Solanum Aethiopicum Research Articles

Milk-clotting activity of berries extracts from nine Solanum plants

Nine Solanum species (Solanum aculeastrum, Solanum aethiopicum, Solanum anomalum, Solanum cerasiferum, Solanum dasyphyllum, Solanum indicum, Solanum nigrum, Solanum nodiflorum and Solanum terminale) berries were studied in order to find a new source of milk-clotting enzymes for artisanal use by Cameroonian farmers. The results showed that milk-clotting activity was obtained by soaking fresh and dried berries in either distilled water or 5% NaCl solution. Maximum milk-clotting activity was obtained by soaking dried berries in 5% NaCl solution at optimum time of extraction for each species. Dried berries released active enzymes more easily than fresh ones, and addition of salt facilitated the extraction process. Extract from S. aethiopicum berries had the highest milk-clotting activity. All extracts had proteolytic activity. High milk-clotting and proteolytic activities were found in extract from S. cerasiferum obtained after 24 h of soaking dried berries in 5% NaCl solution. High milkclotting and low proteolytic activities were found in extract from S. aethiopicum obtained under same conditions

α-Solasonine and α-Solamargine Contents of Gboma (Solanum macrocarpon L.) and Scarlet (Solanum aethiopicum L.) Eggplants

The gboma (Solanum macrocarpon L.) and scarlet eggplants (Solanum aethiopicum L.), which form part of the traditional sub-Saharan African culture, are two of the many neglected crops with potential for increased cultivation or as a genetic resource for improving agronomic traits of the common eggplant. This work is focused on the analysis of glycoalkaloid levels in S. macrocarpon and S. aethiopicum to assess their safety. Liquid chromatography-mass spectrometry was used to quantify glycoalkaloids in S. macrocarpon and S. aethiopicum compared to Solanum melongena L. Fruits of S. aethiopicum and S. melongena contained 0.58-4.56 mg/100 g of alpha-solamargine and 0.17-1 mg/100 g of alpha-solasonine, on a wet basis. S. macrocarpon fruits had much higher values of alpha-solamargine (124-197 mg/100 g) and alpha-solasonine (16-23 mg/100 g). However, the proportions of alpha-solamargine and alpha-solasonine of S. melongena and S. macrocarpon were similar (76-89% of alpha-solamargine), whereas in S. aethiopicum fruit composition was more variable (48-89% of alpha-solamargine). According to these results, the glycoalkaloid levels of S. macrocarpon fruits are 5-10 times higher than the value considered to be safe in foods and might not be considered suitable for human consumption; however, the glycoalkaloid levels of S. aethiopicum were similar to those of S. melongena (about 14% of values considered as toxic) and could be considered as safe for consumption. The incorporation of the cultivated African S. aethiopicum into eggplant breeding programs to develop improved varieties of the common eggplant may represent an alternative to crossing with wild species.

Host Use of <I>Bactrocera latifrons</I>, a New Invasive Tephritid Species in Tanzania

Bactrocera latifrons (Hendel) is a pest of Asian origin, first detected in Africa in 2006. We assessed the host utilization of this quarantine pest in Morogoro region, eastern central Tanzania, by collecting a wide range of cultivated and wild host plants of species belonging to Solanaceae and Cucurbitaceae from April 2007 to April 2008. Fruit were collected from 29 plant species and varieties (16 Solanaceae and 13 Cucurbitaceae) in all agroecological zones of Morogoro region. Twelve solanaceous fruit species yielded B. latifrons of which four are new host records: Capsicum annuum L. cov. longum A. DC., Capsicum chinense Jacq., Solanum sodomeum L., and Solanum scabrum Mill. Similarly, three cucurbitaceous fruit species provided positive rearings and are new host records: Citrullus lanatus (Thunb.) Matsum & Nakai, Cucumis dipsaceus L., and Momordica cf trifoliata L. The infestation rate and incidence of the pest was mainly high in the solanaceous hosts of nightshades (Solanum nigrum L. and Solanum scabrum) and African eggplants (Solanum aethiopicum Lam. and Solanum anguivi). In a host preference study involving limited number of cultivated solanaceous crops, S. scabrum was recorded as the most preferred host. The pest has been found to outnumber Bactrocera invadens (Drew et al.), Bactrocera cucurbitae (Coquillett), and Ceratitis capitata (Wiedemann) in most of the common solanaceous hosts.

