Eggplant Hybrids Research Articles

Biostimulant Application Enhances Fruit Setting in Eggplant—An Insight into the Biology of Flowering

Eggplant (Solanum melongena L.) is a warm climate crop. Its cultivation extends to temperate regions where low temperatures can affect the course of the generative phase, which is primarily sensitive to abiotic stress. The novelty of the present investigation consisted of characterising the heterostyly, pollination, and fertilisation biology of eggplants in field cultivations, which provided a basis for explaining the effect of a protective biostimulant on these processes. We aimed to investigate the flowering biology of three eggplant hybrids treated with Göemar BM-86®, containing Ascophylum nodosum extract, to determine the crucial mechanisms behind the increased flowering and fruit set efficiency and the final effect of increased yield. The flower phenotype (long, medium or short styled), fruit setting, and the number of seeds per fruit were recorded during the two vegetation periods. The numbers of pollen tubes and fertilised ovules in ovaries were evaluated during the generative stage of development to characterise the course of pollination and fertilisation for all types of flowers depending on the cultivar and biostimulant treatment. The expression of heterostyly depended on the eggplant genotype, age of the plant, fruit load, and biostimulant treatment. Domination by long-styled flowers was observed, amounting to 41%, 42%, and 55% of all flowers of “Epic” F1, “Flavine” F1, and “Gascona” F1, respectively. This flower phenotype contained the highest number of pollen tubes in the style and the highest number of fertilised ovules. The biostimulant had a positive effect on the flower and fruit set numbers, as well as on the pollination efficiency in all genotypes. Ascophylum nodosum extract could be used as an efficient stimulator of flowering and fruit setting for eggplant hybrids in field conditions in a temperate climatic zone.

Combining capacity and heterosis in eggplant hybrids under high temperatures

ABSTRACT The objective of this work was to estimate the combinatorial capacity and heterosis of eggplant hybrids under high temperature conditions. Seven genitors, twelve hybrid combinations, originated from a partial diallel, and the Ciça F1 hybrid, as control, were evaluated. The experiment was conducted under greenhouse conditions in randomized block design with four replications, from April to December 2017. The assessed traits related to high temperatures were pollen viability (PV) and fruit fixation index (FFI); the morphoagronomic traits were number of fruits per plant (NFP), fruit weight (FWe), production per plant (PP), fruit length (FL), fruit width (FWi), fruit length/width ratio (FLWR) and plant height (PH). The variance analysis showed greater participation of the additive gene effects in relation to the non-additive gene effects in most traits, except for PV. The genitors CNPH 141, CNPH 135, CNPH 109 and CNPH 51 stood out with favorable gene effects to obtain genotypes tolerant to high temperatures, since they present good general combining ability (GCA) for the traits FFI, NFP and PP. The 1x4 and 3x4 hybrids presented positive estimates for both GCA and specific combining ability (SCA), demonstrating a greater potential to be used in breeding to increase the FFI, NFP and PP, under high temperatures. The 1x4, 1x5 and 1x6 hybrids expressed positive heterosis for most analyzed traits. The 1x4 hybrid stood out for the highest averages for PV, FFI, NFP and PP. For FWe, FL, FWi and FLWR, both positive and negative heterosis were observed, as consequence of the phenotypic variability of the genitors for these traits and suggests the possibility of selection for different sizes and formats.

Interaction of Eggplant Genotypes by Cropping Systems and Correlations between Characters

