High Heritability Estimates Research Articles

Genetic and Environmental Contributions to Subcortical Gray Matter Microstructure and Volume in the Developing Brain

Using baseline (ages 9–10) and two-year follow-up (ages 11–12) data from monozygotic and dizygotic twins enrolled in the longitudinal Adolescent Brain Cognitive DevelopmentSM Study, we investigated the genetic and environmental contributions to microstructure and volume of nine subcortical gray matter regions. Microstructure was assessed using diffusion MRI data analyzed using restriction spectrum imaging (RSI) and diffusion tensor imaging (DTI) models. The highest heritability estimates (estimate [95% confidence interval]) for microstructure were found using the RSI model in the pallidum (baseline: 0.859 [0.818, 0.889], follow-up: 0.835 [0.787, 0.871]), putamen (baseline: 0.859 [0.819, 0.889], follow-up: 0.874 [0.838, 0.902]), and thalamus (baseline: 0.855 [0.814, 0.887], follow-up: 0.819 [0.769, 0.857]). For volumes the corresponding regions were the caudate (baseline: 0.831 [0.688, 0.992], follow-up: 0.848 [0.701, 1.011]) and putamen (baseline: 0.906 [0.875, 0.914], follow-up: 0.906 [0.885, 0.923]). The subcortical regions displayed high genetic stability (rA = 0.743–1.000) across time and exhibited unique environmental correlations (rE = 0.194–0.610). Individual differences in both gray matter microstructure and volumes can be largely explained by additive genetic effects in this sample.

Diagnostic yield and clinical impact of chromosomal microarray analysis in autism spectrum disorder.

Autism spectrum disorder (ASD) is characterized by high heritability estimates and recurrence rates; its genetic underpinnings are very heterogeneous and include variable combinations of common and rare variants. Array-comparative genomic hybridization (aCGH) offers significant sensitivity for the identification of copy number variants (CNVs), which can act as susceptibility or causal factors for ASD. The aim of this study was to evaluate both diagnostic yield and clinical impact of aCGH in 329 ASD patients of Italian descent. Pathogenic/likely pathogenic CNVs were identified in 50/329 (15.2%) patients, whereas 89/329 (27.1%) carry variants of uncertain significance. The 10 most enriched gene sets identified by Gene Ontology Enrichment Analysis are primarily involved in neuronal function and synaptic connectivity. In 13/50 (26.0%) patients with pathogenic/likely pathogenic CNVs, the outcome of array-CGH led to the request of 25 additional medical exams which would not have otherwise been prescribed, mainly including brain MRI, EEG, EKG, and/or cardiac ultrasound. A positive outcome was obtained in 12/25 (48.0%) of these additional tests. This study confirms the satisfactory diagnostic yield of aCGH, underscoring its potential for better, more in-depth care of children with autism when genetic results are analyzed also with a focus on patient management.

Analyzing genetic variation for important yield-contributing attributes in genotypes of orange-fleshed sweet potatoes

An experiment was conducted to estimate genetic variability of 47 orange-fleshed sweetpotato(OFSP) genotypes. It was established in two locations(Umudike and Igbariam) in a RCBD fashion with three replications. Data collected were subjected to ANOVA using the software; AGD-R. The results showed that all the characters studied were highly significant (p<0.01) for genotypes. All the traits were significant for location except the vine length, days to 50% flowering and root yield. Most of the characters were also significant for genotypes-location interaction. Significant differences observed among genotypes for most traits indicated the presence of genetic variation among the materials. The genotypic coefficient of variation(GCV) was very high for beta carotene(73.8%) and vitamin A(70.0%). Phenotypic coefficient of variation(PCV) was very high for beta carotene(183.5%), root yield per hectare(151.6%), total root weight per plant(150.6%) and total number of roots per plant(113.5%). The PCV was higher than their corresponding GCV for all the characters studies, indicating that the expression of these characters was influenced by environment. The GCV was consistently higher than PCV in all the traits. The genotypic variance was high for days to 50% flowering(373.16), dry matter(220.30), root girth (140.73), root length (68.10) and root yield per hectar (349.66). The magnitude of VA was consistently larger than that of VD for all the traits suggesting that the additive genetic variance was more important than the dominance genetic variance in the inheritance of most studied traits. All the characters studies had high heritability (>60%). High heritability estimates for those traits indicated a high response to selection

