Genetic analysis of longevity and their associations with fertility traits in Holstein cattle.

The increase of longevity is intended to reduce involuntary culling rates, not extend the life span, and it reflects the ability of animals to successfully cope with the environment and disease during production. Sire model, animal model and repeatability animal models were used to estimate the (co) variance components of longevity and fertility traits. Six longevity and thirteen fertility traits were analysed, including herd life (HL), productive life (PL), number of days between first calving and the end of first lactation or culling (L1); number of days between first calving and the end of the second lactation or culling (L2); number of days between first calving and the end of the third lactation or culling (L3); number of days between first calving and the end of the fourth lactation or culling (L4); age at first service, age at first calving (AFC), the interval from first to last inseminations in heifer (IFLh), conception rate of first insemination in heifer, days open (DO), calving interval, gestation length, interval from calving to first insemination (ICF), interval from first to last inseminations in cow (IFLc), conception rate of first insemination in cow, calving ease (CE), birth weight, and calf survival. The estimated heritabilities (±SE) were 0.018 (±0.003), 0.015 (±0.003), 0.049 (±0.004), 0.025 (±0.003), 0.009 (±0.002) and 0.011 (±0.002) for HL, PL, L1, L2, L3 and L4, respectively. Strong correlations were appeared in HL and PL; the genetic and phenotypic correlation coefficients were 0.998 and 0.985, respectively. There were high genetic and phenotypic correlations which were observed in L1 and L2, L2 and L3, L3 and L4, respectively. All fertility traits of heifer showed medium to high heritability, while the cow showed low heritability. All heifer fertility traits had low genetic associations with longevity traits, ranging from -0.018 (L2 and IFLh) to 0.257 (L3 and AFC). Most of the fertility traits showed negative correlations with longevity traits in different parities, and we recommend DO, ICF, IFLc and CE as indirect indicators of longevity traits in dairy cows, but we also need to take into account the differences between parities.

Grayanotoxin I variation across tissues and species of Rhododendron suggests pollinator-herbivore defence trade-offs.

Grayanotoxin I (GTX I) is a major toxin in leaves of Rhododendron species, where it provides a defence against insect and vertebrate herbivores. Surprisingly, it is also present in R. ponticum nectar, and this can hold important implications for plant-pollinator mutualisms. However, knowledge of GTX I distributions across the genus Rhododendron and in different plant materials is currently limited, despite the important ecological function of this toxin. Here we characterise GTX I expression in the leaves, petals, and nectar of seven Rhododendron species. Our results indicated interspecific variation in GTX I concentration across all species. GTX I concentrations were consistently higher in leaves compared to petals and nectar. Our findings provide preliminary evidence for phenotypic correlation between GTX I concentrations in defensive tissues (leaves and petals) and floral rewards (nectar), suggesting that Rhododendron species may commonly experience functional trade-offs between herbivore defence and pollinator attraction.

Residual feed intake breeding value associated with growth, carcass traits, meat quality, bone properties and humoral immunity in Japanese quail.

Improved feed efficiency (FE) is one of the most important achievements in animal breeding programs. The present investigation aimed to determine the phenotypic correlations of residual feed intake (RFI) breeding value with some traits in growing Japanese quail. A total of 48 birds (24 males and 24 females) were selected from 220 quail chicks divided into three classes based on breeding values (BV) for RFI including low (LBV; n = 16), medium (MBV; n = 16), and high-BV (HBV; n = 16) were used to test FE. The effects of three groups of BV on the studied traits including carcass traits, meat quality, humoral immunity, and bone properties were evaluated. The BV for RFI was positively correlated with feed conversion ratio (FCR) and feed intake (FI) but not with metabolic BW (MBW0.75). Live body weight, carcass, breast, and thigh weight in the LBV-RFI group were significantly greater than those in the HBV-RFI group. The BV for RFI had a negative correlation with live body weight and thigh weight. Our findings suggested that the selection of LBV-RFI quails may be useful to increase live body weight without any adverse impact on meat quality and bone properties, and live body weight can be implemented in breeding programs as an indirect selection indicator for improvement of FE in quails.

Estimates of genetic and phenotypic parameters for feeding behaviour and feed efficiency-related traits in Nelore cattle.

