Current Breeding Research Articles

Mother’s curse on conservation: assessing the role of mtDNA in sex‐specific survival differences in ex‐situ breeding programs

AbstractFor captive breeding to be an effective conservation tool, population fitness needs to be guaranteed according to the latest insights. Preserving genetic diversity has been a major pillar in conservation breeding, as it is a proxy for long‐term population viability. Small differences on the DNA level can impact an individual’s overall fitness and when situated on the mitochondrial genome might more specifically affect the process of aging and fertility. In general, mitochondrial DNA is transmitted via the mother. In the process of natural selection, variants beneficial for female fitness will be selected for whereas male‐harming variants that are neutral or beneficial in females will never be selected against. This biased selective sieve results in the accumulation of male‐harming mutations in the mitochondrial DNA, a process labelled “mother's curse”. Regardless of the susceptibility of zoo populations to “mother’s curse”, mitochondrial‐induced fitness effects have remained unstudied within captive breeding programs. While current conservation breeding strategies focus on retaining nuclear diversity, studies that specifically concentrate on aberrant extra‐nuclear genetic processes might improve breeding practices. Here, we provide a framework and empirical evidence for the presence of mtDNA‐induced sex‐specific differences starting from readily available population information. We analyzed whether an individual’s mitochondrial background partly affects survival in a sex‐specific manner using studbook data from captive populations representing 16 species. Our results indicate male survival is affected in five maternal lineages on pre‐ and postnatal level. Additionally, we describe the overall beneficial effects some maternal lineages have over others in terms of survival. These results are of interest in the debate on the maintenance of healthy captive populations and how to further improve safeguarding their genetic diversity for both ex‐situ and in‐situ conservation.

Low Repeatability of Breeding Events Reflects Flexibility in Reproductive Timing in the Pied Flycatcher Ficedula hypoleuca in Spain

Individual flexibility in breeding time is essential to respond to unpredictable changes in environmental conditions. Repeatability quantifies the consistency of the expression of phenotypes over time due to differences between individuals. Here, we estimate the repeatability of breeding date (laying date of first egg), hatching date and timing of pre-breeding events in a population of Pied Flycatchers Ficedula hypoleuca monitored over three decades in central Spain. We found low repeatabilities of breeding and hatching dates (respectively, R = 0.135 and R = 0) and among-year fluctuations (R = 0.276 and R = 0.218) in the expression of these traits. Repeatabilities of mating dates and of the interval between mating and egg laying were also very low (respectively R = 0.053 and R = 0) and among years (respectively R = 0.218 and R = 0.172), suggesting that Pied Flycatcher females are flexible to adjust their breeding schedule to current breeding conditions. We interpret the low consistency of traits related to breeding phenology as strong support for female phenotypic plasticity in breeding timing and the potential of such traits to respond to changing environmental conditions.—Le Vaillant, J., Potti, J., Camacho, C., Canal, D. & Martínez-Padilla, J. (2022). Low repeatability of breeding events reflects flexibility in reproductive timing in the Pied Flycatcher Ficedula hypoleuca in Spain. Ardeola, 69: 21-39.

Determination and Metabolite Profiling of Mixtures of Triterpenoid Saponins from Seeds of Chilean Quinoa (Chenopodium quinoa) Germplasm

The seed pericarp of Chenopodium quinoa Willd. (quinoa) contains a mixture of triterpenoid saponins conferring undesired organoleptic properties. In this study, we evaluated saponin content and their corresponding sapogenins in 114 different quinoa accessions. Relative saponin content ranged from 0.22 to 15.04 mg/g of seed dry weight among the genotypes studied and the genotype effect was significant (p < 0.001). About 75% of the genotypes could be classified as low-saponin content lines which is promising in view of ongoing plant breeding efforts. In addition to the quantitative determination of saponins, metabolic profiling was performed by LC-FTICR-MS and LC-MS/MS. We obtained highly accurate mass estimation from ion spectra allowing the identification of twelve saponins of the oleanane type. These differ in their aglycons and in the number and type of glycoside units. Interestingly, we identified a saponin compound that, to our knowledge, had not been reported previously. Our study highlights that there is considerable variability concerning saponin content in quinoa, which contributes to the valorization of genetic resources towards the identification of genotypes that could be utilized in current and future quinoa breeding programs.

