Positive Phenotypic Correlations Research Articles

347 Quantifying phenotypic and genetic variation for cow fertility phenotypes in American Simmentals using total herd reporting data

Abstract Inefficiencies in reproduction are the largest drivers of loss in United States beef production. Nearly all reproductive traits are at least modestly heritable, making genetic selection and improvement possible over the long term. Cow-centric reproductive traits present unique challenges, as they are not expressed in male animals and will not be observed until later in the productive life of a female, if at all. This makes cow-centric fertility traits ideal candidates for selection with Expected Progeny Differences (EPDs). We used a commercially generated dataset from the American Simmental Association (ASA) to explore the phenotypic and genetic variation in these traits. The dataset comprised Total Herd Enrollment (THE) records, which required unbiased reporting of enrollment, calving, and disposal for 303,158 females (132,403 cows and 170,755 heifers). Using the THE data, we calculated three continuous and two discrete traits that are indicators of heifer and cow fertility and rebreeding ability. These traits were: 1) calving date (calving date of the cow relative to the start of the calving season), 2) calving interval (days between calves), 3) first calving interval (calving interval observation between the first and second calving record for a female), 4) heifer pregnancy (did the animal calve as 2-yr-old?), and 5) discrete early calving (did animal calve in the first 30 d of the calving season?). We observed a significant difference in calving date in mature cows that calved in the first 30 d of the calving season of their contemporary group as heifers compared with those that calved later (Table 1). Early calving heifers averaged a nearly 10 d sooner calving date throughout their productive lives compared with those that calved after 30 d as heifers (29.9 d vs. 40.2 d, P-value < 0.01). We used a combined pedigree and genomic approach, implemented in GIBBSF90+, to estimate genetic, environmental, and permanent environmental variance components. We estimated heritabilities of 0.24 (± 0.037215) for heifer pregnancy, 0.06 (± 0.009265) for calving date, 0.07 (± 0.015451) for discrete early calving, 0.04 (± 0.003954) for calving interval, and 0.04 (± 0.009604) for first calving interval. We observed positive phenotypic and genetic correlations between these traits, ranging from 0.01 to 0.96 (Table 2). This work provides an extensive population survey of phenotypic trends in reproductive performance and management in a large seedstock population. The heritable nature of the inspected traits motivates further work in understanding their genetic architectures and how they are affected by heterosis in crossbreeding programs.

Association and Path Coefficient Analysis of Some Arsi Coffee Accesions (<i>Coffea arabica </i>L.) for Quality Traits at Mechara, Ethiopia

Coffee is still one of Ethiopian’s primary agricultural export crops accounting for more than 25% of export earnings. Arsi coffee is known to produce Harar C coffee quality grade and known for its unique flavor and aroma. Therefore, this study was conducted to determine association among coffee bean quality traits and, the direct and indirect effects of bean quality traits on overall quality of coffee. A total of 56 Arsi coffee accessions and four Hararghe coffee varieties were evaluated for bean physical and organoleptic coffee quality traits using Completely Randomized Design with three replications. The analysis of variance results showed significant variation among Arsi coffee accession for all traits except astringency, bitterness, and odor. The overall coffee quality had positive and significant phenotypic and genotype correlations with aromatic intensity, aromatic quality, acidity, body, flavor, overall standard quality and overall cup quality. These traits also had positive direct effects on overall coffee quality however; aromatic intensity and body exerted negligible negative direct effects at genotypic level whereas aromatic quality had negative direct effect at phenotypic level. All these traits through overall standard quality, and aromatic intensity, aromatic quality and acidity via each other and through body and flavor exerted positive direct effects on overall coffee quality at genotypic level. Thus majority of quality traits could be used for indirect selection of genotypes for overall coffee quality.

