Breeding Schemes Research Articles

Parameter Estimation of Host Genomic and Gut Microbiota Contribution to Growth and Feed Efficiency Traits in Meat Rabbits.

Rabbits can efficiently utilize plant fibers that are indigestible to humans, and hence may contribute to the alleviation of feed-food competition. Therefore, it is economically and ecologically important to genetically improve the growth performance and feed efficiency of meat rabbits. In this study, we combined pedigree, genomic, and gut microbiota data to estimate genetic and microbial parameters for nine growth and feed efficiency traits of 739 New Zealand White rabbits, including body weight (BW) at 35 (BW35), 70 (BW70), and 84 (BW84) days of age, and average daily gain (ADG), feed conversion ratio (FCR), and residual feed intake (RFI) within two age intervals of 35-70 days (ADG70, FCR70, and RFI70) and 35-84 days (ADG84, FCR84, and RFI84). Based on single-step genomic best linear unbiased prediction, three BW traits and two ADG traits had the high estimates (±standard error, SE) of heritability, ranging from 0.44 ± 0.13 of BW35 to 0.66 ± 0.08 of BW70. Moderate heritabilities were observed for RFI70 (0.22 ± 0.07) and RFI84 (0.29 ± 0.07), whereas the estimates did not significantly deviate from zero for the two FCR traits. There was moderate positive genetic correlation (±SE) between BW70 and ADG70 (0.579 ± 0.086), but BW70 did not correlate with RFI70. Based on microbial best linear unbiased prediction, the estimates of microbiability did not significantly deviate from zero for any trait. Based on the combined use of genomic and gut microbiota data, the parameters obtained in this study could help us to implement efficient breeding schemes in meat rabbits.

Genetic Component Analysis in Fruit Yield and Quality Traits in Okra [Abelmoschus esculentus (L.) Moench

A half-diallel cross involving nine okra genotypes was utilized to investigate the inheritance of fruit yield and its component traits. Data from the F1 generation and the parent genotypes were analysed using Hayman's (1954) diallel method. The additive genetic component (D) was found to be significant for the traits like days to last picking in environment E1, and for the number of fruits per plant in environments E2 and E3, but non-significant across all environments for fruit yield per plant. The dominant components (H1 and H2) were found significant for all traits studied under all environmental condition. This revealed that both additive and non-additive gene actions play a vital role in the expression of the traits studied. The dominant component's (H1 and H2) relative magnitude was greater than the additive component for most of the traits, suggesting the importance of dominance effects on expression of those traits. The average degree of dominance showed an overdominance effect for the traits studied. The ratio of dominant to recessive genes indicated that the parents had an excess of dominant genes for fruit yield per plant. Thus stated the presence of overdominance for yield, reciprocal technique is the most effective recurrent breeding scheme for producing improved hybrids.

A Functional Analysis of Inflorescence Architecture in Musa L. (Musaceae)

ABSTRACTInflorescence architecture underpins sexual reproduction in wild Musa species and productivity in edible banana cultivars. In a functional analysis, we identified the apical inflorescence and lateral ‘cushion’ meristems and the change in flower type as the three primary components that generate inflorescence architecture. Five genotypes of two clone sets of edible plantains (Musa AAB) were grown for four generations along an elevation gradient (1100–2200 m, 16°C–24°C) straddling the equator in the humid highlands of East Africa. The data consisted of reproductive peduncle length at harvest (Pr), fruit per hand (Fh) and hands per bunch (Hb). The activity of the apical inflorescence meristem drives peduncle length and generates lateral ‘cushion’ meristems which determine Fh. However, Hb is determined by a change in flower type—from fruit forming to non‐fruit forming. Site temperature affected Hb more than Fh, while the development of the genet (rhizome) changed the allocation of resources between Hb and Fh, independently of the effect of site temperature. Clone sets differed in their response to genet development. Cooler temperatures reduced the number of fruit‐forming flowers in an inflorescence and changed the balance away from female towards male flowers. In banana breeding schemes, manipulating inflorescence components independently raises options for producing genotypes better suited to markets, environments and cultural practices.