Genomic analysis of firework fear and noise reactivity in standard poodles

BackgroundFear of firework noises and other loud, sudden noises (noise reactivity) is a significant problem for many dogs and may have a negative effect on both welfare and, in severe cases, the life expectancy of dogs. A wide range of behavior traits, including fear-related behaviors, have high heritability estimates in dogs. The aim of this study was to estimate genomic heritability for fear of fireworks and loud noises in dogs.ResultsA genomic heritability estimate was performed based on genome-wide SNPs from standard poodles with records of fear of fireworks and noise reactivity. The study was based on questionnaires answered by owners, who also volunteered to return a cheek swab from their dog for DNA analyses. SNP-based heritability was estimated to be 0.28 for firework fear and 0.16 for noise reactivity. We also identified an interesting region on chromosome 17 that was weakly associated with both traits.ConclusionsWe have estimated low to medium genomic heritabilities for fear of fireworks and noise reactivity in standard poodles. We have also identified an interesting region on chromosome 17, which harbors genes that have been shown to be involved in different psychiatric traits with anxiety components in humans. The region was associated with both traits; however, the association was weak and need further verification from other studies.

Single-step genomic evaluation for growth traits in a Mexican Braunvieh cattle population.

The objective was to compare (pedigree-based) BLUP, genomic BLUP (GBLUP), and single-step GBLUP (ssGBLUP) methods for genomic evaluation of growth traits in a Mexican Braunvieh cattle population. Birth (BW), weaning (WW), and yearling weight (YW) data of a Mexican Braunvieh cattle population were analyzed with BLUP, GBLUP, and ssGBLUP methods. These methods are differentiated by the additive genetic relationship matrix included in the model and the animals under evaluation. The predictive ability of the model was evaluated using random partitions of the data in training and testing sets, consistently predicting about 20% of genotyped animals on all occasions. For each partition, the Pearson correlation coefficient between adjusted phenotypes for fixed effects and non-genetic random effects and the estimated breeding values (EBV) were computed. The random contemporary group (CG) effect explained about 50, 45, and 35% of the phenotypic variance in BW, WW, and YW, respectively. For the three methods, the CG effect explained the highest proportion of the phenotypic variances (except for YW-GBLUP). The heritability estimate obtained with GBLUP was the lowest for BW, while the highest heritability was obtained with BLUP. For WW, the highest heritability estimate was obtained with BLUP, the estimates obtained with GBLUP and ssGBLUP were similar. For YW, the heritability estimates obtained with GBLUP and BLUP were similar, and the lowest heritability was obtained with ssGBLUP. Pearson correlation coefficients between adjusted phenotypes for non-genetic effects and EBVs were the highest for BLUP, followed by ssBLUP and GBLUP. The successful implementation of genetic evaluations that include genotyped and non-genotyped animals in our study indicate a promising method for use in genetic improvement programs of Braunvieh cattle. Our findings showed that simultaneous evaluation of genotyped and non-genotyped animals improved prediction accuracy for growth traits even with a limited number of genotyped animals.

