Indirect Selection Research Articles

Study on characters associations and path coefficient analysis for quantitative traits of amaranth genotypes from Ethiopia

Selection based on yield alone may not be effective for yield improvement in plant breeding programs. Thus, in order to progress the genetic gains during selection, yield should be considered along with potential yield contributing traits. The objective of this study was to improve the genotype of amaranth and increase the effectiveness of selection in the program by identifying the correlation and path coefficients between yield and its relevant attributes. On 120 genotypes of amaranth planted during two growing seasons in 2020 and 2021, the study was carried out using an alpha lattice design with two replications. The results revealed significant positive phenotypic and genotypic associations on leaf yield, with leaf area, leaf breadth, branch number, leaf number, plant height at flowering, and grain yield all having positive direct effects. Similar strong positive phenotypic and genotypic relationships were found for grain yield and grain sink filling rates. Using path coefficient analysis, the direct and indirect effects of yield-related traits on yield were also determined. In addition to having a strong direct impact on grain output, the grain sink filling rates showed both phenotypic and genotypic evidence of substantial positive relationships with grain yield. It was further suggested that leaf yield in amaranth genotypes may increase through the indirect selection of plant height at maturity, leaf length, and terminal inflorescence lateral length, which showed such significant indirect influences, mostly through leaf area, days to maturity, and days to emergence, which displayed such strong indirect effects, primarily through plant height at flowering. This study consequently shows the need for traits with significant positive indirect impacts via leaf area to be considered indirect selection criteria for improving leaf yield in amaranth genotypes. The grain sink filling rate also significantly improved grain yield indirectly at both the phenotypic and genotypic levels, mainly via days to flowering and leaf yield. This demonstrated that selection that mainly targeted days to flowering, leaf yield, and grain sink filling rate would ultimately boost the grain yield in amaranth genotypes.

Optimizing selection strategy for enhancing reproduction efficiency in Indian crossbred goats using milk productivity as a selection criterion.

The present study was aimed at optimizing the selection strategy for enhancing reproductive efficiency and milk productivity of Alpine × Beetal crossbred goats. The data set included 2949 milk trait records across parities and 1389 milk records from first parity and corresponding reproductive traits. The traits included for analysis were 150-day milk yield (150DMY), days in milk (DIM), peak yield (PY) and total milk yield (TMY). The litter size (LS) and litter weight (LW) were used for specifically formulating selection plan using indirect selection. The least squares mean for lactation traits during the first parity were 150DMY: 195.32 ± 2.09 kg, DIM: 236.42 ± 3.04 days, PY: 1.82 ± 0.02 kg, TMY: 269.62 ± 4.52 kg. Notably, Alpine × Beetal goats demonstrated genetic superiority pan India for milk productivity as compared to other native goat breeds. The least squares mean for 150DMY across all parities was 236 ± 3.13 kg. An animal model employing average information restricted maximum likelihood was used for (co)variance component estimation to get the genetic parameters. The analysis revealed total heritability estimates for 150DMY, DIM, PY and TMY as 0.18 ± 0.06, 0.04 ± 0.04, 0.12 ± 0.06 and 0.08 ± 0.05, respectively. Repeatability estimates for 150DMY, DIM, and TMY were 0.28 ± 0.04, 0.21 ± 0.03 and 0.37 ± 0.03, respectively. Bivariate analysis of 150DMY with reproductive traits revealed heritability for LS and LW as 0.05 ± 0.01 and 0.10 ± 0.01, respectively using Gibbs sampling. Strong and positive genetic correlations of 150DMY with other production and reproduction traits was observed, such as DIM (0.72), PY (0.98), TMY (0.88), LS (0.57) and LW (0.33). Moderate heritability and repeatability estimate of 150DMY, along with its positive correlation with production and reproductive traits suggested it as a suitable selection criterion for early selection and overall genetic progress of lactation traits. The genetic trend analysis showed an overall improvement in all these traits, with observed gain of 98.4 g per year for 150DMY, 0.04 days per year for DIM, 0.5 g per year for PY and 220.5 g per year for TMY. We observed that selecting based on 150DMY would lead to a favourable indirect improvement for LW as 79 g and LS 0.04 units per generation. We, therefore, recommend employing 150DMY as the single trait selection criteria to enhance both milk productivity and reproductive potential of Alpine × Beetal goats.