The number of drones to inseminate a queen with has little potential for optimization of honeybee breeding programs

BackgroundMating control is a crucial aspect of honeybee breeding. Instrumental insemination of queens gives the breeder maximum control over the genetic origin of the involved drones. However, in addition to the drones’ descent, the breeder’s control also extends over the number of drones to use for inseminations. Thus far, this aspect has largely been ignored in attempts to optimize honeybee breeding schemes. The literature provides some comparisons between single drone inseminations (SDI) and multi drone inseminations (MDI) but it is unclear whether the number of drones used in MDI is a relevant parameter for the optimization of honeybee breeding programs.MethodsBy computer simulations, we investigated the effect of the number of drones per inseminated queen in breeding programs that relied on best linear unbiased prediction (BLUP) breeding values. We covered a range of 1 to 50 drones per queen and observed the developments of genetic gain and inbreeding over a period of 20 years. Hereby, we focused on insemination schemes that take the drones for one queen from a single colony.ResultsSDI strategies led to 5.46% to 14.19% higher genetic gain than MDI at the cost of 6.1% to 30.2% higher inbreeding rates. The number of drones used in MDI settings had only a negligible impact on the results. There was a slight tendency that more drones lead to lower genetic gain and lower inbreeding rates but whenever more than five drones were used for inseminations, no significant differences could be observed.ConclusionThe opportunities to optimize breeding schemes via the number of drones used in inseminations are very limited. SDI can be a viable strategy in situations where breeders are interested in genetically homogeneous offspring or precise pedigree information. However, such strategies have to account for the fact that the semen from a single drone is insufficient to fill a queen’s spermatheca, whence SDI queens will not build full-strength colonies. When deciding for MDI, breeders should focus on collecting enough semen for a succesful insemination, regardless of how many drones they need for this purpose.

Evolutionary Fate of the Opine Synthesis Genes in the Arachis L. Genomes.

Naturally transgenic plants are plants that have undergone Agrobacterium-mediated transformation under natural conditions without human involvement. Among Arachis hypogaea L., A. duranensis Krapov. & W.C. Greg, A. ipaensis Krapov. & W.C. Greg, A. monticola Krapov. & Rigoni, and A. stenosperma Krapov. & W.C. Greg are known to contain sequences derived from the T-DNA of "Agrobacterium". In the present study, using molecular genetics and bioinformatic methods, we characterized natural transgenes in 18 new species from six sections of the genus Arachis. We found that small fragments of genes for enzymes of the agropine synthesis pathway were preserved only in some of the studied samples and were lost in the majority of the species during evolution. At the same time, genes, similar to cucumopine synthases (cus-like), remained intact in almost all of the investigated species. In cultivated peanuts, they are expressed in a tissue-specific manner. We demonstrated the intraspecific variability of the structure and expression of the cus-like gene in cultivated peanuts. The described diversity of gene sequences horizontally transferred from Agrobacterium to plants helps to shed light on the phylogeny of species of the genus Arachis and track possible hybridization events. Data on the ability of certain species to hybridize are useful for planning breeding schemes aimed at transferring valuable traits from wild species into cultivated peanuts.

Insight into a region of chickpea (Cicer arietinum L.) Chromosome 2 revealed potential candidate genes linked to Foc4 Fusarium wilt resistance.

Two markers on Chromosome 2 of chickpea (Cicer arietinum ) are reportedly associated with resistance to race 4 Fusarium wilt, and are frequently used in breeding. However, the genes in this region that actually confer wilt resistance are unknown. We aimed to characterise them using both in silico approaches and marker trait association (MTA) analysis. Of the 225 protein-encoding genes in this region, 51 showed significant differential expression in two contrasting chickpea genotypes under wilt, with potential involvement in stress response. From a diverse set of 244 chickpea genotypes, two sets of 40 resistant and 40 susceptible genotypes were selected based on disease incidence and amplification pattern of the TA59 marker. All cultivars were further genotyped with 1238 single nucleotide polymorphisms (SNPs) specific to the 51 genes; only seven SNPs were significantly correlated with disease. SNP Ca2_24099002, specific to the LOC101498008 (Transmembrane protein 87A) gene, accounted for the highest phenotypic variance for disease incidence at 16.30%, whereas SNPs Ca2_25166118 and Ca2_27029215, specific to the LOC101494644 (β-glucosidase BoGH3B-like) and LOC101505289 (Putative tRNA pseudouridine synthase) genes, explained 10.51% and 10.50% of the variation, respectively, in the sets with contrasting disease susceptibility. Together with the TA59 and TR19 markers, these SNPs can be used in a chickpea breeding scheme to develop wilt resistance.

