Genetic Coefficient Of Variation Research Articles

Study on the Genetic Relationship of Pepper Based on Fruit Traits and Molecular Markers

To explore the genetic diversity of pepper germplasm resources in China and to improve the efficiency of pepper breeding. In this study, 45 pepper germplasm resources that came from USA and Guizhou province, China, were used to explore the quantitative traits of pepper fruits, and the ISSR analysis of germplasm resources genetic diversity. The results showed that the variance among eight quantitative traits of 45 peppers have a significant variation. The average genetic variation coefficient was 70.7%, and there were intricate correlations among the eight quantitative traits. Based on the fruit number traits, 45 pepper germplasms were clearly classified into six taxa by cluster analysis. The genetic diversity of pepper germplasm resources can be evaluated more accurately by molecular markers and phenotypic traits. This study provides a scientific basis for identification and evaluation of pepper germplasm resources, the selection of superior quality traits, and the selection of parents for crossbreeding.

Genetic Variability in Growth Characteristics among Different Clones of Eucalyptus tereticornis Sm.

The present investigation was carried out at the College of Forestry, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, India during August, 2018 to June, 2019 to study the genetic variability in growth characteristics among different clones of Eucalyptus tereticornis. Different clones of Eucalyptus tereticornis Sm. were planted in RCBD, with 4 replications revealed significant variations among all eight treatments (clones) with respect to 9 different characters. Based on the mean performance, treatment-1 (clone-526) showed maximum value for characters like biomass (1124.17), plant height (247.9 cm), collar diameter (23.25 mm), and a number of leaves plant-1 (463.25 number). Similarly, the maximum value was observed in treatment-8 (clone-136) for traits like leaf area (42.70 cm2), leaf length (15 cm), and leaf width (5.75 cm). The highest leaf length to leaf width ratio (3.57) and lowest number of branches plant-1 (18.75 number) were found in treatment-2 (clone-288). All characters had exhibited higher genotypic variance than an environmental variance. Similarly, the genetic coefficient of variation in the case of all variables was also found greater than an environmental coefficient of variation. Heritability was found maximum in plant height (87.35%) and all other characters also showed high heritability. Genetic advance as % of mean was found maximum in biomass (71.15%). Based on the overall mean performance of growth characters, Treatment-1 (Clone-526) was found as a superior clone with respect to the most important character biomass for the test locality. High GCV, heritability, and GAM value for biomass indicated that the character would respond to selection for the improvement program.

Genetic variability in the feeding behavior of crossbred growing cattle and associations with performance and feed efficiency.

The objectives of the present study were to estimate genetic parameters for several feeding behavior traits in growing cattle, as well as the genetic associations among and between feeding behavior and both performance and feed efficiency traits. An additional objective was to investigate the use of feeding behavior traits as predictors of genetic merit for feed intake. Feed intake and live-weight data on 6,088 growing cattle were used of which 4,672 had ultrasound data and 1,548 had feeding behavior data. Feeding behavior traits were defined based on individual feed events or meal events (where individual feed events were grouped into meals). Univariate and bivariate animal linear mixed models were used to estimate (co)variance components. Heritability estimates (± SE) for the feeding behavior traits ranged from 0.19 ± 0.08 for meals per day to 0.61 ± 0.10 for feeding time per day. The coefficient of genetic variation per trait varied from 5% for meals per day to 22% for the duration of each feed event. Genetically heavier cattle, those with a higher daily energy intake (MEI), or those that grew faster had a faster feeding rate, as well as a greater energy intake per feed event and per meal. Better daily feed efficiency (i.e., lower residual energy intake) was genetically associated with both a shorter feeding time per day and shorter meal time per day. In a validation population of 321 steers and heifers, the ability of estimated breeding values (EBV) for MEI to predict (adjusted) phenotypic MEI was demonstrated; EBVs for MEI were estimated using multi-trait models with different sets of predictor traits such as liveweight and/or feeding behaviors. The correlation (± SE) between phenotypic MEI and EBV for MEI marginally improved (P < 0.001) from 0.64 ± 0.03 to 0.68 ± 0.03 when feeding behavior phenotypes from the validation population were included in a genetic evaluation that already included phenotypic mid-test metabolic live-weight from the validation population. This is one of the largest studies demonstrating that significant exploitable genetic variation exists in the feeding behavior of young crossbred growing cattle; such feeding behavior traits are also genetically correlated with several performance and feed efficiency metrics. Nonetheless, there was only a marginal benefit to the inclusion of time-related feeding behavior phenotypes in a genetic evaluation for MEI to improve the precision of the EBVs for this trait.

