Genetic Improvement Of Resistance Research Articles

Recent advances in the improvement of genetic resistance against disease in vegetable crops.

Recent advances in the improvement of genetic resistance against disease in vegetable crops.

Isolation of yellow vein mosaic virus (YVMV)‐resistant mutants of okra (Abelmoschus esculentus L.) through applied mutagenesis

AbstractOkra, Abelmoschus esculentus (L.) Moench, being highly susceptible to yellow vein mosaic virus (YVMV) disease warrants its genetic improvement for resistance. Applied mutagenesis programme using two optimum doses of gamma radiation, namely, 350 Gy and 450 Gy radiation, was administered for the variety Pusa Sawani rated as excellent for fruit quality but highly susceptible to YVMV disease. Two selected putative mutant families, namely, 350//10///3‐9////28 and 450//66///2‐4////39, isolated in the M5 generation with slightly different plant morphology as compared to the parental genotype, Pusa Sawani, showed consistent resistance against YVMV disease. Upon evaluation in the M6 generation, eight morphological characteristics and five quantitative characteristics differed significantly among the mutants and Pusa Sawani. Proximate compositions and enzyme activity in leaf were significantly higher in the two YVMV‐resistant mutants. Disease screening under artificial inoculation in the insect proof cages confirmed YVMV resistance in these mutants. DNA fingerprinting further validated the alterations occurred in these two isolated mutants compared to the parental genotype. These mutants deserve due attention towards the development of YVMV‐resistant variety.

Threatening wheat diseases in the eastern Gangetic plains: the current status of disease resistance

Among the different diseases of wheat, spot blotch (causal organism: Bipolaris sorokiniana) is the most dominant disease in the eastern Gangetic plains of Indian subcontinent viz. India, Nepal and Bangladesh. The disease accounts for yield loss of more than 15% even with the adoption of moderately resistant varieties in the farmer’s fields. The severity of the disease has been increased in the last two decades after wide scale adoption of rice–wheat cropping sequence, reduced tillage and occurrence of terminal heat stress. Beside this, wheat blast (Magnaporthe oryzae pathotype Triticum) is also potential threat after its occurrence in Bangladesh in 2016. The present review summarizes current status of knowledge on the importance of the disease, its impact on crop loss, epidemiological conditions for disease development and breeding for disease resistance of both diseases. The future research work on genetics, use of molecular markers, cloning and characterization of genes for spot blotch resistance and monitoring of wheat blast disease, improvement of genetic resistance as well as development of predictive model has been suggested.