Water quality constrained adjustment planning for regional breeding management with nonlinear programming model under uncertainty in Wenchang City, China

Basin water pollution caused by livestock, poultry and fish breeding is still a serious problem for remote villages, however, reliable regional breeding management programming have the potentials to improve pollution status. This paper focuses on the optimal model design and water quality analysis of the livestock, poultry and fish breeding system for Wenchang City, China. Methods of multi-objective programming (MOP), interval parameter programming (IPP), fuzzy-stochastic parameter programming (FSPP), and chance constrained programming (CCP) were incorporated into the developed model to tackle multi uncertainties described by interval values, probability distributions, fuzzy membership function. Based on the estimation of local breeding potential and current situation of surface water section, a multi-objective mixed fuzzy-stochastic nonlinear programming optimization model is presented with one-dimensional water quality model. In order to evaluate the environmental carrying capacity of livestock, poultry and fishery manure, predict its development trend and investigate the implementation effect of different emission reduction policies, this paper designs quantization system of the urban water environmental carrying capacity for the model. The results indicated that the water environment pollutant absorption capacity and carrying capacity of Wenchang city have approached the limit especially the towns in the northeast of City which limited the overall development space of the City. The modeling results are valuable for supporting the adjustment of the existing livestock, poultry and fish breeding schemes within a complicated system benefit and surface water quality situation under uncertainty.

Effects of GH L127V and TG5 C422T polymorphisms on the hormonal profile, slaughter traits, and meat quality of Hereford bulls.

The creation of objective methods for the evaluation and improvement of quantitative and qualitative indicators of meat productivity in farm animals should be based on a comprehensive analysis of the genetic, physiological, and biochemical parameters of the animal. This study aimed to investigate the effects of growth hormone (GH) and thyroglobulin (TG5) gene polymorphisms on the hormonal status, slaughter traits, and chemical, amino acid, and fatty acid composition of meat in Hereford bulls. Hereford bulls (n = 9) were reared under the same feeding and housing conditions until the age of 21 months, after which they were slaughtered. Polymerase chain reaction-restriction fragment length polymorphism was performed for genotyping GH L127V and TG5 C422T polymorphisms. The experimental animals were evaluated to determine slaughter traits (including pre-slaughter weight, carcass, and internal fat weight and yield), chemical, fatty acid, and amino acid composition of ground beef, and hormonal status using serum concentrations of GH, triiodothyronine, and thyroxine. Animals with the valine homozygous (VV) genotype of GH had the maximum serum GH level of 9.33 mIU/mL (p = 0.10) higher than leucine homozygous (LL) genotype carriers. Individuals with the LL genotype outperformed V-allele carriers in serum thyroxine (T4) concentration by 21.3-30.5 nmol/L (16.15%-24.86%; p < 0.01-0.05). Genetic differentiation induced by TG5 C422T polymorphism was determined to a lesser extent by the hormonal status of the Hereford animals. The V-allele was associated with increased carcass weight, with VV homozygotes significantly outperforming LL individuals by 45.0 kg (13.61%; p < 0.05). The T allele at the TG5 gene polymorphism was associated with more intense lipogenesis and less protein synthesis in muscle tissue and these effects were enhanced in the homozygous state. Young animals with the TT variant of the TG5 gene exhibited a significantly superior polyunsaturated fatty acid/saturated fatty acid ratio of 0.012 units (p < 0.01). Carriers of the LL genotype were characterized by minimum amino acid content in muscle tissue. Heterozygous bulls exceeded LL homozygotes in the sum of essential amino acids by 3.09% (p = 0.10) and non-essential amino acids by 1.9% (p < 0.05). The development of breeding programs for the Hereford breed should be carried out considering genetic features that determine the formation of economic traits in animals. Analysis of polymorphisms in the TG5 gene is a promising method for the early diagnosis of the fatty acid composition of beef. Identification of polymorphisms in the GH gene allows the prediction of higher productivity potential and amino acid composition of meat. The different effects of the GH and TG5 genes on the development of various economic traits allowed us to determine further vectors for scientific research on their complex associations in Hereford cattle, which will be useful for planning effective breeding schemes.