PSVI-20 Extent of genetic variation in feeding behavior and genetic associations with performance and feed efficiency in crossbred growing cattle

Abstract To the best of our knowledge, the genetic variability in feeding behavior, as well as relationships with performance and feed efficiency, has not been investigated in a cattle population of greater than 1,500 animals. Our objective was to quantify the genetic parameters of several feeding behavior traits, and their genetic associations with both performance and feed efficiency traits, in crossbred growing cattle. Feed intake and live-weight data were available on 6,088 bulls, steers and heifers; of these, 4,672 cattle had backfat and muscle ultrasound data, and 1,548 steers and heifers had feeding behavior data. Genetic (co)variance parameters were estimated using animal linear mixed models; fixed effects included test group, heterosis, recombination loss, dam parity, age in months at the end of test, and the two-way interaction between age in months at the end of test and sex. Heritability was estimated to be 0.51 (0.097), 0.61 (0.100), 0.44 (0.093), 0.48 (0.094), and 0.47 (0.095) for feed events per day, feeding time per day, feeding rate, feed event duration, and energy intake per feed event, respectively. Coefficients of genetic variation ranged from 0.11 (feeding time per day) to 0.22 (feed event duration). Genetically heavier cattle with a higher energy intake per day, and faster growth rate, had a faster feeding rate and a greater energy intake per feed event. Genetic correlations between feeding behavior and feed efficiency were generally not different from zero, however, there was a genetic correlation of 0.36 (0.11) between feeding time per day and residual energy intake. Significant heritable and exploitable genetic variation exists in several feeding behavior traits in crossbred growing cattle which are also correlated with several performance traits. As some feeding behavior traits may be relatively less resource intensive to measure, they could be useful as predictor traits in beef cattle genetic evaluations.

CHAMOMILE (MATRICARIA CHAMOMILLA L.) EXPLORES AGRO-MORPHOLOGICAL AND GENETIC VARIATION AFFECTED BY CHEMICAL MUTAGEN

Chamomile (Matricaria chamomilla L.) is one of the most important medicinal plants in cosmetics and sanitary industries, with various applications. This research was carried out with a view to elucidate the efficacy of six doses of colchicine (0,025, 0.05, 0.1, 0.2, 0.4 and 0.8%) to improvement yield and enhance genetic diversity of chamomile mediated evaluate agronomical, chemical and molecular characteristics. Mutants with substantially superior economical properties, including number of branches, number of flowers, flower fresh and dry weight and the essential oil content, were all induced in colchicine treatments. The RAPD-PCR study has shown that the inducing mutants have been divided into two clusters. The genetic diversity coefficient has been measured at 30 and 35%. The main of two-stage polymorphism was 67.6%, and the Polymorphism Information Content (PIC) ranged between 0 to 0.449 in the bud stage and from 0 to 0.338 from in the seedling stage. Estimation of genetic diversity and selection of prefered mutants would be considerable importance in enhancement breeding programs and to identify of genotypes with higher desirable traits for further multiplication and commercial production. The usefulness of molecular markers as a method to identify the colchicine effect and meaningfully detect useful mutants was demonstrated in a combination of molecular level findings with physiological and morphological results found during various colchicine treatments. The 0.05% colchicine concentration for effective breeding of chamomile mutation is recommended in the results.

Selection for litter size and litter birthweight in Large White pigs: Maximum, mean and variability of reproduction traits

Gradually increasing trend of litter size poses a challenge to pig farmers in terms of managing larger litters. Therefore, it seems that a balanced approach that optimises litter size, litter birthweight, and uniformity of those traits is needed in order to address animal welfare and farm management concerns. This study aimed to investigate this issue by defining several traits for total number born (TNB), number born alive (NBA) and litter birthweight (LW). First, the highest value from at least five records per sow was selected as maximum (max) value for each reproduction trait. Second, a mean (mean) for each reproduction trait was calculated per sow. Last, the variability of reproduction traits between parities of the sow was calculated as log-transformed variance of residuals of all observations per sow for each reproduction trait (LnVar). In total, 23 193 Large White sows from Topigs Norsvin with 152 282 litter records were used for analysis in ASReml 4.1. Also, a simulation of breeding schemes was performed with the use of SelAction 2.1 and estimates from genetic analysis. Maximum value of reproductive traits had a much higher heritability than repeated observations or mean of reproduction traits, e.g., 0.31 for maxTNB vs. 0.12 for TNB and 0.07 for meanTNB, which allows for a faster response under selection. The maximum value traits, however, were found to carry more risks, i.e. higher ratio of stillborn (not for maxNBA) and increased variability of traits. Thus, using them in breeding programme should be carefully considered. The genetic coefficient of variation on SD level estimated to indicate the genetic magnitude for variability phenotypes indicated a maximum change of 6–9% in genetic SD of TNB, NBA and LW. The genetic correlations between mean and corresponding variability traits varied from 0.66 to 0.74, whereas the correlation between other mean and variability traits ranged from 0.33 to 0.99. The simulation indicated that even with selection targeted against the variability of reproduction traits, a very limited change should be expected due to a complex genetic and phenotypic relationship between the traits. In the scenarios with selection against LnVarTNB and LnVarLW, this was a decrease of 0.1–0.6% per year, whereas in scenario with selection against LnVarNBA, the range was 0.6–1.1% per year. It is still possible to increase litter size and birthweight further, however, a balance between mean and variability of reproduction traits is required, which can be obtained only by a very well designed breeding programme.

