Broad-sense Heritability Estimates Research Articles

Screening for High-Yielding Barley Genotypes with Adequate Foliar Disease Resistance in North Delta of Egypt

In addressing the global impact of fungal foliar diseases on barley yield; namely powdery mildew, net blotch and leaf rust, this study undertakes a robust phenotypic and genotypic evaluation. A set of 132 barley genotypes, were evaluated under conditions of elevated pathogenic stress. Multivariate analyses revealed statistically significant inter-genotypic variances for all measured agronomic and pathological traits, concomitant with noticeable seasonal effects. In a nuanced observation, the genotype-by-season interaction elicited significant impacts across a plethora of traits, with the exception of spike length and thousand grain weight. From a quantitative genetics perspective, broad-sense heritability estimates were remarkably high: 97.2% for powdery mildew, 89.3% for net blotch, and 97.5% for leaf rust. Concurrently, genetic advance estimates for biological yield, grain yield, powdery mildew, net blotch, and leaf rust registered in the high to very high categories. Correlational analyses substantiated a positive linear relationship between grain yield and maturity date, plant height and biological yield. Using biplot analysis, 12 genotypes were identified that showed high yield and resistance to powdery mildew, net blotch, and leaf rust. Thus, investigation illuminates the possibility of deploying high-yielding, disease-resistant barley cultivars as an effective strategy for mitigating the deleterious effects of fungal foliar pathogens on barley production in Egypt.

Genotype × environment interaction and stability analysis for seed yield and yield components in sesame (Sesamum indicum L.) in Benin Republic using AMMI, GGE biplot and MTSI

Increasing production requires the development of high yielding cultivars adapted to various environments. Multi-environment trials (MET) remains the best approach to assess the performance of accessions across environments. The objective of this study was to select the best performing and stable accessions of sesame across different environments in Benin Republic. Nineteen sesame accessions were evaluated across eight environments using a randomized complete block design with four replicates. The accessions were evaluated for three traits: days to 50% flowering (D50F), thousand-seed weight (TSW), and seed yield (SY) during 2020 growing season. The stable and top-performing accessions across environments were determined using AMMI (Additive main effects and multiplicative interaction), GGE (Genotype main effect and genotype × environment interaction), and MTSI (Multi-trait stability index). AMMI analysis of variance showed a significant difference across environments for the three traits. The accessions were affected by environmental conditions for the three traits. The broad-sense heritability estimates were high (>0.60) for all the traits, indicating the improvement is achievable through selection. AMMI1 and AMMI2 biplots identified G10 and G13 as high seed yielding accessions adapted to environments E1, E2. The GGE biplot showed two mega-environments for TSW and three mega-environments for D50F and SY. For SY, G11 and G13 were the best accessions in the first mega-environment, G10 the best accession in the second mega-environment; G3 and G8 were the best accessions in the third mega-environment. AMMI and GGE analyses identified G10, G5, G12 as high seed yielding and stable accessions across environments. GGE biplot revealed that E1 and E2 were the most suitable environments for multi-location trials based on their discriminating ability and representativeness. MTSI indicated G10, G13, G19 as promising germplasm to be recommended for breeding program.

Assessment of yield performances for grain sorghum varieties by AMMI and GGE biplot analyses

Grain sorghum is an exceptional source of dietary nutrition with outstanding economic values. Breeding of grain sorghum can be slowed down by the occurrence of genotype × environment interactions (GEI) causing biased estimation of yield performance in multi-environments and therefore complicates direct phenotypic selection of superior genotypes. Multi-environment trials by randomized complete block design with three replications were performed on 13 newly developed grain sorghum varieties at seven test locations across China for two years. Additive main effects and multiplicative interaction (AMMI) and genotype + genotype × environment (GGE) biplot models were adopted to uncover GEI patterns and effectively identify high-yielding genotypes with stable performance across environments. Yield (YLD), plant height (PH), days to maturity (DTM), thousand seed weight (TSW), and panicle length (PL) were measured. Statistical analysis showed that target traits were influenced by significant GEI effects (p < 0.001), that broad-sense heritability estimates for these traits varied from 0.40 to 0.94 within the medium to high range, that AMMI and GGE biplot models captured more than 66.3% of total variance suggesting sufficient applicability of both analytic models, and that two genotypes, G3 (Liaoza No.52) and G10 (Jinza 110), were identified as the superior varieties while one genotype, G11 (Jinza 111), was the locally adapted variety. G3 was the most stable variety with highest yielding potential and G10 was second to G3 in average yield and stability whereas G11 had best adaptation only in one test location. We recommend G3 and G10 for the production in Shenyang, Chaoyang, Jinzhou, Jinzhong, Yulin, and Pingliang, while G11 for Yili.

