Eggplant Rootstock Research Articles

Grafting of Tomato with Eggplant Rootstock at Penyabangan Village Payangan Subdistrict of Gianyar Bali

Grafting on tomatoes is performed to obtain tomato plants that are resistant to bacterial wilt, waterlogging resistant, resistant to fusarium wilt and nematodes. Bacterial wilt caused by Ralstonia solanacearum causes the tomatoes grown in the rainy season to wilt and die. These bacteria live in the soil and invade plants through roots. To overcome this disease, grafting was carried out by using resistant eggplant as rootstock. This method is expected to reduce the attack of bacterial wilt diseases on tomato plants. The study was conducted in the village of Penyabangan Payangan Gianyar in FY 2014. This area was located at the plateau of AEZ wet climate. The experimental design used was a randomized block design (RBD) with two treatments and 10 replications. Materials used were tomato plants that have been joined with eggplant rootstock (grafted) and tomato plants without root stock (non-grafted) for comparison. The varieties used were varieties F1 Marta. In field applications, the scion was prevented from touching the ground while the rootstock was fully embedded into the ground. Based on the plant height, there was a slower growth of the grafted tomato plants compared with that of non-grafted one in the early stages of growth but became normal in generative phase. It was also found that the yield of the grafted tomato was lower (2.54 kg. tree-1) than that of the non-grafted one (3.19 kg.tree-1). Keywords: grafting; tomatoes; eggplant; stem rot; bacterial wilt (alphabetic in order).

Response of Different Grafted Eggplants in Protected Culture

The study has been conducted in a professional greenhouse where grafted seedlings and grafted eggplants have been produced. Two eggplant hybrids, ‘Classic F1’ and ‘Black Pear F1’ were used as scion and one of the Lycopersicon genus, ‘Kaiser F1’ and three Solanum genus, ‘L1S’, ‘L23B’ and ‘Torpedo’ were used as rootstocks, resulting in eight grafted combinations. It has been observed that for all grafting combinations the grafting percentage was ranging from 95% to 98%. The rootstocks utilized have influenced the vigour of the grafted plants. They influenced plant height which reached values of roughly 1.0 m and number of leaves resulting in values of 2.5-3.0 times higher in comparison to the ungrafted plants. Comparative to the ungrafted plants the grafting combinations also influenced the productivity of plants. The highest fructification potential has been observed at ‘Classic F1’ grafted on all eggplant rootstocks. Compared to ungrafted plants, which has yielded 2.46 kg per plant, the highest yield obtained from ‘Classic F1’ grafted on ‘L23B’ has been of 4.27 kg per plant, followed by ‘Torpedo’ rootstock with 4.1 kg per plant. ‘Black Pearl F1’ have been produced 4.15 kg per plant when grafted on the ‘Kaiser F1’ rootstock and 4 kg per plant when grafted on the ‘Torpedo’ rootstock. Regarding the production per hectare, the largest production augmentation, of 30%, was noted at ‘Classic F1’ grafted on the eggplant rootstock ‘L23B’. The ‘Black Pearl F1’ grafted on the tomato rootstock ‘Kaiser F1’ registered a 20% increment in production. The rootstocks utilized have slightly influenced the content of the soluble dry substance on both hybrids grafted on ‘Kaiser F1’. The result has been a 6% dry substance in comparison to the 5.3% at the ungrafted hybrids. The grafting has had an insignificant influence of the total amount of carbohydrates at all grafting combinations.