Evaluation of brachycephalic obstructive airway syndrome breeding test results in Finland from 2017 to 2022

BackgroundBrachycephalic obstructive airway syndrome (BOAS), observed in many flat-faced dog breeds, is one of the most urgent welfare problems in pedigree dogs. Various breeding schemes against BOAS have been implemented in many countries during recent years, but their impact on breed health remains unknown. The BOAS breeding test, used by the Finnish Kennel Club (FKC), includes an exercise component with a recovery assessment, BOAS grading by a veterinarian that evaluates upper respiratory signs before and after exercise, and a nostril stenosis assessment. The aim of our study was to evaluate BOAS breeding test results and estimate the heritability of the BOAS grade using parent–offspring regression from FKC data collected during 2017–2022.ResultsThe majority (80%) of dogs (n = 957) participating in FKC BOAS testing were English Bulldogs, French Bulldogs, and Pugs. In 2022, 89–100% of the litters from these three breeds registered with the FKC had at least one parent tested for BOAS. The proportion of dogs failing the exercise test was highest in English Bulldogs (11%), followed by French Bulldogs (4%) and Pugs (3%). In these three breeds, moderate to severe BOAS signs were reported in 28%, 22% and 30% of dogs, respectively. The proportion of moderate to severe nostril stenosis was highest (71%) in Pugs, followed by French Bulldogs (55%), and English Bulldogs (40%). Estimates of heritability for BOAS grade were separately calculated for these three breeds and for all dogs, and the estimates were moderate to high, ranging from 0.39 to 0.58.ConclusionsThe exercise test alone did not sufficiently identify dogs with moderate to severe BOAS signs. To better consider the complex nature of BOAS and breed differences, exercise tolerance, the severity of upper respiratory signs (BOAS grade) and nostril stenosis should all be assessed together in breeding animals. The heritability estimates for veterinary-assessed BOAS grade indicated that BOAS grade could be used in selective breeding to obtain less-affected offspring.

Response to Selection of Indigenous Chicken in Rwanda Using Within-Breed Selection Strategy

The study evaluated response to selection from within-breed selection strategy for conventional (&amp;lt;I&amp;gt;CBS&amp;lt;/I&amp;gt;) and genomic (&amp;lt;I&amp;gt;GBS&amp;lt;/I&amp;gt;) breeding schemes. These breeding schemes were evaluated in both high-health environments (nucleus) and smallholder farms (commercial). Breeding goal was to develop a dual-purpose IC for both eggs and meat through selective breeding. Breeding objectives were body weight (BW), egg weight (EW), egg number (EN) and resistance to Newcastle disease (AbR). A deterministic simulation was performed to evaluate rates of genetic gain and inbreeding. Base population in the nucleus was made up of 40 cockerels and 200 pullets. Selection pressure was 4% and 20% in the males and the females, respectively. The impact of nucleus size and selection pressure on rates of genetic gain and inbreeding of the breeding program was investigated through sensitivity analysis. SelAction software was used to predict rates of genetic gain and inbreeding. Results showed that using &amp;lt;I&amp;gt;CBS&amp;lt;/I&amp;gt; in the nucleus, the breeding goal was 340.41\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\$ and 1.13 times higher than that in the commercial flock. Inbreeding rate per generation of selected chicken in the nucleus was 1.45% and lower by 1.32 times compared to their offspring under smallholder farms. Genetic gains per generation in the nucleus for BW and EN traits were 141.10 g and 1.07 eggs and 1.12 and 1.10 times greater than those in smallholder farms, respectively. With &amp;lt;I&amp;gt;GBS&amp;lt;/I&amp;gt;, the breeding goal was increased by 3.00 times whereas inbreeding rate was reduced by 3.15 times. Besides, using &amp;lt;I&amp;gt;GBS&amp;lt;/I&amp;gt;, the selected birds in the nucleus were relatively similar to those in a commercial environment. Finally, the study revealed that the nucleus size and mating ratio influence the rates of genetic gain and inbreeding in both &amp;lt;I&amp;gt;GBS&amp;lt;/I&amp;gt; and &amp;lt;I&amp;gt;CBS.&amp;lt;/I&amp;gt; This study shows that IC in Rwanda have the potential to be improved through within-breed selection strategy using either &amp;lt;I&amp;gt;CBS&amp;lt;/I&amp;gt; or &amp;lt;I&amp;gt;GBS&amp;lt;/I&amp;gt;.