Development of the Male-sterile Line of Eggplant Utilizing the Cytoplasm of Solanum aethiopicum L. Aculeatum Group

In order to develop a new male-sterile line of eggplant (Solanum melongena L.), the F1 rootstock ‘Assist’ (Solanum aethiopicum Aculeatum L. Group × S. melongena ‘DMP’) was continuously backcrossed to S. melongena ‘Uttara’ using ‘Uttara’ as a recurrent pollen parent up to BC4 generation. All examined F1 ‘Assist’ produced pollen grains while BC1 plants segregated into male fertile and sterile plants. The male-sterile plant did not produce any pollen grains. BC2, BC3, and BC4 progenies obtained from male fertile backcross progenies were segregated into male fertile and sterile plants and each segregation ratio fitted 3 : 1. BC3 and BC4 progenies obtained from male-sterile backcross progenies were fixed to male-sterility without segregation. Selfed progenies of the male fertile BC2 progeny were segregated into male fertile and sterile plants and the segregation ratio fitted 15 : 1. Therefore, the pollen non-formation characteristic is assumed to be a form of cytoplasmic male-sterility (CMS), induced by incompatibility between the cytoplasm of S. aethiopicum Aculeatum Group and the nucleus of S. melongena. Further, these segregation results indicated that two independent dominant fertility restorer (Rf) genes control the fertility restoration of this CMS. High values of fruit set, number of seeds per fruit, and the seed germination rate found in BC4 progenies indicate that the cytoplasm of S. aethiopicum Aculeatum Group has no notable negative effect on seed fertility of S. melongena. A new male-sterile line of eggplant could be developed by utilizing the cytoplasm of S. aethiopicum Aculeatum Group.

Effect of cow dung and poultry droppings on nutrients uptake, growth and yield of garden egg (Solanum aethiopicum) in Obubra rainforest zone of Nigeria

Field experiments were conducted during the cropping seasons of 2006 and 2007 at the teaching and research farm of the Cross River University of Technology (CRUTECH), Obubra – Nigeria, to determine the effect ofcow dung and poultry droppings on nutrients uptake, growth and yield of garden egg (Solanum aethiopicum). Treatments comprised four levels of cow dung as follows: (0, 10, 20 and 30 t/ha) and four levels of poultry droppings: (0, 5, 10 and 15 t/ha). These were factorially combined to give sixteen treatment combinations and arranged into a randomized complete block design (RCBD) with three replications. The parameters measured were; plant height, number of branches per plant, shoot dry matter, number of fruits per plant and fruit yield (kg/ha). Applications of cowdung at 30 t/ha in 2006 and 20 to 30 t/ha in 2007 produced the tallest plants with highest number of branches, highest number of fruits and highest fruit yield. Application of poultry droppings at 15 t/ha produced tallest plants with highest number of branches, highest number of fruits per plant and fruit yield per unit area. Combined application of cow dungat 30 t/ha and poultry droppings at 15 t/ha produced tallest plants, highest number of branches, highest number of fruits per plant and fruit yield.

Intake, growth and carcass yield of indigenous goats fed market wastes of sweet potato (Ipomoea batatas) vines and scarlet eggplant (Solanum aethiopicum)