Grafting compatibility between selected rootstocks and Tanzanian local tomato cultivars

Objective: The objective of this study was to evaluate the effect of different rootstocks on graft success of Tanzanian local tomato cultivars. Eggplant rootstocks (EG190, EG195, EG203 and EG219, and tomato rootstock (Hawaii 7996) were obtained from AVRDC in Taiwan while local tomato cultivars (Tengeru 97, Tanya, Cal-J and Riogrande) were sourced locally. Methodology and Results: Cleft graft method was carried out when seedlings of eggplant, Hawaii 7996 and local tomato cultivars were 30, 17 and 14 days old, respectively. The grafted seedlings with graft union tied using grafting clips were healed in a dark chamber for three days and then in a transparent chamber for three days. The average temperature and relative humidity in both chambers were maintained at 21-30°C and 85-95 %, respectively. The grafted seedlings were hardened for seven days in an open nursery with 30% overhead shade prior to transplanting. Data on graft success were subjected to analysis of variance using MSTATC statistical software and treatments mean separation was conducted based on Student-Newman Keuls at P < 5%. Results show that graft success between eggplant rootstocks and local tomato cultivars was higher ranging from 86 to 100%. On the contrary, grafting rootstock Hawaii 7996 with local tomato cultivars significantly (PB 5%) resulted in a lower graft success ranging from 30 to 50% during the hardening stage in the open nursery. Conclusion and application of results: Tanzanian local tomato varieties can be grafted onto eggplant rootstocks EG190, EG195, EG203 and EG219 with high graft success. As these eggplant rootstocks are resistant to soil borne diseases, farmers should graft their varieties in order to increase tomato yield. Further studies are therefore required to optimize the grafting conditions to improve graft success between rootstock Hawaii 7996 and local tomato cultivars. Keywords: Grafting, Rootstocks, Local varieties, Tomato, Tanzania

Identification of resistance to bacterial wilt and verticillium wilt in different eggplant rootstock germplasm using quantitative genetic analysis

Identification of resistance to bacterial wilt and verticillium wilt in different eggplant rootstock germplasm using quantitative genetic analysis

Interspecies rootstocks affect cadmium accumulation in postgrafting generation plants of potential cadmium-hyperaccumulator Solanum photeinocarpum.

Pot and field experiments were conducted to study the effects of interspecies rootstocks on cadmium (Cd) accumulation characteristics of the potential Cd-hyperaccumulator Solanum photeinocarpum postgrafting generation plants. Four treatments (ungrafted and S. photeinocarpum seedlings grafted on the rootstocks of eggplant, potato, and tomato) were utilized in the present study. In the 2 pot experiments, eggplant and potato reduced biomass of S. photeinocarpum postgrafting generation plants, whereas tomato increased shoot biomass compared with the control (ungrafted seedlings). Compared with ungrafted seedlings, tomato increased and eggplant decreased Cd contents in shoots of S. photeinocarpum postgrafting generation. Only tomato increased Cd extraction by shoots of S. photeinocarpum postgrafting generation compared with ungrafted seedlings. In the field experiment, only tomato increased shoot Cd content of S. photeinocarpum postgrafting generation by 8.31% and shoot Cd extraction by 9.30% compared with ungrafted seedlings. Therefore, use of tomato as rootstock could enhance the ability of S. photeinocarpum postgrafting generation plants to remediate Cd-contaminated soil. Environ Toxicol Chem 2016;35:2845-2850. © 2016 SETAC.

Effect of Grafting Eggplant (Solanum melongena L.) on its Selected Useful Characters

