Backcross Research Articles

Determining minimum numbers of di-allelic diagnostic markers required to identify introgressions in diploid cross-species hybrid individuals from different types of inter- and backcross populations.

Cross-species hybridizations have been extensively used to generate animals and plants better suited for draft and food and fiber production since Roman times, and are still important in current agricultural practices with growing uses especially in aquaculture. Diagnostic tools based on marker panels with sufficient numbers of markers for accurate identification of cross-species hybrid individuals from intercrossed and backcrossed populations are increasingly necessary for practical, accurate species-purity certification and management of commercial broodstocks. Minimal numbers of di-allelic markers with species-specific alleles required to accurately identify hybrid individuals in intercrossed and advanced backcrossed populations were estimated using power analysis, and ranged from 5 to 191 (α = .05), and from 7 to 293 (α = .01), considering backcross 1 (BC1) to BC6 populations, respectively. Numbers of markers required for accurate hybrid identification observed in simulated BC1 to BC6 populations ranged from 5 to 1,131 and 7 to 8,065, considering error rates ≤ 5% and ≤ 1%, respectively. Estimated and observed numbers of diagnostic markers required for accurate hybrid identification up to four generations of backcrossing fall within practical operational limits of most commercial platforms currently available for genotyping low-density SNP marker panels. Therefore, cost-effective assay panels could be developed to provide practical tools for accurate species-purity certification.

English

To broaden the genetic base of the allotetraploid peanut (Arachis hypogaea L.), pre-breeding programs have produced interspecific synthetic allotetraploids resulting from the chromosome duplication of hybrids between peanut related diploid species. These allotetraploids were highly cross-fertile with peanut making it possible to access the extensive genetic variability harbored by the wild species. This study aims to evaluate the impact of polyploidization and hybridization in resveratrol content in Arachis hybrids. Resveratrol is a potent antioxidant that has been shown to be useful in the treatment of many human diseases. For that, resveratrol was characterized in five synthetic allotetraploids of wild Arachis, six diploid wild species, three cultivars of A. hypogaea and three backcross (BC) hybrids between synthetic allotetraploids and A. hypogaea. Leaves from these genotypes were ultraviolet (UV) light irradiated for 2 h 30 min and their resveratrol contents were determined by high performance liquid chromatograph (HPLC). Resveratrol was found in all genotypes, but at variable concentrations. Synthetic allotetraploids and peanut did not differ and diploid species had the lowest resveratrol content. The highest concentrations were observed in hybrids between allotetraploids and cultivars of A. hypogaea that were probably the most heterozygous among the genotypes analyzed since their chromosome sets came from different species. This study data suggest a positive effect of polyploidy and hybridization in resveratrol content. Key words: Peanut, wild relatives, polyploidy, pre-breeding.

A review on gene pyramiding of agronomic, biotic and abiotic traits in rice variety development

Rice Oryza sativa L is a staple food crop, and its seeds are the most important component part of the agronomic trait of the cereal crop, rich in nutrient and of economic value to human and even livestock. But, it is often threatened by various abiotic and biotic conditions that reduce the yield, because of high incidences of infectious disease agents and non-pathogenic conditions respectively. Pyramiding of the requisite resistance and tolerance genes into single elite high yielding variety of rice, confers wider spectrum of stress management, resulting to development of single multiline variety of rice. Marker-assisted selection utilizes DNA marker-linked primers for blast resistant gene (RM8225; Piz , RM6836; Piz , Pi2 , Pi9 ), bacteria leaf blight (RM224; Xa-4 , RM122; xa-5 , RG136; xa-13 , RM21; Xa-21 ) and drought tolerance (RM236; qDTY 2.2 , RM520; qDTY 3.1 , RM511; qDTY 12.1 ) in pedigree, backcross and recurrent selection breeding methods. The objectives are to create awareness on the environmental safety of host-resistance, significance of single multiline resistance variety, effect of the interaction of stress conditions and associated simple sequence repeat (SSR) linked markers.