Genetic Diversity and Population Structure of Sugarcane (Saccharum officinarum L.) Collected from Seven Philippine Regions for Use as Breeding Stocks for Crop Improvement

Selection of parents for hybridization relies on the information on their genetic relationship and diversity which are essential in any breeding program. This study aimed to estimate the extent of genetic diversity and population structure of 76 sugarcane accessions from seven regions in the Philippines using 57 morphological characters and 50 microsatellite markers. The sugarcane collections exhibited moderate to high diversity with mean of H’ = 0.72 for qualitative and H’ = 0.75 for quantitative morphological characters, respectively. This is corroborated by the analysis of variance (ANOVA) of agronomic parameters, except for stalk length. Unweighted Pair Group Method with Arithmetic Mean (UPGMA) cluster analysis based on morphology subdivided the accessions into 31 clusters which reveal phenotypic variability among sugarcane samples. The fingerprints of the 76 accessions were also evaluated using 45 Saccharum-based genomic SSR and 5 EST-SSR primer pairs to measure genetic diversity and population structure. Based on UPGMA, a total of six clusters were generated with a 0.65 coefficient of dissimilarity, and the sugarcane accessions were further subdivided into five major sub-populations. Out of 50 markers used, 41 (82%) were found to be highly informative with a mean PIC value of 0.69. It was also expected that Saccharum-based genomic SSRs were more polymorphic (92%) compared to EST-SSRs (82%) since the latter preferably amplify in more conserved and expressed sequences in the genome. Out of 2,850 pairwise combinations based on the Jaccard coefficient index, large diverse parental combinations (genetic dissimilarity= 0.51 -0.70) were observed, indicating substantial diversity from the existing breeding pool of IPB-UPLB for genetic improvement. Cluster analysis based on UPGMA, STRUCTURE analysis, and Principal Coordinate Analysis (PCoA) were predominantly consistent. However, no association was observed between the geographical origin and genetic distance of the genotypes based on molecular data. The results showed that accessions were grouped into five sub-populations and genetic differentiation within sub-population was higher (85%) as compared to between sub-population (15%) based on the analysis of molecular variance (AMOVA), suggesting an active exchange of genetic pool across provinces and regions of both Luzon and Visayas islands. The findings from this study will be useful for future breeding efforts by exploiting genetic variation existing in the current breeding population.

Temporal analysis shows relaxed genetic erosion following improved stocking practices in a subarctic transnational brown trout population

Maintaining standing genetic variation is a challenge in human-dominated landscapes. We used genetic (i.e., 16 short tandem repeats) and morphological (i.e., length and weight) measurements of 593 contemporary and historical brown trout (Salmo trutta) samples to study fine-scale and short-term impacts of different management practices. These had changed from traditional breeding practices, using the same broodstock for several years, to modern breeding practices, including annual broodstock replacement, in the transnational subarctic Pasvik River. Using population genetic structure analyses (i.e., Bayesian assignment tests, DAPCs, and PCAs), four historical genetic clusters (E2001A-D), likely representing family lineages resulting from different crosses, were found in zone E. These groups were characterized by consistently lower genetic diversity, higher within-group relatedness, lower effective population size, and significantly smaller body size than contemporary stocked (E2001E) and wild fish (E2001F). However, even current breeding practices are insufficient to prevent genetic diversity loss and morphological changes as demonstrated by on average smaller body sizes and recent genetic bottleneck signatures in the modern breeding stock compared to wild fish. Conservation management must evaluate breeding protocols for stocking programs and assess if these can preserve remaining natural genetic diversity and morphology in brown trout for long-term preservation of freshwater fauna.

Unravelling the Effect of Provitamin A Enrichment on Agronomic Performance of Tropical Maize Hybrids.