 The grafting eggplants cultivars onto rootstocks that are resistant to the soil-borne pathogens and nematodes is a method known for many years, but which have improved and spread quickly in the last years (Bletsos et.al .,2003). The objective of these researches was to evaluate the performance of some eggplant rootstocks onto that were grafted Romanian and foreign varieties, in unheated greenhouses. The Romanian eggplant hybrid “Andra F1” and Holland hybrid “Sharapova F1”, were grafted onto the rootstocks “King Kong”,” Emperador”,” Hikyaku”, “KA-312”, “Torvum vigor”and“Espina”. It was determined the influence of eggplants rootstock on the marketable yield, early harvest, fruits quality and nutritional value. For each pathogen agent, percent disease incidence (I %) and percent disease severity (S %) were estimated. The resulted values were used to calculate the attack degree (as an expression of extending attack seriousness) on the following formula: AD% =(S% x I %) /100, where AD% represents attack degree. Presence of root galls induced by nematodes, were visually assessed at the end of the trials on 50% of the plants harvested from the middle of the plots. The rootstocks which led to the recording of increased yield and tolerance to the lower soil temperatures, as well as a character of earliness were Emperador, King Kong and Hikyaku. The proportion of Class First fruit and nutritional value were significantly higher to the grafted plants than to non-grafted control plants, but there was no significant difference between the rootstocks, concerning the nutritional value. The frequency of damage to the plants of eggplants by the soil-born pathogen and nematodes attack was significantly reduced by grafting eggplant scions onto resistant rootstocks. The rootstocks Emperador, King Kong and Hikyaku led to increased marketable yield, fruits quality, early harvest and nutritional value. “Emperador F1” rootstocks reduced the frequency and severity of infection with the soil-borne pathogens and the nematodes attack. Â

Grafting Affects Growth, Yield, Nutrient Uptake, and Partitioning Under Cadmium Stress in Tomato

A greenhouse experiment was conducted to determine the influence of long-term cadmium (Cd) exposure (0, 25, or 50 µm of Cd) on crop productivity, fruit quality, leaf chlorophyll content, fluorescence, and mineral composition in plants of tomato (Solanum lycopersicum L. cv. Ikram), either nongrafted, self-grafted, or grafted onto rootstocks of tomato (Maxifort or Unifort) and eggplant (Black Beauty). Both moderate (25 µm) and high (50 µm) concentration of Cd in root environment considerably decreased the fruit yield and fruit number in response to Cd levels, whereas mean fruit weight decreased but was similar to both Cd supply levels. The fruit yield, shoot and root biomass, and leaf area (LA) were higher in plants grafted onto tomato rootstocks and especially onto Maxifort in comparison with nongrafted or self-grafted plants and especially grafted onto Black Beauty. The higher plant performance of tomato rootstock–grafted plants were related to higher chlorophyll fluorescence and photosynthetic pigments concentration in leaves associated with better nutrient translocation and availability (higher Ca, Mg, Fe, Mn, and Cu) in leaves. The content of Cd was also lower in leaves and fruits of Maxifort-grafted plants. Concerning fruit quality, especially peel color, toxicity symptoms, and Cd concentration, Black Beauty followed by Maxifort-grafted plants were better than the other grafting combinations. However, plants grafted onto Black Beauty rootstock resulted in lowest fruit yield and plant growth attributes due to lower nutrient uptake and translocation indicating some incompatibility reaction between Black Beauty rootstock and Ikram scion.

Improving seed germination of the eggplant rootstock Solanum torvum by testing multiple factors using an orthogonal array design

Solanum torvum is a highly vigorous relative of eggplant that is resistant to a number of harmful soil-borne diseases and is compatible for grafting with eggplant. Being a potential rootstock, this plant frequently presents poor and erratic germination, which makes its practical use difficult. We used an L8 (27) orthogonal array design to evaluate the primary effects of seven factors (soaking of seeds, scarification with sodium hypochlorite (NaClO), application of gibberellic acid (GA3), use of potassium mitrate (KNO3) as a moistening agent, cold stratification, application of a heat shock, and light irradiation during germination) at two levels (L0 and L1) using four germination parameters (early and final germination, germination rate and vigour index) in fresh S. torvum seeds. S. torvum seeds had a strong dormancy with no germination in the untreated seeds and high early and final germination (approximately 100%) in certain treatments. An evaluation of the main effects revealed highly positive effects on germination from seed soaking, and the use of GA3, KNO3, and light irradiation, whereas NaClO scarification had a negative effect. The application of cold stratification and heat shock treatments also had a positive effect on seed germination but to a lesser extent than the other treatments. An improved proposed protocol that consisted of subjecting seeds to soaking, the application of GA3 and KNO3, cold stratification, heat shock, and light irradiation was validated and demonstrated to be highly effective, with seed germination success greater than 60% being observed at 3 days and final germination reaching a plateau at 6 days. A second validation experiment using a commercial growing substrate also showed a high emergence (approximately 50%) at 7 days and a final germination of approximately 80% was recorded with application of the improved protocol. The seed germination protocol that we have developed will facilitate the use of S. torvum as a rootstock for eggplant and its use in breeding programmes. Our results also reveal that orthogonal array designs are a powerful tool for establishing improved protocols for seed germination.