Development and Molecular Characterization of Low Phytate Basmati Rice Through Induced Mutagenesis, Hybridization, Backcross, and Marker Assisted Breeding.

Breeding low phytate crops is the most viable solution to tackle mineral deficiencies. The objective of the present study was to develop high yielding, low phytate (lpa) basmati rice cultivars. Three homozygous lpa mutants, Lpa5, Lpa9, and Lpa59, were developed through induced mutations (gamma rays 60Co) and identified by colorimetric and High Performance Liquid Chromatography (HPLC) analysis. These mutants showed 54%–63% reduction in phytic acid but had poor germination and yield. To improve these traits, hybridization and back cross breeding involving Lpa5, Lpa59, and parent cultivar Super Basmati were performed and F2:3, F3:4, BC1F2:3, and BC1F3:4 generations were developed and screened to target the objective. Within the F2:3, homozygous (226), heterozygous (65), and wild type (46) lpa recombinants were identified. Within the homozygous lpa category, four recombinants (Lpa5, Lpa6, Lpa7, and Lpa30) showed improved germination. Within the F3:4 generation, 86 homozygous lpa recombinants were identified. Further selection, on the basis of better plant type and the low phytate trait resulted in the selection of 38 recombinants. Grain quality and cooking characteristics of these selected recombinants were comparable as compared to parent cultivar. Within the BC1F2:3 generations, two homozygous Lpa recombinant lines, Lpa141, and Lpa205, were selected out of 220. Screening of the BC1F3:4 generation for the desirable agronomic and low phytate trait also resulted in the selection of two homozygous lines. Finally, seven recombinants i.e. Lpa12-3, Lpa111-1, Lpa141, Lpa56-3, Lpa53-4, Lpa99-2, and Lpa205-4 out of 42 homozygous low phytate lines were selected on the basis of yield improvement (4%–18%) as compared to parent cultivar. Association analysis suggested that further selection based on primary branches per plant, panicle length and productive tillers per plant would further improve the paddy yield. For molecular characterization of the Lpa trait, previously reported Lpa1-CAPS and Lpa1-InDel and functional molecular markers were applied. Results indicated the absence of the Z9B-Lpa allele and XS-Lpa mutation in the OsMRP5 gene in tested mutants, possibly suggesting that there may be new mutations or novel alleles in tested mutants that need to be identified and then fine mapped for subsequent utilization. To our knowledge, this is the first report of low phytic acid rice mutant development and their improved germination and yield through backcross breeding in basmati rice.

Amelioration of genetic diversity and its assessment in Brassica napus - carinata introgression lines

One of the breeding goals in Brassica napus has been to facilitate introgression of novel traits from wild or closely related species through inter- and intra-specific crosses. The present study is based on the evaluation of B. napus – carinata introgression lines (ILs) for introgressed morphological and genetic diversity in comparison to the parental B. napus lines. A set of 81 Brassica napus – carinata ILs, developed previously following a back cross strategy, was assessed for introgressed genetic diversity by comparing them with the 15 B. napus recipient parents under two environments (E1: timely sown and E2: late sown) for phenotypic expression of 13 morpho-physiological traits. Trait averages as well as trait variations were generally higher for ILs, indicating introgression of variability in the desired direction. In comparison to the parents, the ILs were observed to be early to flower, early to mature, higher yielding, had more siliquae on the main axis and the siliquae were longer. ANOVA revealed highly significant differences amongst genotypes for 10 traits of which 4 traits, viz., days to 50% flowering, days to 100% flowering, plant height and pod length were highly significant in both the environments. SNP-based chromosome-wise gene diversity, as estimated using software SELECTIONTOOL, indicated high estimates for individual chromosomes in ILs as compared to the parental lines. The phenotypic variability estimated for majority of the traits in ILs is being utilized for developing new high yielding rapeseed varieties.