The objective of this study was to obtain (co)variance components, heritability, and genetic and phenotypic correlation estimates for feed efficiency and feed behaviour-related indicator traits. Further, it aimed to predict the direct and correlated responses for feed efficiency traits when selection was applied for feeding behaviour-related traits in Nelore cattle. Phenotypic records (n = 4840) from 125 feed efficiency tests (RFI: Residual feed intake and DMI: Dry matter intake) carried out between 2011 and 2018 were considered in this study. Animals belonged to five farms located in two Brazilian geographical regions (Midwest and Southeast). Animals under similar management and environmental conditions in the feedlot were evaluated when they attained an average of 13.5 ± 4.15 months of age. Feed behaviour-related traits were also obtained, including meal criteria (MC), meal frequency (MF), average meal duration (AMD), meal duration (MD), average consumption per meal (ACM), and consumption rate (CR) through the GrowSafe System® electronic bunk system. The contemporary groups for all traits were composed of farm, management group, feed efficiency test, sex, and birth year. The (co)variance components were estimated using the restricted maximum likelihood method considering a multi-trait (n = 8) animal model. The heritability estimates for RFI (0.23 ± 0.02), DMI (0.31 ± 0.02), MF (0.65 ± 0.02), AMD (0.29 ± 0.02), ACM (0.24 ± 0.02), MD (0.41 ± 0.02), MC (0.48 ± 0.02), and CR (0.42 ± 0.02) were moderate to high. The highest genetic correlation was obtained between CR and MD (-0.91 ± 0.04), MD and AMD (0.73 ± 0.03), CR and AMD (-0.68 ± 0.04), and RFI and DMI (0.81 ± 0.02). The highest phenotypic correlation was between ACM and AMD (0.76 ± 0.02), DMI and MD (0.77 ± 0.02), and DMI and RFI (0.77 ± 0.02). Genetic improvement for feed efficiency and feeding behaviour-related traits is feasible and the results obtained herein provided valuable information regarding the genetic background of Nelore feeding behaviour-related traits. The genetic association between feeding behaviour and feed efficiency-related traits suggested that animals spending less time feeding at a low feeding rate also had lower DMI and higher feed efficiency (RFI), and likely had lower energy maintenance requirements. The relative efficiency of selection showed that feeding behaviour-related traits were not adequate indicator traits to improve RFI and DMI. The DMI might be an effective selection criterion to improve RFI and reduce the herd's maintenance requirements.

Estimation of genetic correlations of two key feed efficiency traits with production traits in male Hu sheep.

Increased body growth and feed efficiency are important for breeding due to expensive feed costs. This study estimated the genetic parameters for two feed efficiency traits [the feed conversion ratio (FCR) and the residual feed intake (RFI)] and other important economic traits in male Hu sheep using 1642 male Hu lambs. The heritability of the RFI was estimated at 0.31 (±0.10)-0.54 (±0.1) and the heritability of the FCR was 0.05 (±0.07)-0.77 (±0.12). There was a negative genetic correlation between rib-eye muscle area traits and RFI. A positive genetic correlation was found between fat deposition traits and feed efficiency traits. The digestive tract weight decreased with the direction of RFI: however, the FCR showed the opposite: A low FCR was accompanied by a high digestive tract weight. The genetic correlation between feed efficiency (RFI and FCR) and rumen weight was negative. Heritability estimates for feed efficiency generate fluctuations with different experimental intervals. The weight of other traits should be reasonably allocated to avoid losses in production and feed efficiency in the selection of feed efficiency traits. The present study added to our understanding of the genetic parameters of sheep under the condition of house feeding.

Descriptive Statistics and Genome-Wide Copy Number Analysis of Milk Production Traits of Jiangsu Chinese Holstein Cows.