Agronomic Performance, Genetic Variability and Interrelationships of Traits in some Cowpea (Vignaunguiculata L.Walp) Genotypes under the Semi-Arid Tropics of Sudan

The effectiveness of selection in any cropdepends on the magnitude of the available genetic variability in the gene pool of the species. In this study, 12 cowpea genotypes (ten accessions and two check cultivars) were assessed for agronomic performance, extent of genetic variability and the association between different traits. The genotypes were sown in twoconsecutive seasons (October 2015/2016 and 2016/2017) at Shambat using a randomized complete block design with three replicates. Agronomic performance, variance components, genetic coefficient of variation, heritability, genetic advance and genotypic and phenotypic correlation coefficients were estimated. The genotypes exhibited wide variation in all ofthe studied traits. Seed yield ranged from 477.71 (genotypeHSD-5674) to 2204 kg/ha (genotypeHSD-5131).Highest estimates of genetic coefficient of variation (48.98) and genetic advance as percentage of the mean (81.21) were obtained for number of pods/plant and seed yield/plant, whereas days to maturity showed the lowest estimates. However, days to maturity had thehighest heritability estimate (86%) and seed yield/plant had the lowest (40%) value. Seed yield (Kg/ha)had significant positive genotypic and phenotypic association with each of seed yield/plant, number of pods/peduncle and number of pods/plant indicating that selection for these traits may be effective in yield improvement of the present cowpea genotypes. Genotypes HSD-5131, HSD-5130 and HSD-5672 appeared promising for future seed yield improvement breeding programs under the semi-tropics of Sudan

Impacts of genetic selection on Sequoia sempervirens mini-cutting rooting and initial growth in the field

Background: Vegetative propagation from superior individuals allows multiple copies of plants that are genetically identical to the parent plant to be obtained. However, vegetative propagation success varies among individual genotypes, with some clones having more difficulty forming roots than others. The aim of this study was to evaluate the genetic gain in Sequoia sempervirens (D.Don) Endl. clones using parameters describing vegetative propagation success and initial growth in field. Methods: Vegetative propagation success was quantified for 16 clones in a completely randomised design consisting of 10 replications, each containing 10 mini-cuttings. At 90 days, rooting (RT), survival (SV) and the number of new shoots (NS) were evaluated. Performance after planting in the field was assessed using 13 clones from the previous experiment, arranged in linear parcels of 10 plants with 8 replicates. After 18 months, survival (SV), stem diameter (SD), height (H) and dominance breakdown (DB) were assessed. Estimates of variance components, heritability and genetic correlations were obtained using the Selegen-REML/BLUP software. Results: The mini cuttings of the 16 clones had a coefficient of genetic variation (CVgi%) of 32.32% for RT, 5.44% for SV and 5.35% for NS. The heritability of the total genetic effects (H2 g) for RT was 0.68. The clones with the best predicted genotypic classifications for the characteristics evaluated in the field were A116, A140 and A138 for SV, A126, A140 and A138 for SD, A138, A140 and A117 for H and A138, A228 and A116 for DB. Conclusions: In general, it was possible to obtain high genetic gain for rooting and medium gain for dendrometric variables in the field.