Estimation of Genetic Variability for Yield and Yield Attributing Traits in Dolichus Bean [Lablab purpureus (L.) Sweet var. Typicus] Genotypes

Dolichos bean is an indigenous legume grown as vegetable (Lablab purpureus var. typicus) and pulse (Lablab purpureus var. lignosus) throughout India. A wide range of variation exists for the morphological and reproductive characters amongst the land races of Indian Bean grown all over the country. Therefore it is necessary to select variety having desired pod quality with high yield potential. Despite of these good attributing characters it is still regarded as underexploited vegetable because of low productivity, long duration and photosensitivity, flowering irregularity, growth habit and preference of consumers with respect to pod shape, pod size, pod colour, pod aroma. Keeping this in view the present investigation was conducted at All India Co-ordinated Research Project on Vegetable Crops, Odisha University Of Agriculture and Technology, Bhubaneswar during Rabi, 2020-21 for evaluating the yield and yield attributing characters, for estimating the variability, heritability, genetic advance and the association between yield and yield attributing characters for an effective selection to estimate the genetic variability in Dolichus bean [Lablab purpureus (L.) sweet var. typicus] genotypes for further crop improvement study. The genotypic variance ranged from 0.02 for pod weight per plant to 2435 for average leaf area. The phenotypic variance ranged from 0.023 for pod weight per plant to 2879.8 for average leaf area. Phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (PCV) for all the 14 characters taken. This happened because PCV estimates includes variations due to environment (E) and genotype and environment (GE) interaction. PCV was highest (60.31) for pod yield per plant followed by average leaf area (35.09) indicating the presence of wide range of genetic variability in the germplasm for these traits. Higher value of GCV was found for characters like pod yield per plant (59.80) followed by average leaf area (32.26) and number of pods per plant (31.94). Highest estimates of heritability in broad sense was observed in Pod weight per plant (98.30) followed by number of pods per plant (96.17), average leaf area (84.55), number of pods per inflorescence (83.91), pod length (82.22), plant height (78.82), pod yield per hectare (78.66) indicating that these characters are less influenced by environment.

Genetic Variability and Association of Yield and Yield-Related Traits under Moisture Stress in Common Bean Genotypes (Phaseolus vulgaris L.) at Melkassa and Miesso, Ethiopia

Twenty-five common bean genotypes were evaluated to assess the genetic variability, trait association, and determine the direct and indirect effects of traits on seed yield. The genotypes were grown in a lattice design at the research farm of the Melkassa Agricultural Research Center, Melkassa and Miesso, in the 2018 cropping season. Analysis of variance revealed that significant differences were observed among the genotypes at individual locations. The phenotypic coefficient of variation values were moderate for number of nodes, seeds per pod, plant height, and hundred seed weight at Melkassa. Moderate genotypic coefficient of variation values were obtained for pods per plant and seeds per pod. At Miesso, moderate phenotypic coefficients of variation values were recorded for number of nodes, hundred seed weight, and plant height. High heritability estimates were obtained for seed yield and hundred seed weight at Melkassa and for seed yield at Miesso, indicating that selection could be fairly easy and improvement is possible using these traits in a common bean breeding program. High genetic advances were obtained for seed yield and pods per plant at Melkassa, while moderate genetic advances as a percent of the mean were attained for plant height, hundred seed weight, and seeds per pod. Similarly, at Miesso, high and moderate genetic advances as percent of mean values were obtained for seed yield and hundred seed weight, respectively. Seed yield showed positive and significant phenotypic association with days to flowering, internode length, and pods per plant at Melkassa and had positive and significant phenotypic association with seeds per pod and hundred seed weight at Miesso. Hence, selection of those genotypes based on the traits with high genotypic coefficient of variability, heritability, genetic advance, and positive correlation coefficient and direct effect on seed yield can be recommended for further yield improvement at the respective location and at the national level in general.