The eggplant, Solanum melongena L. is a crop that is in the expansion phase, mainly due to the medicinal properties of its fruits in lowering cholesterol levels and blood pressure. The objective of this work was to evaluate eggplant genotypes in different cropping systems, identifying those most adapted to the Meso-region of Atlantic Forest. The experiment was conducted between December 2011 and May 2012, in the experimental area of the Department of Agronomy of the Federal Rural University of Pernambuco - UFRPE, Recife, PE, and at the Experimental Station Luiz Jorge da Gama Wanderley - IPA in Vitória de Santo Antão, PE, located in the Meso-region of Atlantic Forest. We assessed two open-pollinated cultivars and six eggplant hybrids in three cultivation systems: conventional, organic and hydroponic. A randomized complete block design with eight treatments and six replicates was used in each of the three systems. The hydroponic cultivation system exhibited the best results in all the genotypes in the studied variables, in which five hybrids presented better performance in this system. The hybrid of Ciça and Embu, open pollinated cultivar, showed no significant difference between the systems. The hybrids Comprida, Chica and Blanca showed higher commercial fruit yield in all cultivation systems. The hydroponic system presented that the majority of the genotypic and phenotypic correlations smaller than those of the conventional and organic systems.

Response of Certian Vegetable Genotypes to the Root Knot Nematode, Meloidogyne incognita

Resistance evaluation of 60 vegetable cultivars and hybrids of Eggplant, Pepper, Tomato, Cantaloupe, Cucumber and squash were tested against Root-knot nematodes (RKN) Meloidogyne incognita. Among Eggplant genotypes, Arosy1 recorded the lowest reproduction rate (15.1) while the highest population was possessed by kaser abiad (41.1). Pepper genotypes, in general, were less susceptible to RKN compared with Eggplants and Tomatoes, the reproduction rate varied between 3.5 (Romey) to 8.9 (P77). All Tomato genotypes were highly susceptible to RKN infection, Super strain B was the most susceptible cultivar because the nematode success to multiply 38.3 times, the lowest reproduction rate (13.3) registered by 820 and Castel rock (11.6 & 11.8 respectively). Similarly, all cucurbitaceous plants found to be susceptible to RKN infection. Among Cantaloupe genotypes, Alhana possessed the highest reproduction rate (15.8), while Galia 3 recorded the lowest reproduction (7.2). Within Cucumber genotypes, the minimum reproduction rate (6.2) was observed on Almanar, but the maximum population was possessed by Aliaa (13.8). Squash genotypes viz. Sama recorded the lowest reproduction rate (4.8) and the greatest population (10.1) was possessed by Dahab. Plant growth in most cases negatively reacted with nematode infection and the differences between infected and healthy plant was unobvious in many cases. To recommend the less susceptible genotypes as a tool for managing nematode strategy, further experiments are needed in the field for using these selected genotypes, also insertion these genotypes in breeding program for improving their characters specially resistance to nematode.

Estimation of Heterosis of Yield and Yield-Related Traits in the African Eggplant (Solanum Aethiopicum) Hybrids

African eggplant is an important fruit and leafy vegetable in Africa. Heterosis over mid and better parents was estimated in eight crosses of eggplant involving eight pure lines in a field experiment in 2012 and 2013 cropping seasons. The experiment was laid out using a randomized complete block design with three replications. Collected data was subjected to analysis of variance and significant differences were further subjected to Duncan Multiple Range Test. The aim of this study was to identify superior hybrids that can be advanced in the eggplant breeding program for improved yield and related traits. Significant variation was observed among all traits measured for the parents and hybrids. The highest fruit number was observed in NHS10-40 and in NHS 10-71 x NHS 10-40 among the parents and hybrids respectively. The highest heterosis was recorded in the cross between NHS10-71 x NHS10-40.

Suitability of CMS-based Interspecific Eggplant (Solanum melongena L.) Hybrids as Rootstocks for Eggplant Grafting

Suitability of CMS-based Interspecific Eggplant (Solanum melongena L.) Hybrids as Rootstocks for Eggplant Grafting

Reaction of wild eggplant Solanum torvum to different species of root-knot nematodes from Turkey