Variability of some broomrape populations from China. Genotyping and determination of genetic polymorphism (II)

Genetic diversity within a population is reflected by variations in genetic material among individuals and can manifest at the phenotypic level through new characters or traits. The emergence of a large number of O. cumana races in a short period of time demonstrates that there are higher genetic variability in populations and a high ability to adapt in the face of environmental conditions. The aim of the research presented in this article was to study the intraand interpopulation genetic diversity and genetic relationships between individuals of three populations of O. cumana from different geographical regions of the People’s Republic of China based on molecular markers (ISSR and SSR). The high intrapopulation genetic variability calculated on the basis of the allelic diversity parameters and specific genetic diversity coefficients was revealed by SSR markers while as for the ISSR primers a high degree of genetic variations was found at the interpopulation level. UPGMA clustering and principal component analysis performed according to both sets of molecular markers allowed to devide all genotypes into 5 major groups for the degree of dissimilarity and level of aggression. This study is of interest in understanding the population genetic structure of the parasitic species of O. cumana from China and could contribute to the development of pathogen control durable strategies and effective sunflower breeding programs to broomrape resistance.

Comparative analysis of the physicochemical composition of pea cultivars

Peas are an inexpensive nutrient source. Basic information about variation in physicochemical composition is required to manage breeding programs and postharvest operations effectively. Different properties were measured in seeds from 16 promising pea genotypes to study variability between lines, degree of genetic parameters, and associations among different traits. Seed weight and diameter, pH, and titratable acidity showed the highest values for broad-sense heritability and the most negligible differences between the phenotypic and genetic coefficient of variation, indicating that these traits’ variability was predominately due to genotypic differences. Genotypes had a wide-range profile that could be related to morphological and physiological properties. Yellow varieties showed superior values for weight and sizes (27.84 g; 0.57 cm) and small changes in diameter after hydration (48.35 %), while wrinkled varieties showed inferior moisture content (9.54 %), higher hydration capacity (1,314.66 g H2O/kg seeds), and protein content (28.88 %). Cuarentina and B315 were the more resistant and firmer materials; B315 also had the highest water hydration capacity, which would be appropriate for canning. Polyacrylamide gels demonstrated differences in protein composition; Gypsi contained more legumin (47.27 %) than the other genotypes, which is more beneficial nutritionally, and contained less convicilin (7.06 %), making it suitable for the food industry. Using accelerated aging, we studied color changes due to storage and established that the Viper line was highly tolerant to it. We could identify lines that may be exploited by industry or quality breeding programs.

Genetics components of rice root architecture and carbon isotopic fractionation parameters: a tracer for breeding in a water-saving irrigation management

Phenotyping is the major bottleneck in the effort to develop varieties of rice (Oryza sativa L.) suitable for growing under a water-saving irrigation management, such as alternate wetting and drying irrigation techniques (AWD). To analyze if the genotypic variability for carbon isotope discrimination (CID) in rice leaves could be used as a relatively high-throughput tracer to early select superior genotypes highlighting improved root architecture traits when submitted to AWD, a set of twenty varieties grown under semi-natural conditions were submitted to two water irrigation regimes, continuous flooding (CF) and AWD cycles. Coefficients of genetic variance (π2g) obtained for root architecture, micro-morphological and physiological traits were significant for all of them regardless of the adopted irrigation system, except to mean root diameter. The three significant principal components (PCs) with eigenvalue > 1, explain most of the total variation across cycles and water regimes. For most of analyzed traits, the values of heritability coefficients were higher regardless of adopted irrigation management and trait category; for CID, the magnitudes of broad heritability at an individual level (greater than 0.80) were similar in the two irrigation techniques, evidencing that the success of the selection is independent of irrigation management. The higher CID values after three AWD cycles are associated with varieties with higher total root length and volume. To our knowledge, this is the first study demonstrating the potential application of CID as a tracer to select root architecture traits in rice when water-saving irrigation management is of concern.

Genetic Variability and Diversity of the Agro-Morphological Traits of Torch Ginger (Etlingera elatior) Germplasm in Malaysia