Hybrid Vigor and Heritability Estimates in Tomato Crosses Involving Solanum lycopersicum × S. pimpinellifolium under Cool Tropical Monsoon Climate

High humidity is a major constraint to increased tomato fruit production in a cool tropical monsoon climate. However, the genetic variation observed in Solanum pimpinellifolium makes it a good gene donor for breeding tomato cultivars capable of thriving under high humidity. The objective of this study was to estimate heterosis, heritability for higher yield, and to assess the adaptability of the genotypes to humid conditions. Genotypes were raised from five morphologically divergent parents, viz., wild parent (W)–“LA2093,” “CLN2498D” (D), “CLN2417H” (H), “Tima” (T), and “UC Dan INDIA” (U). The F1s were generated by biparental mating design using “LA2093” as a common pollen donor that was selfed to produce F2s and backcrossed to both parents to obtain BC1s and BC2s. The trial was laid out in a randomized complete block design with three replicates. Data were collected on selected yield-influencing traits and analyzed. “D × W” and “U × W” hybrids showed significant positive better parent heterosis for fruit weight per plant (30.4% and 35.5%) and total fruit yield (48.6% and 26.9%), respectively. The additive variance was higher than dominance variance for all the traits, including total fruit yield in all hybrids viz., “H × W,” “D × W,” “T × W,” and “U × W.” High narrow sense heritability estimate of ≥60% was observed in “D × W” and “U × W” hybrids for the majority of the floral and fruit traits including total fruit yield. This makes the improvement of “D × W” and “U × W” hybrids by direct selection advantageous. Hence, the adoption of selection for the affected traits in subsequent tomato breeding programs would enhance fruit yield and adaptability to humid environments.

Genetic variability, genetic advance and heritability of black and brown seeded soybean [Glycine max (L.) Merrill] lines in Jimma and Bonga Southwest Ethiopia

An experiment was conducted with a simple lattice design with two replications to estimate the genetic variability in 62 soybean genotypes and 2 standard check varieties. The variability parameters such as mean, range of variation, genotypic and phenotypic coefficient of variation, heritability in the broad sense, genetic advance, and genetic advance as percentage of mean were estimated for 11 different traits. The values of the phenotypic coefficient of variation (PCV) were greater than the genotypic coefficient of variation (GCV) for all the traits, revealing the influence of environmental factors. The value of heritability was determined to be high for the traits such as grain yield, harvest index, number of seeds per pod, number of primary branches per plant, number of pods per plant and hundred seed weight. Indicating that the larger portion of total variation would be under genetic control and selection based on phenotypic levels would be useful for the improvement of these traits in soybean. High estimates of heritability together with high genetic advance as percentage of mean were recorded for grain yield, harvest index, number of seeds per pod, number of primary branches per plant, number of pods per plant and hundred seed weight, which may be attributed to the presence of additive gene action and had high selective value. Thus, selection pressure could successfully be applied to these traits for soybean improvement programs. Int. J. Agril. Res. Innov. Tech. 12(2): 14-17, December 2022

Variation in Shoot, Peduncle and Fruit Growth of Lagenaria siceraria Landraces.

Lagenaria siceraria (Molina) Standley is a prominent food source as almost all its plant parts are edible. However, no studies have recorded the changes in shoots, peduncles and fruits during its growth. Hence, this study aimed to record changes in shoot traits and relate the peduncle to the fruit traits of L. siceraria landraces across different growth stages. Changes in shoots, peduncles and fruits during growth were compared within and among landraces using analysis of variance, correlation, principal component analysis, cluster analysis and heritability estimates. Almost all landraces had harvestable shoots at 42 days after sowing. Peduncles became shorter and wider as the fruits elongated. Shoots, peduncles and fruits correlated positively with each other. The informative principal components had a total variability of 84.488%, with a major contribution from shoot traits. The biplot and dendrogram clustered landraces with similar growth habits and the harvestable shoot and fruit attributes into three clusters, but KRI and NSRC formed singlets. Shoot width (60.2%) and peduncle length (55.2%) had high heritability estimates. The general low heritability estimates and genetic advances indicated the presence of non-additive gene action. This study is the first report on changes in harvested shoots and the relationship between peduncles and fruits during growth.