The cultivated eggplant species are susceptible to root-knot nematodes (Meloidogyne spp.). However, many wild Solanum species, such as S. torvum, S. sisymbriifolium, S. aethiopicum and S. warscewiczii, are resistant to some root-knot nematodes. Only S. torvum is employed as a rootstock for eggplant cultivation worldwide. This study investigated the response of S. torvum cv. Hawk against the root-knot nematodes Meloidogyne incognita, Mi-1 virulent M. incognita, M. javanica, M. arenaria and M. luci and M. hapla from Turkey, under controlled conditions. A local eggplant cultivar and a commercial eggplant hybrid were included in the bioassay. Eggplant seedlings were each inoculated with 1000 second-stage juveniles of Meloidogyne spp. and uprooted 8 weeks after nematode inoculation. Then, egg masses and galls on the roots were counted. S. torvum was resistant to M. incognita, Mi-1 virulent M. incognita, M. javanica, M. arenaria and M. luci, but susceptible to M. hapla. In Turkey, S. torvum has commonly been used as a rootstock against Meloidogyne spp. The study provided background information of S. torvum rootstock resistance to the mentioned populations of root-knot nematodes, except M. hapla.

INHERITANCE OF RESISTANCE TO ROOT-KNOT NEMATODES IN EGGPLANT HYBRIDS

The results of the research work on inheritance of resistance to root-knot nematode in eggplant hybrids F 1 was presented in the article. The breeding of early-maturing, resistant to root-knot nematode varieties and hybrid may cover all population’s demand on eggplant fruits in spring time and preventing the loss in yield caused by root-knot nematode in Republic of Uzbekistan. The breeding program for these varieties and hybrids requires the knowledge of inheritance of these resistance traits. The line Mk/03 out of 100 accessions had been selected as a line bearing resistance to root-knot nematode, while the line Al/03 and Cc/03 were sensitive and used as second parental component for further crossing. It was shown that resistance to root-knot nematode in eggplant hybrid F 1 was inherited as dominant trait. The type of crossing did not affect degree of dominance. Among combination studied 50-80% of plants did not show any sign of damage, whereas only 20-46.6% of plants were weakly damaged with score 1-2. The degree of dominance was very high for all cases and achieved hp=-0.74, -0.9, i. e. the hybrids F were very close to parental accession insensitive to root-knot nematode. Our study showed that if one of the parental accessions has high resistance to root-knot nematode the first progeny with sensitive accession always shows resistance, and not depending on type of crossing the dominance of resistance can be observed.

Genetic Control and Heterosis of Quantitative Traits in Several Local Eggplant Genotypes

The present study was performed to assess the nature of gene action governing inheritance of agronomic traits in eggplant genotypes and extent of mid parent heterosis (MPH) and better parent heterosis (BPH) in six eggplant hybrids generated from four superior and optimally divergent genotypes of eggplant namely ‘Yalo’, ‘Uyo’, ‘K3’ and ‘Iyoyo’ selected from the germplasm and were crossed in 4×4 half diallel mating design. The six hybrids were found to show a significant (p< 0.05) positive MPH in yield traits and the highest was obtained in the hybrid ‘Yalo’ × ‘K3’ for number of fruits per plant (158.90%) and ‘K3’ × ‘Iyoyo’ for fruit yield per plant (63.14%) and fruit yield per hectare (62.20 %). The hybrid combinations ‘Yalo’ × ‘K3’ and ‘K3’ × ‘Iyoyo’ had significant positive BPH for the number of fruits per plant, 104.08% and 42.43%, respectively. For fruit yield per plant, the hybrid combination ‘Yalo’ × ‘K3’ (7.93%), ‘Uyo’ × ‘K3’ (8.48%) and ‘K3’ × ‘Iyoyo’ (12.26%) had significant positive BPH. However, the hybrid ‘K3’ × ‘Iyoyo’ (11.51%) showed significant positive BPH in fruit yield per hectare. Dominance and dominance × dominance gene effect were found to be positively higher in magnitude in all crosses for number of fruits per plant, fruit yield per plant and fruit yield per hectare. The prevalence of dominance and dominance × dominance gene effect in the yield traits indicate heterosis breeding as the best breeding method to improve the productivity of eggplant.