Aims: The main objective of this study is to quantify the genetic variability and relationship among the quantitative traits of the torch ginger germplasm collected across Peninsular Malaysia.&#x0D; Study design: Initially, the experimental design was randomized complete block design (RCBD) but there were unequal number of replications due to limited planting materials.&#x0D; Place and Duration of Study: The study was conducted at the Malaysian Agricultural Research and Development Institute (MARDI) Research Station, Jerangau, Terengganu, Malaysia on latitude 04°57.704’N and longitude 103°11.007’E. Data on agro-morphological characterization were collected for three years from June 2010 until May 2013.&#x0D; Methodology: A total of 57 torch ginger accessions were collected from various wild/ cultivated sources from seven states of Peninsular Malaysia namely Terengganu (19), Perak (15), Kedah (7), Johor (6), Pahang (5), Kelantan (3) and Melaka (2). The collection was planted in 2009 and maintained as living collection. At three months old torch ginger plantlets were transplanted into 20 cm × 20 cm × 20 cm holes spaced at 100 cm diameter of culvert. The spacing of culvert between rows and within rows were 2 m respectively. Initially, the experimental design was randomized complete block design (RCBD) but there were unequal number of replications due to limited planting materials. Data on agro-morphological characterization were collected for three years from June 2010 until May 2013. All the 57 accessions were characterized according to descriptors list of genera under Zingiberaceae family with some modifications. A total of 6 qualitative and 16 quantitative descriptors were used. The mean values of each quantitative trait data were computed and subjected to statistical analysis to assess the amount of genetic variation using analysis of variance (ANOVA). The ANOVA was using PROC GLM of SAS 9.4 software (SAS Institute Inc., Cary, NC, USA). Genotypic coefficients of variation and error variance were estimated using PROC VARCOMP method Type I of SAS 9.4 software. Phenotypic coefficients of variation, heritability and genetic advance were calculated. Pearson correlation coefficient was determined using SAS 9.4 for comparing the relationship among the different traits. The morphological traits were analyzed by numerical taxonomic methods via cluster analysis and Principal Component Analysis (PCA) which was done using NTSYS-PC Version 2.1. PCA based on 16 quantitative and six qualitative traits was performed to determine the genetic variation in the torch ginger accessions. The cluster and PCA were performed to reveal clustering and grouping pattern of torch ginger accessions. Euclidean distance coefficients were estimated for all pairs of accessions, which was then used to present cluster analysis.&#x0D; Results: Analysis of variance indicated that highly significant variation exists among the 57 accessions for most of the traits. The 57 accessions of torch ginger showed high variability for both qualitative and quantitative traits. Among the quantitative traits, the highest CV was observed from number of spikes with the value of 44.25%. The genetic coefficient of variation for 16 morphological traits ranged from 9.76 to 45.86%. Broad sense heritability estimates varied from low to high. Maximum estimates of broad sense heritability were recorded in bract length (80.16%), bud peduncle length (78.74%), number of leaves (75.66%), number of stems per clump (67.99%), inflorescence peduncle length (67.60%) and bud width (65.11%). The genetic advance (GA) in percent of mean was recorded from 11.82 to 67.97%. Besides that, positive correlation coefficient was obtained between some traits. Generally, the genotypes groups were related with morphological characteristics among the accessions.&#x0D; Conclusion: Considering the distribution pattern, vegetative and yield performance of accessions, it is suggested that accessions from cluster VII (KAN022, KAN047 and KAN048) should be selected for future breeding program. These accessions possessed the highest peduncle length that could influence the yield in terms of bud size. Furthermore, the classification and divergence between torch ginger accessions analyzed in this study may assist in conserving plant materials both in-situ and ex-situ.

Growth and genetic parameters of progenies of Cordia trichotoma in the juvenile phase

Increasing the productive potential of native species is a challenge for forest genetic improvement. Progeny tests are efficient tools to determine the reproductive capacity of individuals and to assist with the selection of superior genotypes. Cordia trichotoma (Vell.) Arrab. ex Steud, is a native species of commercial interest due to its high potential for sawn wood. The performance of seedling production from different progenies was the objective of this work. Seeds were collected from 34 matrices selected phenotypically and georeferenced in the region of Lavras - MG. The experiment was conducted in a completely randomized design with 4 replications of 12 plants. Germination after 70 days of sowing, survival and height at 170 days after germination were evaluated. Height and genetic parameters were estimated according to mixed REML / BLUP models using the Selegen software model 82. Progeny 104 (70.8%) was superior in germination and progenies 86 (35.42%), 92 (35.42%) and 111 (43.75%) had the highest survival rates. Height shows high values for the individual additive genetic variation coefficient (49.18%) and genotypic variation coefficient between progenies (24.59%) and moderate values of heritability in the restricted individual sense (0.45) and heritability within progenies (0.38). Due to high values for the coefficient of genotypic variation and moderate values of heritability, there is a potential for height improvements. Progenies 104 stand out in the germination and the progenies 86, 92 and 111 in the seedlings survival). Regarding height, progeny 95 is the only one that stands out negatively.