Intake, growth and carcass yield of indigenous goats fed basal diets of market wastes of sweet potato (Ipomoea batatas) vines (SPV) and scarlet eggplant (Solanum aethiopicum) (SEP) were examined in two experiments. In experiment I, the effect of presentation method (chopping, hanging or adding molasses) on the intake of SEP and SPV was evaluated. Presentation method did not influence the intake of SPV while hanging resulted in the highest (P < 0.05) intake of SEP. In experiment II, 24 male growing goats were supplemented with a concentrate (25% cottonseed cake +75% maize bran) in four dietary groups: SEPD, SPVD, SEP+SPV and Control where elephant grass (Pennisetum purpureum) was offered as the roughage. SEP were offered by hanging, while SPV were chopped. The goats were slaughtered after 12 weeks of feeding. Goats in the SEPD group constantly lost weight, hence were not followed to the end. Average daily gain and hot carcass weight were highest (P < 0.05) in the SPVD group (44 g/d and 8.4 kg, respectively), but similar between the SEP+SPV (19 and 6.8) and Control (21 and 6.9) groups. In conclusion, SPV can support goat meat production where standard feed resources are scarce when fed with an energy-protein concentrate. SEP are poorly consumed by goats, hence cannot be used as their sole basal feed.

Effectiveness of GF-120NF Fruit Fly Bait as a suppression tool forBactrocera latifrons(Diptera: Tephritidae)

Bactrocera latifrons (Hendel) is a tephritid fruit fly of primarily Asian distribution that has invaded Hawaii and, more recently, the continent of Africa (Tanzania and Kenya). It primarily infests solanaceous fruits, so has the potential to impact production of crops such as peppers (Capsicum annuum L. and Capsicum frutescens L.), eggplant (Solanum melongena L.), African eggplant (Solanum aethiopicum L.) and tomatoes (Solanum lycopersicum L.). Because little work has been done to develop suppression techniques for this fruit fly species, field cage tests of the effectiveness of a commercially available bait spray, GF-120NF Fruit Fly Bait, against wild B. latifrons were conducted. Sexually mature B. latifrons adults (75 male and 75 female) were introduced to both a control cage and a treatment cage, each of which held six fruiting Anaheim chili pepper (C. annuum L.) plants. Fruits were harvested, and assessed for infestation, both before and after the application of the bait spray in the treatment cage. There was no difference in infestation rate between control and treatment cages before the application of the bait spray, whereas there was a significantly lower infestation rate in treatment cages following the application of the bait spray. Post-spray infestation rate in the treatment cages (in two separate, replicated bioassays) was always zero and no live flies were detected in the treatment cages at the end of the trials. The results of this study provide evidence that GF-120NF Fruit Fly Bait should be effective in suppressing B. latifrons populations in the field.

Effect of proportion of component species on the productivity of Solanum aethiopicum and Amaranthus lividus under intercropping

In central Uganda, ‘garden egg’ (Solanum aethiopicum) is commonly intercropped with ‘spleen amaranth’ (Amaranthus lividus) but the productivity of this mixture is unknown. The objective of the experiment was to determine the yield advantage from this mixture. Treatments tested included pure stands of Solanum aethiopicum and Amaranthus lividus, locally called nakati and ebugga, respectively, ‘additive mixtures’, and several ‘replacement series’ mixtures. Generally, pure stands gave the highest total and edible DM yields. For each species, DM yield in mixtures was significantly higher (P<0.05) in mixtures in which it constituted the highest proportion, that is 75:25% Solanumi:Amaranthus replacement series mixture in the case of S. aethiopicum, and 25:75% mixture in the case of A. lividus. Intercropping reduced total S. aethiopicum DM yield by 72% in the 25:75% Solanum:Amaranthus mixture, while A. lividus yield was reduced by 68% in the 75:25% mixture. There was high correlation between S. aethiopicum and A. lividus plant population and edible DM yield (r = 0.71 and 0.98, respectively).The difference in yield between pure stand S. aethiopicum and the 75:25% Solanum:Amaranthus mixture was not significant yet it was associated with 93 kg ha -1 of edible DM yield of A. lividus as a ‘bonus’ yield, equivalent to 27% of the edible DM yield of pure stand A. lividus. Generally, the additive mixtures gave higher S. aethiopicum DM yield than the replacement series mixtures with less than 50% S. aethiopicum. The 37% lower edible DM yield of S. aethiopicum in the double compared to the single additive mixture was attributed to greater competition against S. aethiopicum by the double Amaranthus rows compared to the single Amaranthus rows but the double additive mixture had about 55% more edible Amaranthus DM yield than the single additive. Most mixtures gave yield advantages, with the double (47%) and single (39%) additive mixtures giving higher yield advantages than the replacement series mixtures. On the basis of gross returns, most mixtures were more profitable than the pure stands.