Genotypic effects on the response of soybean (Glycine max (L.) Merrill) to sulfonylurea herbicides

AbstractSulfonylurea (SU) herbicides registered for use in other crops in Australia may leave residues in the soil interrupting rotations involving soybean. However, two unlinked genes (ALS1 and ALS2) confer SU tolerance in soybean. Here, we report experiments that explored the effectiveness of these ALS genes in Australian soybean germplasm. The first two experiments assessed the tolerance to halosulfuron‐methyl or metsulfuron‐methyl of lines with either zero ALS gene (ALS1) or both ALS1 and ALS2 in five different Australian genetic backgrounds. The presence of both ALS1 and ALS2 conferred strong SU tolerance at herbicide application rates as high as four times (4×) the recommended field rate, with evidence of interaction with the genetic background; lines carrying only ALS1 also performed well but demonstrated less tolerance. For the third experiment, the five lines homozygous for both ALS genes were intercrossed in a half‐diallel mating design. The resulting F2 population were screened for tolerance to metsulfuron‐methyl herbicide. In all instances, the presence of the two ALS genes provided absolute protection for the growth tip. Analyses of seedling dry weight and purple leaf discoloration demonstrated significant differences among the crosses. For dry weight, high and significant heritability estimates indicated significant additional genetic variation for SU tolerance in five of the 10 F2 crosses (p ≤ 0.05). The results of these three studies confirm that two ALS genes confer tolerance to SU herbicides when crossed into Australian soybean germplasm, but suggest possible epistatic effects within different backgrounds, and the possibility of other (minor) genes conferring additional SU tolerance.

Enhancing quinoa cultivation in the Andean highlands of Peru: a breeding strategy for improved yield and early maturity adaptation to climate change using traditional cultivars

Quinoa (Chenopodium quinoa Willd.) is an ancient food crop that originated in the Andes. It has good nutritional properties that increasingly attract interest around the world and it is considered as a future crop for food security and climate change adaptation. Currently, there is a great need to develop new quinoa varieties with higher yield, tolerance to biotic and abiotic stresses, and adaptation to new growing areas. Despite the existence of breeding programs, quantitative genetic parameters that are relevant for selection gain have hardly been investigated for quinoa. We estimated these parameters for important agronomic traits in six segregating populations of 96 lines each, derived from crosses of popular traditional Peruvian quinoa varieties. The traits were evaluated in trials at several locations in the Peruvian highlands over 3 years. Maturity was the best phenological stage for trait evaluation because at this stage we obtained high estimates of heritability and high correlation of panicle trait indices with grain yield. Based on these traits, we selected the 18 best lines and characterized them in additional field trials for the same traits. Three lines (HUA × KAN53, SAL × NCO46 and SAL × PAN171) combined advantageous traits of their parents and showed lower plant height, earlier maturity and higher yield. Our work shows that the estimation of variance and variance components in the amphidiploid crop quinoa provides useful information for the design of breeding programs and the selection of improved genotypes for cultivation in the Peruvian highlands.

Genetic analyses of tropical maize lines under artificial infestation of fall armyworm and foliar diseases under optimum conditions.