Estimation of Phenotypic and Genotypic Correlation Analysis in F3 Populations of Bread Wheat Genotypes

Wheat is one of the most important crops all over the world in terms of yield, production, consumption, cultivation, and adoptability. Wheat genotypes exhibiting different yield associated traits which influence each other in many ways. Therefor genotypic and phenotypic correlations are the breeder’s utmost priority to know about the inter-relationship between two or more traits which may be either directly influencing each other in a positive direction or indirectly swaying each other in a negative direction in breeding programs. To find out phenotypic and genotypic correlations among different productive traits, this study was designed at the research area of The Department of Plant Breeding and Genetics, The University of Agriculture, Peshawar, during 2022-23. The experiment was carried out by using 27 wheat genotypes comprising of nine parents and 18 F3 populations evaluated in RCB design with three replications. Overall the study exhibited that kernel yield plant-1, which is one of the most yield contributing trait, was significantly correlated with thousand-kernel weights, tillers plant-1and biomass yield, along some other yield contributing traits. The parental genotype, Janbaz, and cross combinations Watan × AUP-5008, Pirsabak-2005 × AUP-5008, Saleem-2000 × Janbaz and Watan × Tatara were the most promising genotypes for most of quantitative traits and; hence are recommended to be evaluated in further breeding schemes. Both phenotypic and genotypic correlation study exhibited that kernel yield spike-1 was significant and positively associated with plant height, tillers plant-1, thousand-kernel weight and biomass yield. Based on correlations, yield, and production the parental genotype, Janbaz, and F3 combinations Watan × AUP-5008, Pirsabak-2005 × AUP-5008, Saleem-2000 × Janbaz and Watan × Tatara were the most promising genotypes for most of the quantitative traits, which can be incorporated in further breeding program.

Tools and Techniques to Accelerate Crop Breeding.

As climate changes and a growing global population continue to escalate the need for greater production capabilities of food crops, technological advances in agricultural and crop research will remain a necessity. While great advances in crop improvement over the past century have contributed to massive increases in yield, classic breeding schemes lack the rate of genetic gain needed to meet future demands. In the past decade, new breeding techniques and tools have been developed to aid in crop improvement. One such advancement is the use of speed breeding. Speed breeding is known as the application of methods that significantly reduce the time between crop generations, thereby streamlining breeding and research efforts. These rapid-generation advancement tactics help to accelerate the pace of crop improvement efforts to sustain food security and meet the food, feed, and fiber demands of the world's growing population. Speed breeding may be achieved through a variety of techniques, including environmental optimization, genomic selection, CRISPR-Cas9 technology, and epigenomic tools. This review aims to discuss these prominent advances in crop breeding technologies and techniques that have the potential to greatly improve plant breeders' ability to rapidly produce vital cultivars.