Heritability and correlative variability of the conformation linear traits of first-born cows of black-and-white cattle with milk yield

An in-depth analysis the publications of domestic and foreign authors was carried out in the aspect of research on the heritability of linear traits of the conformation type and their correlative variability with milk productivity.The research authors established that the level of existing variability in the heredity of linear traits depends on many genotypic and paratypic factors. However, they argue that despite the variability of traits heritability of dairy cows conformation, their level is generally sufficient for effective selection by linear type traits. Studies on the correlation between linear traits of type and milk productivity of cows of various breeds around the world have shown a high level of this relationship. This testifies about the effectiveness of indirect selection of dairy cattle by type, which will allow obtaining not only constitutionally strong and healthy animals, but also with high milk productivity.The population-genetic aspect of determining the heritability and correlative variability of linear traits with milking of first-born Holstein cows of domestic selection and Ukrainian Black-and-White dairy in the private enterprise "Burynske" of the Podlisniv branch of the Stepaniv territorial community in Sumy district was described. The magnitudes and reliability of the heritability coefficients of group linear traits indicate that they are controlled by the genotype of animals by 24.5-42.2 % in first-born cows of the Holstein breed, and by 26.6-40.1 % in female cows of Ukrainian Black-and-White dairy breed. The final score by type of 48.2 and 45.4 %, respectively, ensures the efficiency selection of cows by genotype. Variability of descriptive traits of Holstein cows ranges from insignificant and unreliable (h2=0.084; location of front teats) to high and reliable (h2=0.484; angularity). In females of the same age of Ukrainian Black-and-White dairy breed, the variability varies from 0.077 (location of rear teats) to 0.422 (angularity).In Holstein and Ukrainian Black-and-White dairy cows, the most reliable relationship was found between the characteristics of the dairy type (0.428 and 0.387), body (0.446 and 0.439), udder (0.486 and 0.478) and, especially, the final type score (0.492 and 0.488), which gives reason to assert about the effectiveness of selection based on these traits.The highest level of reliable positive correlation with the amount of milk yield for the first lactation was found according to the scores of descriptive traits of Holstein and Ukrainian Black-and-White dairy breeds, respectively: height (r=0.363 and 0.322), body depth (r=0.468 and 0.484), angularity (r=0.477 and 0.466), back width (r=0.366 and 0.322), posture of pelvic limbs (r=0.369 and 374), attachment of front (r=0.482 and 0.426) and rear (r=0.371 and 0.351) udder parts, central ligament (r=0.364 and 0.375) and locomotion (r=0.363 and 0.322) at Р<0.001. Key words: Holstein, UkrainianBlack-and-Whitedairy, lineartypeevaluation, conformation, milkyield, first-borncows.

Genetic Variability Studies in F2 Population of the Wheat Cross DDK-1029 x GPM DIC 66

The selection of breeding material heavily relies on genetic variation and its inherited components. A thorough understanding of genetic variation is necessary in order to develop an improved variety. Thus, genetic parameters were assessed in the F2 population of the cross between DDK-1029 and GPM DIC 66. The genetic variability results indicated a moderate to high phenotypic and genotypic coefficient of variation for characters like days to 50% flowering, plant height, productive tillers per plant, spike length, spikelets per spike, grains per spike, thousand grain weight and grain yield. In contrast, the protein, iron and zinc contents exhibited low to moderate phenotypic and genotypic coefficient of variation. All the traits had higher heritability except for grain yield which exhibited a moderate heritability. All the characters exhibited significant GAM except for days to maturity, iron content and protein content which exhibited moderate GAM. This suggests that high genetic variation, heritability, and GAM for such traits will aid in their improvement through both direct and indirect selection.