Milk production traits are the most important quantitative economic traits in dairy cow production; improving the yield and quality of milk is an important way to ensure the production efficiency of the dairy industry. This study carried out a series of in-depth statistical genetics studies and molecular analyses on the Chinese Holstein cows in the Jiangsu Province, such as descriptive statistics and copy number variation analysis. A genetic correlation, phenotypic correlation, and descriptive statistical analysis of five milk production traits (milk yield, milk fat percentage, milk fat yield, milk protein percentage, and milk protein yield) of the dairy cows were analyzed using the SPSS and DMU software. Through quality control, 4173 cows and their genomes were used for genomic study. Then, SNPs were detected using DNA chips, and a copy number variation (CNV) analysis was carried out to locate the quantitative trait loci (QTL) of the milk production traits by Perl program software Penn CNV and hidden Markov model (HMM). The phenotypic means of the milk yield, milk fat percentage, milk fat mass, milk protein percentage, and milk protein mass at the first trimester were lower than those at the other trimesters by 8.821%, 1.031%, 0.930%, 0.003%, and 0.826%, respectively. The five milk production traits showed a significant phenotypic positive correlation (p < 0.01) and a high genetic positive correlation among the three parities. Based on the GGPBovine 100 K SNP data, QTL-detecting research on the fist-parity milk performance of dairy cows was carried out via the CNV. We identified 1731 CNVs and 236 CNVRs in the 29 autosomes of 984 Holstein dairy cows, and 19 CNVRs were significantly associated with the milk production traits (p < 0.05). These CNVRs were analyzed via a bioinformatics analysis; a total of 13 gene ontology (GO) terms and 20 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were significantly enriched (p < 0.05), and these terms and pathways are mainly related to lipid metabolism, amino acid metabolism, and cellular catabolic processes. This study provided a theoretical basis for the molecular-marker-assisted selection of dairy cows by developing descriptive statistics on the milk production traits of dairy cows and by locating the QTL and functional genes that affect the milk production traits of first-born dairy cows. The results describe the basic status of the milk production traits of the Chinese Holstein cows in Jiangsu and locate the QTL and functional genes that affect the milk production traits of the first-born cows, providing a theoretical basis for the molecular-marker-assisted selection of dairy cows.

Heritability enrichment in context-specific regulatory networks improves phenotype-relevant tissue identification.

Systems genetics holds the promise to decipher complex traits by interpreting their associated SNPs through gene regulatory networks derived from comprehensive multi-omics data of cell types, tissues, and organs. Here, we propose SpecVar to integrate paired chromatin accessibility and gene expression data into context-specific regulatory network atlas and regulatory categories, conduct heritability enrichment analysis with genome-wide association studies (GWAS) summary statistics, identify relevant tissues, and estimate relevance correlation to depict common genetic factors acting in the shared regulatory networks between traits. Our method improves power upon existing approaches by associating SNPs with context-specific regulatory elements to assess heritability enrichments and by explicitly prioritizing gene regulations underlying relevant tissues. Ablation studies, independent data validation, and comparison experiments with existing methods on GWAS of six phenotypes show that SpecVar can improve heritability enrichment, accurately detect relevant tissues, and reveal causal regulations. Furthermore, SpecVar correlates the relevance patterns for pairs of phenotypes and better reveals shared SNP-associated regulations of phenotypes than existing methods. Studying GWAS of 206 phenotypes in UK Biobank demonstrates that SpecVar leverages the context-specific regulatory network atlas to prioritize phenotypes' relevant tissues and shared heritability for biological and therapeutic insights. SpecVar provides a powerful way to interpret SNPs via context-specific regulatory networks and is available at https://github.com/AMSSwanglab/SpecVar, copy archived at swh:1:rev:cf27438d3f8245c34c357ec5f077528e6befe829.

Host response to successive challenges with lentogenic and velogenic Newcastle disease virus in local chickens of Ghana.

Newcastle disease (ND) is a highly contagious viral disease that constantly threatens poultry production. The velogenic (highly virulent) form of ND inflicts the most damage and can lead to 100% mortality in unvaccinated village chicken flocks. This study sought to characterize responses of local chickens in Ghana after challenging them with lentogenic and velogenic Newcastle disease virus (NDV) strains. At 4 wk of age, chicks were challenged with lentogenic NDV. Traits measured were pre- and post-lentogenic infection growth rates (GR), viral load at 2 and 6 d post-lentogenic infection (DPI), viral clearance rate and antibody levels at 10 DPI. Subsequently, the chickens were naturally exposed to velogenic NDV (vNDV) after anti-NDV antibody titers had waned to levels ≤1:1,700. Body weights and blood samples were again collected for analysis. Finally, chickens were euthanized and lesion scores (LS) across tissues were recorded. Post-velogenic exposure GR; antibody levels at 21 and 34 days post-velogenic exposure (DPE); LS for trachea, proventriculus, intestines, and cecal tonsils; and average LS across tissues were measured. Variance components and heritabilities were estimated for all traits using univariate animal models. Mean pre- and post-lentogenic NDV infection GRs were 6.26 g/day and 7.93 g/day, respectively, but mean post-velogenic NDV exposure GR was -1.96 g/day. Mean lesion scores ranged from 0.52 (trachea) to 1.33 (intestine), with males having significantly higher (P < 0.05) lesion scores compared to females. Heritability estimates for the lentogenic NDV trial traits ranged from moderate (0.23) to high (0.55) whereas those for the vNDV natural exposure trial were very low (≤ 0.08). Therefore, in contrast to the vNDV exposure trial, differences in the traits measured in the lentogenic challenge were more affected by genetics and thus selection for these traits may be more feasible compared to those following vNDV exposure. Our results can form the basis for identifying local chickens with improved resilience in the face of NDV infection for selective breeding to improve productivity.

