Wild Gene Pool Research Articles

Wild Sorghum as a Promising Resource for Crop Improvement.

Sorghum bicolor (L.) Moench is a multipurpose food crop which is ranked among the top five cereal crops in the world, and is used as a source of food, fodder, feed, and fuel. The genus Sorghum consists of 24 diverse species. Cultivated sorghum was derived from the wild progenitor S. bicolor subsp. verticilliflorum, which is commonly distributed in Africa. Archeological evidence has identified regions in Sudan, Ethiopia, and West Africa as centers of origin of sorghum, with evidence for more than one domestication event. The taxonomy of the genus is not fully resolved, with alternative classifications that should be resolved by further molecular analysis. Sorghum can withstand severe droughts which makes it suitable to grow in regions where other major crops cannot be grown. Wild relatives of many crops have played significant roles as genetic resources for crop improvement. Although there have been many studies of domesticated sorghum, few studies have reported on its wild relatives. In Sorghum, some species are widely distributed while others are very restricted. Of the 17 native sorghum species found in Australia, none have been cultivated. Isolation of these wild species from domesticated crops makes them a highly valuable system for studying the evolution of adaptive traits such as biotic and abiotic stress tolerance. The diversity of the genus Sorghum has probably arisen as a result of the extensive variability of the habitats over which they are distributed. The wild gene pool of sorghum may, therefore, harbor many useful genes for abiotic and biotic stress tolerance. While there are many examples of successful examples of introgression of novel alleles from the wild relatives of other species from Poaceae, such as rice, wheat, maize, and sugarcane, studies of introgression from wild sorghum are limited. An improved understanding of wild sorghums will better allow us to exploit this previously underutilized gene pool for the production of more resilient crops.

Characterization of Genetic and Allelic Diversity Amongst Cultivated and Wild Lentil Accessions for Germplasm Enhancement.

Intensive breeding of cultivated lentil has resulted in a relatively narrow genetic base, which limits the options to increase crop productivity through selection. Assessment of genetic diversity in the wild gene pool of lentil, as well as characterization of useful and novel alleles/genes that can be introgressed into elite germplasm, presents new opportunities and pathways for germplasm enhancement, followed by successful crop improvement. In the current study, a lentil collection consisting of 467 wild and cultivated accessions that originated from 10 diverse geographical regions was assessed, to understand genetic relationships among different lentil species/subspecies. A total of 422,101 high-confidence SNP markers were identified against the reference lentil genome (cv. CDC Redberry). Phylogenetic analysis clustered the germplasm collection into four groups, namely, Lens culinaris/Lens orientalis, Lens lamottei/Lens odemensis, Lens ervoides, and Lens nigricans. A weak correlation was observed between geographical origin and genetic relationship, except for some accessions of L. culinaris and L. ervoides. Genetic distance matrices revealed a comparable level of variation within the gene pools of L. culinaris (Nei’s coefficient 0.01468–0.71163), L. ervoides (Nei’s coefficient 0.01807–0.71877), and L. nigricans (Nei’s coefficient 0.02188–1.2219). In order to understand any genic differences at species/subspecies level, allele frequencies were calculated from a subset of 263 lentil accessions. Among all cultivated and wild lentil species, L. nigricans exhibited the greatest allelic differentiation across the genome compared to all other species/subspecies. Major differences were observed on six genomic regions with the largest being on Chromosome 1 (c. 1 Mbp). These results indicate that L. nigricans is the most distantly related to L. culinaris and additional structural variations are likely to be identified from genome sequencing studies. This would provide further insights into evolutionary relationships between cultivated and wild lentil germplasm, for germplasm improvement and introgression.

Temporal and structural genetic variation in reindeer (Rangifer tarandus) associated with the pastoral transition in Northwestern Siberia.