Hybrids and allied species as potential rootstocks for eggplant: Effect of grafting on vigour, yield and overall fruit quality traits

Abstract Grafting of fruiting vegetables is an effective technique to overcome pests and diseases in modern cropping systems and it is often used to improve yield and fruit quality. Eggplant is an important vegetable crop that benefits significantly from grafting. In this regards, the exploitation, valorization and breeding of new rootstock genotypes as possible substitute to those commonly used (Solanum torvum and tomato hybrids) would permit an intensive eggplant crop system in those situations where a rootstock rotation is required. In the present article, we study the effects of several potential rootstocks including both wild/allied species of eggplant [S. torvum (STO), S. macrocarpon (SMA), S. aethiopicum (accession SASI), S. aethiopicum (accession SASa2), S. paniculatum (jurubeba) (SPA) and S. indicum (SIN)] and Msa 2/2 E7 and 460 CAL. eggplant hybrids on plant vigor, yield and fruit characteristics of eggplant F1 hybrid (‘Birgah’), in two spring-summer growing seasons (2014 and 2015). SPA and the hybrids Msa 2/2 E7 and 460 CAL. displayed a high percentage of grafting success. ‘Birgah’ scion grafted onto the two above-mentioned rootstocks showed a notable vigour and yield. Both rootstocks did not promote any unfavorable effects on apparent fruit quality traits and overall fruit composition. Furthermore, the concentration of glycoalkaloids in the fruit remained below the recommended safety value (200 mg/100 g of dw). These results suggest that SPA and Msa 2/2 E7 and 460 CAL. eggplant hybrids might represent a potential rootstock alternative to S. torvum.

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.

Влияние режима минерального питания на коэффициент водопотребления и урожайность гибридов баклажанов в условиях Астраханской области

Приведены основные результаты изучения воздействия различных норм внесения минеральных удобрений: P90K60 + N120 (2 подкормки) и P90K60 + N180 (3 подкормки) за весь период вегетации растений баклажана. Выявлены оптимальные нормы внесения, что нашло свое отражение в биологической урожайности. Применение минеральных подкормок в дозе N120 [режим минерального питания P90K60 + N120 (2 подкормки)] позволило поднять урожайность до уровня, гарантирующего всем сортам и гибридам баклажанов получение достаточно высоких показателей чистого дохода и уровня рентабельности. Среди высокоурожайных сортов и гибридов баклажанов, таких как Астраком, Маркиз F1, Лебединый, Галина F1 и Нижневолжский, при этом режиме минерального питания чистый доход на 1 га варьировал от 929,04 тыс. до 138,02 млн руб., уровень рентабельности — от 490 до 589 %. Урожайность по вариантам изучения при внесении минеральных азотных подкормок в дозе N180 [режим минерального питания P90K60 + N180 (3 подкормки)] варьировала от 135,1 до 180,93 т/га. Водопотребление баклажанов дифференцировалось в интервале 75 – 80 – 75 % HB и было обеспечено проведением в среднем 30 поливов. Суммарное водопотребление составило в общей сложности за весь период исследований (2012 – 2015 гг.) 4930,3 м3/га. Сорта и гибриды баклажана положительно реагируют на внесение минеральных азотных подкормок, особенно в дозе N180, обеспечивая значительный уровень биологической урожайности, превысив 100-тонный уровень.

A Spontaneous Eggplant (Solanum melongena L.) Color Mutant Conditions Anthocyanin-free Fruit Pigmentation

We identified a single plant in a grow out of the eggplant (Solanum melongena L.) variety ‘Black Beauty’ bearing green fruit. ‘Black Beauty’ normally produces violet/black pigmented fruit attributed to anthocyanin accumulation. We selected the green-fruited true-breeding genotype E13GB42 from the S2 generation obtained from selfing of the S0 green-fruited color mutant. Characterization of 12 simple sequence repeat (SSR) markers, eight fruit morphological attributes and fruit yield support E13GB42 arising as a spontaneous mutant of ‘Black Beauty’. With the exception of fruit calyx prickliness, E13GB42 was not significantly different from ‘Black Beauty’ for fruit morphological attributes and yield. E13GB42 exhibited an SSR marker profile identical to that of ‘Black Beauty’ but polymorphic with that of eight violet/black-fruited modern eggplant hybrids, older open-pollinated varieties and landraces. Transcript levels of key anthocyanin biosynthetic genes (Chs, Dfr, and Ans) and regulatory genes (MybC, Myc, and Wd) were significantly lower in the green-fruited E13GB42 mutant in comparison with the black-fruited variety ‘Black Beauty’ at various stages of fruit development ranging from small post-anthesis fruit to full-size marketable fruit. Progeny obtained from selfing of the original mutant and reciprocal crosses with ‘Black Beauty’ produced violet, green, and green with violet striped color classes that together were not compatible with one or two gene inheritance models, suggesting that the mutation responsible for the E13GB42 phenotype influences multiple genetic factors that control fruit pigmentation.