CONTRIBUTION OF THE ADDITIVE GENETIC EFFECTS IN SOYBEAN BREEDING AIMING AT THE AGRONOMIC IDEOTYPE

The development of new genotypes and their availability to the agricultural market is decisive for the success of the Brazilian soybean production chain. This study aimed to estimate the components of variance and genetic parameters of aspects of agronomic importance and to predict the selection of transgressive soybean populations and families based on the agronomic ideotype. The segregating families were conducted in an enlarged block design, composed of 285 F3 segregating families corresponding to the unusual treatments, and together with seven commercial cultivars assigned as common treatments, arranged in four replications. The characters of agronomic interest were measured the first pod insertion height, plant height, number of pods on the main stem, number of pods on the branches, pods containing only one seed, pods containing two seeds, pods containing three seeds, pods containing four seeds and seed mass. Were estimated additive genetic variance, genetic variance of the F3 segregating families, genetic variance of F2 segregating population, residual variance, phenotypic variance, narrow sense heritability, coefficient of determination for the effects of the F3 segregating family, coefficient of determination for the effects of the progeny, genetic variation coefficient, residual variation coefficient and predicted genetic ranking for the best F2 segregating populations and F3 segregating families. The pronounced additive genetic gains in the progeny showed higher values for the characters measured: first pod insertion height with 1.84%, for the family and population, the additivity presented the highest values for the number of pods with four grains. The selection of the progenies through the agronomic ideotype based on the greatest genetic gains of the morphological characters weighted by the largest seed mass will thus lead these populations to joint selection for the other yield components.

Genetic diversity and relatedness analysis of nine wild species of tree peony based on simple sequence repeats markers

Tree peony has nine wild species, but the evolutionary relationship of them is still unclear. Here, a total of 274 specimens from 22 natural populations of nine wild species were collected, and their genetic diversity and similarity was analyzed based on Simple Sequence Repeats (SSR) molecular markers. A total of 106 alleles were generated based on 20 primers and with an average of 5.3 alleles per primer. Shannon's information index (I) ranged from 0.6333 to 1.7842, and the average of Nei's genetic diversity coefficient (H) was 0.5771. Polymorphism Information Content (PIC) value varied from 0.29 to 0.77, ten of these primers had high polymorphism (PIC ≥ 0.50). All the above genetic parameters of primers reflect more rich genetic diversity information compared with other researches using SSR molecular markers to study the genetic diversity of tree peony wild species. At the population level, the lowest and highest degree of genetic diversity occurred in Paeonia ludlowii-P1 and P. delavayi-P3 population, respectively. Whereas at species level, the genetic diversity of 9 wild peony species was as follows: P. lutea > P. delavayi > P. rockii > P. qiui > P. ostii > P. decomposita > P. potaninii > P. spontanea > P. ludlowii. Furthermore, cluster analysis at species level divided the nine wild tree peony species into two branches. In branch I, the closest phylogenetic relationship was found between P. ostii and P. rockii, followed by P. spontanea, P. qiui, and P. decomposita. In branch II, the closest relationship occurred between P. lutea and P. delavayi, followed by P. potaninii and P. ludlowii. Clustering results supported the division of tree peonies into two subsects (Delavayanae and Vaginatae), it also supported P. potaninii and P. ludlowii as independent species. The results provided novel insight into the genetic diversity and phylogenetic relationship of nine wild tree peony species. It will help formulate comprehensive protection measures of wild germplasm resources and select proper parents for distant hybridization in the future.

Pedigree analysis of a red fox (Vulpes vulpes) population

Abstract Fur animal breeding has a long history. In many countries several fur animal species (including the red fox) have been recognized as livestock. The aim of this study was to estimate the pedigree parameters in the population of red fox on a Polish breeding farm. The data set consisted of information on 39 434 individuals, including 18 697 females and 20 004 males (733 animals were of unknown sex), from the years 1956–2016. The following pedigree parameters were estimated: average number of discrete generation equivalents, individual inbreeding coefficient, total and effective number of founders, effective population size, average relationship, founder genome equivalent, effective number of non-founders, and genetic diversity coefficient. The population size changed in successive years. The average inbreeding level was 5.34% for the population as a whole, and 6.04% for the inbred population. The estimated effective number of founders of the population was 84.18. The founder genome equivalent, which indicates the anticipated loss of genetic diversity caused by genetic drift, reached 9.59 in 2016 from an initial value of 34.22 in 1956. The loss of genetic diversity caused by the unequal contribution of the founder alleles did not change significantly over the years. Generally, the results indicate the good pedigree structure (including pedigree completeness) of the population studied. This implies reliable estimation of the inbreeding level, as one of the most important parameters in the genetic improvement programme.