Genetic variation and correlations for some physiological characters and seed yield in Indian mustard (Brassica juncea L.) under rainfed conditions

An experiment was conducted with 42 Indian mustard genotypes in Randomized Complete Block design to estimate genetic parameters and correlations of some physiological characters and seed yield under rainfed conditions. Specific leaf area, transpiration rate and relative water content were recorded at 30 (vegetative stage), 45-50 (50% flowering stage) and 60-65 days aftersowing (full flowering stage). Total drymatter, harvest index, pod intensity, pod area on main and primary branches, seed : husk ratio and seed yield were recorded at the time of harvest. The analysis of variance indicated highly significant differences among the genotypes for all the characters studied. The maximum phenotypic and genotypic variability was observed for transpiration rate at full flowering stage. Heritability estimates in broad-sense were high for all the characters except relative water contents (RWC) at all the 3 stages, pod area of main and primary branches and pod intensity on main shoot. High heritability combined with high genetic advance was observed for specific leaf area at all the 3 stages, transpiration rate at 50%and fullflowering and total drymatter/plant suggested scope for selection for these characters owing to predominance of additive effects in the expression of these characters. Seed yield/plant had significant and positive correlations with harvest index (r = 0.581**), total drymatter/plant (r = 0.869**), pod intensity on main shoot (r = 0.467**), pod area of main (r = 0.536**) and primary branches ((r = 0.317*) and RWC at all the 3 developmental stages. Thus, selection for high harvest index, total dry matter/plant and pod intensity coupled with low transpiration rate at flowering stage, resulting in maintenance of high RWC in leaves, should be emphasized to increase yield under rainfed conditions.

Identification of superior clones of Satureja rechingeri Jamzad. using progeny test

Satureja rechingeri is a precious plant for the pharmaceutical, feed and food industries due to the high content of antimicrobials in essential oil, mainly carvacrol. As a part of domestication and introduction into the cultivation program, a poly cross design was performed to evaluate genetic parameters and the general combining ability of 58 promising clones of S. rechingeri. Half-sib family seeds were grown in an RCBD with ten replications, and plants were assessed for their quantitative and essential oil traits. General combining ability and genetic parameters, phenotypic and genotypic correlations were estimated for all assessed traits. Analysis of variance revealed significant variation among entries of all the characters, indicating the possibilities of exploiting the available variability for further genetic improvement. Estimates of the genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were highest for essential oil yield (98.38% and 213.95%) and essential oil content (91.60% and 135.14%) in 2021 and 2022, respectively. Broad sense heritability estimates for various traits ranged from 16.68 for leaf width to 91.88 for growth type. Essential oil traits showed a high and positive phenotypic and genotypic correlation with plant height, leaf width, number of lateral branches, plant fresh weight, plant dry weight, and growth type. The growth type, number of lateral branches, plant fresh weight, plant dry weight, leaf width, and number of main branches were identified as influential factors in increasing the quantity of S. rechingeri target traits essential oil traits, and dry weight. Based on general combining ability estimates of principal traits, half-sib families of S. rechingeri clones of ‘Z19′, ‘G48′, ‘Z16′, ‘K48′, ‘F3′, ‘K5′, ‘E41′, ‘G27′ and ‘F71′ showed the highest performance. These clones can be selected as parents of synthetic varieties or new genetic sources to select superior genotypes.

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 < 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 < 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.