Interspecific grafting to enhance physiological resilience to flooding stress in tomato (Solanum lycopersicum L.)

Tomato (Solanum lycopersicum L.) is highly susceptible to flooding stress. In order to improve its flooding tolerance, the study was conducted to determine the effect of grafting tomato plants (cv. Arka Rakshak, AR) onto different eggplant (Solanum melongena L.) rootstocks [BPLH-1, Arka Neelkanth (AN), Mattu Gulla (MG) and Arka Keshav (AK)] against flooding during rainy season (July-September). The tomato plants were subjected to flooding stress at flowering stage for 6 days by submerging in a tank with the water level at 2.0cm above the soil surface in the pots. The gas exchange parameters, photosynthesis rate (PN), stomatal conductance (gs) and internal CO2 concentration (Ci), chlorophyll fluorescence, leaf water potential (ψL) and chlorophyll content showed a lesser decline in eggplant rootstock grafted plants as compared with self-grafted and ungrafted plants. In general, eggplant rootstock grafted plants exhibited better survival, enhanced physiological adaptation and improved fruit yield over the self-grafted and ungrafted plants under flooding. Between the rootstock grafted plants, the graft combinations AR/AN and AR/BPLH-1 were more efficient in sustaining the above attributes. Flooding conditions favoured accumulation of total sugar, reducing sugar, sucrose and individual sugar like sucrose and glucose in the leaves of grafted and ungrafted plants and the eggplant rootstocks grafted plants under flooding conditions accumulated higher sugars and starch as compared with self-grafted and ungrafted plants. Among the grafts, AR/AN showed in high sugar and starch accumulation under flooding. The recovery was better in eggplant rootstock grafted plants as reflected by recovery of PN, gs and ψL, and decline in sugar and starch levels. The study indicated that the eggplant rootstock grafting is of great relevance in improving physiological tolerance in tomato under flooding. Among the eggplant rootstock grafted tomato plants, AR/AN showed better survival and plant yield after experiencing flooding.

Effects of Grafting on Alkali Stress in Tomato Plants: Datura Rootstock Improve Alkalinity Tolerance of Tomato Plants

Plant growth, nutritional status, and proline content were investigated in non-grafted and grafted greenhouse tomato plants onto five rootstocks of eggplant, datura, orange nightshade, local Iranian tobacco, and field tomato, exposed to 0, 5, and 10 mM sodium bicarbonate (NaHCO3) to determine whether grafting could improve alkalinity tolerance of tomato. The leaf fresh mass of ungrafted and grafted tomato plants decreased significantly as NaHCO3 levels increased. Despite other rootstocks and ungrafted plants, alkalinity had no significant effect on stem and root fresh mass and shoot phosphorus (P), potassium (K) and magnesium (Mg) concentrations of datura grafted plants. The lowest solution pH and electrical conductivity (EC) values and the highest leaf proline content were observed in the plants grafted onto datura rootstock. Moreover, sodium (Na) concentration in shoots was lower in plants grafted onto datura rootstock than in other plants especially under high NaHCO3 levels. Overall, using datura rootstock improved alkalinity tolerance of tomato plants under NaHCO3 stress.

Vigor for in vitro culture traits in S. melongena × S. aethiopicum hybrids with potential as rootstocks for eggplant.