Some genetic parameter for maize under different planting dates and environments

"To evaluate the performance of introduced varieties of maize under different sowing dates and locations, in addition to local variety, a field experiment was carried out in two locations;. The study compared five varieties of maize introduced from America, with a local synthetic variety (Ibba 5018) and tested it in two locations at three sowing dates (1, 15 July and 1 August). The Randomized Complete Block Design RCBD was used with four replications, with spilt plot arrangements, the main plots included three sowing dates, the secondary plots included, the varieties. The traits of the days number to tassling and days to silking, plant height, ear height, number of leaves, leaves area, leaf area index, number of ears plant-1 , ear length, the number of rows ear-1, number of grains row-1 , number of grains of the plant, weight of 100 grains, total dry matter weight, the number of days to Physiological maturity, crop growth rate, individual plant yield and yield (tons h-1 ) were studied. The results showed that the values of the standard error (SE) in the two trial locations were low for the studied traits and within the acceptable limit except leaf area which was high in the first and second dates for the Baghdad location and for the three dates of the Diyala incident, as well as the values of the coefficient of variation (CV) were also low and within statistically acceptable limits and for all the traits studied in the three dates and for the two locations. Genetic variations were higher than the = environmental variation for most of the studied traits and the phenotypic coefficient of variation is close to the coefficient of genetic variation for the two locations and the three sowing dates, and this indicates that the traits are genetically governed. The value of heritability in a broad sense was higher than 90% at Baghdad location for first of July for the traits leaves area and its index, weight of the dry matter, number of days to physiological maturity (96.6, 97.4, 93.4 and 94.4%, respectively) and for 15 July for the traits. Leaf area and its index, and number of days to physiological maturity (94.7, 94.7 and 93.4%), and for I Aug for 9 traits; number of days silking, the leaf area and leaf area index, number of ears dry matter, days to maturity, rate of crop growth and yield the plant and unit area ((95.7, 99.4, 99.4, 94, 98.4, 95.5, 98.6, 93.4, 93.5%) Sequentially. As for Diyala, the traits of leaf area, leaf area index, number of days to physiological maturity, yield of plants, and area unit in the three dates were superior to the highest heritability (92.3, 92.3, 98.7, 73.6, 73.6%), (90.2, 90.2, 98.8, 82.9, 82 .9%), (90.9, 90.9, 86.4, 80.7, 80.7% respectively)."

Genetic parameters estimation and factor analysis of morphological and physiological characteristics of F2:4 rice (Oryza sativa L.) genotypes in germination stage under salinity conditions

IntroductionSalinity stress greatly affects crop yields especially in arid and semi-arid climates. The reaction of rice plants; with a special situation among other crops for supplying human nutrition, to salinity varies in different growth stages. Salinity tolerance in plants is a complex process in which morphological changes, physiological and biochemical processes are involved. In order to study the reaction of rice plants to salinity conditions and identification of tolerant genotypes, it is recommended to evaluate the salinity effects at salinity sensitive stages such as germination stage. The use of genetic diversity in crops is one of the most important interests of breeders in understanding the strategies for crops improvements. The aim of this research was to, estimate the genetic diversity of evaluated traits, study the effect of salinity on various morphological and physiological characteristics in the rice germination stage, determine the relationship between traits, and to identify the traits that affect the indirect selection of tolerant genotypes to salinity. Materials and methodsOne hundred seventeen F2:4 generation lines; obtained from the cross between Mousa Tarom and 304 rice genotypes, were cultured in two separate experiments; with and without salinity stress, in a randomized complete block design at the Faculty of Agriculture, Yasouj University. The seeds were placed in petri dishes in germinator at 25 ± 3 ° C. The number of germinated seeds of each genotype was counted during 14 days, and the seed length and weight vigor, germination percentage, seed germination rate, as well as the morpho- physiological characteristics of rootlet and shootlet length, rootlet fresh and dry weight, shootlet fresh and dry weight, Leaf proline, total soluble sugars and leaf protein content were evaluated. Results and discussionIn both the salinity stress and non-stress conditions, the phenotypic coefficient of variation (CVp) was larger than the genetic coefficient of variation (CVg) for all measured traits. Leaf proline, total protein and soluble sugars had the highest CVg in both the stress and non-stress conditions, indicating a wide diversity of the evaluated genotypes. The genotypes showed the lowest CVg and CVp under both the conditions for germination percentage. So, it can be claimed that the genotypes were not significantly different in their reaction to environmental variations.Proline heritability was 98% in both the salinity conditions. The heritability of protein content in stress condition (86%) was about 13 percentage points lower than non-stress (99%). Salinity stress increased 6 percentage points of soluble sugars (98%) compared to non-stress condition. Salinity stress also increased the heritability of germination percentage, shootlet length, shootlet fresh weight, rootlet fresh weight, and shootlet dry weight and Seedling length vigor index compared to non-stress condition. In non-stress condition, the highest positive and significant correlation was found between rootlet and Seedling length vigor index, and between shootlet dry weight and weight vigor index. In stress conditions, the highest correlation was observed between rootlet length and rootlet dry weight. Also, a significant correlation was observed between the characteristics of the Seedling length vigor index with rootlet dry weight, rootlet and shootlet fresh weight, germination percentage and rate in salinity stress condition. Rootlet dry weight with germination percentage, rootlet length and shootlet length showed a positive and highly significant correlations. No significant correlation was seen between soluble proline, total protein content and soluble sugars in germination stage.On the basis of principal component analysis, in non-stress, and salinity stress conditions 5 and 6 factors were identified, respectively, which explained 74% and 78% of the diversity of the total data. In non-stress conditions, the first factor explained 33.92% of the variation, in that, traits such as shootlet length, shootlet fresh and dry weight and seedling weight vigor index had the highest effect with the positive direction. In stress condition, the first factor explained 32.2% of the total variation in which the shootlet fresh weight and length, germination percentage and germination rate, and Seedling length vigor index had the highest positive effect. ConclusionDifferent lines and varieties of rice show different responses to different environmental stresses, which evaluation of such a reactions are of particular importance for breeders. Leaf soluble proline, protein and soluble sugars had the highest genetic variation in both the stress and non-stress conditions. These conditions indicated that selection for soluble sugars, proline, and leaf total protein was promising, and their high heritability suggests that the traits in question are more likely to be transmitted to the offspring. Therefore, they can be used in breeding programs for creation of genetic diversity, hybridization and selection. Based on the results of factor analysis, shootlet fresh weight and length can be used as an effective feature in the selection of salt tolerant genotypes in both stress and non-stress conditions at germination stage.