Just as the domestication of livestock is often cited as a key element in the Neolithic transition to settled, the emergence of large‐scaled reindeer husbandry was a fundamental social transformation for the indigenous peoples of Arctic Eurasia. To better understand the history of reindeer domestication, and the genetic processes associated with the pastoral transition in the Eurasian Arctic, we analyzed archaeological and contemporary reindeer samples from Northwestern Siberia. The material represents Rangifer genealogies spanning from 15,000 years ago to the 18th century, as well as modern samples from the wild Taĭmyr population and from domestic herds managed by Nenetses. The wild and the domestic population are the largest populations of their kind in Northern Eurasia, and some Nenetses hold their domestic reindeer beside their wild cousins. Our analyses of 197 modern and 223 ancient mitochondrial DNA sequences revealed two genetic clusters, which are interpreted as representing the gene pools of contemporary domestic and past wild reindeer. Among a total of 137 different mitochondrial haplotypes identified in both the modern and archaeological samples, only 21 were detected in the modern domestic gene pool, while 11 of these were absent from the wild gene pool. The significant temporal genetic shift that we associate with the pastoral transition suggests that the emergence and spread of reindeer pastoralism in Northwestern Siberia originated with the translocation and subsequent selective breeding of a special type of animal from outside the region. The distinct and persistent domestic characteristics of the haplotype structure since the 18th century suggests little genetic exchange since then. The absence of the typical domestic clade in modern nearby wild populations suggests that the contemporary Nenets domestic breed feature an ancestry from outside its present main distribution, possibly from further South.

Investigations on diverse sesame (S. indicumL.) germplasm and its wild allies reveal wide variation in antioxidant potential.

Free radicals, the key mediators of a range of oxidative reactions involved in lipid oxidation are responsible for food quality deterioration leading to several health hazards. Antioxidants synthesized naturally or synthetically are capable of preventing oxidation of lipids and other related compounds. However, natural antioxidants have many benefits over synthetic ones. Sesame seeds contain large amount of natural bioactive components with high antioxidant potential. In the present study, 14 accessions of sesame containing wild species and cultivars were investigated. The antioxidant potential of sesame seed meal extract was evaluated by total phenolic content (TPC) method using Folin-Ciocalteu reagent, linoleic acid peroxidation by Ferric thiocyanate method, and free radical scavenging assay with 2,2-diphenyl-1-picryl hydrazyl radical. S. laciniatum showed highest mean values for total polyphenol content with maximum % inhibition of linoleic acid peroxidationon 10th day of course of the reaction span and highest antioxidant scavenging power. S. indicum subsp. malabaricum and S. radiatum also showed high total phenol content and radical scavenging capacity. Among the Sesamum indicum cultivars, Gujarat til 2 showed high TPC and high radical scavenging activity. Higher antioxidant property of Sesamum species in comparison to sesame cultivars highlights the need to utilize the wild genepool for the improvement of cultigens for enhanced nutraceutical value.

Development of a micropropagation protocol for Malus orientalis using axillary buds

Caucasian apple trees (Malus orientalis) grow individually or in small groups with a scattered distribution pattern throughout the Hyrcanian forest. The wild gene pool in such trees has a high genetic diversity which is highly important for apple breeders. Micropropagation can be advantageous due to its quick propagation for apple breeders as well as its maintenance of in vitro and in vivo germplasm collection and exchange. Here, for the first time, we investigated the in vitro propagation of M. orientalis from three populations by collecting axillary buds and established a micropropagation protocol. Two strengths of Murashige and Skoog (MS) basal medium (full and half) in combination with different concentrations of 6-benzylaminopurine (BA) were tested for optimal multiplication. The interaction among the BA concentrations, MS strength, and populations was effective in the promotion of shoot development across the three populations. The average number of the produced shoots, shoot length, and number of leaves was significantly affected by this triple interaction. As a result, BA at the concentration of 0.4 mg L−1 worked for all the populations. The results showed that a rooting percentage of 77.8% was obtained on half strength Linsmaier and Skoog (LS) medium in combination with 0.9 mg L−1 3-indole butyric acid (IBA). However, the subculture of shoots on half strength LS medium supplemented with 0.9 mg L−1 IBA increased rooting percentage up to 96% and produced the highest number of roots (7.18 roots per shoot).

