Cribado para tolerancia a sequía en especies silvestres relacionadas con la berenjena e híbridos interespecíficos

UNIVERSITAT POLITECNICA DE VALENCIA Master in Plant Genetics and Breeding Screening for Drought Tolerance in Eggplants relatives and Interspecific Hybrids (Solanum spp.) Master Thesis Presented by : Siti Nur Azizah Fauziyati Rahma Academic Director : D. Dr. Jaime Prohens Tomas Experiment Director : Dna. Ana Maria Fita Fernandez Dna. Mariola Plazas Avila VALENCIA, SPAIN 2016 UNIVERSIDAD POLITECNICA DE VALENCIA Master in Plant Genetics and Breeding Screening for Drought Tolerance in Eggplants relatives and Interspecific Hybrids (Solanum spp.) Master Thesis Presented by : Siti Nur Azizah Fauziyati Rahma Academic Director : D. Dr. Jaime Prohens Tomas Experiment Director : Dna. Ana Maria Fita Fernandez Dna. Mariola Plazas Avila VALENCIA, SPAIN 2016 i RESUMEN El escenario que impone el cambio climático obliga a desarrollar cultivos mejor adaptados a la sequía. La berenjena (Solanum melongena L.) es uno de los 35 cultivos catalogados como más importantes para la seguridad alimentaria mundial y, como tal, está incluido en el Anexo 1 del Tratado Internacional sobre los Recursos Fitogenéticos para la Alimentación y la Agricultura. Aunque la berenjena no es un cultivo muy sensible a la sequía todavía se puede mejorar su tolerancia haciendo uso de sus parientes silvestre (Solanum spp.). El objetivo del presente trabajo fue evaluar la tolerancia a la sequía de la berenjena y algunos de sus parientes silvestres, así como híbridos entre ellos, para determinar el interés de introgresar genes de tolerancia a la sequía desde dichos parientes silvestres. Los experimentos se realizaron en el laboratorio de solanáceas del COMAV, UPV durante 55 días. Se utilizaron las especies S. melongena, S. insanum, S. dasyphyllum, S. linnaeanum, S. anguivi y sus híbridos. Se realizaron dos tratamiento de sequía (déficit de agua y PEG 7%) y un control. Se evaluó la tasa de crecimiento de las plantas (altura de la planta y el área foliar), la biomasa, el color, la tasa de fotosíntesis, la tasa de transpiración, la conductancia estomática, concentración de CO2 intercelular y la eficiencia en la utilización de agua. El resultado de la investigación concluyó que el tratamiento sequía indujo una reducción media del 17% en la altura de la planta, un 30% en el área foliar y el 32% de la biomasa seca en el conjunto de genotipos evaluados. Por otra parte, se demostró que S. anguivi, S. insanum, y los híbridos S. melongena x S. anguivi, S. melongena x S. insanum, y S. melongena x S. dasyphyllum eran más tolerantes a las condiciones de sequía. Por lo tanto estas especies e híbridos podrán ser utilizados en posteriores programas de mejora para la resistencia a la sequía en berenjena. Palabra clave: Solanum spp, híbridos interespecíficos, sequía, selección Abstract The scenario posed by climate change forces to develop better adapted to drought. Eggplant is one of the 35 crops judged to be most important for food security and as such is included in the Annex 1 of the International Treaty on Plant Genetic Resources for Food and Agriculture. Even though the eggplant is not very sensitive crop to drought its tolerance can still be improved using their wild relatives (Solanum spp.). The aim of this study was to evaluate the drought tolerance of eggplant and some of their wild relatives, as well as hybrids between them, to determine the interest of introgress genes for drought tolerance from these wild relatives. Experiments were performed in the Solanaceae laboratory of COMAV, (UPV) for 55 days. Species S. melongena, S. insanum, S. dasyphyllum, S. linnaeanum, S. anguivi and their hybrids were used. Two drought treatment (water deficit and PEG 7%) and one control were applied. The analysis was focused on plant growth rate (plant height and leaf area), biomass, green-color level, photosynthesis rate, transpiration rate, stomatal conductance, intercellular CO2 concentration and water-used efficiency. The research result concluded that drought treatment induced an average reduction of 17% in plant height, 30% in leaf area, and ii 32% in dry shoot biomass. Moreover, it showed that S. anguivi, S. insanum, and the hybrids S. melongena x S. anguivi, S. melongena x S. insanum, y S. melongena x S. dasyphyllum were more tolerant to drought condition. Therefore these species and hybrids can be used in future breeding programs for drought resistance in eggplant. Keyword : Solanum spp, interspecific hybrids, drought, selection Master Thesis Presented by : Siti Nur Azizah Fauziyati Rahma Academic Director : D. Dr. Jaime Prohens Tomas Experiment Director : Dna. Ana Maria Fita Fernandez Dna. Mariola Plazas Avila INDEX ii INDEX RESUMEN ............................................................................................................................ i ABSTRACT ........................................................................................................................... i INDEX ................................................................................................................................... ii FIGURE INDEX .................................................................................................................... iii TABLE INDEX ..................................................................................................................... iv ABBREVIATIONS ............................................................................................................... v 1. INTRODUCTION 1.1. The Economic Importance of Drought 1.1.1. The drought and the crops ................................................................................... 1 1.1.2. Drought mitigation through technology .............................................................. 2 1.2. Breeding for drought-tolerance ................................................................................ 3 1.2.1. Plant breeding for drought-tolerance traits ......................................................... 3 1.2.2. Morphophysiological mechanism associated to drought-tolerant plants ............ 5 1.3. The Eggplant 1.3.1. The origin and distribution of eggplant............................................................... 