Genetic parameters for uniformity of harvest weight in Pacific white shrimp (Litopenaeus vannamei)

BackgroundUniformity of body weight is a trait of great economic importance in the production of white shrimp (Litopenaeus vannamei). A necessary condition to improve this trait through selective breeding is the existence of genetic variability for the environmental variance of body weight. Although several studies have reported such variability in other aquaculture species, to our knowledge, no estimates are available for shrimp. Our aim in this study was to estimate the genetic variance for weight uniformity in a farmed population of shrimp to determine the potential of including this trait in the selection program. We also estimated the genetic correlation of weight uniformity between two environments (selection nucleus and commercial population).MethodsThe database contained phenotypic records for body weight on 51,346 individuals from the selection nucleus and 38,297 individuals from the commercial population. A double hierarchical generalized linear model was used to analyse weight uniformity in the two environments. Fixed effects included sex and year for the nucleus data and sex and year-pond combination for the commercial data. Environmental and additive genetic effects were included as random effects.ResultsThe estimated genetic variance for weight uniformity was greater than 0 (0.06 ± 0.01) in both the nucleus and commercial populations and the genetic coefficient of variation for the residual variance was 0.25 ± 0.01. The genetic correlation between weight and weight uniformity was close to zero in both environments. The estimate of the genetic correlation of weight uniformity between the two environments (selection nucleus and commercial population) was 0.64 ± 0.06.ConclusionsThe existence of genetic variance for weight uniformity suggests that genetic improvement of this trait is possible. Selection for weight uniformity should not decrease weight, given the near zero genetic correlation between these two traits. The strong genetic correlation of weight uniformity between the two environments indicates that response to selection for uniformity in the nucleus will be at least partially transmitted to the commercial population if this trait is included in the breeding goal.

Estimation of the broad-sense heritability of traits in Haloxylon aphyllum native populations in Kerman

To investigate the broad-sense heritability of some Haloxylon traits, an experimental design was performed using native populations collected from different provinces of Iran. 32 native populations were planted based on a randomized complete block design with three replications in Shaheed Zendeh Ruh's research station in Kerman. During three years, seven traits including main stem length, collar diameter, number of tillers, sub-stem length1, sub-stem length2, the small and large diameter of the canopy on shrubs were examined. The data were assessed by simple and combined analysis of variance. For all traits, the difference between the mean of genotypes and years was significant (p < %1). The genotype× year interaction effect was significant for all other traits except the number of tillers, which indicates different effects of genotypes in different years. Heritability of traits was estimated based on simple and combined analysis of variances. The amount of heritability was ranged from 75 to 87% for simple analysis and 51 to 64% for combined analysis, which indicates a decrease in heritability in a combined analysis. This is due to the genotypes by the year interactions effects. In both methods, the main stem length and number of tillers had the highest and lowest broad-sense heritability and coefficients of genetic and phenotypic variation, respectively. Due to the high genetic diversity among the studied Haloxylon genotypes, it will be possible to select the best rootstocks for making windbreaks in desertification projects.