Evaluation of score for subclinical ketosis risk in Czech Holstein cows

Submitted 2020-07-17 | Accepted 2020-08-18 | Available 2020-12-01 https://doi.org/10.15414/afz.2020.23.mi-fpap.250-257 This study aimed to evaluate the score for subclinical ketosis risk, which is routinely monitored in Czech Holstein cows. The score is based on milk recording indicator traits which include fat-to-protein ratio, fat-to-lactose ratio, citric acid, β-hydroxybutyrate, and acetone concentrations. The score was significantly (P <0.001) affected by the age of cow at calving, days in milk (DIM) and season of test-day recording. Variance components were estimated with a univariate linear animal model for the score on the first test-day and with a multivariate linear animal model for the score in 3 successive test-days (6-40, 30-70, 60-100 DIM). The heritability estimate was lower at the beginning of lactation (0.08) and increased gradually to 0.11 at the end of the recorded period. Genetic correlations between the score at the first and the other two test-days were lower than 1 indicating that they are genetically different traits. Estimated breeding values were normally distributed with mean 0.20 and reliabilities up to 0.66 in females and 0.98 in males. Breeding values were negatively correlated with most of other routinely evaluated traits, with the strongest correlations with milk fat percentage (0.39), body condition score (-0.26) and fertility of cows (-0.25). The score for subclinical ketosis risk showed sufficient genetic variability and had the potential to be used in genetic improvement of resistance to (sub)clinical ketosis of Czech Holstein cows. Keywords: metabolic status, indicator trait, ketone body References Bastin, C. et al. (2016) On the role of mid-infrared predicted phenotypes in fertility and health dairy breeding programs. Journal of Dairy Science, 99(5), 4080–4094. https://doi.org/10.3168/jds.2015-10087 Belay, T.K. et al. (2017) Genetic parameters of blood β-hydroxybutyrate predicted from milk infrared spectra and clinical ketosis, and their associations with milk production traits in Norwegian Red cows. Journal of Dairy Science, 100(8), 6298–6311. https://doi.org/10.3168/jds.2016-12458 Costa, A. et al. (2019) Genetic association of lactose and its ratios to other milk solids with health traits in Austrian Fleckvieh cows. Journal of Dairy Science, 102(5), 4238–4248. https://doi.org/10.3168/jds.2018-15883 Gebreyesus, G. et al. (2020) Predictive ability of host genetics and rumen microbiome for subclinical ketosis. Journal of Dairy Science, 103(5), 4557–4569. https://doi.org/10.3168/jds.2019-17824 Hanus, O. et al. (2017) Analyse of relationships between some milk indicators of cow energy metabolism and ketosis state. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 65(4), 1135–1147. Hanus O. et al. (2013) Identification of subclinical ketosis in early lactation of cows according to the results of milk yield and individual milk samples in milk recording scheme and interpretation of results. Certified methodology. Prague: Institute of Dairy Science. In Czech. Jamrozik, J. et al. (2016) Multiple-trait estimates of genetic parameters for metabolic disease traits, fertility disorders, and their predictors in Canadian Holsteins. Journal of Dairy Science, 99(3), 1990–1998. https://doi.org/10.3168/jds.2015-10505 Kasna, E. et al. (2020) Fat-to-protein ratio in milk of Holstein cows. Nas chov, 80(2), 32–36. In Czech. Kasna, E. et al. (2019) Genetic evaluation of reproductive and metabolic disorders and displaced abomasum in Czech Holstein cows. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 67(4), 939–946. Koeck, A. et al. (2014) Genetic analysis of milk β-hydroxybutyrate and its association with fat-to-protein ratio, body composition score, clinical ketosis, and displaced abomasum in early first lactation of Canadian Holstein. Journal of Dairy Science, 97(11), 7286–7292. https://doi.org/10.3168/jds.2014-8405 Madsen, P. & Jensen, J. (2013) A User’s Guide to DMU. Retrieved June 25, 2020 from https://dmu.ghpc.au.dk/DMU/Doc/Current/dmuv6_guide.5.2.pdf Martens, H. (2020) Transition period of the dairy cow revisited: I. Homeorhesis and its changes by selection and management. Journal of Agricultural Science, 12(3), 1–24. https://doi.org/10.5539/jas.v12n3pl Pryce, J. E. et al. (2016) Invited review: Opportunities for genetic improvement of metabolic diseases. Journal of Dairy Science, 99(9), 6855–6873. https://doi.org/10.3168/jds.2016-10854 SAS Institute Inc. (2017) Base SAS® 9.4 Procedures Guide, Seventh Edition. SAS Institute Inc., Cary, NC, USA. Slosarkova, S. et al. (2016) Monitoring of dairy cattle diseases in the Czech Republic. Veterinařstvi, 66(11), 859–866. In Czech. Van der Drift, S. G. A. et al. (2012) Genetic and non-genetic variation in plasma and milk β-hydroxybutyrate and milk acetone concentrations of early-lactation dairy cows. Journal of Dairy Science, 95(11), 6781–6787. https://doi.org/10.3168/jds.2012-5640 Vosman, J. J. et al. (2015) Genetic evaluation for ketosis in the Netherlands based on FTIR measurements. Interbull Bulletin No. 49: Proceedings of the 2015 Interbull Meeting, Orlando, Florida, 1–5.