7 1.3.2. Drought responses in the eggplant ...................................................................... 9 1.4. The wild relatives as genetic resources for tolerance genes 1.4.1. Eggplants, their allied and their wild relatives .................................................... 9 1.4.2. The introgression of tolerance traits from wild relatives into cultivated eggplant ............................................................................................................................. 12 2. OBJECTIVES ................................................................................................................... 15 3. MATERIAL AND METHODS 3.1. Plant material ........................................................................................................... 16 3.2. Experimental design 3.2.1. Cultural practices ................................................................................................ 17 3.2.2. The deficit-irrigated treatment ............................................................................ 19 3.3. Drought-tolerance assesment ................................................................................... 20 3.4. Data analysis ............................................................................................................ 20 4. RESULT AND DISCUSSION 4.1. Plant growth parameter ............................................................................................ 21 4.1.1. Leaf area and plant height ................................................................................... 21 4.1.2. Biomass analysis ................................................................................................. 23 4.2. Physiological state analysis ..................................................................................... 26 4.3. Green-color level analysis ....................................................................................... 28 4.4. Water-use efficiency ................................................................................................ 30 4.5. Final remarks ........................................................................................................... 33 5. CONCLUSION ................................................................................................................. 36 6. BIBLIOGRAPHY ............................................................................................................. 37 iii FIGURE INDEX Figure 1 .................................................................................................................................. 1 Figure 2 .................................................................................................................................. 2 Figure 3 .................................................................................................................................. 6 Figure 4 .................................................................................................................................. 8 Figure 5 .................................................................................................................................. 11 Figure 6 .................................................................................................................................. 16 Figure 7 .................................................................................................................................. 18 Figure 8 .................................................................................................................................. 18 Figure 9 .................................................................................................................................. 20 Figure 10 ................................................................................................................................ 22 Figure 11 ................................................................................................................................ 23 Figure 12 ................................................................................................................................ 23 Figure 13 ................................................................................................................................ 25 Figure 14 ................................................................................................................................ 25 Figure 15 ................................................................................................................................ 26 Figure 16 ................................................................................................................................ 28 Figure 17 ................................................................................................................................ 29 Figure 18 ................................................................................................................................ 30 Figure 19 ................................................................................................................................ 32 Figure 20 ................................................................................................................................ 33 iv TABLE INDEX Table 1 ................................................................................................................................... 16 Table 2 ................................................................................................................................... 17 Table 3 ................................................................................................................................... 19 Table 4 ................................................................................................................................... 21 Table 5 ................................................................................................................................... 24 Table 6 ................................................................................................................................... 27 Table 7 ................................................................................................................................... 