Division of labour in nakati (Solanum aethiopicum) production in central Uganda

Nakati (Solanum aethiopicum) production is labour intensive. This paper reports on the division of labour in the production of this crop in central Uganda. There is significant division of labour between husbands and wives. Heavy duty land preparation is mostly done by husbands and hired male labour in order to do it fast when a large acreages of Nakati are involved. Hired labour (35%) does most of the land preparation and weeding. Women do hand weeding better than men. Sowing is predominantly done by men (50%) who claim better experience than the females in broadcasting the crop. Pest control is mostly done by husbands and hired male labour (78%). Most women can not carry the knapsack sprayer and are often busy with household work. Fertilizer application is also mostly done by men (56%). Harvesting is mostly done by family labour (42%), and mostly by males who can carry the heavy Nakati bundles from the fields. Marketing is predominantly done by husbands (87%). Sometimes wives opt to have a separate plot of Nakati to cater for their unique needs. Generally, men do most of the work in Nakati production but training for Nakati improvement ought to target both men and women. Women should be organized into groups which can also be voluntarily joined by husbands, and these groups can be easily trained by extensions agents. It is preferable for women extensions agents to train the women farmers’ groups because women are likely to relate to fellow women in this regard. Since women are usually busy with household work training should coincide with the dry season when there is less work in the field Farmer field schools could also benefit Nakati growers. Key words: Nakati, Solanum aethiopicum, labour, production, central Uganda.

Performance of growing indigenous goats fed diets based on urban market crop wastes

The effect of feeding diets including market crop wastes (sweet potato vines (Ipomoea batatas) and scarlet eggplant (Solanum aethiopicum)) on growth and digestibility was studied using 32 indigenous intact growing male goats. Adding elephant grass (Pennisetum purpureum), maize bran and Leucaena leucocephala leaves, four isocaloric and isonitrogenous diets (Sweet potato vines, Solanum, Mixed and Control) were formulated. After the growth trial, 12 goats were randomly selected for a digestibility trial with the same diets, and 8 goats for a feed preference test comparing the market wastes and elephant grass. Crude protein (CP) intake was highest (P<0.05) for the Control (48 g/day) and lowest for the Sweet potato vines diet (23 g/day). Average daily gain was between 11.0 and 14.2 g/day, and similar between diets. The DM and CP digestibilities of the diets were 0.56 and 0.56 (Control), 0.62 and 0.56 (Mixed), 0.59 and 0.49 (Sweet potato vines), and 0.54 and 0.45 (Solanum), respectively. Faecal and urinary N excretions were highest in goats fed the Sweet potato vines and Solanum diets. Eggplant wastes were the least (P<0.05) preferred. On average the goats spent 5% of their 8-hour time eating eggplant wastes, 34% on sweet potato vines and 36% on elephant grass. Growth performance and N retention were low due to the low intake of feed, especially eggplant wastes.

Inheritance of Fusarium wilt resistance introgressed from Solanum aethiopicum Gilo and Aculeatum groups into cultivated eggplant (S. melongena) and development of associated PCR-based markers

The two eggplant relatives Solanum aethiopicum gr. Gilo and Solanum aethiopicum gr. Aculeatum (=Solanum integrifolium) carry resistance to the fungal wilt disease caused by Fusarium oxysporum f. sp. melongenae, a worldwide soil-borne disease of eggplant. To introgress the resistance trait into cultivated eggplant, the tetraploid somatic hybrids S. melongena + S. aethiopicum and S. melongena + S.integrifolium were used. An inheritance study of the resistance was performed on advanced anther culture-derived androgenetic backcross progenies from the two somatic hybrids. The segregation fitted a 3 resistant (R): 1 susceptible (S) ratio in the selfed populations and a 1R:1S ratio in the backcross progenies for the trait derived from S. aethiopicum and S. integrifolium. These ratios are consistent with a single gene, which we designated as Rfo-sa1, controlling the resistance to Fusarium oxysporum f. sp. melongenae. The allelic relationship between the resistance genes from S. aethiopicum and S. integrifolium indicate that these two genes are alleles of the same locus. Bulked Segregant Analysis (BSA) was performed with RAPD markers on the BC3/BC5 resistant advanced backcross progenies, and three RAPD markers associated with the resistance trait were identified. Cleaved Amplified Polymorphic Sequences (CAPSs) were subsequently obtained on the basis of the amplicon sequences. The evaluation of the efficiency of these markers in predicting the resistant phenotype in segregating progenies revealed that they represent useful tools for indirect selection of Fusarium resistance in eggplant.