Structure and genetic diversity in wild and cultivated populations of Zapote mamey (Pouteria sapota, Sapotaceae) from southeastern Mexico: its putative domestication center

Tropical fruit trees are an important component of the human diet; however, little is known about their genetic diversity levels. Zapote mamey (Pouteria sapota) is a tree native to southeastern Mexico and Central America, and Mexico is the leading producer in the world. Studies of the genetic diversity of Zapote mamey have been based on cultivated materials using morphological and biochemical characterization or dominant molecular markers. To gain a deeper understanding about the conservation status of Zapote mamey in its center of origin and domestication, we collected 188 individuals from eight wild and five cultivated populations in southeastern Mexico and characterized them using eight microsatellite loci. STRUCTURE, 3D-PCoA, and neighbor-joining analyses showed three groups in the wild gene pool and one group in the cultivated gene pool. FST values were significant between wild and cultivated gene pools, among the four groups observed and among the 13 populations collected (0.13, 0.25, and 0.36, respectively). Overall, we found low levels of genetic diversity (A = 2.77, HO = 0.29, HE = 0.39), permutation tests did not show significant differences between wild and cultivated gene pools. The Garza–Williamson index showed low values in both gene pools (wild = 0.16, cultivated = 0.11) and the Bottleneck program indicated a decrease in genetic diversity in both gene pools (wild, P = 0.027; cultivated, P = 0.054); both analyses suggest a potential genetic bottleneck within this species. This study can help to generate adequate sampling techniques and to develop effective management strategies for Zapote mamey of southeastern Mexico.

Sustainable Agronomic Strategies for Enhancing the Yield and Nutritional Quality of Wild Tomato, Solanum Lycopersicum (l) Var Cerasiforme Mill

Urbanization and global climate change have constrained plant development and yield. Utilization of wild gene pool, together with the application of sustainable and eco-friendly agronomic crop improvement strategies, is being focused on to tackle mounting food insecurity issues. In this aspect, the green seaweed, Ulva flexuosa, was assessed for plant biostimulant potential on cherry tomato, in terms of seed priming effects, nutrition and yield. SEM-EDX analysis of U. flexuosa presented the occurrence of cell wall elements (O, Na, Mg, S, Cl, K and Ca). The phytochemical analyses of liquid seaweed extract (EF-LSE) revealed the presence of carbohydrates, protein, phenols, flavonoids, saponins, tannins and coumarins. The EF-LSEs were found to stimulate seed germination in a dose-dependent manner, recording higher seed germination, and biomass and growth parameters. The seedlings of treated seeds altered the biochemical profile of the fruit, in terms of TSS (93%), phenol (92%), lycopene (12%) and ascorbic acid (86.8%). The EF-LSEs positively influenced fruit yield (97%). Henceforth, this investigation brings to light the plant biostimulant potential of the under-utilized seaweed source, U. flexuosa, to be useful as a bio fertilizer in agronomic fields for a cumulative enhancement of crop vigour as well as yields to meet the growing food demands.

Genetic diversity of the U.S. collection of Chinese hemlock Tsuga chinensis (Franch.) E. Pritz. based on simple sequence repeat markers

The Chinese hemlock, Tsuga chinensis (Franch.) E. Pritz., is becoming more well-known in U.S. landscapes as the native U.S. species (T. canadensis (L.) Carr.) is under attack from the hemlock woolly adelgid. It is important to understand the genetic diversity and relatedness among accessions of T. chinensis to drive decisions about collections management, breeding methods, and forest or ecosystem management. We used SSR markers to evaluate the genetic diversity of 96 samples representing 35 accessions of Chinese hemlock held in collections in the U.S. Using 88 alleles from eleven SSR loci, we found high levels of diversity between and within accessions. Our results indicate that significant genetic diversity is available in the existing U.S. collections of T. chinensis, and, based on collection data, represents the wild gene pool well. This characterization of germplasm can be valuable in choosing accessions for use in horticultural and landscape applications or as part of a hemlock breeding program.