Maize is consumed in different traditional diets as a source of macro- and micro-nutrients across Africa. Significant investment has thus been made to develop maize with high provitamin A content to complement other interventions for alleviating vitamin A deficiencies. The current breeding focus on increasing β-carotene levels to develop biofortified maize may affect the synthesis of other beneficial carotenoids. The changes in carotenoid profiles, which are commonly affected by environmental factors, may also lead to a trade-off with agronomic performance. The present study was therefore conducted to evaluate provitamin A biofortified maize hybrids across diverse field environments. The results showed that the difference in accumulating provitamin A and other beneficial carotenoids across variable growing environments was mainly regulated by the genetic backgrounds of the hybrids. Many hybrids, accumulating more than 10 µg/g of provitamin A, produced higher grain yields (>3600 kg/ha) than the orange commercial maize hybrid (3051 kg/ha). These hybrids were also competitive, compared to the orange commercial maize hybrid, in accumulating lutein and zeaxanthins. Our study showed that breeding for enhanced provitamin A content had no adverse effect on grain yield in the biofortified hybrids evaluated in the regional trials. Furthermore, the results highlighted the possibility of developing broadly adapted hybrids containing high levels of beneficial carotenoids for commercialization in areas with variable maize growing conditions in Africa.

Changes in climate drive recent monarch butterfly dynamics.

Declines in the abundance and diversity of insects pose a substantial threat to terrestrial ecosystems worldwide. Yet, identifying the causes of these declines has proved difficult, even for well-studied species like monarch butterflies, whose eastern North American population has decreased markedly over the last three decades. Three hypotheses have been proposed to explain the changes observed in the eastern monarch population: loss of milkweed host plants from increased herbicide use, mortality during autumn migration and/or early-winter resettlement and changes in breeding-season climate. Here, we use a hierarchical modelling approach, combining data from >18,000 systematic surveys to evaluate support for each of these hypotheses over a 25-yr period. Between 2004 and 2018, breeding-season weather was nearly seven times more important than other factors in explaining variation in summer population size, which was positively associated with the size of the subsequent overwintering population. Although data limitations prevent definitive evaluation of the factors governing population size between 1994 and 2003 (the period of the steepest monarch decline coinciding with a widespread increase in herbicide use), breeding-season weather was similarly identified as an important driver of monarch population size. If observed changes in spring and summer climate continue, portions of the current breeding range may become inhospitable for monarchs. Our results highlight the increasingly important contribution of a changing climate to insect declines.

Exploring the Origin and Relatedness of Maternal Lineages Through Analysis of Mitochondrial DNA in the Holstein Horse.

Maternal lineages are important for the breeding decision in the Holstein horse breed. To investigate the genetic diversity of the maternal lineages and the relationships between founder mares, the maternal inherited mitochondrial genome (except the repetitive part of the non-coding region) of 271 mares representing 75 lineages was sequenced. The sequencing predominantly revealed complete homology in the nucleotide sequences between mares from one lineage with exceptions in 13 lineages, where differences in one to three positions are probably caused by de novo mutations or alternate fixation of heteroplasmy. We found 78 distinct haplotypes that have not yet been described in other breeds. Six of these occurred in two or three different lineages indicating a common ancestry. Haplotypes can be divided into eight clusters with all mares from one lineage belonging to the same cluster. Within a cluster, the average number of pairwise differences ranged from zero to 16.49 suggesting close maternal relationships between these mares. The results showed that the current breeding population originated from at least eight ancestral founder mares.

Mapping the Relative Habitat Quality Values for the Burrowing Owls (Athene cunicularia) of the Canadian Prairies Using an Innovative Parameterization Approach in the InVEST HQ Module.

The range and population of Burrowing Owls (BOs) are declining in the Canadian Prairies. Multiple anthropogenic sources of degradation (threat) are attributed to this trend. Yet, the cumulative degradation caused by these sources has not been quantified across this landscape. Using the InVEST Habitat Quality (HQ) module and a novel approach to parameterize the relative sensitivity scores in this framework, we quantified, mapped, and evaluated the relative HQ values for these species in the prairies. The results illustrate significant differences in the HQ values between the current range and areas within the historical range of these species that do not spatially intersect with their current spatial extent. However, the variations of HQ values are not statistically significant under the different spatial scenarios considered across the current breeding grounds. Nevertheless, the results within the specific land use/cover categories illustrate meaningful variations in the HQ values across the current range of these species. Our findings suggest that the existing declining trends could only be attributed to the synergistic impact of the considered threats and other factors undermining the essential ecological processes for these birds. The results also highlight the importance of expanding the spatial extent of the existing conservation measures to prevent further loss of these charismatic migratory birds from the prairie landscape. A good starting point is to consider the HQ change index, a measure defined to illustrate the relative habitat degradation under different sources of degradation. Further studies are still required to determine the spatiotemporal impacts of all sources of degradation on the habitat of these endangered species in Canada and across their global range.