Genetic Divergence and Cluster Analysis for Bulb Yield and Related Traits in Garlic Genotypes at Fogera, Northwestern, Ethiopia

Identifying morphological variations among garlic genotypes is crucial for enhancing garlic breeding schemes. This study aimed to assess genetic diversity based on morphological traits of garlic genotypes. The experiment was conducted at the Fogera National Rice Research and Training Center, utilizing a simple lattice design with two replications for planting the genotypes. A total of 49 Ethiopian garlic genotypes were included in the study. Multivariate analysis methods were employed to assess approximately sixteen morphological characteristics. The genotypes were classified into five distinct clusters based on divergence analysis. Clusters 5 and 4 exhibited the highest inter-cluster distance (29.448), indicating genetic diversity. Conversely, clusters 3 and 1 showed the minimum inter-cluster distance, suggesting genetic similarity. Cluster 5 had the highest mean genotypes, indicating its potential for increasing genetic gain through heterosis breeding. Plant height contributed the most to variance, followed by leaf length, number of cloves per bulb, and total soluble solids. The first two principal components explained 74% of the overall variance. Therefore, this study underscores significant diversity in genotypes based on phenotypic characteristics, which could be valuable for future heterosis breeding programs.

Reproductive characteristics of ethiopian indigenous sheep breeds in different production and management settings as inputs for selective breeding schemes: a review

Reproductive characteristics of ethiopian indigenous sheep breeds in different production and management settings as inputs for selective breeding schemes: a review

Improvement of cool-season food legumes for adaptation to intercropping systems: breeding faba bean for intercropping with durum wheat as a case study.

Although the transition toward a more sustainable agricultural system is sparking the interest of scientists and farmers around the globe, breeding programs are still focusing on optimizing cultivars intended for the monoculture system, and most cultivars available on the market are not suitable for intercropping. The incorporation of versatile cool-season food legumes (CSFLs) in the intercropping system is a promising way toward more diversified and sustainable cropping systems. However, as the selection of good-performing cultivars under sole cropping does not always lead to a good performance in intercropping, the development of an alternative breeding scheme for intercropping is now a necessity. The case study of faba bean-wheat intercropping was used to select for traits associated with better performance of faba bean, resulting in identifying the combined grain yield, 100-seed weight, number of pods per plant, and canopy height as key traits for faba bean-wheat intercropping suitability. Incorporating these traits in the breeding programs would be the cornerstone of the prospective transition.

Genomic regions, candidate genes, and pleiotropic variants associated with physiological and anatomical indicators of heat stress response in lactating sows

BackgroundHeat stress (HS) poses significant threats to the sustainability of livestock production. Genetically improving heat tolerance could enhance animal welfare and minimize production losses during HS events. Measuring phenotypic indicators of HS response and understanding their genetic background are crucial steps to optimize breeding schemes for improved climatic resilience. The identification of genomic regions and candidate genes influencing the traits of interest, including variants with pleiotropic effects, enables the refinement of genotyping panels used to perform genomic prediction of breeding values and contributes to unraveling the biological mechanisms influencing heat stress response. Therefore, the main objectives of this study were to identify genomic regions, candidate genes, and potential pleiotropic variants significantly associated with indicators of HS response in lactating sows using imputed whole-genome sequence (WGS) data. Phenotypic records for 18 traits and genomic information from 1,645 lactating sows were available for the study. The genotypes from the PorcineSNP50K panel containing 50,703 single nucleotide polymorphisms (SNPs) were imputed to WGS and after quality control, 1,622 animals and 7,065,922 SNPs were included in the analyses.ResultsA total of 1,388 unique SNPs located on sixteen chromosomes were found to be associated with 11 traits. Twenty gene ontology terms and 11 biological pathways were shown to be associated with variability in ear skin temperature, shoulder skin temperature, rump skin temperature, tail skin temperature, respiration rate, panting score, vaginal temperature automatically measured every 10 min, vaginal temperature measured at 0800 h, hair density score, body condition score, and ear area. Seven, five, six, two, seven, 15, and 14 genes with potential pleiotropic effects were identified for indicators of skin temperature, vaginal temperature, animal temperature, respiration rate, thermoregulatory traits, anatomical traits, and all traits, respectively.ConclusionsPhysiological and anatomical indicators of HS response in lactating sows are heritable but highly polygenic. The candidate genes found are associated with important gene ontology terms and biological pathways related to heat shock protein activities, immune response, and cellular oxidative stress. Many of the candidate genes with pleiotropic effects are involved in catalytic activities to reduce cell damage from oxidative stress and cellular mechanisms related to immune response.