Correlations among New Mexico pod‐type green chile (Capsicum annuum) fruit morphology characteristics with destemming force

AbstractDestemming refers to the removal of the calyx and pedicel from chile (Capsicum annuum) fruit, and destemming force is the amount of force required to accomplish this removal. The objective of this study was to describe the relationship between destemming force and fruit width, fruit length, and pericarp thickness, along with the genetic potential for combining the easy‐destemming attribute with the preferred fruit morphology of New Mexico (NM) pod‐type green chile. This investigation will define optimal selection criteria for reducing destemming force, while preserving the distinctive morphology of NM pod‐type green chile. We quantified phenotypic and genetic variation of 285 F3 families from three populations developed from reciprocal crosses between three NM pod‐type cultivars and an easy‐destemming cultivar. The results show destemming force exhibited significant positive phenotypic correlations with pericarp thickness and fruit width (0.90 and 0.92, respectively) and fruit length (0.69). Genetic correlations for each of the three populations for fruit morphological traits ranged from 0.2 to 0.9, with pericarp thickness with the highest genetic correlation with destemming force. Narrow‐sense heritability values were between 0.2 and 0.8, with destemming force and fruit length consistently having higher narrow‐sense heritability values. These findings suggest a correlation between the expression of pericarp thickness and destemming force. The lower estimates for pericarp thickness indicate environmental influences may play a more significant role in determining trait expression. The information generated from this study will aid in the development of efficient cultivars suited for mechanical harvesting in NM pod‐type breeding programs.

Genetic variability and trait associations in bread wheat (Triticum aestivum L.) genotypes under drought-stressed and well-watered conditions

Drought is one of the most important yield-limiting abiotic stresses threatening wheat production and productivity. Development of wheat genotypes with enhanced grain yield under drought-stressed conditions depend on the extent of genetic variation present for drought tolerance-related traits. This study was carried out to determine the level of genetic variation and associations of yield and yield attributing traits among 196 bread wheat genotypes under drought-stressed and well-watered conditions. The genotypes were evaluated under greenhouse and field conditions and phenotyped for yield and yield-related traits. The genotypes varied significantly for the traits under both conditions. Grain yield ranged from 2.13 to 3.74 t ha−1 and from 2.52 to 5.06 t ha−1 under drought-stressed and well-watered conditions, respectively. Under both conditions, variances due to genotype were higher than environment and genotype × environment interaction variances for all the traits. Estimates of phenotypic coefficient of variation (PCV) were higher than genotypic coefficient of variation (GCV) for all the traits under both conditions, with both PCV and GCV being highest for kernel weight spike−1 and lowest for spike fertility. Under both conditions, broad-sense heritability estimates ranged from moderately high to very high, accompanied with high genetic advance as a percentage of the mean. Fertile spikelets spike−1, one thousand kernel weight, kernel weight spike−1, biomass yield and harvest index manifested high positive genotypic and phenotypic correlations and positive direct effects on grain yield under both conditions. The first five principal components accounted for 78.4% (well-watered) and 76.0% (drought-stressed) of the variation among the genotypes. The 196 genotypes were delineated into six major clusters under both water conditions, with clusters 3 (well-watered) and cluster 5 (drought-stressed) containing genotypes with the highest ability to tolerate drought stress. Genotypes Alidoro, Bolo, Dinknesh, ETBW8491 and ETBW172938 had high stable yields under both conditions. The identified traits and genotypes were drought tolerant and could be exploited to develop novel genotypes for drought stress tolerance.

Genetic Variability and Character Association Analysis in Wheat (Triticum aestivum L.) in Saline Water Condition

The study was conducted to evaluate eight germplasms/varieties of wheat during the rabi season (November-April, 2022–23) using a randomized block design with three replications at the research farm of Agricultural Research Sub-Station (ARSS), Nagaur (Rajasthan), India to estimate the variability parameters and characters association for nine characters. The results were revealed that mean sum of squares due to genotypes showed significant differences for all the nine characters under study, suggested that the genotypes were genetically divergent. The phenotypic coefficient of variation values was higher than genotypic coefficient of variation values for all the nine traits which reflect the influence of environment on the expression of traits. Spike length and number of spikelets were showed higher PCV and medium GCV. High heritability estimates were recorded for all the nine characters. High genetic advance as percentage of mean along with high heritability was observed for number of spikelets, spike length, number of effective tillers plant-1, seed yield and number of grains spike-1. This indicated the existence of lesser environmental influence and prevalence of additive gene action in their expression and these traits possessed high selective value. These characters could be further improved through individual plant selection. Grain yield had highly significant and positive genotypic and phenotypic correlations with plant height, number of effective tillers plant-1, spike length, number of spikelets and number of grains spike-1. These characters can be considered as criteria for selection for higher grain yield as these were mutually and directly associated with grain yield.