Assessment of genetic parameters in periwinkle through diallel analysis

Estimation of genetic variability assists in determining the contribution of various plant parameters inexhibiting the improvement of genotypes under a specific set of environmental factors. Genetic analysis allows us to clearly understand various morphological, physiological, and genetic traits, in addition to the type and extent of their role in the advancement of cultivars. The present investigation was carried out to evaluate six inbred lines of periwinkle (Vi-15-1, Vi-13-2, Vi-16, Vi-15-2, Vi-29, Vi-14-3), and their cross combinations in the full diallel fashion for ornamentally important characters. Analysis of variance revealed highly significant variations for all the parameters in all the inbred lines utilized in the study. The highest broad sense heritability estimates were observed for the number of seeds/follicles (H= 97.77 %) in the parents, whereas plant height had the highest heritability in the cross combinations (H= 98.73%). The high values of phenotypic and genotypic coefficient of variation in parents (PCV=34.41; GCV=34.02) and crosses (PCV=25.49; GCV=24.93) were recorded for thenumber of seeds/follicles. In the present study, moderate to high heritability together with a high percentage of genetic advance was recorded for seeds/follicle, follicle length, primary branches/plant, plant height, internode length and plant spread, suggesting that the additive gene action controlled these characters. Therefore, the results suggested the existence of variability for studied traits in these periwinkle inbred lines, which should be improved in future breeding.

Planting Density Does Not Affect Root Shape Traits Associated with Market Class in Carrot

Carrot (Daucus carota var. sativus) cultivars with common root shape, appearance, and end-use are grouped and commercialized in market classes. The shape of the carrot storage root is the result of growth and development, which is highly influenced by genotype; however, the extent to which planting density affects root shape traits and its interaction with genotype remains unexplored. To observe the effects of market class and density on carrot root shape characteristics, five cultivars classified in five different market classes, including Imperator, Nantes, Danvers, Chantenay, and Ball, were each grown at five planting densities ranging from 0.5 million to 4.5 million plants/ha. A generalized complete block design with a two-way factorial treatment arrangement of the two factors, density and genotype, was used in three environments. Roots were phenotyped using a digital imaging pipeline and scored for root size (length, maximum width) and compound root shape traits including traits derived from the principal component analysis of root contour profiles like root fill and tip and shoulder curvature. The results suggest that planting density had minimal impact on the shape of carrot roots, and the expected shape for each market class was maintained regardless of planting density; however, the analysis was constrained by the presence of interactions among genotype, density, and environment, which influence the contribution of main effects to shape. For the Nantes, Danvers, Chantenay, and Imperator market classes, planting density influenced the size of the carrot root, with size decreasing by up to 50% in length and width at high planting densities. We found high estimates of broad-sense heritability for traits that determine the shape of the carrot root, such as root fill and length-to-width ratio, which capture size-independent variation of the storage root. Although environmental signals play a role, our results suggested that the shape of the carrot root is primarily determined by genotype, and that planting density generally does not have a significant effect on its shape.

Diversity Assessment of Winged Bean [Psophocarpus tetragonolobus (L.) DC.] Accessions from IITA Genebank

The capability of winged bean to support food and nutrition security in sub-Saharan Africa is recurrently being affected by several constraints, which include a lack of genetic improvement. The dearth of adequate information on the level of available genetic diversity in winged bean germplasm has been a major setback in planning appropriate improvement programs. Fifteen winged bean accessions were assessed for genetic diversity using 10 quantitative traits and 10 simple sequence repeat (SSR) markers. The accessions were laid out in RCBD with three replicates for two growing seasons. Leaf samples were obtained from 10 plants representing each accession for SSR marker genotyping. The accessions exhibited significant (p < 0.05) differences for measured traits. Broad-sense heritability estimates varied from 10.31% for days to first plant maturity to 72.67% for pod weight. Pod weight had a positive and significant correlations with pod length (0.53, p < 0.05), pod width (0.70, p < 0.01), and number of seeds per pod (0.64, p < 0.01). However, the number of seeds per pod was negatively correlated with days to maturity (−0.71, p < 0.01). Number of seeds per pod was positively predicted by pod weight, seed thickness, and days to maturity. Cluster analysis delineated the accessions into two distinct groups. Average number of alleles of 4.2, gene diversity of 0.25, and polymorphic information content of 0.22 were recorded. Analysis of molecular variance revealed intra-accession variation of 95% as compared to inter-accession variation of 5%. Two primary genetic groups were identified and only three accessions, namely TPt-6, TPt-126, and TPt-48, showed genetic purity. The results of this study provide the basis for exploiting the existing diversity for winged bean improvement.