Potential Use of Image Analysis in Breeding Programs for Growth and Yield Traits in Meagre (Argyrosomus regius)

In the present work, we studied ten new productive traits in meagre (Argyrosomus regius), comprising three related to the carcass (cNiT) and seven related to morphometric (mNiT) characteristics. We harnessed non-invasive technology (NiT) by means of the IMAFISH_ML software. This tool’s potential was leveraged on an industrial scale, encompassing the evaluation of 612 fish from two distinct rearing systems (marine cages and indoor tanks) at the time of harvest. Each fish underwent digital photography for morphometric measurements, manual weighing, and was manually eviscerated and filleted to calculate the carcass and fillet yield. Subsequently, the principal genetic parameters were estimated. The heritabilities for the growth traits were moderate (0.34 and 0.39 for TL and BW), whilst those for the cNiT traits ranged from medium to low (0.32–0.27). For the mNiT, they demonstrated a medium to low range (0.15–0.37), whereas the carcass and fillet yield heritabilities were considered to be medium to high (0.32 and 0.31). Most of the genetic correlations between the growth, NiT, and yield traits were not estimated accurately due to the limited data. As was expected, we observed predominantly high and positive correlations between the growth and mNiT. A genetic correlation to highlight was the fillet yield with the fish maximum height (0.87 ± 0.23) and with the head height (0.87 ± 0.24). This suggests that indirect selection using NiT could improve the growth and yield traits. Employing a multi-trait selection approach enables us to capture a broader spectrum of genetic variability and to potentially identify individuals with superior genetic potential. The use of image analysis software ensures objective and precise measurements, thereby reducing the potential for human error or bias during the selection process. Further studies should be carried out to improve the accuracy of the estimates, especially those of the genetic correlations.

Evolutionary Insights from a Large-Scale Survey of Population-Genomic Variation.

The field of genomics has ushered in new methods for studying molecular-genetic variation in natural populations. However, most population-genomic studies still rely on small sample sizes (typically, <100 individuals) from single time points, leaving considerable uncertainties with respect to the behavior of relatively young (and rare) alleles and, owing to the large sampling variance of measures of variation, to the specific gene targets of unusually strong selection. Genomic sequences of ∼1,700 haplotypes distributed over a 10-year period from a natural population of the microcrustacean Daphnia pulex reveal evolutionary-genomic features at a refined scale, including previously hidden information on the behavior of rare alleles predicted by recent theory. Background selection, resulting from the recurrent introduction of deleterious alleles, appears to strongly influence the dynamics of neutral alleles, inducing indirect negative selection on rare variants and positive selection on common variants. Temporally fluctuating selection increases the persistence of nonsynonymous alleles with intermediate frequencies, while reducing standing levels of variation at linked silent sites. Combined with the results from an equally large metapopulation survey of the study species, classes of genes that are under strong positive selection can now be confidently identified in this key model organism. Most notable among rapidly evolving Daphnia genes are those associated with ribosomes, mitochondrial functions, sensory systems, and lifespan determination.

Heterosis of quality protein maize inbred lines for agronomic traits and association with genetic distances based on SSR and phenotypic markers

Due to high cost, limited labour, and longer time required in hybrid development, identifying promising hybrids at an early stage without large-scale yield trials is crucial. Therefore this study estimated heterosis of quality protein maize hybrids for grain yield (GY) and other agronomic traits and investigated relationship of genetic and phenotypic distances (GD, PD) of inbreds with hybrid performance (HP) and mid-and-better parent heterosis (MPH, BPH). Forty-five hybrids generated by half-diallel with 10 inbreds were evaluated for GY and other agronomic traits at three locations. The yield trials were conducted for two years (2017 and 2018 cropping seasons). The GD and PD were 0.45 and 0.40 based on SSR and phenotypic data, respectively, this shows moderate genetic variation existed among inbreds. GY had highest MPH (77.55%) and BPH (53.96%) with hybrid TZEEQI-9 × TZEEQI-16 having highest MPH (382.8%) and BPH (331.7%), across locations. Positive and significant association existed between SSR-GD with HP, MPH and BPH for ear length, kernels/row and 100-seed weight (r = 0.31** to 0.41**), this suggests these traits can be predicted from SSR-based GD of parents. These traits could be used for indirect selection for yield improvement. However, negative correlation was obtained between SSR-GD with HP, MPH and BPH for anthesis and silking (r = −0.29 to −0.03), this indicates the dominance for earliness to flowering and silking than their parental lines. The two distance measures can be used to differentiate between maize inbreds and assigned them to different heterotic groups and Breeders can therefore prioritize crosses with high heterosis and desirable phenotypic traits, saving time, resources, and field space.