Synthetic cultivar development in cumin: Enhancing yield and drought tolerance

Cumin (Cuminum cyminum L.) is a valuable spice crop with medicinal properties belonging to the Apiaceae family. While farmers often favor the cultivation of cumin, low seed yield, particularly under drought stress, poses challenges to its commercial production. Due to cumin small flowers, self-incompatibility, and cross-pollination attributes, the production of synthetic varieties through polycross breeding can be an effective method for improving seed performance and enhancing drought tolerance in cumin. This study, for the first time, investigates the breeding progress of cumin in three populations over two generations. The first generation resulting from polycross breeding (SYN2 population), along with parental genotypes, was evaluated for agro-morphological traits under normal and low-water irrigation conditions in two locations and compared with the SYN1 population. Additionally, genetic diversity among parental genotypes, SYN1, and SYN2 populations was examined using Start Codon Targeted Polymorphism (SCoT) markers. Low water stress negatively affected all studied traits, except for essential oil content. Improved seed yield, increased drought tolerance, and higher cuminaldehyde content were observed in the SYN2 population compared to parental genotypes. Estimation of genetic parameters indicated a higher heritability and heterosis for traits in the SYN1 population compared to SYN2. Furthermore, trait heritability in the SYN2 population was higher under normal irrigation condition than under water stress. The highest narrow-sense heritability in both SYN1 and SYN2 populations was associated with the thousand-seed weight. Positive and significant phenotypic and genotypic correlations between thousand-seed weight and seed yield were observed in the SYN1 population, while the SYN2 population exhibited the least negative impact of drought stress on this trait. Grouping populations through cluster analysis and principal coordinate analysis based on both molecular and agro-morphological data showed complete concordance, effectively distinguishing cumin populations from one another. The SCoT molecular marker confirmed the homogeneity of the improved populations, demonstrating high efficiency in assessing intra- and inter-population diversity. Molecular variance analysis revealed lower within-population diversity (29 %) compared to between-population diversity (71 %). Among populations, SYN1, equivalent to F2 generation, exhibited the highest level of molecular diversity based on diversity indices.

Phenotypic characterization of ethyl methanesulfonate (EMS) induced bigger pod (bp) with multiple seed mutant in lentil (Lens culinaris Medik.)

Lentils (Lens culinaris Medik.) is a protein- and nutrient-rich crop with limited genetic diversity and climate adaptability, making it ideal for mutation breeding research. Hence, in this study, we aimed to select and characterize distinct mutations in the flower and pod traits of lentil crops for enhanced yield and yield stability. In this study, healthy and viable lentil seeds were mutagenized using different concentrations of ethyl methanesulfonate (EMS) (0.10%, 0.25%, 0.50%, 0.75%, and 1.0%). The mutagenized lentil populations were cultivated up to the third generation (M3) to identify stable mutations in the flower and pod structures with increasing plant height. The notably larger 'bigger pod’ (bp) mutant, characterized by its unusually large pods containing 6–7 seeds per pod, was meticulously studied and quantified for its morphological traits in subsequent generations. Morphological observations of the tall bp mutant revealed significant mutations induced by EMS (0.10%) treatment. The quantitative trait means and confidence intervals showed that the mutant and parent cultivar L-4076 exhibited considerable variation. Seed yield (g) and yield-related components, including pods per plant, pod length (cm), and seeds per pod, were significantly higher in the mutant. Seed yield exhibited a significant positive phenotypic correlation with pod length, followed by branches per plant, seeds per pod, plant height, and pods per plant. The novel bp mutant induced in the present study produced increased number of seeds per plant and ensured optimal resource utilization, thus possibly contributing to yield improvement and stability. Further, it also aided in understanding the genetic networks that control legume flower and pod architecture and in genomics-assisted breeding for the development of superior lentil cultivars.