Plant genetic resources of Ukrainian Podillia

Aim: collection of local wild and cultural gene pool accessions of the plants adapted to the conditions of Podillia region of Ukraine for a selection from them valuable on economic and biological traits, including of them in the plant-breeding and research programs and maintenance in collections of the National Plant Genebank of Ukraine. Results and Discussion. There is carried out expeditionary inspection of the districts of Vinnytsia and Khmel’nytsky areas of Ukraine. 548 gene pool accessions of cultural plants and wild relative forms adapted to the conditions of this region related to 173 botanical taxa are collected. A 151 herbarium sheets of 37 plant species are collected. Natural reserves and objects of the naturally-protected fund are explored for seed collection of rare and regionally rare species, and also vegetation of burial mounds, ravines, beams, slopes, undisturbed steppe areas. Five promising objects have been identified for monitoring the state of coenopopulations of valuable and rare genotypes of fodder and medicinal plants, their study, conservation and reproduction: The local botanical reserve "Krutoshyly" (Tyvrovsky district of Vinnytsia region between the villages of Dolgopolovka and Klishchiv), a site near v. Sadkovtsy of Mogilev-Podil’sky district of Vinnitsia region, a site near Kamenka of the Gorodotsky district of the Khmel’nytsky region, two sites in the Kamenetz-Podil’sky district of the Khmel’nytsky region: near Kitayhorod and Surzhyntsi. For the Red Book species and plant species that are not included in the Red Book of Ukraine but are rare or threatened with extinction under natural conditions, points for the establishment of in situ conservation reserves have been identified in the Vinnitsa and Khmel’nytsky regions. The collected material will ensure the expansion of the genetic base of existing and the creation of new genetic resources collections of field, medicinal and other crops due to samples characterized by adaptability to stress abiotic and resistance to biotic factors, productivity, product quality. Conclusions. 548 seeds packages and planting material units of gene pool accessions are collected during the expedition and transferred to research institutions for the study. The results of the expedition showed the promise of continuing expeditionary surveys and collecting gene pool samples in Ukraine. To do this, it is necessary to equip the NCGRU with a specialized vehicle and provide for a special article to finance expeditions.

Genetic dissection of quantitative and qualitative traits using a minimum set of barley Recombinant Chromosome Substitution Lines

BackgroundExploring the natural occurring genetic variation of the wild barley genepool has become a major target of barley crop breeding programmes aiming to increase crop productivity and sustainability in global climate change scenarios. However this diversity remains unexploited and effective approaches are required to investigate the benefits that unadapted genomes could bring to crop improved resilience. In the present study, a set of Recombinant Chromosome Substitution Lines (RCSLs) derived from an elite barley cultivar ‘Harrington’ as the recurrent parent, and a wild barley accession from the Fertile Crescent ‘Caesarea 26–24’, as the donor parent (Matus et al. Genome 46:1010–23, 2003) have been utilised in field and controlled conditions to examine the contribution of wild barley genome as a source of novel allelic variation for the cultivated barley genepool.MethodsTwenty-eight RCSLs which were selected to represent the entire genome of the wild barley accession, were genotyped using the 9 K iSelect SNP markers (Comadran et al. Nat Genet 44:1388–92, 2012) and phenotyped for a range of morphological, developmental and agronomic traits in 2 years using a rain-out shelter with four replicates and three water treatments. Data were analysed for marker traits associations using a mixed model approach.ResultsWe identified lines that differ significantly from the elite parent for both qualitative and quantitative traits across growing seasons and water regimes. The detailed genotypic characterisation of the lines for over 1800 polymorphic SNP markers and the design of a mixed model analysis identified chromosomal regions associated with yield related traits where the wild barley allele had a positive response increasing grain weight and size. In addition, variation for qualitative characters, such as the presence of cuticle waxes on the developing spikes, was associated with the wild barley introgressions. Despite the coarse location of the QTLs, interesting candidate genes for the major marker-trait associations were identified using the recently released barley genome assembly.ConclusionThis study has highlighted the role of exotic germplasm to contribute novel allelic variation by using an optimised experimental approach focused on an exotic genetic library. The results obtained constitute a step forward to the development of more tolerant and resilient varieties.