Hybrids of Solanum melongena and S. aethiopicum are of interest as rootstocks of eggplant, as they are highly vigorous and can incorporate resistance to several diseases. However, hybridization between both species is difficult. Therefore, protocols for in vitro culture are of great interest for their micropropagation and biotechnological breeding. We assessed the organogenesis response from leaf explants in four interspecific hybrids and in their parents testing two organogenic media: SIM-A, containing 6-benzylaminopurine and kinetin, and SIM-B, which contains thidiazuron. A higher regeneration capacity in the hybrids compared to their parents was observed. Whereas in interspecific hybrids and in one accession of S. melongena similar regeneration rates were observed for SIM-A and SIM-B, higher regeneration was found in the rest of genotypes when thidiazuron was used. Rooting ability in the interspecific hybrids was lower in in vitro micropropagated plants (35–60%) than in plants regenerated from explants (100%). The addition of indolbutiric acid (1 mg L−1) induced roots in nonrooted genotypes. In summary, we have adjusted in vitro culture conditions for regenerating and rooting S. melongena × S. aethiopicum hybrids. We have also demonstrated that these hybrids are heterotic for regeneration, which may be of interest for basic science studies.

Investigation on the Effects of Tomato yellow leaf curl virus Infecting Tomatoes Grafted on Eggplant Rootstock

Investigation on the Effects of <i>Tomato yellow leaf curl virus</i> Infecting Tomatoes Grafted on Eggplant Rootstock

Evaluation of Eggplant Rootstocks and Pepper Varieties for Potential Resistance to Isolates of Phytophthora capsici from Michigan and New York.

Phytophthora capsici is a soilborne pathogen of major economic importance in pepper, and of less importance in tomato and eggplant production. As soil fumigation becomes more expensive and limited, and fungicide insensitivity of P. capsici isolates becomes more prevalent, grafting is quickly becoming an industry-favored method to control soilborne diseases. Greenhouse experiments were performed to evaluate an eggplant cultivar (Classic), two eggplant lines (EG195, EG203), a pepper line (CM334), and three pepper cultivars (Paladin, Camelot, and Red Knight) for root rot resistance to 14 P. capsici isolates. The isolates showed various degrees of virulence between pepper and eggplant in both experiments. Both eggplant and one pepper lines showed moderate resistance to the most virulent isolates tested in experiment one. The partially resistant pepper cultivar, Paladin, was significantly more susceptible than CM334 and the eggplant lines, but was still resistant to most isolates. In the second experiment, the eggplant cultivar Classic and the susceptible pepper cultivar Red Knight were both susceptible to most isolates tested, while EG203 and EG195 were resistant to most isolates. The two eggplant breeding lines, EG195 and EG203, showed moderate resistance to all isolates tested in both experiments. This is the first reported evaluation of eggplant resistance to P. capsici. Further research is warranted to test eggplant lines EG195 and EG203 for resistance to a wide range of soilborne pests and to evaluate their usefulness as P. capsici-resistant rootstocks for peppers, tomatoes, and eggplants.