Selective breeding as a mitigation tool for methane emissions from dairy cattle

The global livestock sector, particularly ruminants, contributes substantially to the total anthropogenic greenhouse gases. Management and dietary solutions to reduce enteric methane (CH4) emissions are extensively researched. Animal breeding that exploits natural variation in CH4 emissions is an additional mitigation solution that is cost-effective, permanent, and cumulative. We quantified the effect of including CH4 production in the Dutch breeding goal using selection index theory. The current Dutch national index contains 15 traits, related to milk yield, longevity, health, fertility, conformation and feed efficiency. From the literature, we obtained a heritability of 0.21 for enteric CH4 production, and genetic correlations of 0.4 with milk lactose, protein, fat and DM intake. Correlations between enteric CH4 production and other traits in the breeding goal were set to zero. When including CH4 production in the current breeding goal with a zero economic value, CH4 production increases each year by 1.5 g/d as a correlated response. When extrapolating this, the average daily CH4 production of 392 g/d in 2018 will increase to 442 g/d in 2050 (+13%). However, expressing the CH4 production as CH4 intensity in the same period shows a reduction of 13%. By putting economic weight on CH4 production in the breeding goal, selective breeding can reduce the CH4 intensity even by 24% in 2050. This shows that breeding is a valuable contribution to the whole set of mitigation strategies that could be applied in order to achieve the goals for 2050 set by the EU. If the decision is made to implement animal breeding strategies to reduce enteric CH4 production, and to achieve the expected breeding impact, there needs to be a sufficient reliability of prediction. The only way to achieve that is to have enough animals phenotyped and genotyped. The power calculations offer insights into the difficulties that will be faced in trying to record enough data. Recording CH4 data on 100 farms (with on average 150 cows each) for at least 2 years is required to achieve the desired reliability of 0.40 for the genomic prediction.

Effects of GnRH agonists on testosterone and testosterone-stimulated parameters for contraception and aggression reduction in male lion-tailed Macaques (Macaca silenus).

Managing social groups in zoos requires controlling reproduction in individuals that do not have a current breeding recommendation, while simultaneously maintaining social harmony and animal well-being. Contraceptives, such as gonadotropin releasing-hormone (GnRH) agonists, that suppress testosterone production, offer a potential solution. They achieve infertility by interrupting spermatogenesis and may ameliorate androgen-induced aggression. This study investigated the effects of two GnRH agonists, histrelin and deslorelin, on testosterone, testis size, body weight and sperm production in male lion-tailed macaques, along with subjective observations of aggressive behavior. Five trials at three institutions with 14 males demonstrated that 100 mg histrelin or 9 to 12 mg of deslorelin could at least temporarily reduce testosterone, but a lower 6 mg dose was ineffective. However, ability of deslorelin to produce azoospermia varied among males, even at the highest dose. In general, a higher dose was needed (1) to achieve than to maintain suppression of any measured parameter and (2) to suppress sperm production than testosterone concentration. Testosterone production was also more likely than sperm production to recover, suggesting possible damage to seminiferous tubules but not to Leydig cells. Aggressive behavior was reduced in all but the group receiving the lowest dose. This allowed social groups to be maintained for many years despite recovery of testosterone in some males, suggesting that new social roles had been learned and become independent of androgen influence.

Susceptibility of some Flax Lines to Powdery Mildew and Effect of The Disease on Agronomic and Technological Traits. قابلية بعض سلالات الکتان للإصابة بالبياض الدقيقى و تأثير المرض على الصفات المحصولية و التکنولوجية.