Genetic variability and path coefficient analysis among bread wheat (Triticum aestivum L.) genotypes for yield and yield‐related traits in bale highlands, southeastern Ethiopia

AbstractWheat (Triticum aestivum L.) is one of the most important strategic crops to overcome food security problems in the world including Ethiopia. This can be achieved through genetic improvement of the crop and its production practices. In this connection, information on the mutual association of traits is important for effective selection in wheat‐breeding programs. In 2021/2022 production year, a field experiment was undertaken to estimate the extent of genetic variability, path analysis, and association of yield and yield‐related characteristics for the selection of desirable wheat genotypes. A total of 64 bread wheat genotypes, including yellow rust‐resistant Boru (resistant), Hachalu (moderately resistant), and Madda‐Walabu (susceptible) as control, were used for the field experiment at Sinana and Agarfa Agricultural Research Centers. The experiment was laid out in a simple alpha lattice design. The mean analysis of variances showed highly significant differences (p < 0.001) for all traits among the tested genotypes. The value of the phenotypic coefficient of variance was higher than the genotypic coefficient of variance for all studied traits, indicating the presences of higher genetic variability among the tested genotypes. Grain yield had a significant positive correlation with days to maturity, grain‐filling period, plant height, kernels spike−1, thousand seed weight, and biological yield at both genotypic and phenotypic levels including spike length at phenotypic levels at both locations and with plant height, thousand seed weight, and biological yield at both locations at genotypic and phenotypic levels. Similarly, days to maturity and grain‐filling period also showed a significant positive phenotypic correlation with grain yield. The analyzed path coefficients at both genotypic and phenotypic levels also indicated how grain yield is influenced directly and indirectly by other yield and yield‐related traits. The result also showed the existence of good heritability values along with high genetic advance, higher phenotypic coefficient of variation and genotypic coefficient of variation for grain yield, biological yield, and grain‐filling period. This implies the true relationship among these traits and grain yield; therefore, due attention should be paid to such traits during selection for further improvement. Hence, the present study indicated the importance of the direct and indirect effects of the studied traits on yield and yield components which makes selection desirable for improving the grain yield of wheat and its genetic resistance against yellow rust in the study area.

Estimation of genetic parameters as well as trends for growth traits in Harnali sheep

The current study focussed on the growth traits pertaining to Harnali sheep maintained at Sheep Farm, LUVAS, Hisar and data were recorded from pedigree sheets of 1278 animals. Growth traits considered were birth weight (BW), weaning weight (WW), six-month weight (6MW), yearling weight (YW), and pre-weaning average daily gain (PRWDG) and least-squares means for corresponding traits found to be 3.28±0.02 kg, 12.89±0.07 kg, 17.06±0.06 kg, 24.36±0.06 kg, and 106.74±0.61 g, respectively. Effect of different factors like period of birth, sex of animal and dams’ weight at lambing was studied on growth traits. Except YW, significant effect of period of birth was observed on all the growth traits. Sex had significant influence on BW only however, dams’ weight at lambing affected significantly all the considered growth traits except YW. By leveraging the sire component of variance and covariance from mixed model analysis, the paternal half-sib correlation method was used to estimate genetic as well as phenotypic parameters. Estimates of heritability for BW, WW, 6MW, YW and PRWDG were 0.28±0.07, 0.33±0.07, 0.31±0.07, 0.12±0.04 and 0.27±0.06, respectively. Genetic as well as phenotypic trends for WW and PRWDG were found to be positive. Moderate range of genetic variability at weaning weight and its positive genetic and phenotypic correlations with growth traits specially six month’s weight indicated that genetic improvement could be possible through early selection at weaning weight in Harnali sheep.

Estimate of Genotypic and Phenotypic Correlation and Path Coefficient in Brinjal (Solanum melongena L)

The significant positive correlation among phenotypic and genotypic performance, as well as path correlation of crops, contributes to the selection of superior cultivars. Based on the essential relevance of these estimations, it was used in our research. The current research was carried out during autumn winter season 2021-2022 with the aim of to estimate correlation coefficient among the growth and yield attribute and to elucidate the direct and indirect effects of different traits on yield through path coefficient analysis. The experimental material for the study consisted of 40 genotypes including one check (KS-224), laid in Randomized Complete Block Design with three replications. Observations were recorded on twelve quantitative characters. The most important trait, total fruit yield per plant had exhibited highly significant and positive phenotypic correlation with average fruit weight (0.662), number of fruits per plant (0.476), fruit circumference (0.394) and fruit polar length (0.392). Average fruit weight, number of fruits per plant, fruit circumference and fruit polar length were found significantly and positively correlated among themselves. The genotypic direct and indirect effects of most of the traits were similar in nature and higher in magnitude than the phenotypic direct and indirect effect. The higher magnitude of positive direct effect on total fruit yield was exerted by average fruit weight (0.793), number of fruits per plant (0.684) and fruit circumference (0.046). While, negative direct effect on total fruit yield per plant was exerted by days to 50 per cent flowering (-0.093), calyx length (-0.052) and pedicel length (-0.022). Thus, it can be inferred from the data above that selecting for these qualities will effectively enhance the crop for increased production and contributing traits.