Development and deployment of high-yielding maize varieties with native resistance to Fall armyworm (FAW), turcicum leaf blight (TLB), and gray leaf spot (GLS) infestation is critical for addressing the food insecurity in sub-Saharan Africa. The objectives of this study were to determine the inheritance of resistance for FAW, identity hybrids which in addition to FAW resistance, also show resistance to TLB and GLS, and investigate the usefulness of models based on general combining ability (GCA) and SNP markers in predicting the performance of new untested hybrids. Half-diallel mating scheme was used to generate 105 F1 hybrids from 15 parents and another 55 F1 hybrids from 11 parents. These were evaluated in two experiments, each with commercial checks in multiple locations under FAW artificial infestation and optimum management in Kenya. Under artificial FAW infestation, significant mean squares among hybrids and hybrids x environment were observed for most traits in both experiments, including at least one of the three assessments carried out for foliar damage caused by FAW. Interaction of GCA x environment and specific combining ability (SCA) x environment interactions were significant for all traits under FAW infestation and optimal conditions. Moderate to high heritability estimates were observed for GY under both management conditions. Correlation between GY and two of the three scorings (one and three weeks after infestation) for foliar damage caused by FAW were negative (-0.27 and -0.38) and significant. Positive and significant correlation (0.84) was observed between FAW-inflicted ear damage and the percentage of rotten ears. We identified many superior-performing hybrids compared to the best commercial checks for both GY and FAW resistance associated traits. Inbred lines CML312, CML567, CML488, DTPYC9-F46-1-2-1-2, CKDHL164288, CKDHL166062, and CLRCY039 had significant and positive GCA for GY (positive) and FAW resistance-associated traits (negative). CML567 was a parent in four of the top ten hybrids under optimum and FAW conditions. Both additive and non-additive gene action were important in the inheritance of FAW resistance. Both GCA and marker-based models showed high correlation with field performance, but marker-based models exhibited considerably higher correlation. The best performing hybrids identified in this study could be used as potential single cross testers in the development of three-way FAW resistance hybrids. Overall, our results provide insights that help breeders to design effective breeding strategies to develop FAW resistant hybrids that are high yielding under FAW and optimum conditions.

Phenotypic and genetic parameters of circadian rhythms from core body temperature profiles and their relationships with beef steers' production efficiency profiles during successive winter feeding periods.

This 2-year study evaluated differences in circadian parameters obtained from measures of core body temperatures using telemetric reticulo-rumen and rectal devices during two winter feeding regimes in western Canada. The study also estimated phenotypic correlations and genetic parameters associated with circadian parameters and other production traits in each feeding regime. Each year, 80 weaned steer calves (initial age: 209 ± 11days; BW: 264 ± 20kg) from the same cohort were tested over two successive regimes, Fall-Winter (FW) and Winter-Spring (WS) at Lanigan, Saskatchewan, Canada. The steers received forage-based rations in both regimes where the individual feed intake was measured with automatic feeding units. During the trial, the reticulo-rumen (RTMP) and rectal (RCT) temperatures were simultaneously measured every 5min using telemetric devices. These were used to calculate the circadian parameters (Midline Estimating Statistic Of Rhythms, amplitude, and acrophase/peak time) for both temperature measures. Growth and efficiency performance traits were also determined for all steers. Each steer was assigned into inefficient, neutral, and efficient classes based on the SD of the residual feed intake (RFI), residual gain (RG), and residual intake and gain (RIG) within each year and feeding regime. Higher (p < 0.0003) RTMP and rectal temperature MESORs were observed in the Fall-Winter compared to the Winter-Spring regime. While the two test regimes were different (p < 0.05) for the majority of the RTMP or RCT temperature parameters, they did not differ (p > 0.10) with the production efficiency profiles. The heritability estimates were higher in FW (0.78 ± 0.18 vs. 0.56 ± 0.26) than WS (0.50 ± 0.18 vs. 0.47 ± 0.22) for the rumen and rectal MESORs, respectively. There were positive genetic correlations between the two regimes for the RTMP (0.69 ± 0.21) and RCT (0.32 ± 0.59). There was a negative correlation (p < 0.001) between body temperature and ambient temperature. The high heritability estimates and genetic correlations for rumen and rectal temperature parameters demonstrate their potential as beef genetic improvement tools of economic traits associated with the parameters. However, there are limited practical implications of using only the core-body temperature as a proxy for production efficiency traits for beef steers during winter.

Genetic liability to schizophrenia and cardiac structure and function

Schizophrenia is a complex disorder with high heritability estimates of 60–80% based on population and twin studies.1 Moreover, the lifespan of patients with schizophrenia is approximately 20 years shorter than that of the general population.2 This outcome might be partly explained by various comorbidities, including cardiovascular disease and associated features such as smaller cardiac volumes.3,4 Although many environmental factors link schizophrenia to cardiovascular outcomes, genetic overlap has also been observed.