Early-life patterns of growth are linked to levels of phenotypic trait covariance and postfledging mortality across avian species.

Life history studies have established that trade-offs between growth and survival are common both within and among species. Identifying the factor(s) that mediate this trade-off has proven difficult, however, especially at the among-species level. In this study, we examined a series of potentially interrelated traits in a community of temperate-zone passerine birds to help understand the putative causes and consequences of variation in early-life growth among species. First, we examined whether nest predation risk (a proven driver of interspecific variation in growth and development rates) was correlated with species-level patterns of incubation duration and nestling period length. We then assessed whether proxies for growth rate covaried with mean trait covariance strength (i.e., phenotypic correlations ( rp), which can be a marker of early-life stress) among body mass, tarsus length, and wing length at fledging. Finally, we examined whether trait covariance strength at fledging was related to postfledging survival. We found that higher nest predation risk was correlated with faster skeletal growth and that our proxies for growth corresponded with increased trait covariance strength ( rp), which subsequently, correlated with higher mortality in the next life stage (postfledging period). These results provide an indication that extrinsic pressures (nest predation) impact rates of growth, and that there are costs of rapid growth across species, expressed as higher mean rp and elevated postfledging mortality. The link between higher levels of trait covariance at fledging and increased mortality is unclear, but increased trait covariance strength may reflect reduced phenotypic flexibility (i.e., phenotypic canalization), which may limit an organism's capacity for coping with environmental or ecological variability.

The role of genus and life span in predicting seed and vegetative trait variation and correlation in Lathyrus, Phaseolus, and Vicia.

PREMISE: Annual and perennial life history transitions are abundant among angiosperms, and understanding the phenotypic variation underlying life span shifts is a key endeavor of plant evolutionary biology. Comparative analyses of trait variation and correlation networks among annual and perennial plants is increasingly important as new herbaceous perennial crops are being developed for edible seed. However, it remains unclear how seed to vegetative growth trait relationships correlate with life span. METHODS: To assess the relative roles of genus and life span in predicting phenotypic variation and trait correlations, we measured seed size and shape, germination proportion, and early-life-stage plant height and leaf growth over 3 mo in 29 annual and perennial, herbaceous congeneric species from three legume genera (Lathyrus, Phaseolus, and Vicia). RESULTS: Genus was the strongest predictor of seed size and shape variation, and life span consistently predicted plant height and leaf number at single time points. Correlation networks revealed that annual species had significant associations between seed traits and vegetative traits, whereas perennials had no significant seed-vegetative associations. Each genus also differed in the extent of integration between seed and vegetative traits, as well as within-vegetative-trait correlation patterns. CONCLUSIONS: Genus and life span were important for predicting aspects of early-life-stage phenotypic variation and trait relationships. Differences in phenotypic correlation may indicate that selection on seed size traits will impact vegetative growth differently depending on life span, which has important implications for nascent perennial breeding programs.

Improved Estimation of Phenotypic Correlations Using Summary Association Statistics.

Estimating the phenotypic correlations between complex traits and diseases based on their genome-wide association summary statistics has been a useful technique in genetic epidemiology and statistical genetics inference. Two state-of-the-art strategies, Z-score correlation across null-effect single nucleotide polymorphisms (SNPs) and LD score regression intercept, were widely applied to estimate phenotypic correlations. Here, we propose an improved Z-score correlation strategy based on SNPs with low minor allele frequencies (MAFs), and show how this simple strategy can correct the bias generated by the current methods. The low MAF estimator improves phenotypic correlation estimation, thus it is beneficial for methods and applications using phenotypic correlations inferred from summary association statistics.

Relationship between Temperament and Stage of Lactation, Productivity and Milk Composition of Dairy Cows.