Estimation of Correlation Coefficient Analysis for Yield and Component Traits in Field Pea (Pisum sativum L.)

The present investigation entitled “Estimation of Correlation Coefficient Analysis for Yield and Component Traits in field pea (Pisum sativum L.)” for 10 characters. The experiment comprising of 23 genotypes of pea were grown in a Randomized Block Design (RBD), with three replications at Research Farm, Department of Genetics & Plant Breeding, Post Graduate College, Ghazipur, during rabi season of 2017-2018, plant to plant and row to row distance was kept 10 cm and 45 cm, respectively. The maximum positive and significant phenotypic correlation coefficient (0.834) was found between seed yield per plant, biological yield per plant. Positive and significant correlations were observed between seed yield per plant and number of pods per plant, plant height. Positive and significant correlations were also recorded between biological yield per plant and plant height, number of pods per plant. Similarly number of pods per plant had positive and significant correlation with plant height.

Evaluation of Common Bean (<i>Phaseolus vulgaris </i>L) Cultivars for Yield and Yield-Related Traits at Sekoru District, South Western Ethiopia

The low productivity of common beans is attached to many yield constraints such as lack of improved varieties; poor management practices, biotic and abiotic factors. This study was conducted to evaluate the performance of improved common bean varieties for yield and yield related traits in the Sekoru district of the Jimma zone and identify high-yielding varieties for the study area. Eleven released and one local common bean variety were tested in two locations (Yero Sekoru and Inkure), using a randomized complete block design with three replications. Data were collected for 12 quantitative traits and subjected to analysis using SAS software. The interaction effect of genotype by location showed a highly significant variation for all traits except for plant height, dry biomass yield, and hundred seed weight. The phenotypic coefficient of variation was higher than the genotypic coefficient of variation for all traits. Higher The phenotypic coefficient of variation was recorded for 100 seed weight (52.78), pod length (28.9), pods per plant (27.63), harvest index (25.94) and seed yield (24.6) and also a high genotypic coefficient of variance (GCV) was observed for 100 seed weight (20.24) and pods per plant (20.34). Low (20) and high (93.5) heritability in broad sense were recorded in days to 50% flowering and dry biomass yield, respectively. At the phenotypic level, all traits had a positive phenotypic significant correlation with seed yield per hectare except for primary branches per plant day to 95% physiological maturity and hundred seed weight, while a negative significant correlation with seed yield per hectare was observed for days to 50% flowering. Genotypic path coefficient analysis indicates that the traits studied showed a positive direct effect on seed yield per hectare, while plant height, primary branches and secondary branches per plant, days to 50% flowering, days to 95% physiological maturity and 100 seed weight exhibited a negative direct effect. However, a positive direct phenotypic effect was observed for traits such as dry biomass yield, pod length, primary branches per plant, seeds per pod, and days to 95% physiological maturity. Among the varieties tested in both locations, the highest yield was recorded for the Ser119 variety (2865.2 kg/ha) followed by the Ser125 variety (2699.2 kg/ha). Therefore, recommending these varieties to farmers in the study area is very important to increase production and income.

Effect of Correlation and Path Analysis in Brinjal (Solanum melongena L.)