Correction: Genetic structure of wild pea (Pisum sativum subsp. elatius) populations in the northern part of the Fertile Crescent reflects moderate cross-pollination and strong effect of geographic but not environmental distance.

[This corrects the article DOI: 10.1371/journal.pone.0194056.].

Genetic structure of wild pea (Pisum sativum subsp. elatius) populations in the northern part of the Fertile Crescent reflects moderate cross-pollination and strong effect of geographic but not environmental distance.

Knowledge of current genetic diversity and mating systems of crop wild relatives (CWR) in the Fertile Crescent is important in crop genetic improvement, because western agriculture began in the area after the cold-dry period known as Younger Dryas about 12,000 years ago and these species are also wild genepools of the world’s most important food crops. Wild pea (Pisum sativum subsp. elatius) is an important source of genetic diversity for further pea crop improvement harbouring traits useful in climate change context. The genetic structure was assessed on 187 individuals of Pisum sativum subsp. elatius from fourteen populations collected in the northern part of the Fertile Crescent using 18,397 genome wide single nucleotide polymorphism DARTseq markers. AMOVA showed that 63% of the allelic variation was distributed between populations and 19% between individuals within populations. Four populations were found to contain admixed individuals. The observed heterozygosity ranged between 0.99 to 6.26% with estimated self-pollination rate between 47 to 90%. Genetic distances of wild pea populations were correlated with geographic but not environmental (climatic) distances and support a mixed mating system with predominant self-pollination. Niche modelling with future climatic projections showed a local decline in habitats suitable for wild pea, making a strong case for further collection and ex situ conservation.

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Geographical and environmental determinants of the genetic structure of wild barley in southeastern Anatolia.

Despite the global value of barley, compared to its wild progenitor, genetic variation in this crop has been drastically reduced due to the process of domestication, selection and improvement. In the medium term, this will negatively impact both the vulnerability and yield stability of barley against biotic and abiotic stresses under climate change. Returning to the crop wild relatives (CWR) as sources of new and beneficial alleles is a clear option for enhancing the resilience of diversity and adaptation to climate change. Southeastern Anatolia constitutes an important part of the natural distribution of wild barley in the Fertile Crescent where important crops were initially domesticated. In this study, we investigated genetic diversity in a comprehensive collection of 281 geo-referenced wild barley individuals from 92 collection sites with sample sizes ranging from 1 to 9 individuals per site, collected from southeastern Anatolia and 131 domesticated genotypes from 49 different countries using 40 EST-SSR markers. A total of 375 alleles were detected across entire collection, of which 283 were carried by domesticated genotypes and 316 alleles were present in the wild gene pool. The number of unique alleles in the wild and in the domesticated gene pool was 92 and 59, respectively. The population structure at K = 3 suggested two groups of wild barley namely G1-W consisting wild barley genotypes from the western part and G1-E comprising those mostly from the eastern part of the study area, with a sharp separation from the domesticated gene pool. The geographic and climatic factors jointly showed significant effects on the distribution of wild barley. Using a Latent Factor Mixed Model, we identified four candidate loci potentially involved in adaptation of wild barley to three environmental factors: temperature seasonality, mean temperature of driest quarter, and precipitation of coldest quarter. These loci are probably the targets of genomic regions, with potential roles against abiotic stresses.