가지대목 EG203을 이용한 토마토 풋마름병 경감효과

Ralstonia solanacearum에 의한 시들음 피해는 고온기 재배가 증가함에 따라 피해가 증가하고 있다. 이에 재배적 방법으로 토마토대목을 이용하고 있으나 병이 다 발생하는 지역에서는 효과가 기대에 미치지 못한다. 이에 따라서 AVRDC에서 수집한 풋마름병 저항성 가지 대목인 EG203을 재료로 하여 풋마름병 다 발생포장인 부여 토마토시험장 비닐하우스에서 2003-2005년, 구미시 비닐하우스에서 2009-2011년까지 두 곳에서 각각 3년간 실시하였다. EG203(가지)는 광발아 종자로 파종 시 육묘 트레이에 직접 파종하여야 하며 EG-203(가지)의 파종 적기는 토마토 접수보다 3주전에 파종해야 접수와 비슷한 경경(2.5-3.0 mm)에 도달하여 접목하기에 알맞았다. 접목방법은 맞접과 삽접이 93-96%의 활착률을 보여 대목으로 사용가능한 것으로 확인되었다. 접목 후 포장에 정식한 후의 풋마름병 발생을 2003년부터 2005년까지 3년 동안의 평균은 EG203(가지) 접목 시 4.3%로 실생의 58.0%보다 매우 낮았으며 대목용 품종의 25.0-36.7%보다도 낮게 나타났다. 구미에서 2009년부터 2011년까지 3년간 대목 효과에 대하여 시험한 결과는 2009년 5농가에서 EG203과 실생묘를 비교한 결과 EG203에서는 풋마름병 발생률이 2-5%였으나 실생은 20-80%를 보였다. 2010년에는 토마토대목('B-blocking', '청강')과 가지대목(EG203)을 갖고 비교 한 결과 풋마름병 발생률의 차이는 보이지 않았으나 가지대목(EG203)에서 복화방 출현이 늦어 수확이 감소되는 경향을 보였다. 2011년 토마토대목('청강')과 가지대목(EG203)으로 3농가에서 시험한 결과 토마토대목('청강')에서 풋마름병 발생률은 60-85%, 가지대목(EG203)은 0-1%로 가지대목에서 병발생률이 매우 낮았다. 가지대목(EG203)을 이용할 경우 토마토대목과 비교 복화방이 늦게 발생하여 토마토 생산량이 줄었다. 따라서 병 발생이 낮은 곳에서는 토마토대목을 활용하여 접목을 하고 병이 다 발생하는 지역에서는 가지대목(EG203)을 활용하는 것이 재배에 유리하다고 판단되어진다. Wilt damage on tomato plants caused by Ralstonia solanacearum has been increased as the areas of tomato cultivation increased during the warm seasons. Also, the tomato rootstocks used to prevent the disease occurrence are not effective in the highly prevailing regions. Therefore, bacterial wilt resistant eggplant rootstock EG203, collected from AVRDC, was tested for its effect to deter the Ralstonia solanacearum wilt disease in the greenhouses at Buyeo Tomato Experiment Station from 2003 to 2005, and at Gumi, Kyungpook province from 2009-2011. Planting of eggplant rootstock EG203 should be done three weeks before the planting of tomato scions so that they can have similar stem diameter (2.5-3.0 mm) and can be easily grafted. Both insertion and inarching grafting showed 93-96% success rates. In the greenhouse tests at Buyeo Tomato Experiment Station from 2003 to 2005, eggplant rootstock EG203-grafted tomatoes showed the disease occurrence of 4.3%. On the other hand, non-grafted or other commercial rootstock-grafted tomatoes showed disease occurrence of 58.0% and 25.0-36.7%, respectively. In the greenhouse tests at Gumi, Kyungpook province in 2009, the disease occurrence on the EG203-grafted and non-grafted tomatoes was 2-5% and 20-80%, respectively. In 2010, at Gumi, Kyungpook province, when the wilt disease occurred slightly, the tomatoes grafted with tomato rootstocks B-blocking and Chung-gang, and eggplant rootstock EG203 showed similar disease severities, but EG203-grafted tomatoes formed lately cluster, resulting in the reduction of yield compared to tomato-grafted tomatoes. In 2011, at Gumi, Kyungpook province, when the wilt disease occurred severely, the tomato rootstocks 'B-blocking' and Chung-gang and eggplant rootstock EG203-grafted tomatoes showed disease occurrences of 60-85% and 0-1%, respectively. Therefore, it was concluded that tomato rootstocks 'B-blocking' and 'Chung-gang' are more useful in the areas contaminated with low levels of pathogen and eggplant rootstock EG203 is more useful in the areas contaminated with high levels of pathogen.