Increased Amylopectin Content Potential in Corn Grains of Quality Protein Maize (QPM)

Maize can be developed as an alternative staple food in anticipation of dependence on rice consumption which continues to increase along with the increase of population. In order for increase corn consumption it needs to be assembled to improve corn nutrition and taste at an affordable price. The objective of this research was to increase amylopectin content in QPM corn grains without reducing the potential of protein quality and production potential.The method used in this research was Back Cross Breeding. This research was done until the formation of Genotype F2. Stages of the method that has been done were started by hybridization between corn Variety of Srikandi Putih (Recipient’s parents) and corn Local Waxy Corn (Donor Parents). Recipientparents were planted in 3 rows and donor parents in 1 row. Each row consisted of 40 plants. The crosses resulted in the genotype F1. Genotype F1 planted in 2 rows and then selfing 21 plants to yield Genotype F2. The research results showed that amylopectin content of corn grains in F1, F2, Parent of Srikandi Putih Variety and Local Waxy Corn were 92,57%, 91,31%, 81,92% and 97,80%, respectively. At this stage of the study, it is concluded that there was a change of amylopectin content of grains in Genotype F1 and Genotype F2 due to crosses compared to their parents.

Germination of hybrid potato seeds under the influence of radiation

The article is devoted to determining the response of hybrid seeds in the process of germination to γ-irradiation. The main difference between its results was the study of the interaction of two methods: ionized irradiation and interspecific hybridization on the viability and germination of botanical seeds.
 The source material used was seed from backcrossing complex interspecific hybrids. Maternal forms varied significantly in origin, and pollinators used varieties: Letana, Podolia, Tiras and Mezhirichka. The studies were performed according to the techniques adopted for use in potato studies. Seed germination was carried out under laboratory controlled conditions. Determined its viability (by number sprouted in the first four days) and laboratory similarity (on the ninth day after wetting). The seeds were treated with gamma rays, the source of which was 60Сo at the installation of "Theratron Elit-80". Dosing options for seed treatment: 100, 150 and 200 Gy. The control used untreated seeds.
 One of the objectives of the experiment was to determine the overall effect on seed germination by γ-irradiation, regardless of the specificity of the heredity of the material under study. It was found that the germination energy with the greatest stimulating effect was the use of a dose of 200 Gy, which allowed to get 11.2 % more seed covered. Close control data were obtained with a 150 Gy dose. On the contrary, the viability of hybrid seeds decreased significantly by using a dose of 100 Gy – by 26.5 %. To a large extent, it concerned the proportion of all sprouted seeds.
 The specificity of the reaction of offspring of combinations on γ-irradiation is proved. In terms of seed viability, it was the best in the combination of 10.6G38 x Tiras – 74.9 %. To a small extent, it was inferior in this respect to populations of 10.6G38 x Letana and 08.195/73 x Podolia. The opposite was true for the intersections of 08.195/73 x Podolia and 08.195/73 x Letana, considered because of the unsuccessful combination of hereditary back crosses 08.195 / 73 and Podolia and Letana varieties.
 A specific relationship between heredity is revealed. hybrid seeds and the influence of radiation on its viability, field germination. With respect to the first indicator, a population of 08.195 / 73 x Letan was distinguished, in each of which there was an excess of control with a maximum difference of 74 % for irradiation doses of 150 Gy. With the exception of the 100 Gy variant, this statement referred to the offspring of 10.6G38 x Letane. Specificity of reciprocal influence of heredity of the offspring of the population 08.195/73 x Podolia in the absence of a stimulating effect on the viability of seeds of radiation exposure.
 Positive influence on the laboratory germination of seeds using radiation irradiation with a dose of 150 and 200 Gy in combination with 10.6G38 x Letana. Only in populations 08.195/73 x Mezhirichka and 08.195 / 73 x Letana stimulating effect on seed viability had a small dose of 200 Gy. The same control results were obtained from the use of said dose in a population of 08.195/73 x Podolia. Only among the offspring with the origin of 10.6G38 x Tiras in all variants, compared with the control, there was a decrease in the viability of hybrid seeds.
 Therefore, a specific reaction of dry irradiated seeds during germination was detected, which depended on both the heredity of the material under study and the doses of irradiation.