27 Table 8 ................................................................................................................................... 29 Table 9 ................................................................................................................................... 31 v ABBREVIATION WUE : Water-use efficiency FAO : Food and Agricultural Organization CIMMYT : Centro Internacional de Mejoramiento de Maiz y Trigo CRI : Crop Research Institute IITA : International Institute of Tropical Agriculture ICARDA : International Center for Agricultural Research in the Dry Area IRRI : International Rice Research Institute TPE : Target Population of Environment RFLP : Restriction Fragment Length Polymorphism RAPDs : Random Amplification of Polymorphic DNA CAPS : Cleaved Amplified Polymorphic Sequences PCR : Polymerase Chain Reaction AFLP : Amplified Fragment Length Polymorphism SSRs : Simple Sequence Repeats SNPs : Single Nucleotide Polymorphism QTL : Quatitative Traits Locus PEG : Polyethylene Glycol IRGA : Infra-red Gas Analysis 6 time period (E). On the other hand, at plant level, WUE defines as the assimilated dry matter named biomass (WUE biomass) or accumulation dry matter partitioned the economical product, such as grain (WUE yield) (Tambussi et al., 2007; Medrano et al., 2015). Figure 3. Scheme of Water Use Efficiency definition. Each genotypes has different WUE under drought conditions. Passioura (1977), defined WUE yield as formula : Y = T x WUE x HI where T is the amount of water transpired by the crop and evaporated from the field, and HI is the harvest index (the ratio between yield (Y) and total biomass). The variables are interdependence to each other. Improving water-use efficiency (WUE) in order to increase yield (Y) may be partially equated to reduce the water absorbtion from the soil. Furthermore, it has to be kept in mind that agronomist and farmers are interested in yield. Therefore, WUE should not be equated to the drought tolerance, since there is possibility that WUE could negatively associated with the yield (Y) (Tuberosa, 2012). Meanwhile, Richards (1991) proposed the other formula related to the crops which grown in waterlimited location : WUE (biomass) = TE/(1 + Es/T) where TE is transpiration efficiency, Es is the water lost due to the evaporation, and T is water lost by the transpiration. This formula is useful for identifying the agronomic and breeding strategies (Tuberosa, 2012). Drought stress also induced different distribution of mass to the plants organs. The previous research implied that a significant decrease occured in leaves but not in shoot or roots. Furthermore, it explained that drought-tolerant plants usually have higher roots Water-Use Efficiency Gas Exchange WUE instantaneous : A/E WUE intrinsic : A/gs Integrated WUE biomass : Dry matter/ total water consumed WUE yield : grain yield/ total water consumed 7 mass than sensitive one (Erice et al., 2010; Krisnamurthy et al., 2011). A well-developed roots system will provide plants to adapt better in drought condition (Bacon et al., 2002; Yu et al., 2007). The faster growing and deeper roots will increase water harvest and help to stabilize yield under drought condition (King et al., 2009). Morpho-physiological traits are important tools which could be use for select drought-tolerant plant. However, those characters should associated with yield, and having greater heritability than yield. So, it may assist in development and adaptations of new genotypes with higher yield that are able survive on water scarcity. 1.3. The Eggplant 1.3.1. The Origin and Distribution of Eggplant Eggplant (Solanum melongena L.) (2n = 24) has been classified as : Kingdom : Plantae Division : Tracheophyta Subdivision : Spermatophytina Class : Magnoliopsida Order : Solanales Family : Solanaceae Genus : Solanum Species : Solanum melongena L. The name “Solanum melongena” comes from a sixteenth-century Arabic term for one kind of eggplant. United states, Australia, New Zealand and Canada named it “Eggplant” due to their fruits that resembled goose or hens egg. This plant called “Aubergine” in British English derived from French aubergine. It known as “Brinjal” in Indian and South African (New World Encyclopedia, 2013). Eggplant as one of species on the Solanaceae family or nightshade family, has choosen and developed as human food plants, others include of the New world crops tomato (Solanum lycopersicum L.), potato (Solanum tuberosum L.) and chilli pepper (Capsicum spp.). This plant contains vitamins, minerals, fibre and an important phytonutrients (Raigon et al., 2008; Rotino et al., 2014). Instead of food, they were used as traditional medicine in history. Moreover,its leaves and flowers can be poisonous if it consumed in large quantities due to their solanine (Rotino et al., 2014). The origin and evolution of eggplant are still under debate. Relationship among wild species, semi-cultivated and cultivated are still controversial. Genetic studies on the relationship within eggplant and its closely allied have only determined the position of 8 them but not their origin and progenitor. Several hypotheses have developed about the eggplant evolution and biogeography (Lester and Hasan, 1991; Mace et al., 1999; Daunay et al., 2001; Weese and Bohs, 2010). Some taxonomists argue that S. incanum and S. undatum are the candidate progenitor of S. melongena. Solanum incanum, native to north Africa and middle east, gave rise to S. undatum as it spread to east asia (Lester and Hasan, 1991). Alternatively, some believed that S. undatum as true wild species, whereas S. melongena domesticated directly from S.insanum in India (De Candolle, 1886; Prain, 1903). The advanced study described that probably there is differences between S. incanum in Africa and Asia (Karihaloo, 2009). The investigation of eggplant domestication process has proposed three theories. First theory explained that cultivated eggplant originated from India and spread to Western Asia and Europe (see Figure 4) brought by Arabic traders (Mace et al., 1999; Doganlar et al, 2002a;2002b; Daunay, 2008; Weese and Bohs, 2010, Meyer et al., 2012). The evidence of eggplant domestication was recorded in Sanskrit literature, dated to 300 BC (Khan, 1979; Wang et al., 2008). Second theory implied that the landraces of eggplant