The economic value of R0 for selective breeding against microparasitic diseases

BackgroundMicroparasitic diseases are caused by bacteria and viruses. Genetic improvement of resistance to microparasitic diseases in breeding programs is desirable and should aim at reducing the basic reproduction ratio {text{R}}_{0}. Recently, we developed a method to derive the economic value of {text{R}}_{0} for macroparasitic diseases. In epidemiological models for microparasitic diseases, an animal’s disease status is treated as infected or not infected, resulting in a definition of {text{R}}_{0} that differs from that for macroparasitic diseases. Here, we extend the method for the derivation of the economic value of {text{R}}_{0} to microparasitic diseases.MethodsWhen {text{R}}_{0} le 1, the economic value of {text{R}}_{0} is zero because the disease is very rare. When {text{R}}_{0}. is higher than 1, genetic improvement of {text{R}}_{0} can reduce expenditures on vaccination if vaccination induces herd immunity, or it can reduce production losses due to disease. When vaccination is used to achieve herd immunity, expenditures are proportional to the critical vaccination coverage, which decreases with {text{R}}_{0}. The effect of {text{R}}_{0} on losses is considered separately for epidemic and endemic disease. Losses for epidemic diseases are proportional to the probability and size of major epidemics. Losses for endemic diseases are proportional to the infected fraction of the population at the endemic equilibrium.ResultsWhen genetic improvement reduces expenditures on vaccination, expenditures decrease with {text{R}}_{0} at an increasing rate. When genetic improvement reduces losses in epidemic or endemic diseases, losses decrease with {text{R}}_{0} at an increasing rate. Hence, in all cases, the economic value of {text{R}}_{0} increases as {text{R}}_{0} decreases towards 1.Discussion{text{R}}_{0} and its economic value are more informative for potential benefits of genetic improvement than heritability estimates for survival after a disease challenge. In livestock, the potential for genetic improvement is small for epidemic microparasitic diseases, where disease control measures limit possibilities for phenotyping. This is not an issue in aquaculture, where controlled challenge tests are performed in dedicated facilities. If genetic evaluations include infectivity, genetic gain in {text{R}}_{0} can be accelerated but this would require different testing designs.ConclusionsWhen {text{R}}_{0} le 1, its economic value is zero. The economic value of {text{R}}_{0} is highest at low values of {text{R}}_{0} and approaches zero at high values of {text{R}}_{0}.

Genetic improvement of resistance to cyclaneusma needle cast in Pinus radiata

Progeny testing of resistance to needle loss caused by Cyclaneusma minus (cyclaneusma needle cast) has been included in the needle disease resistance strategy of Pinus radiata D. Don in New Zealand since the late 1970s. Data on progeny trials, two in the North Island of New Zealand and one in Tasmania, Australia, were available to estimate heritability between trait genetic correlations and genotype × environment interaction. Resistance to cyclaneusma needle cast had moderate estimates of heritability (0.25 to 0.46) at all sites. Genetic correlations between the assessed traits indicated that selection for faster early growth, i.e., tree height at age 4 years and diameter at breast height at age 6 years, favours trees that are prone to Cyclaneusma infection, while a favourable genetic association between resistance to cyclaneusma needle cast and productivity was evident at a later assessment at age 9 years. No significant genotype × environment interaction was found for resistance to cyclaneusma needle cast; however, stability of genotypes across a wider range of environments and with a high genetic connectedness requires more research. Considerable genetic improvement can be achieved for resistance to cyclaneusma needle cast and indirect selection for the trait should be pursued by selecting for productivity and culling susceptible genotypes from breeding.

ANALYSIS OF POLYMORPHISM IN MUCIN 4 GENE ASSOCIATED WITH ANIMAL RESISTANCE TO COLIBACTERIOSIS IN PIGS OF DOMESTIC AND FOREIGN SELECTIONS

