in a collectionof different varietal types and hybrids ofeggplant: Implications for breeding for highernutritional quality and reduced browning. J.Amer. Soc. Hort. Sci. 132:638–646.

Sesena, S. and M.L. Palop. 2007. An ecologicalstudy of lactic acid bacteria from Almagroeggplant fermentation brines. J. Appl. Micro-biol. 103:1553–1561.

Sesena, S., I. Sanchez-Hurtado, M.A. Gonzalez-Vinas, and L. Palop. 2001. Contribution ofstarter culture to the sensory characteristics offermented Almagro eggplants. Intl. J. FoodMicrobiol. 67:197–205.

Stommel, J.R. and B.D. Whitaker. 2003. Phenoliccomposition of eggplant fruit in a germplasm coresubset. J. Amer. Soc. Hort. Sci. 128:704–710.

Tigchelaar, E.C., J. Janick, and H.T. Erickson.1968. The genetics of anthocyanin colorationin eggplant (Solanum melongena L.). Genetics60:475–491.

van der Weerden, G.M. and G.W.M. Barendse.2007. A web-searchable database developedfor the EGGNET Project and applied to theRadboud University Solanaceae database. ActaHort. 745:503–506.

Fig. 4. Differences in fruit calyx prickliness be-tween ‘H15’ (left) and the Almagro landrace(right) grown under the same conditions.

Table 2. Performance of ‘H15’ and of the Almagro and Andalusian landraces at multilocation trials foryield (kg�m–2) and fruit calyx prickliness [measured on a 0 to 9 scale: 0 = no prickles; 1 = very few (lessthan 3); 3 = few (�5); 5 = intermediate (�10); 7 many (�20); 9 = very many (greater than 30)].

2006 2007 2008

Yield Prickliness Yield Prickliness Yield Prickliness

H15 9.4 az 1.2 b 6.3 a 1.4 b 5.7 a 1.3 bAlmagro landrace 6.0 b 2.0 a 5.8 ab 1.9 a 4.2 b 1.8 aAndalusian landrace 7.9 ab 0.5 c 4.9 b 0.4 c 5.3 a 0.6 czMeans within columns with different letters are significantly different (P < 0.05) according to the Student-Newman-Keuls test.

Table 3. Scores obtained by ‘H15’ and by the Almagro and Andalusian landraces in sensory quality testsperfomed in 2006 using a hedonic scale (lowest values = dislike; highest values = like) after beingsubjected to the traditional procedures of boiling, fermentation, and pickling according to color (0 to 20points), fruit conformation (1 to 5 points), harmonious appearance (1 to 10 points), firmness (1 to 10points), texture (1 to 10 points), and total score (4 to 55 points).

ColorFruit

conformationHarmoniousappearance Firmness Texture Total

H15 15.0 abz 3.0 a 6.0 a 8.0 a 8.0 a 40.0 aAlmagro landrace 16.7 a 3.3 a 6.0 a 8.0 a 8.0 a 42.0 aAndalusian landrace 13.8 b 3.3 a 7.0 a 5.3 b 4.0 b 33.3 bzMeans within columns with different letters are significantly different (P < 0.05) according to the Student-Newman-Keuls test.

Fig. 2. Fruits of ‘H15’ at the harvesting stage, inwhich the acrescent calyx must cover all ora major part of the berry. The rectangular plateof the T-label plate stake measures 9.4 · 5.4 cm.

Fig. 3. Fruit pedicel of Andalusian pickling egg-plant landrace (above) and of ‘H15’ (below).The pedicel of ‘H15’ is slender and smooth atthe proximal end, whereas the Andalusian land-race is wider and rougher. Scale in centimeters.

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