were cultivated in China and distributed to northeast and southeast into Japan, mainland Southeast Asia and Malesia, and Eastern Asia (see Figure 4) (Wang et al., 2008; Ali et al., 2011; Meyer et al., 2012). It recorded in Chinese literature, Tong yue, dated to 59 BC. The earliest domestic relatives of eggplant had round and green fruit. The domestication process has changed the quality of fruit : size, shape and taste. Figure 4. Proposed scheme of eggplant distributions. First, landraces originating from India were proposed spread to west to western Asia and Europe. Second, landraces occurs to China distributed to northeast and 9 southeast into Japan. Furthermore, third proposed domestication event, Solanum melongena subsp. ovigerum originated in Malesia which spread into Indochina only (Meyer et al., 2012) The third theory arose from AFLP analysis conducted by Meyer et al., 2012. It described that there was domestication process for S. melongena subsp. ovigerum in Malesia which has restricted spreading only into Indochina (Figure 4). However, it is generally concurred that Asia is the center of diversity of eggplants (Meyer et al., 2012; Knapp et al., 2013). 1.3.2. Drought Responses in the Eggplant Solanum melongena is the third most important crops worldwide. It has been widely cultivated for centuries in Asia, Africa, Europe and Near East. Eventhough it commonly sold in American, European and Australian markets. Over of 90% of eggplant production is concentrated into seven countries including of China, Egypt, Turkey, India and Japan (Lucier and Jerardo, 2006). In 2015, the production of eggplant exhibited an increase with 49,418,212 tonnes (FAO, 2015). Nonetheless, the production of eggplant may decrease due to diseases and stresses. Drought is one of abiotic stress which has potential to make severe losses in eggplant. It can decrease both the quality and productivity of crops. The reduction in leaf area, dry matter, weight, volume, height and diameter of fruits, which impact to decrement of fresh yield hence of water stressed in the eggplant were reported in the previous study (Kirnak et al., 2002; Chaves et al., 2003; Madramooto and Rigby, 1991; Lovelli et al., 2007; Mitchell et al., 1991; Tan and Blake, 1993; Smittle et al. 1994, Hartz, 1997). However, eggplant has the ability to survive better under drought condition than other crops. Likely, a better stomatal control and a better photosyntesis maintenance are the pivotal factors which maintain plant physiological state in water stress condition (Behboudian, 1997a; Behboudian, 1997b; Ludlow 1976). Nonetheless, there were variation of tolerance levels which eggplant could stand or not to the drought condition. For instance, the tolerance levels variations were found on the eggplant accession from certain landraces that tolerance to drought in Indonesia (Sudarmonowati, 2012). 1.4.The Wild Relatives as Genetic Resources for Tolerance Genes 1.4.1. Eggplants, their allied and their wild relatives Solanum melongena belongs to the subgenus Leptostemonum, the largest subgenus in the Solanum with 450 species diffuse worldwide. Unlike most of genus, eggplant and its relatives belong to the Old World. The majority of wild relatives of eggplant derived from 10 Africa. Solanum melongena is differentiated from their wild relatives which usually have small, round, yellow fruits and the plant are very abundantly prickly (Weese and Bohs, 2010; Daunay and Hazra, 2012; Knapp et al.,2013). There are three cultivated eggplants whithin the large leptostemonum clade including of S. melongena L, S. macrocarpon, and S. aethiopicum L. Both of S. melongena and S. macrocarpon belongs to sections Melongena Mill. (Dunal), whereas Solanum aethiopicum L. belongs to sections Oliganthes Dunal (Bitter) (Daunay et al., 2001; Daunay and Hazra, 2012; Knapp et al., 2013). Common Eggplant Solanum melongena L. (Figure 1.4., J,K,L) is known as common eggplant, or brinjal eggplant. Currently, it is one of the most important crop which grown worldwide. According to Lester and Hasan, 1991, Solanum melongena divided into groups E-H which refers to S. insanum L., S. cumingii Dunal, S. ovigerum Dunal and S. melongena L. They were wild and weedy plants, landraces and derived cultivar which found in Asia and India. However, a new classification made groups E-F into S. insanum L., meanwhile groups G-H refers to S. melongena L (Knapp et al., 2013) Solanum incanum L., is known as putative wild anchestor of Solanum melongena. It is native to Africa. It can cross compatible with Solanum melongena. Different to Solanum melongena, S. incanum has small green, yellow or even white fruit, prickly stem and leaves. Lester and his colleagues considered S.incanum into groups A-D which refers to S.campylacanthum A. Rich, S.Panduriforme E.Mey, S.delagoense, S.incanum L. sensuu stricto, and S. lichtensteinii. Nonetheless, Knapp and colleagues considered S. incanum L. groups A-B refers to S. campylacanthum A. Rich, group C refers to S. incanum L., whereas group D refers to S. lichtensteinii Willd (Lester and Hasan, 1991; Mace et al., 1999; Knapp et al., 2013). Scarlet Eggplant Complex Solanum aethiopicum L., commonly known as scarlet eggplant, is native from south africa. It has been introduced primary to the Brazil, then to the West Indies and South Africa (Lester and Niakan, 1986; Daunay et al., 2001; Weese and Bohs, 2010). It has small white corolla and usually bright scarlet fruits that resemble to Capsicum peppers. Solanum anguivi (Figure 5, A,B,C), as known for the wild progenitor of S. aethiopicum, could produce the fully fertile hybrids with the S. aethiopicum. Solanum anguivi, Solanum aethiopicum and their intermediate fertile formed scarlet eggplant complex (Lester and Niakan, 1986; Lester and Thitai, 1989; Plazas et al., 2014) 11 Gboma Eggplant Complex Solanum macrocarpon L, the Gboma eggplant, is native from the humid tropics of central Africa. It has deeply lobed leaves and very large calyces (Daunay et al., 2001; Weese and Bohs, 2010). Solanum macrocarpon was cultivated from the wild S. dasyphyllum Schum and Thonn. The cross breeding of both species also gain the fully interfertile hybrids. Solanum macrocarpon L., S. dasyphyllum and their intermediate fertile are usually called as Gboma Eggplant complex (Bukenya and Carasco, 1994; Plazas et al., 2014) Both Scarlet and gboma eggplant are an important genetic resources for common eggplant breeding. All three cultivated eggplants can be intercrossed giving intermediate fertile hybrids. (Daunay et al., 1991; Oyelana and Ugborogho, 2008; Prohens et al., 2012, Khan et al., 2013; Plazas et al., 2014). Nevertheless, scarlet eggplant and gboma eggplant are distantly related with and not involved in evolution of common eggplant (Whalen, 1984; Plazas et al., 2014). Figure 5. A,B, C are photos of S. anguivi leaves, fruit, and flower. D,E,F are photos of S. Insanum leaves, flower and fruit. G, H, and I are images of S. lichtensteinii. Whereas J, K, and L are photos of S. melongena (Zamkova, 2015). 