Investigation of the ameliorating effects of eggplant, datura, orange nightshade, local Iranian tobacco, and field tomato as rootstocks on alkali stress in tomato plants

Among the most important quality parameters of irrigation water used for greenhouse crops, alkalinity of water is considered critical due to its impact on soil or growing medium solution pH. In this study, plant growth, Fe content, photosynthetic pigment content, maximal quantum yield of PSII photochemistry (Fv/Fm), performance index (PI), leaf relative water content (LRWC), and soluble sugars concentration were investigated in nongrafted and grafted tomato (Lycopersicon esculentum Mill. cv. Red stone) plants onto five rootstocks of eggplant (Solanum melongena cv. Long purple), datura (Datura patula), orange nightshade (Solanum luteum Mill.), local Iranian tobacco (Nicotiana tabacum), and field tomato (Lycopersicon esculentum Mill. cv. Cal.jn3), exposed to 0, 5, and 10 mM NaHCO3 concentrations, to determine whether grafting could improve alkalinity tolerance of tomato. Significant depression of leaf area, leaf and stem dry mass, shoot and root Fe content and LRWC under high NaHCO3 level was observed in both grafted and ungrafted plants. The highest reduction in the shoot Fe content was observed at 10 mM sodium bicarbonate in control plants (greenhouse tomato). Moreover, at high HCO3 - level, the highest percentage of LRWC reduction was also recorded in ungrafted plants. Values of Fv/Fm and PI decreased significantly at 5 and 10 mM NaHCO3 irrespective of rootstock type. The present study revealed that soluble sugars content, photosynthetic pigments content, Fv/Fm and PI values in plants grafted onto datura rootstock were higher than those in nongrafted and rest of the grafted plants. Thus, the use of datura rootstock could provide a useful tool to improve alkalinity tolerance of tomato plants under NaHCO3 stress.

Performance of eggplant grafted onto cultivated, wild, and hybrid materials of eggplant and tomato

Eggplant (Solanum melongena) is amenable to grafting and this technique can be exploited to improve production of this vegetable crop. Here, we study the performance of the ‘Cristal F1’ eggplant cultivar grafted onto a total of 17 rootstocks, including five families, each of which is made by two parents and their hybrid, as well a commercial eggplant rootstock and a self-grafted control. Three families consist of eggplant rootstocks, including a S. melongena intraspecific family and two interspecific families of S. melongena with S. incanum and S. aethiopicum. Two other families are made of interspecific hybrids between tomato (S. lycopersicum) and S. habrochaites. Overall, eggplant rootstocks showed a good compatibility and graft success, while tomato rootstocks had a poor compatibility and only S. habrochaites rootstocks could be evaluated for yield and fruit production. Important differences were found for susceptibility to nematodes, with some S. melongena accessions showing the best results. Eggplant hybrids were intermediate to their parents in nematode resistance and tomato rootstocks proved to be very susceptible to nematodes. Yield, fruit number and earliness were higher in the most vigorous rootstocks, in particular in the S. melongena × S. aethiopicum hybrid. Good performance was also observed for some S. melongena accessions, but poor results were obtained when using S. incanum, S. aethiopicum and S. habrochaites rootstocks. Some differences were observed for fruit size and shape among the different rootstocks, but for the best rootstocks no differences of commercial relevance were apparent. The results suggest that S. melongena germplasm and both intraspecific and interspecific eggplant hybrids seem to be promising materials for developing new rootstocks for eggplant production.