A two-year field study was conducted at El-Giza Agricultural Research Station to (1) estimate heritability of powdery mildew (PM) resistance when disease incidence (DI) or disease severity (DS) was used as criterion for evaluating resistance, (2) assess PM resistance of ten flax genotypes (lines), (3) determine relationship between each of DI and DS ratings and agronomic or technological traits. Genotypes component of variance of DI and DS were highly significant each year indicating that extensive genetic variation for DI and DS were present within the tested genotypes. Heritability and genetic advance of DS were greater in both years than those of DI demonstrating that considerable progress in breeding for PM resistance could be expected in current breeding programs when DS is used as criterion for evaluating resistance. DI ratings ranged from 72 to 100 % in 2019 and from 51 to 93 % in 2020. DS ratings were also high and ranged from 65 to 98 % in 2019 and from 44 to 97 % in 2020. None of the tested genotypes were significantly less susceptible than genotypes no. 3, but the genotypes were either as susceptible as genotypes 3 or significantly more susceptible. Genotype 3 was a promising genotype for commercialization for the following reasons: firstly, it was the least susceptible genotype. Secondly, it showed environmently stable performance. Thirdly, it showed superiority in some traits compared to some of the tested genotypes. No significant correlations were observed between disease intensity variables ( DI and DS) and agronomic or technological traits. Correlations among agronomic or technological traits were sensitive to changes in environmental conditions. Possible mechanisms of resistance to PM in flax were also discussed.

Prospects of Developing Novel Genetic Resources by Chemical and Physical Mutagenesis to Enlarge the Genetic Window in Bread Wheat Varieties

Sustainable production and improved genetic gains can be achieved by broadening the genetic window of elite wheat germplasm. Here, we induced mutations in two spring wheat varieties, viz., NN-Gandum-1 (NN-1) and Punjab-11 (Pb-11), by exposing their seeds to ethyl methane sulfonate (EMS) and γ-rays, respectively. We characterized >3500 lines of each NN-1 and Pb-11 derived population in three consecutive generations, viz., M5, M6, and M7, for important traits, e.g., plant height, heading date, spike morphology and rust resistance. We observed significant genetic variation and correlations in both populations for all investigated traits. We observed differences in terms of number of mutants between NN-1 (22.76%) and Pb-11 (26.18%) which could be ascribed to the genotype-by-mutagen interaction. High broad-sense heritability (H2) estimates, that are vital for higher genetic gains, were observed for all of the investigated traits in both populations (H2 = 0.69–0.91 in NN-1 and 0.84–0.98 in Pb-11). Particularly, to breed for rust resistance, we selected a subset (n = 239) of M7 lines that also showed phenotypic variation for other traits. Our studies (1) show the relevance to artificial mutagenesis to create genetic variation in elite germplasm for their immediate use in current breeding programs, and (2) provide material for downstream identification of genes associated with traits of high agronomic importance.

Deterministic and stochastic modelling of impacts from genomic selection and phenomics on genetic gain for perennial ryegrass dry matter yield

Increasing the efficiency of current forage breeding programs through adoption of new technologies, such as genomic selection (GS) and phenomics (Ph), is challenging without proof of concept demonstrating cost effective genetic gain (∆G). This paper uses decision support software DeltaGen (tactical tool) and QU-GENE (strategic tool), to model and assess relative efficiency of five breeding methods. The effect on ∆G and cost ($) of integrating GS and Ph into an among half-sib (HS) family phenotypic selection breeding strategy was investigated. Deterministic and stochastic modelling were conducted using mock data sets of 200 and 1000 perennial ryegrass HS families using year-by-season-by-location dry matter (DM) yield data and in silico generated data, respectively. Results demonstrated short (deterministic)- and long-term (stochastic) impacts of breeding strategy and integration of key technologies, GS and Ph, on ∆G. These technologies offer substantial improvements in the rate of ∆G, and in some cases improved cost-efficiency. Applying 1% within HS family GS, predicted a 6.35 and 8.10% ∆G per cycle for DM yield from the 200 HS and 1000 HS, respectively. The application of GS in both among and within HS selection provided a significant boost to total annual ∆G, even at low GS accuracy rA of 0.12. Despite some reduction in ∆G, using Ph to assess seasonal DM yield clearly demonstrated its impact by reducing cost per percentage ∆G relative to standard DM cuts. Open-source software tools, DeltaGen and QuLinePlus/QU-GENE, offer ways to model the impact of breeding methodology and technology integration under a range of breeding scenarios.