12 Other than three cultivated and their wild relatives already mentioned, there are a few of wild relatives of Solanum melongena which usually used in breeding since they have close relationship with Solanum melongena. In this following, the explanation about the wild relatives : Solanum insanum L. (Figure 5, D,E,F) distributes from India to South East Asia, and also found in Madagascar and Mauritius. It usually mistaken with Solanum incanum. According to Lester and Hasan (1991), this species was a variety from Solanum melongena. Nevertheless, in the new classification, Knapp et al., 2013, Solanum insanum has considered as wild plant, which is almost certainly the wild progenitor of Solanum melongena (Daunay and Hazra, 2012; Knapp et al., 2013). In addition, the group E (wild) and F (weedy) of Lester and Hasan (1991) have been unified and belongs to this taxa (Daunay et al., 2001). Solanum lichtensteini Willd. (Figure 5, G,H,I) is spreading from South Africa to Angola, DR Congo and Tanzania. This species is morphologically similar with Solanum incanum. Nevertheless, it can be differentiated by its ridged young stem and its geographic. The dwarf form also found in upland dry areas of South Africa. This species is placed to Solanum incanum group D (Lester and Hasan, 1991). It also sister to S. linnaeanum (Weese and Bohs, 2010) Solanum linnaeanum Hepper & P. is likely native to South Africa then diffuse to mediterranean region. In spain, the fruit from S. linnaeanum don’t seems for feeding any animals. Weese and Bohs, 2010, have found the clearly relationship of S. linnaeanum and the eggplants wild relatives. This species has almost glabrous leaves which different from the other eggplants relatives. It is also a good candidate to make ILs that beneficial for eggplant breeding resources (Knapp et al., 2013). Solanum tomentosum L. is known as snake apple which belongs to Section Oliganthes. It occurs on roadside, undisturbed soil, and rocky grassland in coastal belt of South Africa, except Malawi and Zambia. It is a shrub which grows up to 60 cm high. This species usually use as medicine to threat syphilis, sore throat, toothache and for treatments of boils. It also potential for antimicrobial activities (Schmelzer and GuribFakim, 2008; Aliero and Afolayan, 2006). 1.4.2. The introgression of tolerance traits from wild relatives into cultivated eggplant In eggplants, the wild germplasm resources are important tools to get the potential genetic variability and allelic variation of many potential agronomic traits. They are good resources for tolerance to disease and pest resistance, abiotic and biotic stresses. For 13 instance, several previous studies that inform resistance to root-knot nematodes in Solanum aethiopicum (Hebert, 1985; Prohens, 2012), resistance to salinity in Solanum linnaeanum (Daunay et al., 1991; Rotino et al., 2014), or high tolerance to salt in S. torvum (Bletsos et al., 2003; Rotino et al., 2014). The wild relatives usually used in an interspecific hybridisation to introduce the potential traits from wild relatives to cultivated eggplants for crop improvement. However, since there are certain fertilization barriers, the capability of eggplants to cross over with other genera or subgenera was very low (Rotino et al., 2014). Most of publications investigated about interspecific crosses in eggplants and wild relatives assumed that there were inconsistency result. It occured because of ambigous or miss-applied Solanum species nomenclature, heterogenous, or not specified criteria used for imply the succes or failure of crosses. In the conventional breeding, sterility, reduced fertility and/or infertility were displayed as a common phenomenon in the interspecific hybrid which may associated to self-incompatibility due to wild parents, being eggplants self-compatible. Therefore, the conventional breeding should be provided by biotechnology approach to accomplished the fertility progenies. Many biotechnology attempts such as somaclonal variation, somatic hybridizations, in vitro embryo rescue, genetic engineering (transformation), and molecular marker have been conducted to further enlarge the genetic variability. However, despite genetic engineering very useful for plant breeding, there are still many people don’t believed in genetic modified crop production (Devi et al., 2015; Kashyap et al., 2002; Daunay and Hazra, 2012; Rotino et al., 2014). The reviewed on wide scale inter-specific hybridization experiments between Solanum melongena with Solanum species exhibited that there were 27 species belongs to section Melongena (11 species), section Oliganthes (15 species) and section Nycterium (S.lidii) which have successfully breeding with eggplants (using minimum threshold 10% of pollen stainability or more). To put it another way, most of Solanum species having partially fertile hybrids with eggplants, including of S. dasyphyllum, S. anguivi, S. tomentosum, S. linneanum, S. macrocarpon, S. aethiopicum. By contrast, only limited having fertile hybrids with eggplants, such as S. lichtensteinii, S. incanum and S. insanum (Daunay, 2008; Daunay and Hazra, 2012; Rotino et al., 2014). The interspecific hybridisations between wild relatives with cultivated eggplants may result the introgression undesired susceptible traits, for example, susceptible S. torvum to 14 fruit anthracnosis. Therefore, a susceptible traits in given wild relatives should be systematically looked and eliminated from eggplant breeding (Daunay, 2008). According to drought-tolerance traits, many of researchers has worked