The present investigation was carried out in thirty two genotypes of brinjal with a view to estimate the extent of variability, analysis of variance and genetic divergence. The experiment was conducted in Randomized Block Design with three replications at Department of Vegetable Science, Acharya Narendra Deva University of Agriculture and Technology Narendra Nagar, (Kumarganj), Ayodhya (U.P.), during Kharif, 2020-21. Each treatment consisted of twelve plant in two rows, having spacing of 60 cm x 50 cm with net plot size of 1.2 m x 3.00 m2. The magnitudes of genotypic correlation was higher than the phenotypic correlation coefficients for all the character combinations. The most important trait, total fruit yield per plant had exhibited highly significant and positive phenotypic correlation with average fruit weight (0.747), number of fruits per plant (0.672) and fruit circumference (0.468) at both phenotypic and genotypic levels. Positive direct effect on total fruit yield was exerted by total sugars (0.474), average fruit weight (0.396), fruit circumference (0.358), number of fruits per plant (0.254), plant height (0.242), fruit polar length (0.194) and day to 50 % flowering (0.168). The higher magnitude of positive direct effect on total fruit yield was exerted by total sugars (0.474), average fruit weight (0.396), fruit circumference (0.358), number of fruits per plant (0.254), plant height (0.242), fruit polar length (0.194), day to 50 % flowering (0.168).

Genetic parameter estimation and molecular foundation of chicken beak shape

The bird beak is mainly functioned as feeding and attacking, and its shape has extremely important significance for survival and reproduction. In chickens, since beak shape could lead to some disadvantages including pecking and waste of feed, it is important to understand the inheritance of chicken beak shape. In the present study, we firstly established 4 indicators to describe the chicken beak shapes, including upper beak length (UL), lower beak length (LL), distance between upper and lower beak tips (DB) and upper beak curvature (BC). And then, we measured the 4 beak shape indicators as well as some production traits including body weight (BW), shank length (SL), egg weight (EW), eggshell strength (ES) of a layer breed, Rhode Island Red (RIR), in order to estimate genetic parameters of chicken beak shape. The heritabilities of UL and LL were 0.41 and 0.37, and the heritabilities of DB and BC were 0.22 and 0.21, indicating that beak shape was a highly or mediumly heritable. There were significant positive genetic and phenotypic correlations among UL, LL, and DB. And UL was positively correlated with body weight (BW18) and shank length (SL18) at 18 weeks of age in genetics, and DB was positively correlated with BC in terms of genetics and phenotype. We also found that layers of chicken cages played a role on beak shape, which could be attributed to the difference of lightness in different cage layers. By a genome-wide association study (GWAS) for the chicken UL, we identified 9 significant candidate genes associated with UL in RIR. For the variants with low minor allele frequencies (MAF <0.01) and outside of high linkage disequilibrium (LD) regions, we also conducted rare variant association studies (RVA) and GWAS to find the association between genotype and phenotype. We also analyzed transcriptomic data from multiple tissues of chicken embryos and revealed that all of the 9 genes were highly expressed in beak of chicken embryos, indicating their potential function for beak development. Our results provided the genetic foundation of chicken beak shape, which could help chicken breeding on beak related traits.

Genetic parameter estimation and molecular foundation of chicken egg-laying trait

The age of first egg (AFE) in chicken can affect early and even life-time egg production performance to some extent, and therefore is an important economic trait that affects production efficiency. To better understand the genetic patterns of AFE and other production traits including body weight at first egg (BWA), first egg weight (FEW), and total egg number from AFE to 58 wk of age (total-EN), we recorded the production performance of 2 widely used layer breeds, white leghorn (WL) and Rhode Island Red (RIR) and estimated genetic parameters based on pedigree and production data. The results showed that the heritability of AFE in both breeds ranged from 0.4 to 0.6, and AFE showed strong positive genetic and phenotypic correlations to BWA as well as FEW, while showing strong negative genetic and phenotypic correlations with total-EN. Furtherly, by genome-wide association analysis study (GWAS), we identified 12 and 26 significant SNPs to be related to AFE in the 2-layer breeds, respectively. A total of 18 genes were identified that could affect AFE based on the significant SNP annotations obtained, but there were no gene overlapped in the 2 breeds indicating the genetic foundation of AFE could differ from breed to breed. Our results provided a deeper understanding of genetic patterns and molecular basement of AFE in different breeds and could help in the selection of egg production traits.

Evaluation of models for estimation of genetic parameters for post-weaning body measurements and their association with yearling weight in Nellore sheep.