ISSR and Isozyme Characterization of Androgenetic Dihaploids Reveals Tetrasomic Inheritance in Tetraploid Somatic Hybrids between Solanum melongena and Solanum aethiopicum Group Gilo

Gene exchanges between Solanum melongena and its allied relative Solanum aethiopicum are a crucial prerequisite for introgression of useful traits from the allied species into the cultivated eggplant. In order to evaluate the extent of genetic recombination between the 2 species, biochemical and molecular markers were employed. A dihaploid population obtained through anther culture of the corresponding tetraploid somatic hybrids was genetically analyzed. The extent of disomic/tetrasomic inheritance and segregation ratios of 3 isozyme systems and intersimple sequence repeat (ISSR) markers were evaluated. The dihaploids, being derived from microspores, allowed for simple, complete, and accurate analyses. The segregation of 280 ISSR markers (110 aethiopicum-specific, 104 melongena-specific, and 66 monomorphic) were evaluated in 71 dihaploids. According to the genetic constitution (simplex/duplex/triplex), almost 64% of the fragments revealed the tetrasomic and/or disomic inheritance. With regard to the assigned species-specific fragments, 68% and 4% were unambiguously the result of tetrasomic and disomic inheritance, respectively. Twenty-four of the 66 monomorphic ISSRs were inherited according to random chromatid segregation. The phenotypes of glucose-6-phosphate dehydrogenase (G-6-PDH), 6-phosphogluconate dehydrogenase (6-PGDH), and shikimate dehydrogenase (SKDH) were studied in 70 dihaploids and inferences were made about the allelic state of their 5 loci. The isozyme markers segregated in the dihaploids in a distorted manner, their segregations did not fit in with any of the expected segregation ratios. However, tetrasomic inheritance might be suggested for G-6-PDH 2 and SKDH 1 loci. Our results demonstrated that gene exchanges occurred readily in the somatic hybrids between S. melongena and S. aethiopicum gr. Gilo.

Nutritional characterization of some tropical urban market crop wastes

Market crop wastes of banana ( Musa acuminata) leaves and pseudo-stem sheaths, sweet potato ( Ipomoea batatas) vines and Solanum aethiopicum (traditionally known as nakati) were collected from three major markets in Kampala (Uganda). The wastes were evaluated for chemical composition during the dry and wet seasons, rumen degradation using three cannulated indigenous mature ewes, and digestibility using 12 indigenous intact growing male goats, 4–6 months old and weighing 15.8 kg (S.D. 2.1). The goats in the digestibility study were kept in metabolism cages and fed the wastes as sole diets, either fresh or wilted. Mean dry matter (DM) content was 97, 121, 197 and 216 g/kg for pseudo-stem sheaths, nakati, sweet potato vines and banana leaves, respectively. Crude protein (CP) was 34, 109, 112 and 114 g/kg DM for pseudo-stem sheaths, banana leaves, sweet potato vines and nakati, respectively. The chemical composition was similar among seasons and markets for the banana based wastes. However, for sweet potato vines and nakati, the wet season wastes had significantly higher CP and lower NDFom and ADFom. Chemical composition was different (P<0.05) among the markets for nakati. Effective degradability differed (P<0.05) between the wastes, averaging 0.43 (banana leaves), 0.47 (pseudo-stem sheaths) and 0.56 ( nakati) to 0.69 g/g DM incubated (sweet potato vines). DM intake, N retention and digestibility were not significantly affected by wilting. Average DM intake was 176, 270 and 559 g/day; CP intake was 26, 30 and 63 g/day, while metabolizable energy (ME) intake was 1.3, 1.7 and 5.1 MJ/day for nakati, banana leaves and sweet potato vines, respectively. N retention (as a fraction of N intake) was −0.51 (banana leaves), 0.62 ( nakati) and 0.39 (sweet potato vines). The organic matter (OM) and CP digestibilities of banana leaves were low, averaging 0.52 and 0.49, respectively. The high moisture content of nakati wastes resulted in low intake, whereas banana leaves had a low degradation rate and a low N retention. Market sweet potato vine wastes were sufficient to provide the CP and ME required by growing goats under tropical conditions.