in a varies of plants, including of eggplant and their wild relatives, to find the best genotypes which can survive in dry environment. The previous studies implied that Solanum macrocarpon and Solanum eleagnifolium possesed tolerance to drought (Daunay et al., 1991; Fita et al., 2015). COMAV as a research center in UPV, Spain, has been investigated onto droughttolerance experiments. They observed to the cultivated eggplant, and their wild relatives about their tolerance to drought. The eggplants and the wild relatives also were crossed over to obtain a new genotypes withstand drought climate. However, the further investigation were needed to acquire information about those genotypes. Therefore, in these experiments, the simple analysis was conducted to find the best drought-tolerant Solanum spp. 2. OBJECTIVES 20 7 Mel 5.3 x Ins 2.1 PEG 5 63,89 8 Mel 5.3 x Ang 2.2 Control 2 72,06 8 Mel 5.3 x Ang 2.2 Deficit Irrigation 3 40,44 9 Mel 5.2 x lic 1.1 Control 2 71,43 9 Mel 5.2 x lic 1.1 Deficit Irrigation 3 42,86 3.3. Drought Tolerance Assesment Plant height, foliar length and width (from three leaves) were measured with ruler to calculate Leaf Area (LA) as the length per width divided by 2. Plant fresh and dry weight were measured. Water used efficiency (biomass) were measured as the ratio of dry weight and total amount of water used. Green colour levels were determined using colorimeter Minolta CR-300 in three replicas per each plant. Then, after 8 weeks of treatments, all of the plants were measured with an Infrared Gas Analyzer (Li-Cor 6400, Nebraska, USA) for photosynthetic rate (A), transpiration rate (E), stomatal conductance to H2O (gs) and Intercellular CO2 concentration (Ci). All of measurements were done in the morning, out of growth climatic chamber, with a 900 PAR and with CO2. Afterwards, water-used efficiency (intrinsic and instantaneous) were calculated from ratio between photosynthetic rate (A) and stomatal conductance (g) or ratio between photosynthetic rate (A) and transpiration rate (E). Figure 9. (left) Image of Li-cor 6400 portable photosynthesis system. The eggplant leaves were measured out of growth climatic chamber in the morning. (right) Illustration when the leaves were measure using Li-cor 6400 portable photosynthesis (the eggplants leaves measurement was not recorded). 3.4.Data Analysis 21 All the data which obtained from the measurement were put into microsoft excell and ANOVA was performed with statgraphics. 4. RESULTS AND DISCUSSION 21 4.1. Plant Growth Parameter Water stress limits plant growth rate including of decline in plant height, leaf area, number of branches, and dry weight of shoots and roots (Byari and Al-Rabighi, 1995; Antholin and Sanchez-Diaz, 1992; Aranjuelo et al., 2007). Nevertheless, the drought-tolerant plants have the ability to minimize their impaired growth rate. They still can growing, flowering and displaying the economic yield under water scarcity (Beck et al., 2007; Farooq et al., 2009a). Eggplants, their wild allied and their hybrids have variable levels of drought-tolerance as can be seen in the following results. 4.1.1. Leaf Area and Plant height ANOVA analysis for Leaf Area and plant height (table 4) indicated that there were significant differences among genotypes and treatments. The general effect of the drought treatment was to reduce LA and plant height. In any case there was significant genotype x treatment interactions meaning that all the genotypes were affected to a certain extend by the water deficit. Table 4. Multifactor ANOVA results table showing the effects of the Solanum accessions and treatments (water deficit and control) and the genotype over Leaf Area and Plant Height Mean squares df 1 Leaf Area (cm2) Plant Height (cm) Main effects Treatment (T) 1 5903 * ** 50 *** Accession (A) 8 3401 *** 31 *** Interactions TxA 8 343 ns 1 ns Error 54 514 4 1 Degrees of freedom; ns non-significant, *,** ,*** significant at P-value < 0.05, 0.01, and 0.001 respectively Despite of lack interraction of genotype x treatment, the individual analysis on the leaf area and plant height measurements showed that different responses against drought condition. Solanum melongena (Mel), S. dasyphyllum (Das) and S. linneanum (Lin), had significant reduction in their plant height and leaf area, whereas S. melongena x S.lichtensteinii hybrid (Mel x Lic) only has significant decrease in leaf area. Regarding the LA (leaf area) and plant height linneanum (Lin) S. dasyphyllum hybrid (Mel x Lic) were more sensitive to drought condition (Figure Figure 10. Bar diagram showing estimation measurement assayed under control and water deficit conditions. * indicate within an accession at Pvalue < 0.05 Solanum anguivi and experiment were observed. Their hybrids with melongena x S. anguivi ( Mel x Ang conditions. Interestingly, the reduction in LA melongena x S. dasyphyllum (figure 12). Regarding the LA (leaf area) and plant height data, Solanum melongena dasyphyllum (Das) and Solanum melongena x Solanum lichtensteinii were more sensitive to drought condition (Figure 10). estimation measurement for leaf size area and plant height assayed under control and water deficit conditions. * indicate significant differences between treatment values value < 0.05 and S. insanum were poorly affected by drought treatment, in our Their hybrids with S. melongena perform well being the Mel x Ang ) hybrid the genotype less affected by the drought the reduction in LA (Leaf Area) and plant height in the hybrid (Mel x Das) hybrid was less intense than in any of its parents 22 Solanum melongena (Mel), S. Solanum melongena x Solanum lichtensteinii leaf size area and plant height for every accession significant differences between treatment values drought treatment, in our perform well being the S. hybrid the genotype less affected by the drought and plant height in the hybrid S. was less intense than in any of its parents 23 Figure 11. Comparation of eggplant growth between control, drought and PEG 7% in the genotypes Solanum melongena x Solanum insanum hybrid (Mel x Ins) hybrid. Leaf size, plant height and number of leaves were decrease in both water-deficit treatment and PEG 7%. Leaves scarcities were also occured in both treatments. Figure 12. Comparation between control and water-deficit treatment on Solanum