The objective of this study was to obtain (co) variance components and genetic parameter estimates for post-weaning body measurements such as body length (BL), height at withers (HW), and chest girth (HG) recorded at six (SBL, SHW, and SHG), nine (NBL, NHW, and NHG) and twelve (YBL, YHW, and YHG) months of age along with yearling weight (YW) in Nellore sheep maintained at livestock research station, Palamaner, Andhra Pradesh, India and also the association among body measurements with YW was studied. Data on 2,076 Nellore sheep (descended from 75 sires and 522 dams) recorded between 2007 and 2016 (10 years) were utilized in the study. Lambing year, sex of lamb, season of lambing and parity of dam were included in the model as fixed effects and ewe weight was kept as a covariate. Analyses were conducted with six animal models with different combinations of direct and maternal genetic effects using restricted maximum likelihood procedure. Best model for each trait was determined based on Akaike's information criterion. Moderate estimates of direct heritability were obtained for the studied traits viz., BL (0.02 to 0.24), HW (0.31 to 0.49), and CG (0.08 to 0.35) and their corresponding maternal heritability estimates were in the range of 0.00 to 0.07 (BL), 0.13 to 0.17 (HW), and 0.07 to 0.13 (CG), respectively. Positive direct genetic and phenotypic correlations among the traits and they ranged from 0.07 (YBL-YW) to 0.99 (SBL-SHG, SHG-YW, and NBL-YBL) and 0.01 (SBL-YBL) to 0.99 (NBL-NHG), respectively. Further, the genetic correlations among all the body measurements and YW were positive and ranged from 0.07 (YW and YBL) to 0.99 (YW and SHG). There was a strong association of chest girth at six months with YW. Further, it is indicated that moderate improvement of post-weaning body measurements in Nellore sheep would be possible through selection.

Innovative use of sensor technology to study grazing behaviour and its associations with parasitic resistance in sheep

Gastrointestinal nematodes (GINs) are a concern for sheep production and are associated with significant economic losses globally, driving the need for effective management strategies. The aims of this research were first to determine the influence of GIN infections on sheep grazing behaviours, specifically grazing time (GT) and grazing event length (GL), and then to estimate the genetic and phenotypic correlation between faecal egg counts (FEC) and salivary specific IgA activity vs GT and GL. Data were collected from 146 Merino sheep on a commercial farm in Victoria, Australia. Faecal, saliva and body weight (BW) were collected at four time points (A: Oct 2019, B: early May 2020, C: late May 2020, and D: Jul 2020), while tri-axial accelerometer sensors recorded GT and GL for the length of 26 days between B and C. Univariate linear regression and Bayesian Generalised Linear Mixed Model, estimated using Markov Chain Monte Carlo, were used to assess the relationships between the behaviours and infection indicators. We found an increase in the logarithm of FEC was associated with a significant rise in grazing time (p < 0.05), suggesting compensatory behaviour in infected sheep. GT also accounted for 6% of the FEC variation. In contrast, the effect of IgA on GT was not significant (p > 0.05). There was a positive genetic and phenotypic correlation estimated between GT and FEC, however, the High Posterior Density interval for the genetic and phenotypic correlations between GT and FEC indicates some uncertainty in these estimates. These results imply that sheep may modify their grazing strategies as an adaptive response to parasitic infections to ease the impact on their nutritional intake. This study improves our understanding of how natural GIN infections affect sheep behaviour and highlights the potential to use animal behaviours as a precision livestock farming tool and in breeding for resilience against parasites.

Association of quantitative traits and genetic diversity in Ethiopian sesame (Sesamum indicum L.) genotypes