SSR markers based DNA fingerprinting and it’s utility in testing purity of eggplant hybrid seeds

Conventionally, the genetic identity and purity of seeds is assessed by field plot test. However, field plot test method is time consuming, requires large area of land and involves skilled personnel often making subjective decisions. These limitations and the environmental dependency of the entire procedure can be overcome effectively by employing DNA fingerprinting technology. Therefore, the present study was undertaken to identify simple sequence repeat (SSR) markers that could be used to test the genetic identity and purity of six brinjal hybrids and their respective parental lines based on generated DNA fingerprint. In the present study, four markers were found to be polymorphic between parental lines of four respective hybrids (viz. PH-5, PH-9, NDBHL-20 and Kashi Komal) and were found to be suitable for ensuring the genetic identity and purity of these hybrids. Among the identified markers, a set of three markers (emg01B17, emd05F05 and CSM31) could be used for ensuring the identity of the hybrids. Utility of SSR marker based DNA fingerprinting in ensuring the seed purity has been further demonstrated in comparison with that of field plot test.

Phenotyping of Eggplant Wild Relatives and Interspecific Hybrids with Conventional and Phenomics Descriptors Provides Insight for Their Potential Utilization in Breeding.

Eggplant (Solanum melongena) is related to a large number of wild species that are a source of variation for breeding programmes, in particular for traits related to adaptation to climate change. However, wild species remain largely unexploited for eggplant breeding. Detailed phenotypic characterization of wild species and their hybrids with eggplant may allow identifying promising wild species and information on the genetic control and heterosis of relevant traits. We characterizated six eggplant accessions, 21 accessions of 12 wild species (the only primary genepool species S. insanum and 11 secondary genepool species) and 45 interspecific hybrids of eggplant with wild species (18 with S. insanum and 27 with secondary genepool species) using 27 conventional morphological descriptors and 20 fruit morphometric descriptors obtained with the phenomics tool Tomato Analyzer. Significant differences were observed among cultivated, wild and interspecific hybrid groups for 18 conventional and 18 Tomato Analyzer descriptors, with hybrids generally having intermediate values. Wild species were generally more variable than cultivated accessions and interspecific hybrids displayed intermediate ranges of variation and coefficient of variation (CV) values, except for fruit shape traits in which the latter were the most variable. The multivariate principal components analysis (PCA) reveals a clear separation of wild species and cultivated accessions. Interspecific hybrids with S. insanum plotted closer to cultivated eggplant, while hybrids with secondary genepool species generally clustered together with wild species. Many differences were observed among wild species for traits of agronomic interest, which allowed identifying species of greatest potential interest for eggplant breeding. Heterosis values were positive for most vigor-related traits, while for fruit size values were close to zero for hybrids with S. incanum and highly negative for hybrids with secondary genepool species. Our results allowed the identification of potentially interesting wild species and interspecific hybrids for introgression breeding in eggplant. This is an important step for broadening the genetic base of eggplant and for breeding for adaptation to climate change in this crop.