Comparative anatomical and transcriptomic insights into Vaccinium corymbosum flower bud and fruit throughout development

BackgroundBlueberry (Vaccinium spp.) is characterized by the production of berries that are smaller than most common fruits, and the underlying mechanisms of fruit size in blueberry remain elusive. V. corymbosum ‘O’Neal’ and ‘Bluerain’ are commercial southern highbush blueberry cultivars with large- and small-size fruits, respectively, which mature ‘O’Neal’ fruits are 1 ~ 2-fold heavier than those of ‘Bluerain’. In this study, the ontogenetical patterns of ‘O’Neal’ and ‘Bluerain’ hypanthia and fruits were compared, and comparative transcriptomic analysis was performed during early fruit development.ResultsV. corymbosum ‘O’Neal’ and ‘Bluerain’ hypanthia and fruits exhibited intricate temporal and spatial cell proliferation and expansion patterns. Cell division before anthesis and cell expansion after fertilization were the major restricting factors, and outer mesocarp was the key tissue affecting fruit size variation among blueberry genotypes. Comparative transcriptomic and annotation analysis of differentially expressed genes revealed that the plant hormone signal transduction pathway was enriched, and that jasmonate-related TIFYs genes might be the key components orchestrating other phytohormones and influencing fruit size during early blueberry fruit development.ConclusionsThese results provided detailed ontogenetic evidence for determining blueberry fruit size, and revealed the important roles of phytohormone signal transductions involving in early fruit development. The TIFY genes could be useful as markers for large-size fruit selection in the current breeding programs of blueberry.

Flow Cytometry-Based Determination of Ploidy from Dried Leaf Specimens in Genomically Complex Collections of the Tropical Forage Grass Urochloa s. l.

Urochloa (including Brachiaria, Megathyrus and some Panicum) tropical grasses are native to Africa and are now, after selection and breeding, planted worldwide, particularly in South America, as important forages with huge potential for further sustainable improvement and conservation of grasslands. We aimed to develop an optimized approach to determine ploidy of germplasm collection of this tropical forage grass group using dried leaf material, including approaches to collect, dry and preserve plant samples for flow cytometry analysis. Our methods enable robust identification of ploidy levels (coefficient of variation of G0/G1 peaks, CV, typically <5%). Ploidy of some 348 forage grass accessions (ploidy range from 2x to 9x), from international genetic resource collections, showing variation in basic chromosome numbers and reproduction modes (apomixis and sexual), were determined using our defined standard protocol. Two major Urochloa agamic complexes are used in the current breeding programs at CIAT and EMBRAPA: the ’brizantha’ and ’humidicola’ agamic complexes are variable, with multiple ploidy levels. Some U. brizantha accessions have odd level of ploidy (5x), and the relative differences in fluorescence values of the peak positions between adjacent cytotypes is reduced, thus more precise examination of this species is required. Ploidy measurement of U. humidicola revealed aneuploidy.

Genetic parameters and litter trait trends of Danish pigs in South Vietnam.

ObjectiveThe objective of this study was to estimate the genetic parameters and various litter trait trends of Danish pigs in South Vietnam, including the number born alive (NBA), number weaned (NW), and litter weight at the 21st day (LW21).MethodsRecords of 936 Yorkshire sows with 3361 litters and 973 Landrace sows with 3161 litters were used to estimate the variance components, genetic parameters, and trends of NBA, NW, and LW21. The restricted maximum likelihood method was applied using VCE6 software to obtain the variance components and genetic parameters. Thereafter, the best linear unbiased prediction procedure with an animal model was applied using PEST software to estimate the breeding values of the studied traits.ResultsThe heritability estimates were low, ranging from 0.12 to 0.21 for NBA, 0.03 to 0.04 for NW, and from 0.11 to 0.13 for LW21. The genetic correlation between the NBA and NW was relatively strong in both breeds, at 0.77 and 0.60 for Yorkshire and Landrace, respectively. Similarly, the genetic correlation between the NW and LW21 was considerably stronger in Landrace pigs (0.71) than in Yorkshire pigs (0.48). The estimates of annual genetic progress were 0.0431, 0.0233, and 0.0461 for NBA, NW, and LW21 in Landrace pigs and 0434, 0.0202, and 0.0667 for NBA, NW, and LW21 in Yorkshire pigs, respectively.ConclusionThe positive genetic trends estimated for the additive genetic values of the selected traits indicated that the current breeding system has achieved favorable results.