Genetic studies on iron and zinc concentrations in common bean (Phaseolus vulgaris L.) in Ghana

Iron and zinc deficiencies cause high health risk to young children and expectant mothers in sub Saharan Africa. The development of biofortified common bean (Phaseolus vulgaris L.) varieties could address the acute micronutrient deficiencies with associated improvement in the nutrition and health of women, children and adults. The objective of this study was to determine the mode of gene action and genetic advance in iron and zinc levels in common bean. Field experiment was carried out using six generations of two populations made of crosses between pairs of low iron, low zinc and high iron, moderate zinc genotypes (Cal 96 ˣ RWR 2154; MCR-ISD-672 ˣ RWR 2154). Each generation (P1, P2, F1, F2, BC1P1 and BC1P2) was evaluated on the field in a randomized complete block design with three replications. Generation mean analysis were performed for each trait measured in each of the crosses while iron and zinc levels were quantified by x-ray fluorescence. The study showed that both additive and non-additive gene effects were important in determining the expression of high iron and zinc levels. Iron concentration in the common bean seeds ranged from 60.68 to 101.66 ppm while zinc levels ranged from 25.87 to 34.04 ppm. Broad sense heritability estimates of iron and zinc were high in the two crosses (62–82% for Fe and 60–74% for Zn) while narrow sense heritability ranged from low to high (53–75% for Fe and 21–46% for Zn). Heritability and genetic gain were used as selection criteria for iron and zinc, and it was concluded that doing so would be beneficial for future improvement.

Molecular mapping of quantitative trait loci for resistance to early blight in tomatoes.

Early blight (EB), caused by Alternaria linariae (Neerg.) (syn. A. tomatophila) Simmons, is a disease that affects tomatoes (Solanum lycopersicum L.) throughout the world, with tremendous economic implications. The objective of the present study was to map the quantitative trait loci (QTL) associated with EB resistance in tomatoes. The F2 and F2:3 mapping populations consisting of 174 lines derived from NC 1CELBR (resistant) × Fla. 7775 (susceptible) were evaluated under natural conditions in the field in 2011 and in the greenhouse in 2015 by artificial inoculation. In all, 375 Kompetitive Allele Specific PCR (KASP) assays were used for genotyping parents and the F2 population. The broad-sense heritability estimate for phenotypic data was 28.3%, and 25.3% for 2011, and 2015 disease evaluations, respectively. QTL analysis revealed six QTLs associated with EB resistance on chromosomes 2, 8, and 11 (LOD 4.0 to 9.1), explaining phenotypic variation ranging from 3.8 to 21.0%. These results demonstrate that genetic control of EB resistance in NC 1CELBR is polygenic. This study may facilitate further fine mapping of the EB-resistant QTL and marker-assisted selection (MAS) to transfer EB resistance genes into elite tomato varieties, including broadening the genetic diversity of EB resistance in tomatoes.