Harnessing monocrop breeding strategies for intercrops.

Intercropping is considered advantageous for many reasons, including increased yield stability, nutritional value and the provision of various regulating ecosystem services. However, intercropping also introduces diverse competition effects between the mixing partners, which can negatively impact their agronomic performance. Therefore, selecting complementary intercropping partners is the key to realizing a well-mixed crop production. Several specialized intercrop breeding concepts have been proposed to support the development of complementary varieties, but their practical implementation still needs to be improved. To lower this adoption threshold, we explore the potential of introducing minor adaptations to commonly used monocrop breeding strategies as an initial stepping stone towards implementing dedicated intercrop breeding schemes. While we acknowledge that recurrent selection for reciprocal mixing abilities is likely a more effective breeding paradigm to obtain genetic progress for intercrops, a well-considered adaptation of monoculture breeding strategies is far less intrusive concerning the design of the breeding programme and allows for balancing genetic gain for both monocrop and intercrop performance. The main idea is to develop compatible variety combinations by improving the monocrop performance in the two breeding pools in parallel and testing for intercrop performance in the later stages of selection. We show that the optimal stage for switching from monocrop to intercrop testing should be adapted to the specificity of the crop and the heritability of the traits involved. However, the genetic correlation between the monocrop and intercrop trait performance is the primary driver of the intercrop breeding scheme optimization process.

Trends and gaps in sweet potato (Ipomoea batatas L.) improvement in sub‐Saharan Africa: Drought tolerance breeding strategies

AbstractThe main challenge facing agricultural crop production in the current global climate change scenario is sustainability. Drought, as a yield‐limiting factor, has become a major threat to international food security. Tolerance to drought is a complex trait and its response is carried out by various genes, transcription factors, microRNAs, hormones, proteins, cofactors, ions and metabolites. The complexity of the trait has limited the development of drought‐tolerant sweet potato cultivars by traditional breeding. Advances in sweet potato breeding to exploit the full potential of the crop to contribute to improved and higher performing sweet potato cultivars, adapted to increasingly risky rainfed conditions, mainly drought, are key to making food production systems more efficient and more tolerant to pressure from drought and other stressors. Genetic gain for yield potential in sweet potato has improved mostly in African countries, mainly as a result of an accelerated breeding scheme. The focus on maximising the utilisation of molecular tools for sweet potato improvement and yield has been recently explored in breeding programmes in sub‐Saharan Africa (SSA). This article provides an update on the trends and gaps in sweet potato breeding in SSA, reviewing the relevant strategies used to improve sweet potato in the region. Finally, the perspectives of using new advanced tools including genetic engineering and genome editing, and the challenges associated with climate change for further improvement of the crop are highlighted. Collaborative efforts in African countries are driving advances in breeding methods through the incorporation of molecular tools to develop drought‐tolerant sweet potato varieties that are important to global food security despite challenges posed by the drastic change in climate.

Evaluation of Teratogenic Profile of Combination of Lumacaftor and Ivacaftor in Sprague–Dawley Rats