Needle functional features in contrasting yield phenotypes of slash pine at three locations in southern China

Pine resin, a valuable secondary metabolite, is derived from the products of photosynthesis. Pine needles, serving as the primary organ for photosynthesis and nutrient absorption, facilitate the continuous transport of nutrients to all plant organs through photosynthesis. The functional traits of pine needles exhibit a close association with the photosynthetic efficiency of pine trees, thereby affecting resin yield. The selection of superior trees with high-resin yield (RY) for slash pine (Pinus elliottii Engelm.) faces difficulties due to low selection efficiency and a high false selection rate caused by the absence of reliable indirect selection traits. The objective of this study was to systematically investigate the relationships between slash pine needle functional traits and RY in different regions. Understanding the relationship between functional traits of pine needles and RY is essential for addressing the challenges mentioned above. There were positive correlations between RY and most morphological traits, except for leaf dry matter content (LDMC), which showed a negative correlation. Moreover, low-resin yield trees exhibited lower values for most morphological variables, except for LDMC. High-yield trees exhibited higher stomata number per mm2 (STN), larger stomata diameter (STD) and size (STS), and stomata area per mm2 (STA) across all periods and sites when compared with low-yield individuals. Chloroplast pigment component analysis revealed that high yielders exhibited higher levels of chloroplast a (CHL a) and chloroplast a+b (CHL a+b) compared to low yielders, and positive correlations were found between resin yield and CHL a, chloroplast b (CHL b), and CHL a+b. Higher nutrient contents were observed in high resin yield individuals, and positive correlations were found between resin yield and most nutrients, except for potassium (K). Different needle functional traits exhibited varying periodic patterns of resin production. Most needle functional traits could be useful criteria for evaluating resin production in slash pine breeding programs, which could improve the efficiency of breeding, shorten the breeding cycle, and accelerate the breeding process.

Selection of Cordia trichotoma Vell. clones for adventitious rooting and determination of the plantlet quality produced by mini-cuttings

This study aimed to evaluate and define strategies for the selection of C. trichotoma clones with competence for adventitious rooting and production of high-quality plantlets by mini-cuttings. For adventitious rooting, mini-cuttings were treated with 3,000 mg L-1 of indole butyric acid and grown in 110 cm³ tubes, consisting of equal proportions of the commercial substrate and vermiculite. The percentage of rooting, number of roots, and mini-cuttings rooted per mini-stump were evaluated after 30 days of cultivation in a humid chamber. The rooted mini-cuttings were transferred to a shade house and the survival percentage, stem diameter, height, and number of leaves were evaluated at 120 days. Data were analyzed using the restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) method and Pearson´s correlation analysis. The number of rooted mini-cuttings and stem diameter presented the highest repeatability and accuracy values for rooting and plantlet growth, respectively. These traits also presented significant positive correlation estimations with others, indicating the possibility of indirect selection gain. Cordia trichotoma clones can be selected for vegetative propagation, considering the number of rooted mini-cuttings and the stem diameter of the plantlets produced by mini-cutting. Early selection for adventitious rooting and plantlet quality can aid in genetic improvement programs for the development of new cultivars for vegetative propagation via the use of mini-cuttings.