Genetic analysis for bacterial blight resistance in indica rice (Oryza sativa L.) cultivars

Prior information on genetics of bacterial blight (BB) resistance (R) genes is imperative for its successful utilization in trait development and breeding for new resistant varietiesin rice. This experiment was aimed to assess the genetics of BB resistance in susceptible but popular rice variety HUR-917 and IRBB 66 (isogenic lines of IR 24) which harbors five R genes. Bioassay results in the parental lines and crosses were revealed resistance and susceptible disease response in R gene(s) positive and negative lines, respectively with varying range of Xoo (Xanthomonas oryzae pv oryzae) pathotype specificity. Phenomics of F2 and Back Cross (BC) generations showed existence of non-allelic interaction (13:3) between R genes with substantial variability in disease severity. The plants carrying mono hetero-allelic R gene has exsertedModerately susceptible (MS) disease reaction with 6.42 to 8.86 disease severities, however, lines carrying 2 R gene(s) could be able to disease severity Moderate susceptible MS to Moderate Resistant MR against all pathotypes existing in the region make it valid that the doses complementarity and presence of interaction in R genes are major determinant in R expression. It was recorded that presence of two or more R genes (Xa21+xa13; Xa21+ xa13+xa5) exerted broad spectrum BB resistance, hence found more suitable to combat this disease in HUR-917.

Penampilan Fenotipik Populasi Dasar Jagung Pulut Lokal Sulawesi Selatan dengan Seleksi Back Cross

This research aims to see the phenotypic appearance of selected families from the basic population of  local waxy corn of South Sulawesi which is back cross with the parents. The technique of crosses used is repeated selection that is to make a cross between selected families (recombination) by means of free crossing. The number of cross-test of 5 selected families and 5 varieties of comparison (parents) with 2 replications. Each replica was planted with 10 lines of  20 lines of with 20 cm x 50 cm spacing), the total number of plants in this research were 400 plants. Each line represented 5 sample plants, so the total sample of 200 plants. The results showed that from 5 selected families who crossed with their parents as a whole can improve the phenotype character. The selected local waxy corn has a superior appearance of the phenotype character. Of the 200 plant samples, there are 75 plants that have superior appearance (better phenotype appearance than their parents) on the character : plant height , the height of cob location, male flowering, female flowering, and  husk cover.

Selection and Inheritance of Tomato Resistance against Ralstonia solanacearum

Ralstonia solanacearum is a plant pathogen causes wilting which is a major obstacle in the cultivation of tomato plants. In plant breeding, knowledge of the source of resistance genes and inheritance patterns is important in the development of bacterial wilt resistant varieties. This study aimed to obtain bacterial wilt resistant lines and to find out the inheritance pattern of tomato resistance to bacterial wilt. Selection of resistant plant involved the selected breeding lines from irradiation and crossing collections of the Genetic Laboratory, Faculty of Agriculture, Universitas Gadjah Mada. Introduced lines of H-7996 and F1 Permata and Timoti were used as a control. H-7996 as resistant parents and GM2 as susceptible parents, and their offspring include F1 GM2 x H-7996, F1 reciprocal, F2, Back Cross 1 (F1 x GM2), and Back Cross 2 (F1 x H-7996) used in testing inheritance patterns. Inoculation was carried out 1 week after planting by pouring 100 ml of water suspension of R. solanacarum (108 cfu/ml) on the roots. Completely Randomized Design (CRD) was used in this experiment. The scoring observation was carried out every week for one month. This study showed that Permata as a control was the most resistant, while Timoti and H-7996 were medium resistant. The CLN, G6, G8, and G7 lines were susceptible medium, yet only G8 and G7 with the smallest percentage of disease intensity and not significantly different than Timoti. The resistance gene to bacterial wilt on H-7996 was controlled by genes in the cell nucleus with additive-dominant gene action. Resistance to bacteria has a moderate level of heritability.