The aim of this study was to assess the relationship between temperament and milk performance in cows at different stages of lactation, describing their productivity, metabolic status and resistance to mastitis. This study showed that with increasing lactation, cows' temperament indicators decreased (p < 0.001) and they became calmer. The highest temperament score on a five-point scale was found in cows between 45 and 100 days of lactation. In the group of pregnant cows, we found more cows (p = 0.005) with a temperament score of 1-2 compared with non-pregnant cows A normal temperament was usually detected in cows with lactose levels in milk of 4.60% or more and when the somatic cell count (SCC) values in cow milk were <100,000/mL and 100,000-200,000/mL, with a milk fat-to-protein ratio of 1.2. A larger number of more sensitive and highly aggressive cows was detected at a low milk urea level. In contrast to a positive phenotypic correlation (p < 0.05), this study showed a negative genetic correlation between the temperament of cows and milk yield (p < 0.001). Positive genetic correlations between temperament scores and milk somatic cells (p < 0.001) and milk fat-to-protein ratio (p < 0.05) were found to indicate a lower genetic predisposition in cows with a calmer temperament to subclinical mastitis and ketosis. On the other hand, the heritability of temperament (h2 = 0.044-0.100) showed that only a small part of the phenotypic changes in this indicator is associated with genetic factors.

Utilization of genetic diversity and marker-trait to improve drought tolerance in rice (Oryza sativa L.).

Drought stress is one of the main problems for the rice crop, as it reduces the production and productivity of the grain yield significantly. In Egypt, many restrictions were made on the cultivation of rice due to its high-water demand. Producing promising drought-tolerant rice cultivars combined with high yielding is one of the main targets for rice breeders. A set of 22 highly diverse rice genotypes were evaluated under normal and drought conditions. Morphological, physiological, and yield traits were recorded on each genotype. Drought susceptibility index (DSI) was estimated for six yield traits to identify the most drought-tolerant rice genotypes. A high genetic variation was found among genotypes tested in the experiment. Under normal conditions, the highest phenotypic correlation was found between grain yield (GY) and sterility percentage (SP) (- 0.73**), while it was among GY and chlorophyll content (CC) (0.82**) under drought conditions. To identify quantitative trait loci (QTL) controlling yielding traits under drought and normal, a single marker analysis was performed between all yield traits under both conditions and a set of 106 simple sequence repeat (SSR) marker alleles. The genetic association analysis revealed 14 and 17 QTL under drought and normal conditions, respectively. The most drought-tolerant genotypes were selected based on phenotypic traits, the number of QTL in each selected genotype, and the level of genetic diversity existed among the genotypes. As a result, five genotypes (Giza 178, IET1444, GZ1368-S-5-4, Nahda, Giza 14) were identified as the most promising drought-tolerant rice genotypes. Eight QTL controlling drought tolerance were identified in Giza 178, Nahda, and GZ1368-S-5-4, while four QTL were found in IET1444. The number of different QTLs were estimated among the five selected genotypes. Giza 178 and GZ1368-S-5-4 shared the same QTLs. Seven different QTLs were found among Nahda, IET1444, GZ1368-S-5-4, and Giza 14. Combining information from phenotypic traits, genetic diversity analysis, and QTL analysis was very useful in identifying the true drought-tolerant rice genotypes that can be used for crossing in the future breeding program.

Attention-deficit/hyperactivity disorder symptoms and dietary habits in adulthood: A large population-based twin study in Sweden.

Associations between adult attention-deficit/hyperactivity disorder (ADHD) symptoms and dietary habits have not been well established and the underlying mechanisms remain unclear. We explored these associations using a Swedish population-based twin study with 17,999 individuals aged 20-47 years. We estimated correlations between inattention and hyperactivity/impulsivity with dietary habits and fitted twin models to determine the genetic and environmental contributions. Dietary habits were defined as (a) consumption of food groups, (b) consumption of food items rich in particular macronutrients, and (c) healthy and unhealthy dietary patterns. At the phenotypic level, inattention was positively correlated with seafood, high-fat, high-sugar, high-protein food consumptions, and unhealthy dietary pattern, with correlation coefficients ranging from 0.03 (95%CI: 0.01, 0.05) to 0.13 (95% CI: 0.11, 0.15). Inattention was negatively correlated with fruits, vegetables consumptions and healthy dietary pattern, with correlation coefficients ranging from -0.06 (95%CI: -0.08, -0.04) to -0.07 (95%CI: -0.09, -0.05). Hyperactivity/impulsivity and dietary habits showed similar but weaker patterns compared to inattention. All associations remained stable across age, sex and socioeconomic status. Nonshared environmental effects contributed substantially to the correlations of inattention (56-60%) and hyperactivity/impulsivity (63-80%) with dietary habits. The highest and lowest genetic correlations were between inattention and high-sugar food (rA = .16, 95% CI: 0.07, 0.25), and between hyperactivity/impulsivity and unhealthy dietary pattern (rA = .05, 95% CI: -0.05, 0.14), respectively. We found phenotypic and etiological overlap between ADHD and dietary habits, although these associations were weak. Our findings contribute to a better understanding of common etiological pathways between ADHD symptoms and various dietary habits.