Genetic parameters of various local corn cultivars in high salinity stress

Future demand for maize will not be easily met due to climate change and its development using marginal soils that are stressed by salinity. This study aims to identify the genetic parameters of corn plants under high salinity stress. The research was arranged in a randomized completely block design (RCBD) consisting of six local maize cultivars, namely Gento, Lanca, Pulut, Lokal, Lei, and Sigi Merah. Each treatment was repeated four times. The results showed that two traits had a high coefficient of genotypic diversity, four traits had a high coefficient of phenotypic diversity and six traits had high heritability and genetic progress. Plant height, the greenness of the leaves, age of male flower release, age of blooming female flowers, the position of the ear, harvest age, length of cob without stalks, and diameter of the cob were positively and significantly correlated with yield. Plant height and cob height can be used as criteria for increasing maize yields through indirect selection. In future studies suggest that various local maize cultivars can be applied to situations of high salinity stress.

Heritability and Genetic Correlation Between Productive and Biochemical Traits of White Japanese Quail

Studying heritability and genetic correlation between traits is important to improvement genetic programs and indirect selection, for that, this study was conducted in the poultry field of Animal Production department - College of Agriculture - University of Kirkuk for the period from 28/3/2022 to 15/1/2023, to study heritability and genetic correlation between production and biochemical traits of white Japanese quail. One day hatched white quail chicks were obtained from College of Agriculture - University of Kirkuk, and reared for 35 days until reaching sexual maturity. Then chicks were randomly distributed to 30 families, with a male and a female for each family for two generations. Simple correlation between productive traits and blood biochemical were estimated, and heritability using full sibs method by variance between dam and total variances. The results of the study showed that there was a highly and significant genetic correlation between estrogen hormone in blood serum, egg production and egg mass, while a negative and highly significant genetic correlation was found between estrogen hormone and feed conversion ratio. Heritability values for productive and blood biochemical traits ranged from 0.22 to 0.42 and they considered within mediate heritability. The study recommended to use of selection programs and indirect genetic improvement based on some blood biochemical values (estrogens, total protein and glucose) due to their positive and significant association with productive traits of white Japanese quail.

Genotypic variability and genetic parameters for root yield, dry matter and related traits of cassava in the Guinea Savannah ecological zone of Ghana

The aim of this study was to assess the agronomic performance and genetic parameters governing storage root yield and related traits in cassava genotypes in order to identify superior genotypes. The study involved 18 elite cassava genotypes which were arranged in a randomized complete block design with three replications and assessed for storage root yield and yield components (12 months after planting) in the Guinea savannah ecology of Ghana for three seasons. Analysis of variance indicated significant (p &lt; 0.05) genotype and year main effects for fresh and dry root yields, dry matter content, starch yield and harvest index. Genotype × year effect was significant (p &lt; 0.05) for fresh root yield, dry root yield and starch yield. Estimates of the variance components revealed greater genotypic influence for starch yield, fresh and dry root yields implying the potential for genetic gain with selection for these traits among the genotypes. Relatively high (69 %) broad sense heritability estimate was observed for dry storage root yield indicating the depth of genetic influence. Path coefficient analysis revealed a direct positive effect of dry matter content on dry storage root yield whilst dry storage root yield had direct positive effect on starch yield suggesting the possibility of indirect selection for starch yield through dry storage root yield. The study revealed ample genotypic variability among the cassava genotypes to warrant selection. Four genotypes, IBA 070134, IBA 419, IBA 950289 and IBA 980581 were identified for high and stable fresh and dry root yields for multilocational testing.

Genetic and phenotypic characterization of Tinopiro (Thinopyrum intermedium) as a dual-purpose perennial crop in the Southern Cone: Doctoral thesis abstract