Marker Assisted Foreground Selection of Back Cross Genotypes for Leaf Rust Resistance in Wheat (Triticum aestivum L.)

Marker Assisted Foreground Selection of Back Cross Genotypes for Leaf Rust Resistance in Wheat (Triticum aestivum L.)

The engraftment dynamics evaluation of skin grafts via aluminium phthalocyanine nanoparticles using spectroscopic methods

The research and comparison of spectroscopic methods for assessment of skin grafts engraftment/rejection after the back cross skin transplantation of laboratory mice were carried out. The spectral analysis was performed via inflammatory reaction evaluation of the studied area. The inflammatory reaction intensity correlates with the fluorescence intensity of the aluminum phthalocyanine nanoparticles. The photodynamic therapy was carried out to improve the skin engraftment and reduce the inflammatory reaction.

Screening of Applicable SSR Molecular Markers Linked to Creeping Trait in Crape Myrtle

Creeping plants have unique ornamental value because they have more branches and flowers and the creeping trait is rare in crape myrtle (Lagerstroemia indica L.). In this study, the first filial generation (F1) population was derived from Lagerstroemia fauriei Koehne (standard) and L. indica “Creole” (creeping) and the backcross1 (BC1) population was derived from the backcross of F1 individual S82 (creeping) and L. fauriei. The segregation of the creeping trait was analyzed for 174 seedlings of the BC1 population to examine the linkage relationship between simple sequence repeat (SSR) molecular markers and the creeping trait. Creeping genes were screened using bulked segregant analysis combined with 322 SSR primers, which were detected with good polymorphism. The results show that two SSR markers (S364 and LYS12) were detected, with genetic distances of 23.49 centimorgan (cM) and 25.86 cM from the loci controlling the plant opening angle trait and the branching angle trait, respectively. The accuracy rate for phenotypic verification using S364 and LYS12 was 76.51% and 74.14%, respectively. Our results provide basic information for the molecular marker-assisted selective breeding and cloning of the creeping gene to improve architecture diversity in the breeding of crape myrtle.

Environmental impacts of transgenic Bt rice and non-Bt rice cultivars in northern Iran

Abstract In the future, rice production is likely to be impacted by climate change and associated risks including pest complexes and consumption of chemical inputs, thereby decreasing production at a regional scale and one of the major global concerns. In fact, among the biotic stresses, damage caused by insect pests, which can be categorized as either minor or major pests, can severely constrain the potential yield of rice. Hence, planting transgenic rice is considered a solution for reducing environmental and human health impacts. Therefore, in this research, life cycle assessment for environmental and human health impacts of transgenic and non-transgenic rice cultivars was considered. Hence, four transgenic lines (driven from back cross of Khazar cultivar with transgenic line of Tarom Molaii) along with conventional cultivars (non-transgenic parents) were cultivated under the standard of biosafety protocol in three isolated sites in north of Iran in 2016. In order to conducted life cycle assessment, first, the results of each site were analyzed separately, and since there were not differences among the impact categories and indices in different sites, the average for the results of the three sites are being presented. Results show that decreased insecticides application in transgenic cultivars lowers the need for labor, machineries, and fuel, thereby contributing to reduction in use of energy and greenhouse gases emission from construction, transportation and application of inputs during cultivation. Furthermore, most investigated impact categories were obtained high for Tarom Molaii and Khazar and less for three transgenic lines. In addition, the most important categories were non-renewable energy, global warming, aquatic eutrophication, aquatic acidification, terrestrial acid/nutri, land occupation, terrestrial ecotoxicity, ozone layer depletion, ionizing radiation, respiratory inorganics, respiratory organics, cumulative energy demand, ecological footprint, greenhouse gas protocol, water footprint, carcinogens and non-carcinogens. Therefore, according to the findings of this research, it was observed that the emission amount of environmental pollutants has a positive correlation with the consumption of inputs and field management practices.