melongena x Solanum dasyphyllum (Mel x Das) hybrid. Leaves size and plant height decreasing occured in water-deficit 4.1.2. Biomass Analysis Drought stress can reduce production of plant biomass. Nonetheless, the reduction of biomass applied differently in plants organs (Krisnamurthy et al., 2011). To put it another way, water stress is effective to decreasing leaf biomass, but not shoot or roots biomass. Moreover, roots tend to be less reduced than other organs and usually drought-tolerance plants have higher root biomass than susceptible ones (Spollen et al., 1993; Erice et al., 2010). A well-developed roots system will allow plants to exploit deep soil water in drought- 24 prone environment. Therefore, the accumulation of dry matter will re-allocating to the roots rather than in other plant organs ( Xu et al., 2010; Esmailpour et al., 2015). In this experiment, ANOVA analysis for fresh weight roots, dry weight roots, fresh shoot biomass and dry shoot biomass (table 5) concluded that there were significant differences among genotypes. The general effect of drought treatment was not really significant on reduces roots weight. Despite lack interraction of genotype x treatment, each of genotype has different response to drought condition (figure 13) Table 5. Multifactor ANOVA results table showing the effects of the Solanum accessions and treatments (water deficit and control) and their genotype over fresh weight roots, dry weight roots, fresh shoot biomass and . Mean squares df 1 Fresh weight roots Dry weight roots Fresh Shoot biomass Dry Shoot biomass Main effects Treatment (T) 1 45,54 ** 0,01 ns 277,56 *** 3,27 ** Accession (A) 8 28, 11 * * * 0,36 * 86,98 *** 0,89 * Interactions TxA 8 8,71 ns 0,01 ns 9,91 ns 0,19 ns Error 54 16,85 0,10 14,74 0,40 1 Degrees of freedom; ns non-significant, *,**,*** significant at P-value < 0.05, 0.01, and 0.001 respectively Furthermore, the roots weight increased in genotypes with good response in drought condition, Solanum anguivi (Ang), S. insanum (Ins) and S. melongena x S. insanum (Mel x Ins) hybrid (figure 13). Interestingly, S. melongena x S. dasyphyllum (Mel x Das) hybrid which performed better than any of the parents also showed an increase in dry root weight under stress. The individual analysis of shoot biomass showed that the drought do not really influence the reduction of accumulation dry matter in eggplants leaves. A good response in drought was performed well by S. melongena x S. anguivi hybrid (figure 14 and figure 15). Probably, it happened because Solanum melongena x Solanum anguivi hybrid could maintain their photosynthesis to accumulate dry matter eventhough in drought stress. Meanwhile, S. melongena x S. dasyphyllum hybrid, S. insanum, and S. melongena x S. insanum hybrid were also showed tolerance to drought stress (figure 13). The less reduction of accumulation dry matter occured on those genotypes. 25 Figure 13. Bar diagram showing estimation of fresh weight roots, dry weight roots, fresh shoot biomass, and dry shoot biomass for every accession of Solanum spp. assayed under control and water deficit treatment. * indicate significant differences between treatment values within an accession at P-value < 0.05 Figure 14. Comparation between control and water-deficit of Solanum melongena x Solanum anguivi (taken from front of the pots). Deficit-watered plant experienced reduction at plant height and leaves size. However, they still growth well. 26 Figure 15. Comparation between control and water-deficit of Solanum melongena x Solanum anguivi (taken from above). It seems that the leaves of Solanum melongena x Solanum anguivi hybrid were could grow better in drought. 4.2.Physiological state analysis Drought stress can impair plant growth rate by influence their physiological and biochemical process, such as photosynthesis, transpiration, ion uptake, etc. (Farooq et al., 2009b). Plants under drought stress tend to reduce their photosynthesis. In severe drought, plants can close their stomata, decrease their internal CO2 concentration (Ci), reduce transpiration rate, and inhibit photosynthesis rate (Dulai, 2006; Rahbarian et al., 2011). However, despite the closure of stomata, the drought-tolerant plants usually are able to maintain their photosynthesis under drought stress. The multifactorial analysis of variance showed that there were significant differences in the average values among treatments (table 10) for the photosynthetic rate (A), transpiration rate (E), stomatal conductance of H2O (gs) and the intercellular CO2 concentration (Ci). There were also significant differences in the averages among accessions, and there were no treatment x accession interaction. 27 Table 6. Multifactor ANOVA results table showing the effects of the Solanum accessions and treatments (water deficit and control) and their genotype over the photosynthetic rate (A), transpiration rate (E), stomatal conductance of H2O (gs) and the intercellular CO2 concentration (Ci) values. Mean squares df1 A (µmol CO 2 m-2 s-1) E (mmol H 2 O m-2 s-1) gs (mol H 2 O m-2 s-1) Ci (µmol CO 2 mol-1) Main effects Treatment (T) 1 17.68 ** 2.99 *** 0.013 *** 5273 * Accession (A) 8 13.92 *** 0.83 *** 0.01 *** 18321 *** Interactions TxA 8 3.90 ns 0.22 ns 0.001 ns 1940 ns Error 55 1.92 0.16 0.0006 1281 1 Degrees of freedom; ns non-significant, *,**,*** significant at P-value < 0.05, 0.01, and 0.001 respectively In general, the IRGA showed low values for photosynthetic variables (A, E, gs and Ci) this means that all plants, regardless the treatment, were a little bit stressed (table 7) This could be due to the fact that the measures were done out of the growth chamber in a windy morning of March, therefore plants were under wind (which causes the closure of the stomata) and in a cold morning (which does not stimulate the metabolism). Nevertheless, ANOVA analysis showed there were significant differences among treatments indicating that there existed a drought stress. Table 7. General averages by treatment of the 17 Solanum accessions assayed. Each value is the mean of at least 37 plants ± SE. A (µmol CO2 m-2 s-1) E (mmol H2O m-2 s-1) gs (mol H2O m-2 s-1) Ci (µmol CO2 mol-1) Control 4.4 ± 0.3 1.29 ± 0.1 0.07 ± 0.01 263± 11 Water deficiency 3.7 ± 0.3 0.84 ± 0.06 0.05 ± 0.005 250± 8 Photosynthetic rate (A), transpiration