Harnessing Genetic Diversity of Wild Gene Pools to Enhance Wheat Crop Production and Sustainability: Challenges and Opportunities

Wild species are extremely rich resources of useful genes not available in the cultivated gene pool. For species providing staple food to mankind, such as the cultivated Triticum species, including hexaploid bread wheat (Triticum aestivum, 6x) and tetraploid durum wheat (T. durum, 4x), widening the genetic base is a priority and primary target to cope with the many challenges that the crop has to face. These include recent climate changes, as well as actual and projected demographic growth, contrasting with reduction of arable land and water reserves. All of these environmental and societal modifications pose major constraints to the required production increase in the wheat crop. A sustainable approach to address this task implies resorting to non-conventional breeding strategies, such as “chromosome engineering”. This is based on cytogenetic methodologies, which ultimately allow for the incorporation into wheat chromosomes of targeted, and ideally small, chromosomal segments from the genome of wild relatives, containing the gene(s) of interest. Chromosome engineering has been successfully applied to introduce into wheat genes/QTL for resistance to biotic and abiotic stresses, quality attributes, and even yield-related traits. In recent years, a substantial upsurge in effective alien gene exploitation for wheat improvement has come from modern technologies, including use of molecular markers, molecular cytogenetic techniques, and sequencing, which have greatly expanded our knowledge and ability to finely manipulate wheat and alien genomes. Examples will be provided of various types of stable introgressions, including pyramiding of different alien genes/QTL, into the background of bread and durum wheat genotypes, representing valuable materials for both species to respond to the needed novelty in current and future breeding programs. Challenging contexts, such as that inherent to the 4x nature of durum wheat when compared to 6x bread wheat, or created by presence of alien genes affecting segregation of wheat-alien recombinant chromosomes, will also be illustrated.

Testing Domestication Scenarios of Lima Bean (Phaseolus lunatus L.) in Mesoamerica: Insights from Genome-Wide Genetic Markers.

Plant domestication can be seen as a long-term process that involves a complex interplay among demographic processes and evolutionary forces. Previous studies have suggested two domestication scenarios for Lima bean in Mesoamerica: two separate domestication events, one from gene pool MI in central-western Mexico and another one from gene pool MII in the area Guatemala-Costa Rica, or a single domestication from gene pool MI in central-western Mexico followed by post-domestication gene flow with wild populations. In this study we evaluated the genetic structure of the wild gene pool and tested these two competing domestication scenarios of Lima bean in Mesoamerica by applying an ABC approach to a set of genome-wide SNP markers. The results confirm the existence of three gene pools in wild Lima bean, two Mesoamerican gene pools (MI and MII) and the Andean gene pool (AI), and suggest the existence of another gene pool in central Colombia. The results indicate that although both domestication scenarios may be supported by genetic data, higher statistical support was given to the single domestication scenario in central-western Mexico followed by admixture with wild populations. Domestication would have involved strong founder effects reflected in loss of genetic diversity and increased LD levels in landraces. Genomic regions affected by selection were detected and these may harbor candidate genes related to domestication.

Transposon-based genetic diversity assessment in wild and cultivated barley

Transposable element-based molecular markers can be utilized to investigate genetic diversity and to create genetic linkage maps. In this study, Class I and class II transposons were employed to obtain a comparative account of genetic diversity between wild and cultivated barley genotypes. Three types of PCR-based techniques were used: IMP (Inter MITE Polymorphism), IRAP (Inter-Retrotransposon Amplified Polymorphism) and REMAP (Retrotransposon-Microsatellite Amplified Polymorphism). Specific primer pairs for IMP, IRAP, and REMAP detected a total of 200 bands with an average of 20 bands per marker. The mean polymorphic information content (PIC) and discrimination power (D) values in all 47 genotypes from these three types of transposon-based polymorphisms were 0.910 and 0.935, respectively. Unweighted Pair Group Method with Arithmetic mean (UPGMA)-based cluster analysis classified all 47 genotypes, both wild and cultivated, into separate groups consistent with their geographical origins. Sequencing followed by chromosome location of polymorphic bands enables precise gene introgression from wild gene pool to cultivated barley. The highly polymorphic nature of these marker systems makes them suitable for use in varietal identification and MAS-based breeding programs in barley and other cereals.