Genetic parameters of girolando crossbred cows in dairy herds in the State of Acre, Brazil / Parâmetros genéticos de vacas mestiças girolando em rebanhos leiteiros no Estado do Acre, Brasil / Parámetros genéticos de vacas cruzadas girolando en ganados lecheros en el Estado de Acre, Brasil

This study aimed at estimating genetic parameters for milk production and conformation characteristics in Girolando crossbred dairy cows reared in the High and Low Acre region using the restricted maximum likelihood methodology, under an animal model. We estimated the variance components and genetic parameters using the REML/BLUP procedure (Restricted Maximum Likelihood Methodology/Best Linear Unbiased Prediction). The estimated average for milk production for 305 days of lactation (P305) was of 1523.25 ± 481.11 kg, with a heritability of 0.38 for this characteristic. The conformation characteristics showed no significant correlation with milk production. The phenotypical correlations between the linear characteristics of type were, in general, positive and moderate. The P305 obtained in this study can be considered low and indicates that there is a possibility of increasing milk production through selection in herds along with the use of tested and proven bulls. The heritability estimate found (0.38) indicates that there is genetic variability for milk production, demonstrating that selection for this characteristic would result in genetic progress.(AU)

Este estudo teve como objetivo estimar parâmetros genéticos para produção de leite e características de conformação em vacas leiteiras mestiças Girolando criadas na região do Alto e Baixo Acre, utilizando a metodologia da máxima verossimilhança restrita, sob modelo animal. As estimativas dos componentes de variância e dos parâmetros genéticos foram realizadas pelo procedimento REML/BLUP (Máxima verossimilhança restrita/Melhor predição linear não viesada). A média estimada para produção de leite aos 305 dias de lactação (P305) foi de 1.523,25 ± 481 kg e a herdabilidade para esta característica foi de 0,38. As características de conformação não apresentaram correlação significativa com a produção de leite. As correlações fenotípicas entre as características lineares de tipo foram em geral positivas e de magnitude moderada. A P305 obtida neste estudo pode ser considerada baixa e indica que existe a possibilidade de aumento da produção de leite através de seleção nos rebanhos, juntamente com a utilização de touros testados e provados. A estimativa de herdabilidade encontrada (0,38) indica que há variabilidade genética para produção de leite, demonstrando que a seleção para esta característica resultaria em progresso genético.(AU)

El objetivo del estudio fue estimar los parámetros genéticos para la producción de leche y las características de conformación en vacas lecheras cruzadas Girolando criadas en la región de Alto y Bajo Acre utilizando el método de máxima verosimilitud restringida, con un modelo animal. Estimamos los componentes de la varianza y los parámetros genéticos mediante el procedimiento REML / BLUP (metodología de máxima verosimilitud restringida / mejor predicción lineal insesgada). El promedio estimado para la producción de leche para los 305 días de lactancia (P305) fue de 1523.25 ± 481.11 kg, con una heredabilidad de 0.38 para esta característica. Las características de conformación no mostraron correlación significativa con la producción de leche. Las correlaciones fenotípicas entre las características lineales de tipo fueron, en general, positivas y moderadas. El P305 obtenido en este estudio puede considerarse bajo y muestra que existe la posibilidad de incrementar la producción de leche a través de la selección en rebaños, junto con el uso de toros probados y comprobados. La estimación de heredabilidad encontrada (0,38) indica que existe variabilidad genética para la producción de leche, lo que demuestra que la selección de esta característica daría lugar a un progreso genético.(AU)

Genetic and non-genetic factors influencing the performance of the West African Dwarf (WAD) goat kept at the Kintampo Goat Breeding Station of Ghana.