Developing green super rice varieties with high nutrient use efficiency by phenotypic selection under varied nutrient conditions

The development of green super rice varieties with improved nutrient use efficiency (NuUE) is a vital target area to increase yield and make it more stable under rainfed conditions. In the present study, we followed an early backcross (BC) breeding approach by using a high-yielding and widely adapted Xian variety, Weed Tolerant Rice 1 (WTR-1), as a recipient and a Geng variety, Hao-An-Nong (HAN), as a donor. Starting from the BC1F2 generation, the BC population went through one generation of selection under irrigated, low-input, and rainfed conditions, followed by four consecutive generations of screening and selection for high grain yield (GY) under six different nutrient conditions (NPK, 75N, -N, -P, -NP, and -NPK), leading to the development of 230 BC1F6 introgression lines (ILs). These 230 ILs were evaluated under the same six nutrient conditions for 13 agro-morphological and grain yield component traits in comparison to four checks and parents. Significant trait variations were observed between the treatments and ILs. Positive correlations were identified for GY with biomass, panicle length, flag-leaf area, flag-leaf width, filled grain number per panicle, 1000-grain weight, and tiller number under -N, -P, -NP, and -NPK conditions. Out of 230 ILs, 12 were identified as promising under two or more nutrient deficiency conditions. The results demonstrated an efficient inter-subspecific BC breeding procedure with a first round of selection under rainfed-drought conditions, followed by four generations of progeny testing for yield performance under six nutrient conditions. The promising ILs can be useful resources for molecular genetic dissection and understanding the physiological mechanisms of NuUE.

Testes Proteases Expression and Hybrid Male Sterility Between Subspecies of Drosophila pseudoobscura.

Hybrid male sterility (HMS) is a form of postmating postzygotic isolation among closely related species that can act as an effective barrier to gene flow. The Dobzhansky-Muller model provides a framework to explain how gene interactions can cause HMS between species. Genomics highlights the preponderance of non-coding DNA targets that could be involved in gene interactions resulting in gene expression changes and the establishment of isolating barriers. However, we have limited knowledge of changes in gene expression associated with HMS, gene interacting partners linked to HMS, and whether substitutions in DNA regulatory regions (cis) causes misexpression (i.e., expression of genes beyond levels found in parental species) of HMS genes in sterile hybrids. A previous transcriptome survey in a pair of D. pseudoobscura species found male reproductive tract (MRT) proteases as the largest class of genes misregulated in sterile hybrids. Here we assay gene expression in backcross (BC) and introgression (IG) progeny, along with site of expression within the MRT, to identify misexpression of proteases that might directly contribute to HMS. We find limited evidence of an accumulation of cis-regulatory changes upstream of such candidate HMS genes. The expression of four genes was differentially modulated by alleles of the previously characterized HMS gene Ovd.

Overcoming Cabbage Crossing Incompatibility by the Development and Application of Self-Compatibility-QTL- Specific Markers and Genome-Wide Background Analysis.