Differentiation and genetic diversity of Phaseolus lunatus wild populations from Chiapas, Mexico, and their genetic relationships with MI and MII groups

Background . Understanding the genetic structure of wild relatives of domesticated species is crucial for its conservation and to elucidate the sites of crop domestication. Lima bean is one of the five domesticated Phaseolus species and Mexico is one of its centers of domestication. Recent studies showed the existence of two wild gene pools (MI and MII) of this species in Mexico and suggested that their genetic divergence occurred in southeast Mexico.
 Question . Did MI and MII groups diverged around the Isthmus of Tehuantepec, Mexico?
 Studied species . Lima bean: Neotropical plant species, herbaceous, with an annual/short life cycle and with autogamous tendency.
 Study site and years of study . Seven wild populations were collected in 2012 in the State of Chiapas, México, area underrepresented in previous studies.
 Methods . Genetic diversity and grouping patterns of collected populations and their relationship to MI and MII groups were analyzed at eight microsatellite loci.
 Results. High genetic structure ( F ST: 0.42 to 0.96) and a high level of genetic diversity ( H E = 0.48) were found. The analyses, and presence of admixed populations in MI and MII, suggested that the genetic divergence of these groups is an ongoing process centered around the Isthmus of Tehuantepec.
 Conclusions . Our results support the hypothesis that MI and MII groups diverged around the Isthmus of Tehuantepec; however, sampling should be increased both at population and genomic levels, to determine the precise organization of the genetic diversity of wild P. lunatus from Mexico

Growth and survival of a diallel cross for five strains of climbing perch (Anabas testudineus Bloch, 1792) in Thailand

A complete diallel cross experiment was conducted with five strains of climbing perch (Anabas testudineus) representing three wild populations collected from main river basins in Thailand and two farm populations in southern Thailand. Growth performance was recorded from 794 individually tagged progeny of the 24 different strain combinations after a grow-out period of about 130 d in an earthen pond. Least squares means of body weight at harvest and absolute growth rates were computed for each strain combination. The Chumphon strain showed the highest growth performance (81.1 ± 1.1 g). The Surat Thani × Chumphon (the first strain represents the sire) showed the highest survival (65.4± 25.50%) among the purebreds and the crossbreds. The domesticated gene pool had much better growth in aquaculture than the wild gene pool. The correlation between the least squares means of body weight and the survival rates in the 24 strain combinations was 0.51 (p < 0.05). The mean heterosis of all crossbreds across traits was negative (−10.2± 22.7%). Heterosis appeared to decrease when different gene pools were crossed. This suggests that there may be outbreeding depression. The advantage of crossbred performance was clearly not shown in the study.

Effects of limited introgressions from Triticum timopheevii Tausch. into the genome of bread wheat (Triticum aestivum L.) on physiological and biochemical traits under normal watering and drought

Alien hybridization in cereals is used for the comparative investigation of the genome structure and evolution, as well as for extracting useful genes from the wild gene pool. The tetraploid species Triticum timopheevii has long been used as a source of genes for resistance to fungal diseases. Line 821 was developed on the genetic background of cultivar Saratovskaya 29 (S29), which is drought-resistant but is very susceptible to diseases and carries large introgressions in 2A and 2B chromosomes and a small introgression in the subtelomeric region of the 5A chromosome. The two genotypes were compared for the parameters associated with the direct and indirect reaction of the photosynthetic apparatus to water stress. In the flag leaves of line 821, an increased transpiration rate and stomatal conductance (1.6 times the value in optimal watering and 1.2 times the value under a water deficit) and, correspondingly, reduced efficiency of water usage were found compared to the initial cultivar. Additionally, the actual effectiveness and electron transport rate of photosystem II, the chlorophyll and carotenoid content, and the total antioxidant capacity were reduced by approximately a factor of three under water stress. Under the same conditions, the activity of lipoxygenase doubled. On the whole, tolerance to a water deficit declined in the line in comparison to the parent cultivar and was accompanied by leaf senescence. Thus, it may be supposed that 2A, 2B, and 5A chromosomes of the drought-tolerant cultivar S29 carry important genetic factors responsible for the reaction to water stress in wheat plants.