Strategy for allergenicity assessment of ‘natural novel foods’: clinical and molecular investigation of exotic vegetables (water spinach, hyacinth bean and Ethiopian eggplant)

Foods not commonly consumed in the European Union must be proven safe before being brought to market, including an assessment of allergenicity. We present a three-stepwise strategy for allergenicity assessment of natural novel foods using three novel vegetables, namely, water spinach, hyacinth bean, Ethiopian eggplant. First, vegetable extracts were analyzed for the presence of pan-allergens [Bet v 1 homologous proteins, profilins, nonspecific lipid transfer proteins (LTP)] by immunoblot analysis with specific animal antibodies. Secondly, the IgE-binding of the food extracts was investigated by EAST (Enzyme-allergosorbent test) and immunoblot analysis using sera with IgE-reactivity to known pan-allergens or to phylogenetically related foods from subjects (i) allergic to birch, grass and mugwort pollen, (ii) with food allergy to soy, peanut, tomato, multiple pollen-related foods and (iii) sensitized to LTP. Thirdly, the clinical relevance of IgE-binding was assessed in vivo by skin prick testing (SPT) and open oral food challenges (OFC). Profilin and LTP were detected by animal antibodies in all vegetables, a Bet v 1 homologue selectively in hyacinth bean. IgE-binding to LTP, profilin and a Bet v 1 homologue was proven by immunoblot analysis and EAST. Positive SPT and OFC results were observed for all vegetables in pollen-allergic patients. Our stepwise procedure confirmed the presence and IgE-binding capacity of novel vegetable proteins homologous to known allergens in endemic vegetable foods. In vivo testing proved the potential of the novel vegetables to elicit clinical allergy. Hence, our described algorithm seems to be applicable for allergenicity testing of natural novel foods.

Detection of the solanum fruit fly, Bactrocera latifrons (Hendel) in Tanzania (Dipt., Tephritidae)

Abstract: The presence of the Solanum fruit fly, Bactrocera latifrons, in Africa is reported for the first time, based on trapped and reared specimens in Tanzania. Two new host records, Solanum aethiopicum and Solanum macrocarpon, are reported.

Relationships between abiotic soil factors and epidemiology of the biocontrol bacterium Pasteuria penetrans in a root-knot nematode Meloidogyne javanica-infested field

Abstract The epidemiology of Pasteuria penetrans, parasite of Meloidogyne javanica, was studied in a field cultivated with an African egg-plant (Solanum aethiopicum) in Senegal. Abiotic and biological parameters were analyzed from 100 soil samples. Soil physical characteristics were studied with principal component analysis (PCA). Similarity between the parameters according to biotic and abiotic variables was established by hierarchical classification and corroborated by Discrimin analysis (AFD). The coarser fractions (>200 μm) were positively correlated to intensive irrigation, whereas finest fractions (

First report of Verticillium dahliae causing verticillium wilt of Solanum aethiopicum in Italy

First report of <i>Verticillium dahliae</i> causing verticillium wilt of <i>Solanum aethiopicum</i> in Italy

Distribution of Pasteuria penetrans in size fractions of a Meloidogyne javanica-infested field soil