Genetic Parameters and Genotype × Diet Interaction for Body Weight Performance and Fat in Gilthead Seabream

There has been thorough research on the genotype by diet interaction and the extent of its impact on the genetic evaluation, using a partly replaced marine animal protein on the gilthead seabream. To do that, 8356 individuals were gathered from two batches and followed different diets: a high-plant-protein diet containing 85% plant proteins and a standard commercial one containing 30% marine animal protein. During the experiment, body weight, growth and fat content were recorded. High heritability estimates were detected for the body weight performance and fat content. A small effect of genotype by diet interaction was detected in all phenotypes (presented as the genetic correlations from 0.95 to 0.97) but a medium-high ranking correlation between the breeding values for each trait was estimated (0.72-0.70). A higher expected response to selection for the body weight performance was detected using the standard commercial rather than the plant-based diet. Based on the findings, the establishment of a plant-based diet breeding strategy can be achieved provided the reduction of the cost of aquafeed is attained, though a lower genetic gain is expected.

STUDIES ON VARIABILITY, HERITABILITY AND GENETIC ADVANCE FOR YIELD AND YIELD RELATED TRAITS IN GREENGRAM [VIGNA RADIATA (L.) WILCZEK

This investigation was conducted to evaluate 19 parents (16 lines x 3 testers), 48 F1 and 48 F2 . Analysis of variance showed high significant differences among 115 greengram genotypes for 13 studied quantitative traits. In F1 , the highest phenotypic and genotypic coefficient of variation was observed for 100 seed weight followed by harvest index. Moderate phenotypic and genotypic coefficient of variation was observed in seed yield per plant and subsequently number of clusters per plant. While low PCV and GCV were observed in days to maturity followed by seed protein content. In the F2 generation, phenotype coefficient of variation (PCV) estimates was higher than genotypic coefficient of variation (GCV) for all traits. The highest phenotypic and genotypic coefficient of variation was observed for the harvest index. A high phenotypic and medium genotypic coefficient of variation was observed for biological yield. Moderate phenotypic and genotypic coefficient of variation was observed in seed yield per plant and subsequently number of clusters per plant. While low PCV and GCV were observed in days to maturity followed by seed protein content. In the F1 generation, high heritability estimates were observed for 100 seed weight, followed by harvest index, biological yield, seed yield per plant, plant height, days to 50% flowering, seed protein content. Medium heritability was observed in number of clusters per plant, number of pods per plant, pod length and number of seeds per pod. Low heritability was observed for the number of branches per plant. High heritability associated with high genetic progress as a percentage of mean was observed for 100 seed weight, biological yield and harvest index. High heritability with moderate genetic progress was observed from days to 50% flowering and plant height. In the F2 generation, high heritability estimates were observed for harvest index followed by seed yield per plant, 100 seed weight, plant height, days to 50% flowering, days to maturity, number of pods per plant and seed protein content. Medium heritability was observed in number of clusters per plant followed by pod length. Low heritability was observed for number of branches per plant followed by number of seeds per pod and biological yield. High heritability associated with high genetic progress as a percentage of mean was observed using harvest index, followed by seed yield per plant, 100 seed weight. High heritability with moderate genetic progress was observed for plant height followed by days to 50% flowering and number of pods per plant and days to maturity. Medium heritability was observed in number of clusters per plant, number of pods per plant, pod length and number of seeds per pod. Low heritability was observed for the number of branches per plant. High heritability associated with high genetic progress as a percentage of mean was observed for 100 seed weight, biological yield and harvest index. High heritability with moderate genetic progress was observed from days to 50% flowering and plant height

Utilizing genetic variability parameters of garden pea (Pisum sativum L.) germplasm for yield and quality traits