Discovery of a novel eIF4E1.S allele conferring PVY resistance in Chinese tobacco (Nicotiana tabacum) landraces

AbstractThe tobacco eIF4E1.S gene is a well‐recognized susceptibility factor for potato virus Y (PVY) and a dominant target locus for current PVY resistance breeding in tobacco. In this study, over 900 tobacco landraces from China were screened for resistance to PVY and the DNA sequence of eIF4E1.S was analysed for all resistant accessions. Eight PVY‐resistant lines were identified from this screen, and a naturally occurring mutant allele of eIF4E1.S carrying a single nucleotide insertion was discovered in seven, including a landrace called Kaiyangxiaoheiyan (Kaixiao), and designated eIF4E1.Kai. Knowledge of the mutant gene sequence enabled the development of a codominant PCR‐based marker that can distinguish eIF4E1.S/eIF4E1.Kai heterozygotes from both homozygous classes. Using this marker, we genotyped F2 plants segregating for the eIF4E1.Kai mutant and confirmed the relationship between genotype and phenotype. The results described here provide valuable genetic insights into Chinese tobacco landraces as a source of naturally occurring PVY resistance, as well as a powerful tool for the molecular marker‐assisted breeding of tobacco varieties containing the resistance source eIF4E1.Kai.

Productivity and parameters of ecological adaptability of alfalfa samples under the conditions of the South of Russia

Introduction . The initial material is the basis of the current breeding work with all agricultural crops, including alfalfa. The purpose of the conducted work is to estimate the productivity of alfalfa samples in the collection nursery, depending on the growing conditions and the identification of the most adapted samples according to the trait “green mass productivity”. Materials. The objects of the current study were 30 alfalfa samples (16 samples from Canada; 11 samples from the USA; 1 sample from Peru; 2 samples from France) from the collection ARIGCR named after N.I. Vavilov. Results. The estimation of alfalfa samples for the presence of adaptive properties based on the trait ‘green mass productivity’ showed that: — the genotypes К-27116, К-43269, К-43272, К-48771, К-48775, К-48776, К-50545, К-50561, К-45119 are more responsive to changes in environmental conditions; the genotypes К-32873, К-33299, К-42684, К-42249, К-47803 are characterized with a slight b i &lt; 1 response to changes in environmental conditions; the genotypes К-36104, К-48778, К-42694, К-45715, К-47800, К-47801, К-47802, К-43260 are characterized with high stability to stresses; the genotypes К-43272, К-50545, К-47806, К-47807 are characterized with genetic adaptability; the genotypes К-36104, К-48778, К-48715, К-47800, К-43260 are characterized with more stability of response to changes in environmental conditions; the genotypes К-36104, К-48778, К-45715, К-47800, К-47801, К-47802, К-39978, К-43260 are characterized with great homeostasis (ecological adaptability).

Health traits in current dairy cattle breeding: A review

The review focuses on breeding practices aimed at improving resistance to diseases and health disorders that are associated with better efficiency, welfare and longevity of cows. It is commonly known that diseases like mastitis, foot and claw disorders, metabolic and reproductive issues seriously violate dairy cows’ well-being. The cause of prevailing health and fertility deterioration has been the intensive selection merely based on higher milk production starting after the Second World War. Therefore since the last decades of the 20th-century genetic selection programs have been increasingly focused on increasing resistance to diseases and improving fertility traits using several omics techniques, including genomics. The first steps for maintaining the goal of genetic breeding for disease resistance were the introduction of disease data collection at national levels followed by an elaboration of gene evaluation systems. It was proved that diseases exhibit additive genetic variability exploitable in the breeding. For greater breeding efficiency, the indicator traits are used, which were strongly genetically correlated with health traits, have higher heritability, and above all, are usually easily measurable at low cost. Genome-wide association studies have identified several polymorphisms associated with disease liability that could also be used for speeding up selection efforts. Keywords: cow; clinical mastitis; foot and claw disease; metabolic disease; genomics