To enhance sesame yield, it is important to utilize diverse parents in breeding programs and implement an effective selection procedure, which exploits the association of quantitative traits. Therefore, the objective of this experiment was to explore the correlation among quantitative traits and assess genetic variability and diversity using both qualitative and quantitative traits. Correlation coefficients indicated a noteworthy (P < 0.001) positive phenotypic (rp) and genotypic (rg) correlation between seed yield and various traits: plant height (rp = 0.60; rg = 0.58), length of the capsule-bearing zone (rp = 0.77; rg = 0.80), number of capsules on the main stem (rp = 0.80; rg = 0.85), primary branches (rp = 0.66; rg = 0.66), and capsules per plant (rp = 0.90; rg = 0.91). In contrast, a negative correlation (P < 0.001) was observed between yield and bacterial blight disease severity, both phenotypically (rp = −0.60) and genotypically (rg = −0.76). The analysis of path coefficients indicated that the most substantial positive direct effect on yield (0.77) was attributed to capsules per plant, whereas other traits associated with yield exhibited a significant indirect influence on yield through capsules per plant. Qualitative traits exhibited diversity, except for plant growth type, plant growth habit, and stem branching. Shannon-Weaner (H) and Simpson (1-D) diversity indices were higher for interior corolla color (H = 1.63; 1-D = 0.66), seed color (H = 1.50; 1-D = 0.46), and capsule beak type (H = 1.08; 1-D = 0.50). The analysis of variance indicated a notable variation among the examined genotypes regarding quantitative traits, excluding internode length. The plant materials were divided into five clusters through cluster analysis, where clusters I to V consisted of 21, 29, 4, 4, and 6 genotypes, respectively. The current study has shown that the yield of sesame can be enhanced through indirect selection for traits associated with yield, particularly the highest number of capsules per plant. Furthermore, examinations of genetic diversity confirmed the presence of variability within the assessed genotypes, providing valuable insights for upcoming sesame breeding programs.

Estimates of Genetic Variability and Correlation Coefficient for Yield and Its Attributes in Fenugreek (Trigonella foenum-graecum L.)

The study was conducted throughout the autumn/winter season 2021-2022 with the aim of estimating genetic variability for different characters in available Fenugreek germplasm viz: heritability in broad sense, genetic advance in per cent of mean and correlation coefficient among the characters pairs. The study's experimental material comprised 42 genotypes along with one check (Hisar Sonali). There were eleven quantitative characteristics (traits) on which observations were made. The magnitude of the phenotypic coefficient of variation (P.C.V.) was greater than the genotypic coefficient of variation (G.C.V). The greatest differences in phenotype and genotype have been found in seed yield per plant followed by (no.) number of branches per plant, harvest index, days to maturity, test weight and no number. of seed per pod. The heritability estimates for various traits ranged from 15.9 (no number. of branches per plant) to 68.3 (plant height). Genetic advance in per cent of mean ranged from 3.36 per cent (No. number of seed per pod) to 12.64 per cent (days to maturity). The phenotypic and genotypic correlation coefficients were computed among the eleven characters. The most (A very) important trait, seed yield per plant exhibited highly significant and positive phenotypic correlation with, harvest index (0.948) and test weight (0.935). While, days to 50% flowering (-0.678) was significantly and negatively correlated with seed yield per plant. These findings suggested that the current fenugreek germplasm has a great deal of promise for effective crop improvement and better yield and yield-(components) attributing traits.

Polygenic Variations and Character Association Study of Tomato (Solanum lycopersicon L.) Genotypes for Yield and Quality Attributes

An experiment was conducted in the Vegetable Farm of Bihar Agricultural University in Rabi Season with the objective to study the genetic variability and character association for yield and quality attributes in thirty tomato genotypes. The experiment was laid out in randomized block design with three replications. The results indicated significant differences amongst the genotypes for all the characters studied. Yield per plant showed the highest coefficient of variations (56.41 %, 58.93%) at both genotypic and phenotypic level. High genotypic and phenotypic coefficient of variation was also noted for average fruit weight (48.33%, 48.98%) and number of fruits/plant (35.14%, 33.55%). Traits like average fruit weight (97.4%, 41.85), number of fruits per plant (91.2%, 25.90), and plant height (95.8%, 69.38) exhibited high heritability coupled with high genetic advance. Genetic advance as percentage of mean ranged from 11.81-111.22% for different characters. The highest genetic advance as percentage of mean (111.2%) was recorded for yield per plant. Fruit yield per plant expressed highly significant and positive genotypic and phenotypic correlations with average fruit weight (0.697, 0.694), equatorial diameter (0.637, 0.596) and polar diameter (0.488, 0.454). The genotypes, Hisar Lalit, Pusa Ruby, Arka Alok, Pant T-7 and Pusa Rohini which have been found to be promising with respect to fruit weight and yield per plant may further be exploited to create new genetic variations by random mutation, somaclonal variation and modern molecular techniques for studying disease resistance, post-harvest and processing qualities.