A study was conducted to analyze the effect of genetic and non-genetic factors influencing the growth performance of the West African Dwarf goat. Breed records of 836 kids born by 259 does, and 8 bucks from 2011 to 2017 at the station were used. Growth performance traits studied were birth weight, weaning weight, 6-month body weight, 9-month body weight, yearling weight, and pre-weaning and post-weaning growth rates. The fixed effects of sex of kid (male or female), season of kidding (major, minor, and dry), year of kidding (2011-2017), and type of birth (single, twins, or triplets) on growth performance were determined. Genetic parameters such as heritability and correlations among the traits were also estimated. The non-genetic data (fixed factors) obtained were analyzed using the general linear model procedures of GenStat (Discovery Edition 12). Heritability estimates obtained for the growth traits were 0.45 ± 0.15, 0.57 ± 0.29, 0.04 ± 0.05, 0.74 ± 0.59, 0.49 ± 0.35, 0.55 ± 0.39, and 0.54 ± 0.36, respectively, an indication of high genetic variation existing among the traits (with the exception of 6-month body weight). This could be harnessed and utilized for genetic improvement within the flock. The phenotypic correlation coefficients among the traits ranged from low to high (0.04-0.95), indicating that there is a linear relationship among body traits of the goats which may be caused by either genetic or environmental factors of correlation. The genetic correlations were also medium to high (0.30-0.96). The general implications are that selection for any of these growth traits in a breed improvement programme would have a considerable simultaneous positive impact on each other. The overall birth weight, weaning weight, 6-month body weight, 9-month body weight, yearling weight, and pre- and post-weaning growth rates obtained were 1.48 kg, 5.35 kg, 6.56 kg, 8.30 kg, 10.00 kg, 32.26 g/day, and 19.39 g/day, respectively. These growth performances were found to be significantly influenced by the non-genetic factors studied. There is therefore the need to factor these in future breed improvement programmes to ensure their success.

Factors affecting wool characteristics of sheep reared in Kashmir.

This study was conducted on 82,908 records of purebred and upgraded Kashmir Merino sheep to evaluate the performance of breed over the years. The data pertaining to fiber diameter (FD), staple length (SL), clean wool yield percent (CWY %), number of crimps/cm (NCPC), and medullation percent (MP) spread over a period of 15 years (2013-2017) was collected from Fleece Testing Laboratory Nowshera, Srinagar. The highest CV (%) was observed for MP, whereas the lowest CV (%) was observed for FD (2.07%). The least-squares means were 20.96 ± 0.002 µm, 4.05 ± 0.01 cm, 66.68 ± 0.01%, 4.38 ± 0.02 No/cm and 0.79 ± 0.05% for FD, SL, CWY (%), NCPC and MP, respectively. The year of shearing had highly significant (p < 0.01) effect on all the traits under the study. The study concludes that crossbreeding with exotic fine wool breeds has resulted improved genetic potential of native germplasm with respect to wool quality traits with Merino sheep performing better in the agro-climatic conditions of the State. Environment was also found to play a significant role in expression of wool quality traits during the period of the study.

Effect of stress on the leaf anatomy of sugarcane cultivars with different drought tolerance(Saccharum officinarum, Poaceae)

Introduction: Drought is an important stress factor for sugarcane production in many areas of the world. Water proportion and moisture indices are applicable information for agronomic planning to forecast water excess or deficit during the crop cycle. Objective: Leaf anatomical features of two different sugarcane Saccharum 'UT12' (drought susceptible cultivar) and Saccharum 'UT13' (drought tolerant cultivar) were compared under early drought stress situation between 30 and 90 days after planting. Methods: Forty leaf anatomical features were investigated using peeling and free hand sectioning technique. Results: Some anatomical characteristics showed response to drought stress. Saccharum 'UT12' demonstrated higher sensitivity toward anatomical characteristics than Saccharum 'UT13'. A total of 23 and 15 out of the 40 anatomical characteristics showed significance in Saccharum 'UT12' and Saccharum 'UT13', respectively. Some anatomical features such as cell wall and cuticle thickness, vascular bundle size, stomatal size and density can be used as important markers for drought stress assessment in sugarcane leaf. Conclusions: This is the first report describing comparative leaf anatomy of sugarcane Saccharum 'UT12' and Saccharum 'UT13' in Thailand under drought stress. Results will provide important information to improve adaptation mechanisms of tolerant sugarcane cultivars under initial drought stress situations.