Summary In Senegal, a study was carried out in a field cultivated with African egg-plant ( Solanum aethiopicum ) in order (1) to determine soil size fractions infested both with Meloidogyne javanica and Pasteuria , (2) to compare the efficacy of soil fraction dispersion methods in the recovery of both organisms and (3) to estimate the concomitant distribution of the two organisms in the different soil fraction sizes. Samples were taken from four areas: severely-infested (M+) with M. javanica with a high percentage (I+) of Pasteuria -infected juveniles, severely-infested (M+) with a low percentage of infected juveniles (I−), minimally-infested (M−) with a high percentage of infected juveniles (I+) and minimally-infested (M−) with a low percentage of infected juveniles (I−). The samples were dispersed and fractionated using two different techniques in order to evaluate soil aggregation (size fractions >200, 50–200, 20–50 and 0–20 μm). The numbers of free entities of Pasteuria penetrans were estimated per size fractions. The proportion of Pasteuria -infected juveniles (biological detection of P. penetrans ) was estimated in order to correlate the infection rate to the distribution of free entities of P. penetrans . Regardless of sampling area, the 50–200 μm size fraction predominated, followed by largest particle (>200 μm) size. The distribution of Pasteuria spores in the soil was not linearly correlated to the distribution of Pasteuria -infected juveniles. The influence of the soil characteristics on the relationship between the two organisms is discussed.

Yield of scarlet eggplant ( Solanum aethiopicum L.) as influenced by planting date of companion cowpea

Growth and fruit yield of scarlet eggplant were examined under intercropping with an erect and semi-spreading early maturing cultivars of cowpea in an additive intercropping model with scarlet eggplant as the main crop, in two dry seasons, under irrigation. Cowpea was planted simultaneously with scarlet eggplant, 2 and 4 weeks ahead of scarlet eggplant. Land equivalent ratio (LER) of the intercrops ranged from 1.38 to 1.94, indicating that the intercrops were more productive than the pure crops. Reduction in fruit yield of the main crop, when intercropped with the semi-spreading cowpea cultivar was significantly ( p < 0.01) greater than with the erect cowpea cultivar. Simultaneous planting of cowpea and scarlet eggplant produced 90–99% the fruit yield of sole scarlet eggplant, while planting cowpea 2 and 4 weeks ahead produced 65–80% and 58–60% of sole crop yield, respectively. Competition between component crops was however most favourable for both cultivars of cowpea when planted 2 weeks ahead of scarlet eggplant. Planting cowpea 2 weeks ahead of the main crop also produced the highest LER most likely due to more efficient utilization of sunlight, water and soil nutrients. Simultaneously planting cowpea and transplanting scarlet eggplant, is recommended for such additive intercropping system, aimed at full yield of scarlet eggplant with additional cowpea for food, income or fodder.

Morphological and Molecular Variation in a Collection of Eggplants from a Secondary Center of Diversity: Implications for Conservation and Breeding

Eggplant (Solanum melongena L.) was introduced by the Arabs into Spain. Since then, many local cultivars have arisen. These materials are grouped in four cultivar groups: “round,” “semi-long,” “long,” and “listada de Gandía.” We studied the morphological and molecular [amplified fragment length polymorphism (AFLP)] diversity of a collection of 28 Spanish traditional cultivars of eggplant. Four eggplant accessions from different origins were used as controls and three scarlet eggplant (Solanum aethiopicum L.) accessions as outgroups. Morphology and AFLP markers showed that S. melongena and S. aethiopicum are separate taxonomic entities, and that, compared to controls, Spanish eggplants are very variable, indicating that the Iberian Peninsula can be regarded as a secondary center of diversity. Morphological differences were found among cultivar groups in traits other than those used for the grouping although, in some cases, accessions from different cultivar groups shared a similar general morphology. Eggplant cultivar groups also showed some genetic differences, which are revealed in the gene diversity statistics (GST = 0.30). Nonetheless, no individual AFLP markers specific and universal to one cultivar group could be found. “Round” cultivars were genetically more diverse than the other cultivar groups. A positive correlation (r = 0.68) was found between morphological and molecular distances. However, correlations between geographical and either morphological or molecular distances were low. Results suggest that evolution of eggplants in Spain has involved frequent hybridizations and a frequent movement and exchange of seeds. Structure of diversity among regions indicates that most of the diversity can be collected in single selected regions. All these results have important implications in eggplant germplasm conservation and breeding.