Background The individual teratogenicity profiles of Lumacaftor and Ivacaftor are known, but the combined effects remain unexplored. Purpose To evaluate the teratogenic profile of a combination of Lumacaftor and Ivacaftor in Sprague-Dawley Rats. Materials and Methods This study adhered to the Committee for Control and Supervision of Experiments on Animals (CCSEA) and Organisation for Economic Co-operation and Development (OECD) guidelines. Sprague–Dawley rats were acclimated and housed individually under controlled conditions. A polygamous breeding scheme was implemented, and pregnant female rats were assigned to control, vehicle control or treatment group following OECD Test Guideline 414. Lumacaftor and Ivacaftor were administered to pregnant rats at various doses, such as MRHD, 5MRHD, 8MRHD and 10MRHD, from gestation days 6 to 17. Clinical observations, body weight and food consumption of pregnant rats were monitored. Postmortem examinations included caesarean section, reproductive performance (the number of corpora lutea, implantation sites, early and late resorptions and live foetuses) and assessment of foetal analysis. The foetal analysis incorporated external malformation evaluation, visceral examination and skeletal examination using alizarin red solution. Results In pregnant rats exposed to Lumacaftor and Ivacaftor, the external examination was conducted on 206, 209, 199, 184, 198 and 201 foetuses in their respective groups, each consisting of 19 litters. Within this cohort, approximately 33% of foetuses underwent visceral examination. Additionally, across six groups approximately 50% of foetuses underwent skeletal examination. Importantly, no abnormalities were detected in skeletal, visceral or histopathological assessments across the treatment groups encompassing doses of a combination of Lumacaftor and Ivacaftor at MRHD, 5MRHD, 8MRHD and 10MRHD. Additionally, no significant morbidity or mortality related to the treatment was observed. Conclusion In conclusion, the study indicates that the combination of Lumacaftor and Ivacaftor at doses equivalent to MRHD, 5MRHD, 8MRHD and 10MRHD did not induce significant teratogenic effects, affirming their safety during pregnancy in rats.

Genomic analysis of inbreeding and coancestry in Nordic Jersey and Holstein dairy cattle populations

In recent years, Genomic Selection (GS) has accelerated genetic gain in dairy cattle breeds worldwide. Despite the evident genetic progress, several dairy populations have also encountered challenges such as heightened inbreeding rates and reduced effective population sizes. The challenge has been to find a balance between achieving substantial genetic gain while managing genetic diversity within the population, thereby mitigating the negative effects of inbreeding depression. This study aims to elucidate the impact of GS on pedigree and genomic rates of inbreeding (ΔF) and coancestry (ΔC) in Nordic Jersey (NJ) and Holstein (NH) cattle populations. Furthermore, key genetic metrics including the generation interval (L), effective population size (Ne), and future effective population size (FNe) were assessed between 2 time periods, before and after GS, and across distinct animal cohorts in both breeds: females, bulls, and approved semen-producing bulls (AI-sires). Analysis of ΔF and ΔC revealed distinct trends across the studied periods and animal groups. Notably, there was a consistent increase in yearly ΔF for most animal groups in both breeds. An exception was observed in NH AI-sires, which demonstrated a slight decrease in yearly ΔF. Moreover, NJ displayed minimal changes in yearly ΔC between the periods, whereas NH exhibited elevated ΔC values across all animal groups. Particularly striking was the substantial increase in yearly ΔC within the NH female population, surging from 0.02% to 0.39% between the periods. Implementation of GS resulted in a reduction of the generation interval across all animal cohorts in both NJ and NH breeds. However, the extent of reduction was more pronounced in males compared with females. This reduction in generation interval influenced generational changes in ΔF and ΔC. Bulls and AI-sires of both breeds exhibited reduced generational ΔF between periods, in contrast to females that demonstrated an opposing pattern. Between the periods, NJ maintained a relatively stable Ne, 29.4 before and 30.3 after GS, while NH experienced a notable decline from 54.3 to 42.8. Female groups in both breeds displayed a negative Ne trend, while males demonstrated either neutral or positive Ne developments. Regarding FNe, NJ exhibited positive FNe development with an increase from 40.7 to 57.2. The opposite was observed in NH, where FNe decreased from 198.8 to 42.7. In summary, it was evident that the genomic methods could detect differences between the populations and changes in ΔF and ΔC more efficiently than pedigree methods. GS implementation yielded positive outcomes within the NJ population regarding the rate of coancestry but the opposite was observed with NH. Moreover, analysis of ΔC data hints at the potential to decrease future ΔF through informed mating strategies. Conversely, NH faces more pressing concerns, even though ΔF remains comparatively modest in contrast to what has been observed in other Holstein populations. These findings underscore the necessity of genomic control of inbreeding and coancestry with strategic changes in the Nordic breeding schemes for dairy to ensure long-term sustainability in the forthcoming years.