In present study, 159 diverse pea genotypes were evaluated at Vegetable Research Farm, Punjab Agricultural University, Ludhiana, Punjab, India to study genetic variability, heritability and genetic advance involving 14 morphological traits. The analysis of variance showed significant differences among genotypes for all the traits under study except node at which 1st pod appears. On the basis of mean performance, the maximum yield was observed in PB-90 which was followed by PB-89 and 2009/PMVAR-6. Highest coefficient of variation was observed for number of seeds/pod and highest genotypic and phenotypic coefficients of variation were recorded for number of pods/plant followed by plant height and total yield/plant. Very high heritability estimates were observed for plant height (99.89) followed by total yield/plant (99.71) and days to 1st picking (99.43) while genetic advance as percent of mean was observed high for number of pods/plant (65.35) followed by plant height (58.66) and total yield/plant (42.17). High heritability along with high genetic advance was found for all traits under study. High heritability estimates coupled with high genetic advance reflects the presence of additive gene action for expression of these traits.

Diallel crosses in Picea abies IV. Genetic variation and inheritance patterns in short-term trials

Abstract The complete diallel cross is the only mating design that provides estimates of variance components of general combining (GCA), specific combining ability (SCA), maternal and reciprocal effects, in addition to heritabilities and genetic correlations. To obtain such estimates, complete diallels were made among 10 trees in each of three natural Norway spruce populations from altitude 300 and 500 m in southern Norway. Seedlings from families from the diallels and open pollinations were tested in short-term tests on agricultural soil at one site at altitude 85 m until age 10 years from seed. Tree height at ages 7 and 10 years and diameter at age 10 had strongly significant GCA variance components within each population. The components for SCA and maternal effects were small and not significant, indicating low levels of non-additive genetic variation. For the days of initiation and cessation of the shoot elongation period the GCA components were dominating and had the highest heritability estimates in two of the diallels. Estimates of genetic correlations between traits measured in earlier nursery trials and height and diameter in the short-term trials had low and not consistent values in the three diallels. The duration of the shoot growth period and rate of growth showed positive relationships with height and diameter. Strong relationships were present between half-sib family means from the diallels and open-pollinated families for height, diameter and phenology traits. Progeny trials testing open-pollinated half-sib families from natural populations can be used for selection of candidates for the initial breeding populations.

Assessment of genetic variability and genetic parameters of morphological and agro-physiological traits in Camelina sativa (L.)

The present investigation was done to evaluate genetic variability and estimation of genetic parameters of morphological and agro-physiological traits in Camelina sativa (L.) using biometrical genetic techniques. For this purpose, 136 Camelina doubled haploid line genotypes were assessed in a randomized complete blocks design with three replicates in the Field Research, Razi University, Kermanshah, Iran, during the 2014-2015 cropping season. The results of the analysis of variance showed significant differences between the genotypes for all studied traits. High estimates of genetic gain and broad-sense heritability were observed for the number of pods per plant, the number of pods per main branch plant, and the weight of 1000 seeds indicating high genetic potential, a low effect of environment, and the predominant role of additive gene effect on their expression. The number of pods per plant, biological yield, shoot weight, and pod straw weight showed the highest genetic positive correlation with kernel yield. Some agronomic traits such as the number of pods per plant, the number of pods per main branch plant, biological yield, root weight, shoots weight, pod straw weight and the number of lateral branches showed the highest phenotypic positive correlation with kernel yield. Moreover, the highest genotypic and phenotypic covariance was observed for kernel yield with the number of pods per plant, the number of pods per main branch plant, biological yield, plant height with roots, shoots weight, and length of lateral branch respectively. We observed the highest environmental covariance of kernel yield with biological yield. High coheritability was observed between seed length and root weight, seed length and plant height, the number of pods per lateral branch and the number of seeds per pod, kernel yield and seed length, plant height and weight of 1000 seeds. This suggests the selection of either of the traits would simultaneously affect the others, positively.