Cabbage hybrids, which clearly present heterosis vigor, are widely used in agricultural production. We compared two S5 haplotype (Class II) cabbage inbred-lines 87–534 and 94–182: the former is highly SC while the latter is highly SI; sequence analysis of SI-related genes including SCR, SRK, ARC1, THL1, and MLPK indicates the some SNPs in ARC1 and SRK of 87–534; semi-quantitative analysis indicated that the SI-related genes were transcribed normally from DNA to mRNA. To unravel the genetic basis of SC, we performed whole-genome mapping of the quantitative trait loci (QTLs) governing self-compatibility using an F2 population derived from 87–534 × 96–100. Eight QTLs were detected, and high contribution rates (CRs) were observed for three QTLs: qSC7.2 (54.8%), qSC9.1 (14.1%) and qSC5.1 (11.2%). 06–88 (CB201 × 96–100) yielded an excellent hybrid. However, F1 seeds cannot be produced at the anthesis stage because the parents share the same S-haplotype (S57, class I). To overcome crossing incompatibility, we performed rapid introgression of the self-compatibility trait from 87–534 to 96–100 using two self-compatibility-QTL-specific markers, BoID0709 and BoID0992, as well as 36 genome-wide markers that were evenly distributed along nine chromosomes for background analysis in recurrent back-crossing (BC). The transfer process showed that the proportion of recurrent parent genome (PRPG) in BC4F1 was greater than 94%, and the ratio of individual SC plants in BC4F1 reached 100%. The newly created line, which was designated SC96–100 and exhibited both agronomic traits that were similar to those of 96–100 and a compatibility index (CI) greater than 5.0, was successfully used in the production of the commercial hybrid 06–88. The study herein provides new insight into the genetic basis of self-compatibility in cabbage and facilitates cabbage breeding using SC lines in the male-sterile (MS) system.

The role of root plasma membrane ATPase and rhizosphere acidification in zinc uptake by two different Zn-deficiency-tolerant wheat cultivars in response to zinc and histidine availability

ABSTRACTWe investigated the effect of histidine (His) and Zn deficiency on H+-ATPase activity and H+ release from wheat roots. Two bread wheat (Triticum aestivum L. cvs. Kavir and Back Cross Roshan) were grown in a nutrient solution for four weeks before being transferred to treatment solutions consisting of two concentrations of His (0 and 50 µM) and two concentrations of Zn (0 and 10 μM). The Zn-only and the Zn+His treatments were observed to release more H+ in the root media than did the control ones, with the highest achieved under the Zn+His treatment which was roughly 2.1 times higher than that under the control conditions. The H+ release from wheat roots increased slightly but significantly in the presence of only His when compared with the control solutions. The hydrolytic and transport activities of H+-ATPase were affected by both Zn deficiency and His supply. In both cultivars, application of Zn and His resulted in a higher hydrolytic activity of H+-ATPase when compared with the control solutions. The highest hydrolytic activity of H+-ATPase in the root plasma membrane vesicles was achieved with the Zn+His treatment. The ‘Back Cross Roshan’ exhibited a higher (PM) H+-ATPase activity and H+ pumping than did ‘Kavir’.

QTL Mapping of Important Agronomic Traits on Chromosomes Showing Marker Segregation Distortion in Interspecific Backcross Cotton Populations

QTL Mapping of Important Agronomic Traits on Chromosomes Showing Marker Segregation Distortion in Interspecific Backcross Cotton Populations

Experimental Analysis of the Reproductive Potential of House Mice (Mus musculus sensu lato, Rodentia, Muridae) in Transcaucasia and Other Regions

The fecundity, fertility, and fitness of house mice from Transcaucasian populations have been investigated in laboratory conditions. We interpret our data in accordance with Milishnikov’s hypothesis (2004) that the ancestral form might have come from Transcaucasia. It is genetically close to Mus musculus s. str. and has kept a relict gene pool. The already differentiated M. musculus and M. domesticus have been introduced into this region as well. All three forms have crossed with one another, resulting in a very complicated hybrid zone formed in Transcaucasia. In our experiment, house mice from Moscow and Moscow oblast and from the hybrid zone of Transcaucasia were characterized by a similar reproduction rate. Reproduction indices weren’t significantly differ in different variants of crossings of mice from Transcaucasia with M. musculus as well as in hybrids from direct and back crosses and in backcrosses. Nevertheless, these rates differed significantly from those in M. musculus and Transcaucasian mice. In some cases, the mortality of the young was relatively high. The data obtained disagree with the presumed reduced fitness of house mice in Transcaucasia. No serious evidence has been obtained for the presence of postcopulative isolating mechanisms contributing to separation of mice from Transcaucasia from M. musculus. The results of these studies are consistent with the assumed kinship of house mouse populations of Transcaucasia and M. musculus.