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

Genetic Purity of Interspecific Hybrids of Solanum melongena and S. macrocarpon Assessed Using SSR Markers

Traditionally hybrid purity of F1 hybrids is assessed through grow-out tests, which are time consuming and labor intensive. There is need for a fast and reliable alternative method for hybrid purity testing. The objective of this work was to assess purity of interspecific hybrids of Solanum melongena L. (‘IIHR3’, Arka Keshav (‘AK’), ‘2BMG’) and Solanum macrocarpon L. (‘SM’) using simple sequence repeats (SSR). Genomic DNA from parents and F1 hybrids were subjected to SSR analysis to detect parental polymorphism. Among 119 SSRs screened, 5 SSRs were codominant. There were five unique microsatellite markers, two for ‘IIHR3’ בSM’, emf 01C03 and emh 02E08; one for ‘AK’ בSM’, emi 02 F16; and two for ‘2BMG’ בSM’, emb 01E 03 and emg 11I03, which were useful to detect purity of three interspecific eggplant hybrids. This is the first report demonstrating the utility of SSR markers for assessment of genetic purity of interspecific hybrids in eggplant.

Eggplant relatives as sources of variation for developing new rootstocks: Effects of grafting on eggplant yield and fruit apparent quality and composition

We propose the utilization of eggplant ( Solanum melongena L.) interspecific hybrids derived from crosses with closely related species as an approach for developing new improved rootstocks for eggplant. Here we investigate rootstock effects on fruit yield, apparent quality and proximate and mineral composition of S. melongena ‘Black Beauty’ (BB) scions grafted on interspecific hybrid rootstocks developed from crosses of S. melongena with Solanum incanum L. (SI × SM) and Solanum aethiopicum L. (SM × SA). The results are compared with non-grafted (BB control) and self-grafted (BB/BB) controls and with S. melongena ‘Black Beauty’ scions grafted onto Solanum torvum Sw. (STO) and Solanum macrocarpon L. (SMA) rootstocks. All treatments were grown in a soil naturally infested with root-knot nematodes (mostly Meloidogyne incognita (Kofoid and White) Chitwood). SI × SM and SM × SA interspecific hybrids had high germination (≥90%) and total graft success (100%). Contrary to what occurred with all other treatments, no plants from scions grafted onto these hybrid rootstocks died during the experiment. In particular, the SI × SM hybrid rootstock conferred the highest vigour to the scion, which resulted in the highest values for fruit earliness and early and total yield. Little difference was observed among treatments for apparent fruit quality traits, except for a greater fruit calyx length and prickliness of fruit grafted onto SMA rootstocks. A similar result was obtained for fruit composition where phenolics content was higher in fruit from plants grafted onto SMA rootstocks. Grafting eggplant onto interspecific eggplant hybrids, especially on the SI × SM hybrid, has proved advantageous for eggplant production, as the high vigour and good compatibility of the rootstock with scion results in improved early and total yield without negative effects on apparent fruit quality or composition. Interspecific hybrids represent an alternative to the commonly used STO rootstock, which is a wild species with irregular germination.

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.

Preferência alimentar de adultos de Metriona elatior Klug (Coleoptera: Chrysomelidae, Cassidinae) por diferentes híbridos de Solanum melogena Linnaeus (Solanaceae)

Metriona elatior Klug is a potential biocontrol agent for Solanum viarum Dunal (tropical soda apple), because larvae and adults feed on its leaves and this species shows a low dispersion rate. Specificity plays a major role in the feasibility of an organism as a biological control agent, especially in the inundative strategy. The feeding preference of M. elatior adults was evaluated to 14 eggplant (Solanum melogena Linnaeus) hybrids. Mass rearing was carried out under lab conditions, with the insect feeding directly on S. viarum leaves. The study started with dual and multiple choice tests in 24 and 48 hour feeding times, by offering leaf disks in Petri dish conditions. Survival and leaf consumption analysis were performed in newly adults in tropical soda apple and eggplant leaves kept turgid by immersing the petioles in water. The leaf area was measured before and after four days of insect exposure. M. elatior showed higher feeding preference, survival and consumption of the weed species, especially in comparison with the hybrid Ryoma. The highest feeding preference among the eggplant hybrids was observed in ‘Minikuro Kowishiki’.