Agriculture based on annual crops requires intensive input management, which has been associated with significant degradation of natural resources. The development of perennial grain crops such as intermediate wheatgrass - (Thinopyrum intermedium) may greatly contribute to reduce this problem, however, previous research has been carried out in high latitude environments and there is no information on this crop for temperate regions with mild winters. The aims of this thesis were a) to determine the cold requirements of intermediate wheatgrass, b) to evaluate the agronomic performance of intermediate wheatgrass managed as a dual-purpose crop in Uruguay, c) to understand the genetic architecture of grain and forage yield components in intermediate wheatgrass under dual-purpose management. Three experiments were carried out, the first one in growth chambers and the other two in the field during two years in Paysandú, Uruguay. Flowering percentage and most grain yield components increased as the length of the cold incubation period at 5°C and 10 h photoperiod increased from 3 to 7 weeks. High intra-population phenotypic diversity was estimated. The effects of two populations produced under contrasting environments and the effects of three doses of nitrogen on grain and forage yield under dual-purpose management were evaluated in the second experiment. The first year, both populations had similar flowering percentages of about 48%, which resulted in an average grain yield of 316 kg ha -1. The average forage yield for the first year was 14695 kg ha -1 and decreased to 4037 kg ha -1 the second year. Fertilization with 160 kg ha -1 nitrogen increased grain yield by 63% and forage yield by 28%. In the third experiment, grain yield components, forage and phenological traits were evaluated in 30 half-sib families. Most of the traits evaluated showed no genotype x age interaction. Indirect selection for spikes per plant and/or yield per spike could have a greater response to selection than direct selection for yield per plant. No trade-off was detected between grain yield components and aboveground biomass production. These results suggest that expansion of this species as a dual-purpose crop to temperate regions with mild winters is feasible after some cycles of selection.

Correlation and Path Coefficient Analysis for Yield, Quality and their Component Traits in Rice (Oryza sativa L.)

Investigation was carried out at the Agricultural research Institute, Hyderabad, during kharif 2018-19 with the objective of assessing the trait association and direct and indirect effects of yield and quality related traits on grain yield in fifty rice (Oryza sativa L.) genotypes. Among eighteen characters, panicle length, 1000-grain weight, kernel L/B ratio, kernel length after cooking and kernel elongation ratio had positive and highly significant association with seed yield and positive correlation with kernel length, alkali spread value and gel consistency. Genotypic path coefficient analysis of seed yield revealed that milling, kernel length after cooking, 1000-grain weight and panicle length exerted highest positive direct effect on grain yield. The existence of strong positive correlation between grain yield and other traits helps in identifying traits that could be used for indirect selection for the improvement of grain yield, Therefore, to facilitate selection in breeding for high yield, quality and other desirable traits. Hence emphasis can be laid out on these traits and give more attention to those having the greatest influence on grain yield.

Disentangling the interplay between genes, cognitive skills, and educational level in adolescent and young adult smoking – The TRAILS study

Recent studies suggest that smoking and lower educational attainment may have genetic influences in common. However, little is known about the mechanisms through which genetics contributes to educational inequalities in adolescent and young adult smoking. Common genetic liabilities may underlie cognitive skills associated with both smoking and education, such as IQ and effortful control, in line with indirect health-related selection explanations. Additionally, by affecting cognitive skills, genes may predict educational trajectories and hereby adolescents’ social context, which may be associated with smoking, consistent with social causation explanations. Using data from the Dutch TRAILS Study (N = 1581), we estimated the extent to which polygenic scores (PGSs) for ever smoking regularly (PGSSMOK) and years of education (PGSEDU) predict IQ and effortful control, measured around age 11, and whether these cognitive skills then act as shared predictors of smoking and educational level around age 16, 19, 22, and 26. Second, we assessed if educational level mediated associations between PGSs and smoking. Both PGSs were associated with lower effortful control, and PGSEDU also with lower IQ. Lower IQ and effortful control, in turn, predicted having a lower educational level. However, neither of these cognitive skills were directly associated with smoking behaviour after controlling for covariates and PGSs. This suggests that IQ and effortful control are not shared predictors of smoking and education (i.e., no indirect health-related selection related to cognitive skills). Instead, PGSSMOK and PGSEDU, partly through their associations with lower cognitive skills, predicted selection into a lower educational track, which in turn was associated with more smoking, in line with social causation explanations. Our findings suggest that educational differences in the social context contribute to associations between genetic liabilities and educational inequalities in smoking.