Introducción: La sequía es un factor de estrés importante para la producción de caña de azúcar en muchas áreas del mundo. La proporción de agua y los índices de humedad son información aplicable en la planificación agronómica para pronosticar el exceso o el déficit de agua durante el ciclo del cultivo. Objetivo: Se compararon las características anatómicas de las hojas de dos cañas de azúcar diferentes Saccharum 'UT12' (cultivar susceptible a la sequía) y Saccharum 'UT13' (cultivar tolerante a la sequía) bajo una situación de estrés por sequía temprana entre 30 y 90 días después de la siembra. Métodos: Se investigaron las características anatómicas de cuarenta hojas utilizando la técnica de seccionamiento de pelado y manos libres. Resultados: Algunas características anatómicas mostraron respuesta a estrés por sequía. Saccharum "UT12" demostró una mayor sensibilidad hacia las características anatómicas que Saccharum 'UT13'. Un total de 23 y 15 de las 40 características anatómicas mostraron significancia en Saccharum 'UT12' y Saccharum 'UT13', respectivamente. Algunas características anatómicas como la pared celular y el grosor de la cutícula, el tamaño del haz vascular, el tamaño y la densidad de los estomas se pueden utilizar como marcadores importantes para evaluar el estrés por sequía en la hoja de caña de azúcar. Conclusiones: Este es el primer reporte que describe la anatomía comparada de la hoja de la caña de azúcar Saccharum 'UT12' y Saccharum 'UT13' en Tailandia bajo estrés por sequía. Los resultados proporcionarán información importante para mejorar los mecanismos de adaptación de cultivares tolerantes de caña de azúcar bajo situaciones iniciales de estrés por sequía.

Single Nucleotide Polymorphisms Influence Histological Type and Grade of Canine Malignant Mammary Tumours.

Histological examination of canine mammary tumours is mandatory for determining the histological type and grade of the lesions, features that provide relevant information regarding the biological behaviour of the disease. Different histological classification systems and grading methods have been used to characterize canine mammary tumours. In this study, the relationship between the genetic profile of 87 female dogs (i.e. single nucleotide polymorphisms [SNPs] in genes known to be involved in mammary carcinogenesis) and the histological type and grade of malignant mammary tumours was assessed. The results demonstrated a significant relationship between genetic variation in genes RAD51, BRCA2, CHEK2, HER2, CDH1, COMT and PGR and these morphological features of the mammary lesions. Specifically, SNPs in RAD51 (rs23623251 and rs23642734), CHEK2 (rs397511718), HER2 (rs24537329) and PGR (rs8875007) were related to aggressive histotypes, with moderate to high histological grade. In contrast, SNPs in BRCA2 (rs23255542), HER2 (rs24537331), CDH1 (rs852280880 and rs850805755) and COMT (rs851328636, rs853133060 and rs85346495) were associated with tumour histotypes of good prognosis and of low histological grade. These data provide preliminary evidence for a genotypic-phenotypic correlation in canine mammary tumours, highlighting the mechanisms of their genesis, development and progression.

Correlation and genetic analysis of seed shell thickness and yield factors in Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.).

In order to solve the difficult problem of the outer shell covering in the processing of Tartary buckwheat, we conducted a genetic analysis in segregating F2 and F3 populations derived from a hybrid between 'Yunqiao No. 1' and 'Rice buckwheat', and the F3 population was used to analyze the phenotypic and genetic correlation among the traits. The results showed that the variety with a value of trait for seed shell thickness over 0.20 mm is a hard-shelled type (The thick shell type = seed shell rate > 20%), and that with a value of trait for seed shell thickness below 0.15 mm is a easily-shelled type (The thin shell type = seed shell rate < 20%), while that with a value of trait for seed shell thickness ranging from 0.15 mm to 0.20 mm is a hard-shelled type or easily-shelled type. In addition, alleles for traits of number of seed per plant and total seed weight per plant have larger dominance variance relative to their additive variance, indicating that genes controlling these traits have larger dominant effects, it is not suitable for the selection of single plant in offspring plants at the early stage of development, because these traits do not show up then. The alleles for traits of 1000 kernel weight and seed shell thickness have larger additive variance relative to their dominant variance, indicating that genes governing these traits have greater additive effects, with which the single plant can be selected in the progeny at the early stage of development. Although, the value of seed shell thickness has been shown to correlated positively with that of 1000 kernel weight, almost all the seeds of easily-shelled type are those with thin shell. However, ideal single plants with easily-shelled trait are those with intermediate phenotypes of seed shell thickness and 1000 kernel weight, by which the traits of large number of seeds per plant and total seed weight per plant could be selected. In the progeny population of this study, there were excellent single plants with high-yield and easily-shelled traits, of which the value of seed shell thickness was 0.17 mm (0.15 mm to 0.20 mm), the value of 1000 kernel weight was 14 g, the value of number of seeds per plant was 1137 and value of total seed weight per plant was 15.9 g. The results showed that taking the hybrid combinations of easily-shelled trait with the trait of seed shell thickness was the most effective selection indexes to breed the high-yield buckwheat varieties with the trait of easy shelling.