rate (E), stomatal conductance of H2O (gs) and the intercellular CO2 concentration (Ci) values Despite the lack of interaction T x A, the individual analysis of the photosynthesis measurements showed that the stress effect of the water deficit condition was not equal in every accession (Figure 16). Solanum melongena (Mel) and Solanum dasyphyllum (Das 1) 34 efficiency, photosynthesis rate, stomatal conductance and transpiration rate in the Solanum spp. Drought stress often reduce plant growth development, decrease chlorophyll content, decline photosynthetic rate, close stomata and reduce dry weight of plant. According to these experiments, drought treatment induced an average reduction of 17% in plant height, 30% in leaf area, and 32% in dry shoot biomass. Nevertheless, drought-tolerance plant has ability to minimize drought impact by maintain their photosynthesis rate and evapotranspiration rate to produce great yield. Likewise, S. anguivi, S. insanum, and their hybrid with S. melongena (Solanum melongena x Solanum insanum hybrid, Solanum melongena x Solanum anguivi hybrid) emerge as genotypes that tolerant to drought condition. In addition, Solanum melongena x Solanum dasyphyllum hybrid also seems has ability for survive in drought stress. Those genotypes can minimize drought impact to themselves since they only experience slight reduction on their plant height and their size area. Their roots dry weight in water-deficit treatment have an average weight increment of 32% than control one which means their roots grew longer to find the moisture soil. They also could maintain their photosynthetic rate and minimize their transpiration. Furthermore, they have higher water-use efficiency comparing with other genotypes. By contrast, Solanum melongena, Solanum dasyphyllum, Solanum linnaenum and Solanum melongena x solanum lichtensteinii exhibited sensitivity in drought condition. Their growth plant rate, dry weight roots, plant height and size area seems experience significant decrease. They also seems couldn’t manage their water-use efficiency. Based on the result, it can be assumed that the hybrid eggplants possess drought-tolerance traits. It probably due to the introgression of drought-tolerance traits from the wild relatives to eggplant was successful. However, it seems that the ability of drought-tolerance also formed when eggplant and wild genotypes were united. The eggplant hybrids tend have more tolerant to drought condition, such as Solanum melongena x Solanum insanum hybrid, Solanum melongena x Solanum anguivi hybrid and S. melongena x S. dasyphyllum hybrid. Nevertheless, it depends on the wild relatives, whether it has tolerant to drought stress or not. Likewise, the previous research (Zamkova, 2015) about roots of eggplants, wild relatives and their hybrid in vitro compelling evidence as pot experiment. It was explained that Solanum melongena x Solanum insanum hybrid and Solanum melongena x Solanum anguivi hybrid have longer deep growing roots with many lateral roots. In the other words, those genotypes have more tolerant to dry environment. 35 Having said that, Solanum melongena x Solanum lichtensteinii hybrid seems less tolerant than other genotypes. Low and uneven germination of wild relatives and hybrids were the main problems of this research. Most of eggplants, wild relatives and their hybrid seeds did not germinated in petridish which only filled by water, except Solanum melongena, Solanum melongena x Solanum dasyphyllum, Solanum melongena x Solanum insanum, Solanum insanum (data not shown). Most of them germinated and grown better in pot which filled by soil. Nonetheless, Solanum tomentosum (Tom), Solanum incanum (Inc), Solanum lichtensteinii (Lic), Solanum tomentosum x Solanum melongena (Tom x Mel) did not germinate both in petridish nor in pot. Likewise, previous in vitro experiments (Zamkova, 2015) conviced the similar evidence as pot experiment. It was explained that wild eggplants and their hybrids showed difficulties in germination. Therefore, several protocol (soaking, adding KNO3, place plate in the light, and bleaching) were made to solve this germination problems in the previous research. The limited number of growing Solanum spp. become first obstacle to gain information from PEG 7% treatment. PEG 7% treatment has function as water-deficit treatment which leads to drought in plants. Since it is similar to water-deficit treatment, so PEG 7% treatment only used for comparison with water-deficit treatment. Maintaining eggplants, wild relatives and hybrids growth and development assayed under control, water deficit treatment and PEG 7% treatment were an important thing to have significant result. Since each genotypes has different ability to absorb water, so differ amount of water has applied according to their treatments (see material and method). It has function for keep and maintain soil moisture in eggplants. An amount of fertilizer has also provided to when they seems emergence. In spite of having lack of information, the tentative result showed that there were a few of candidate wild relatives and their hybrid which more tolerant to drought stress as mentioned before. However, an advanced research are needed in the future for obtain new information. 5. CONCLUSION 36 The simple analysis on eggplants, wild relatives and their hybrids (Solanum spp.) assumed that there were variation level of drought-tolerance. The analysis were focused on plant growth rate (plant height and leaf area index), biomass, green-color level, photosynthesis rate, transpiration rate, stomatal conductance, intercellular CO2 concentration and water-used efficiency. The comparison between control and water-deficit treatment exhibited that drought induced an average reduction of 17% in plant height, 30% in leaf area, and 32% in dry shoot biomass. Accordingly, it concluded that S. anguivi, S. insanum, S. melongena x S. anguivi hybrid, Solanum melongena x Solanum insanum hybrid, and Solanum melongena x Solanum dasyphyllum hybrid were more tolerant to drought condition. 6. BIBLIOGRAPHY 37 Ali, Z., Xu, Z., Zhang, D., He, X., Bahadur, S., and Yi, J.X., 2011. Molecular diversity analysis of eggplant (Solanum melongena) genetic resources. Genet. Mol. Res. 10, 1141– 1155. 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