Adaptation and Promotion of Improved Beard Wheat (Triticum aestivum L.) Varieties under Irrigation Condition in North West Amhara, Ethiopia

Twenty-two bread wheat varieties eight of them were heat tolerant and fourteen bread wheat varieties released under rain feed were evaluated in two sets for adaptation and promotion of the best-adapted varieties (2020-2021) cropping season under irrigation condition at Metema and Belesa districts. The objective of this experiment was to identify and promote the best adapted, high yielding, and heat tolerance bread wheat varieties for irrigated areas of the different agroecology regions. The experiments were conducted one year for a variety adaptation trial and a second year for demonstration of the best adapted, high yielding, and heat tolerance varieties from the two sets in the selected farmers filed under irrigation. The analysis of variance in both sets of experiments indicated that there was a highly significant difference (p&lt;0.01) among the varieties for for most of the studied traits. The average mean of days to maturity for both sets was 92 days ranging from 80-96 days for heat tolerance &amp; 83-97 days for released under rain feed. Early maturity was observed on the variety Ardi &amp; kingbird (80 &amp; 84 days) and late maturity was observed on the variety Werer-2 &amp; Lemu (96 &amp; 97 days) heat tolerance &amp; rain feed respectively. The mean grain yield was 5670 kg ha-1 in heat tolerance &amp; 3954 kg ha-1 released under rain feed. The grain yield was ranged from 5167 kg ha-1 (Amibara-2) to 6212 kg ha-1, 6195 kg ha-1 (Werer-2 &amp; Fentale-2) and 2814 kg ha-1, 2820 kg ha-1 (Kingbird &amp; Hidasie) to 6094 kg ha-1, 5220 kg ha-1 (Ogolcho &amp; Adet-1) heat tolerance &amp; released under rain feed prospectively. Three best adapted &amp; high yielding varieties from both the trails were selected and promoted to participatory evaluation and promotion on different farmer’s fields. Grain yield showed a positive and highly significant correlation (P&lt;0.01) with biological yield and thousand seed weight. There was also a highly significant (0&lt;0.01) correlation (r=0.55, r=0.59, r=0.79 &amp; r=0.46) between plant height with thousand seed weight, spike length, and biological yield and spikelets per spike. Days to maturity shows strong positive correlation (r=0.88) with the grain filling period. Therefore these traits could be used as indirect selection traits for grain yield according to the significance correlation suggestion. Farmers were also invited and evaluated the varieties based on their selection criteria during maturity time in both districts. Therefore, based on the analysis and farmers' preference, Fentale-2 was recommended for production with its full production packages under irrigation condition in the lowland areas of Gondar and other similar agro-ecologs.

Genetic analysis of geometric morphometric 3D visuals of French jumping horses

BackgroundFor centuries, morphology has been the most commonly selected trait in horses. A 3D video recording enabled us to obtain the coordinates of 43 anatomical landmarks of 2089 jumping horses. Generalized Procrustes analysis provided centered and scaled coordinates that were independent of volume, i.e., centroid size. Genetic analysis of these coordinates (mixed model; 17,994 horses in the pedigree) allowed us to estimate a variance–covariance matrix. New phenotypes were then defined: the “summarized shapes”. They were obtained by linear combinations of Procrustes coordinates with, as coefficients, the eigenvectors of the genetic variance–covariance matrix. These new phenotypes were used in genome-wide association analyses (GWAS) and multitrait genetic analysis that included judges’ scores and competition results of the horses.ResultsWe defined ten shapes that represented 86% of the variance, with heritabilities ranging from 0.14 to 0.42. Only one of the shapes was found to be genetically correlated with competition success (rg = − 0.12, standard error = 0.07). Positive and negative genetic correlations between judges’ scores and shapes were found. This means that the breeding objective defined by judges involves improvement of anatomical parts of the body that are negatively correlated with each other. Known single nucleotide polymorphisms (SNPs) on chromosomes 1 and 3 for height at withers were significant for centroid size but not for any of the shapes. As these SNPs were not associated with the shape that distinguished rectangular horses from square horses (with height at withers greater than body length), we hypothesize that these SNPs play a role in the overall development of horses, i.e. in height, width, and length but not in height at withers when standardized to unit centroid size. Several other SNPs were found significant for other shapes.ConclusionsThe main application of 3D morphometric analysis is the ability to define the estimated breeding value (EBV) of a sire based on the shape of its potential progeny, which is easier for breeders to visualize in a single synthetic image than a full description based on linear profiling. However, the acceptance of these new phenotypes by breeders and the complex nature of summarized shapes may be challenging. Due to the low genetic correlations of the summarized shapes with jumping performance, the methodology did not allow indirect performance selection criteria to be defined.