Nowadays one of the most common and critical problem in pig breeding is colibacteriosis. This infectious disease has acute course and it is caused by enteropathogenic strains of bacteria Escherichia coli. One of the recent and effective approaches to prevent colibacteriosis is using markers of selection; it involves pig genotyping by genome loci. The chosen loci are associated with animal sensitivity to the disease and selection of animals with increased resistance by the results of genotyping. According to several researches, one of such loci is Mucin 4 (MUC4) gene. MUC4 gene is located in the13-th chromosome (SSC13q41). Mucins (MUC) are macromolecular glycoproteins synthesized by goblet enterocytes and play main role in protecting the intestinal epithelium from pathogens, including adhesive strains of Escherichia coli. As a result of spot replacement g.1849 G&gt;С in intron 7, structure of mucin protein encoded by gene is changing which leads to changes in the sensitivity of the intestinal mucosa to pathogenic Escherichia coli. G allele and respectively GG genotype determine the resistance of animals to colibacteriosis, while СС і GС genotypes are susceptible to this disease. In Ukraine, the studies of polymorphism MUC4 g.1849 G&gt; C were held fragmentally and only at certain populations of Ukrainian Meat and Large White. The aim of the work was to determine the genetic structure of pig breeds of domestic and foreign selection for MUC4 gene and to establish the possibility of organizing marker associated selection for genetic improvement of resistance to colibacteriosis. For research the samples of blood and hair were used from the animals of Large White of English selection, Large White of Ukrainian selection Type 1 and Type 3, Red White-Belt, Mirgorod, Poltava Meat and Landrace breeds. DNA isolation from the samples of biomaterial were carried out using ion exchange resin Chelex-100. Genotyping was performed by PCR-RFLP by Jorgensen methods (2006) with own modifications, concerning the selection of primer annealing temperature and optimum concentration of the gel to separate the restriction fragments. Genetic structure was determined using DNA analysis of MUC4 locus at seven breeds and intrabreed types. Predominance of potentially beneficial G allele frequency over undesirable C allele was established in all the populations of the studied pigs. The highest frequencies of G allele were characterized for Mirgorod (0.795), Poltava Meat (0.740) and Red White-Belt (0.820) breeds. Analysis of the distribution of genotypes showed domination of genotypes GG and GC in all analysed populations. Positive Wright fixation index and predominance of expected heterozygosity (0.484) over actual one (0.460) for Large White of Ukrainian selection Type 3 indicate the existence of moderate inbreeding and selective pressure in this herd. Other populations were characterized by a negative value of fixation index, which is indicative of an excess of heterozygotes, these breeds are in outbreeding depression. Statically significant deviation of actual frequencies of genotypes from expected ones was identified using Hardy-Weinberg criterion for pig population of Large White of English selection and Large White of Ukrainian selection Type 1. This may indicate that these populations aren’t in condition of equilibrium and about inclusion of the chosen gene to the selection process. The valuation was performed by calculating the PIC (polymorphic information content) of the marker. Based on the calculated PIC index MUC4 locus could be perspective to be used in marker associated selection with improving genetic resistance to colibacteriosis. The data of Mucin 4 gene polymorphism at Ukrainian pig populations of different origins and productive direction show the possibility of marker selection to improve the genetic resistance of animals to colibacteriosis regardless of their belonging to breed. This creates prerequisites for the establishment and implementation of the early molecular diagnosis of carriers of harmful C allele in MUC4 gene in pig breeding.

Immunological characteristics and response to lipopolysaccharide of mouse lines selectively bred with natural and acquired immunities

Genetic improvement of resistance to infectious diseases is a challenging goal in animal breeding. Infection resistance involves multiple immunological characteristics, including natural and acquired immunity. In the present study, we developed an experimental model based on genetic selection, to improve immunological phenotypes. We selectively established three mouse lines based on phagocytic activity, antibody production and the combination of these two phenotypes. We analyzed the immunological characteristics of these lines using a lipopolysaccharide (LPS), which is one of the main components of Gram-negative bacteria. An intense immunological reaction was induced in each of the three mouse lines. Severe loss of body weight and liver damage were observed, and a high level of cytokine messenger RNA was detected in the liver tissue. The mouse line established using a combination of the two selection standards showed unique characteristics relative to the mouse lines selected on the basis of a single phenotype. Our results indicate that genetic selection and breeding is effective, even for immunological phenotypes with a relatively low heritability. Thus, it may be possible to improve resistance to infectious diseases by means of genetic selection.