가지의 Ralstonia solanacearum에 의한 풋마름병 발생과 생리형의 분화

Batcterial wilt caused by Ralstonia solanacearum is one of important and widespread diseases worldwide as well as in Korea. Bacterial wilt disease caused by R. solanacearum has been reported mainly in solanaceous crops including eggplant (Solanum melongena), tomato (Solanum lycopersicum), potato (S. tuberosum), and pepper (Capsicum annuum). A total of 48 strains of R. solanacearum from eggplant were collected during 2005 and 2006. They were confirmed as R. solanacearum by PCR amplification with primer pair flipcF/flipcR resulting in production of 470-bp DNA fragment. The 15 isolates exhibited pathogenicity on eggplant and tomato, but less virulent on pepper than other species. The biovar of collected isolates, which have been reported of five types worldwide, were classified as biovars 3 and 4 by physiological test. Biovar 4 was the dormant type without pathogenicity on eggplant rootstock, whereas biovar 3 had pathogenicity on eggplant rootstocks that is resistant to R. solanacearum, indicating necessity of breeding new rootstock with resistance to R. solanacearum biovar 3

Fertile somatic hybrids between Solanum integrifolium and S. sanitwongsei (syn. S. kurzii) as candidates for bacterial wilt-resistant rootstock of eggplant

UV-irradiated cotyledonary protoplasts of Solanum integrifolium and iodoacetamide-treated cotyledonary protoplasts of S. sanitwongsei were electrofused and cultured. Regenerated plants were classified into three groups based on morphology and genomic in situ hybridization data. Morphology of the first group was intermediate between those of parental species. The plants bore fruits with viable seeds and had a chromosome number of 2n� 48, the sum of the parental chromosome numbers, suggesting that they were symmetric fusion hybrids. Morphology of the plants in the second group was more S. integrifolium-like than that of the first group, and had two sets of S. integrifolium chromosomes and one set of S. sanitwongsei chromosomes. In contrast, plants in the third group had one set of S. integrifolium chromosomes and two sets of S. sanitwongsei chromosomes. Plants in the second and third groups were less vigorous than those in the first group, and bore few fruits. Electrophoretic analysis of the isozymes shikimate dehydrogenase, isocitrate dehydrogenase, and phosphoglucomutase, as well as random amplified polymorphic DNA analysis, demonstrated that 23 of regenerated plants from the three groups were somatic hybrids. The plants in the first group grew more vigorously than the parental plants and produced more than 5000 seeds per plant. The fertile somatic hybrids obtained in this study may be suitable candidates for eggplant rootstocks.

Efficient plant regeneration from protoplasts of eggplant rootstock cultivar and its wild relatives

Protoplast culture and shoot regeneration from protoplast-derived calli were compared among different organs of Solanum integrifolium and three of its wild relatives (S. abutiloides, S. scabrum, and S. toxicarium). Leaves, cotyledons, and hypocotyls were used as sources of protoplast preparation. After one month of culture, a high frequency of visible colony formation was obtained from cotyledon protoplasts of S. integrifolium and S. scabrum, hypocotyl protoplasts of S. integrifolium and S. abutiloides, and leaf protoplasts of S. integrifolium and S. toxicarium. In addition, when the primary culture was started at a density of 2.5−5×104 protoplasts ml−1, the highest frequency of colony formation was obtained. Moreover, when the colonies were subcultured for 7 days on solid callus-proliferation medium before being transferred to shoot-induction medium, the plant regeneration frequency improved to between 91.8 and 98.8%.

Effects of Scarlet Eggplant Rootstock on Growth, Yield, and Sugar Content of Grafted Tomato Fruits

Control of growth, fruit yield and sugar content of fruits were studied by comparing between tomato plants grafted on rootstocks of tomato (Lycopersicon esculentum Mill.) and scarlet eggplant (Solanum integrifolium Poir.). Vegetative growth tended to be depressed and the incidence of blossom end rot of fruits to be increased by grafting on scarlet egg-plant rootstocks. Fruit yield on scarlet eggplant rootstocks was lower than that on tomato rootstocks. Guttation was not observed in plants grafted on scarlet eggplant rootstocks. However, concentrations of leaf chlorophyll and the soluble solids and sugar contents in fruits were all higher in plants grafted on scarlet eggplant than on tomato rootstocks. These results indicate that plants grafted on scarlet eggplant rootstocks are likely in a state of water deficiency.