Direct and Indirect Effects of Yield Contributing Traits in Rice (Oryza sativa L.)

At the Field Experimentation Centre of the Department of Genetics and Plant Breeding, 20 rice genotypes, including one check variety, were assessed in order to research genetic variability, heritability, genetic progress, correlation, and path coefficient for 13 quantitative features. In Kharif 2022, the experiment was carried out utilising a Randomised Block Design with three replications. Over the NDR 359 (check), BRRI DHAN-75 (26.133) and A.K.DHAN (23.067) demonstrated a greater yield. Number of spikelets per hill, Number of panicles per hill, Biological yield, Number of tillers per hill, Grain yield per hill, Harvest index, Panicle length, Test weight, Days to maturity, and Plant height all had high to moderate estimations of GCV, PCV, and Genetic Advance as Percent Mean. Estimates of heritability ranging from high to moderate, genetic progress for the quantity of spikelets per panicle, biological yield,plant height, and days to 50% blooming. At both the phenotypic and genotypic levels, grain yield showed a strong positive connection with biological yield, the number of spikelets per panicle, and harvest index. Harvest index and biological yield showed both genotypic and phenotypic positive significant direct influences on grain yield per hill. Thus, in the current experimental materials, these qualities are recognised as the effective and prospective for indirect selection for the increase of rice yield.

Determination of low‐temperature stress during the vegetative stage as a tool to predict plant yield in rice genotypes with contrasting tolerance levels

AbstractIn this study, the first aim was to develop a rapid and non‐destructive method for analysing rice genotypes' tolerance to low temperatures (LT) during the seedling stage. Using a growth parameter and a physiological parameter, a discriminant formula was developed to differentiate between tolerant and sensitive genotypes based on their LT tolerance score. The study identified several benefits of the discriminant formula, including its low classification error rate, scalability, and ability to be used in controlled and reduced environments. Additionally, a second study was conducted, which found a strong correlation between the LT tolerance score during the seedling stage and plant yield at the ripening stage in plants grown under field LT during the vegetative stage. Panicle weight was the main mediator of the effect of the LT tolerance score on plant yield, but the number of panicles per plant also played a role. Overall, the results suggest that the LT tolerance score can serve as an indirect selection factor for plants for both LT tolerance and plant yield. This is especially relevant for rice‐growing regions with temperate climates and LT at the beginning of the cultivation season.

Estimation of Association among the Yield and Yield Attributing Traits in the Segregating Population of Rice

Indirect selection, using correlation coefficients, linear regression coefficients and path analysis, uses a variety of yield determinants that are more heritable than yield itself and less influenced by environmental factors and therefore are stable. Therefore, indirect selection based on the characters makes the selection process more efficient, especially in the early generations. Correlation coefficient analysis and the use of path coefficients are particularly important for economical and complex traits such as yield, where direct selection is less effective. Thus the present experiment was undertaken to decipher the character association between the characters in a segregating population (F2) obtained from a cross between Naveen x IR 64 Drt1rom the study, it was evident that the characters like leaf breadth, leaf area, plant height, panicle length, number of primary branches, number of secondary branches, number of filled grains, grain length and test weight had the maximum association with yield among the characters under the study. Correlation coefficient and path coefficient analysis, revealed that the characters viz., number of filled grains per plant followed bygrain breadth, total number of grains, number of secondary branches, plant height, number of panicles, leaf breadth, flag leaf area, 1000 seed weight, panicle lengthand number of primary branches had a highly significant and positive correlation with yield and positive direct effect on yield. Thus, emphasis may be given to these traits for the effective selection of promising lines under study.