Review: Breeding common bean for resistance to insect pests and nematodes

Singh, S. P. and Schwartz, H. F. 2011. Review: Breeding common bean for resistance to insect pests and nematodes. Can. J. Plant Sci. 91: 239-250. Various insect pests and nematodes cause severe losses (35-100%) globally to the yield and quality of dry and green common bean (Phaseolus vulgaris L.). The objectives of this review are to briefly describe major insect pests and nematodes in the Americas, breeding strategies and methods used, and research progress achieved. We also describe integrated genetic improvement for resistance to multiple insect pests and nematodes and cultivar development. Breeding for resistance to one insect pest or nematode at a time has been practiced in most instances. Backcross, pedigree, and bulk-pedigree breeding methods have been used. Considerable progress has been made in genetics and germplasm enhancement for resistance to bean pod weevil (Apion godmani Wagner), tropical bruchid (Zabrotes subfasciatus Boheman), leafhoppers (Empoasca kraemeri Ross and Moore), and root- knot nematode (Meloidogyne species). However, improvement in resistance to Acanthoscelides obtectus (Say), lesion (Pratylenchus species) and soybean cyst (Heterodera glycines) nematodes, and other regional insect pests has been minimal or non-existent. Furthermore, dry or green common bean cultivars with high levels of resistance to one or more insect pests and nematodes are rare. Breeding strategies for integrated and simultaneous genetic improvement of multiple qualitatively and quantitatively inherited resistances for cultivar development are briefly described.

Maize Silk Antibiotic Polyphenol Compounds and Molecular Genetic Improvement of Resistance to Corn Earworm (Helicoverpa zea Boddie) in sh2 Sweet Corn

The flavor of sh2 super-sweet corn is preferred by consumers. Unfortunately, sh2 sweet corn has little genetic variation for insect resistance. In this paper we review the functions of two loci, p1 and a1. The P1 allele has a major role in sh2 sweet corn resistance to corn earworm, an allele that was lost in historical selection because of its pleiotropic effect on undesirable cob color and silk browning. The P1 allele has significant effects on biosyntheses of silk antibiotic compounds, maysin, apimaysin, methoxymaysin, and chlorogenic acid. The effect of a1 shows gene action for lowered maysin and significant epistatic action with p1. The dominant functional allele A1 causes anthocyanin pigments in aleurone, plant, and pericarp tissues; the recessive a1 allele causes absence of pigment in these tissues. If silk browning and cob color are critical factors for maysin production but lack the customer’s preference, then separating red cob and browning silk, which are controlled by the P1 allele, may be difficult if not impossible. One high silk maysin sh2 sweet corn germ­plasm, shrunken Zapalote Chico, has been released. There is some field corn germplasm with p1-wwr alleles, but the amount of antibiotic flavones and their potential as a donor need further investigation.

Aplicación de un planteamiento global en el uso de marcadores moleculares para incrementar la resistencia a las enfermedades

The improvement and utilisation of host genetic resistance to disease is an attractive option as a component of livestock disease control in a wide range of situations. This paper reviews the situations where genetic resistance of the host is likely to be a useful component of disease control and provides a framework for deciding whether genetic improvement of resistance is likely to be worthwhile. Discussion is focused on low-input production systems in the developing world, where disease resistance is particularly important. The authors propose an integrated strategy for the use of molecular markers in assessing genetic diversity and in utilising and improving host genetic resistance to disease. The integrated approach assures that there is value in the molecular genetic information whether or not it proves useful in genetic selection, a feature that should prove attractive to funding and executing agencies.

Introduction

A scientific workshop was held with specific emphasis on genetic improvement of resistance to mastitis based on SCC. The first objective was to present current knowledge of physiological and genetic aspects of resistance to mastitis. The second objective was to provide a forum for discussion of various strategies for genetic improvement of resistance to mastitis with particular emphasis on use of genetic evaluations for SCC. Contributions covered physiological, immunological, and genetic aspects of resistance to mastitis and SCC, as well as developments in genetic evaluation for SCC.

Cypress canker disease in Italy: biology, control possibilities and genetic improvement for resistance

AbstractThe life cycle of Seiridium cardinale, the principal symptoms of the cypress canker disease, the results of chemical control, and the research directed toward genetic improvement of Italian cypress for resistance to the canker are described.

Breeding for Genetic Resistance to Disease: Specific or General?

All basic approaches to disease control: eradication, vaccination or medication and improvement of genetic resistance should be considered together in planning an effective programme of disease con...