Determination of Drought Tolerance Indices as Selection Criteria of Rice Genotypes under Water Deficit Conditions in Egypt

The development of rice genotypes with impressive tolerance to abiotic stress is one of the primary objectives of rice breeding programs. The current study was carried out to assess the capability of different indices to identify rice genotypes that are drought-tolerant under Egyptian conditions during the two growing seasons 2018 and 2019. Thirteen drought tolerance indices were calculated using the grain yield of twenty rice genotypes. According to the combined analysis of variance for grain yield, there were highly significant differences between genotypes (G), irrigation regimes (I), and their interactions. All drought tolerance indices, as well as grain yields under non-stress and stress conditions (Yp and Ys), exhibited significant variations among genotypes. For Yp, Ys, and all indices assessed, estimates of broad sense heritability (h2) and genetic advance as a percentage of mean (GAM%) were high. Using mean performances, drought tolerance indices, and multivariate analysis, the genotypes Giza 179, Sakha 104, IET 1444, and GZ 6296-12-1-2-1 were superior genotypes under both stress and non-stress conditions, as were the genotypes Sakha 107, IRAT 170, IR 68552-55-3-2, WAB 56-104, IRGA 318-11-6-2-6, and NERICA -4 under stress conditions. Hence, it was suggested that they can be utilized as parents in hybridization programs that aim to improve the drought tolerance of other rice genotypes in Egypt. Furthermore, mean productivity index (MP), geometric mean productivity (GMP), stress tolerance index (STI), harmonic mean (HM), and yield index (YI) were the tolerance indices that can be classified as better predictors of drought tolerance considering the yield potentials of the genotypes.

Estimation of Inheritance Leaf Rust, Powdery Mildew, Yield and Yield Components in Barley through Generation Means Analysis

The success of breeding program for improvement any crop depends mainly on the available background of the inheritance of the studied traits to be selected. This study was carried out during 2018/2019, 2019/2020 and 2020/2021 grown seasons at the experimental farm of Sakha Agricultural Research Station, Agricultural Research Center, Egypt to estimate the effect of genetic parameters controlling yield and yield component traits in addition severity of leaf rust and powdery mildew disease infection. Six generations (P1, P2, F1, F2, BC1 and BC2) model was used. Results indicated that, mean effect (m) was highly significant in all evaluated crosses for all studied traits. The relative importance of additive and dominance effects differed from trait to another in each cross. For epistatic components, dominance × dominance interaction effects were more effective than other components in most studied traits. Significant or/and highly significant values in desirable direction of heterosis compared to mid and better parent were obtained from most studied crosses in yield and its attribute traits, but it found over mid parents only for cross no.1 in leaf rust and crosses no. 1 and 2 in powdery mildew infection. The estimation of broad-sense heritability showed high values for studied traits and crosses, while narrow-sense heritability and genetic advance from selection ranged from low to medium in most crosses for the agronomic traits, while it ranged from low to high for leaf rust and powdery mildew infection. Finally, the results of this study recommended the barley crosses no. 4 for improve yield potential and resistant to leaf rust and cross no. 5 to improve resistance to powdery mildew, where it had high genetic advance associated with high heritability.

Pedigree selection in two Egyptian cotton crosses for some traits

One cycle of direct Pedigree selection was performed with selection intensity 5 % to improve productivity with accepTable fiber quality of the two Egyptian cotton ( G. barbadense L.) cross combinations. Comparing mean performance of F2 with those of F3 generation revealed increased mean values for all traits with advanced generations from F2 to F3, indicating accumulation of increasing alleles. The phenotypic variance for all traits was highly significant through F2 and F3 generations. Heritability estimates in broad sense improved considerably for all traits from F2 to advanced F3 generations. The genotypic correlation between three earliness characters was highly significant negative with most yield traits in F2 pop. I. While genotypic correlation between the previous earliness traits with yield traits in F3 generation was positively non-significant except for lint percentage that was highly significant positive. Genotypic correlation was highly significant positive among most yield and yield component traits in both generations, which helps pedigree selection to achieve high fast genetic advance. The data of the genotypic correlation among studied characters in F2 and F3 generations in population II showed highly significant negative genotypic correlation between earliness traits in F2 generation, changed to highly significant positive in F3 generation after applying pedigree selection. The genotypic correlation between most yield characters and fiber properties showed highly significant positive correlation in population II in both generations. The superior ten families in F3 generation in both populations ranked on high yield, yield components and fiber quality showed higher means than that of F2, F3, better parent and check in most yield characters

Snap bean response to pyroxasulfone in a diversity panel

AbstractIf available for use on snap bean, pyroxasulfone would provide valuable preemergence control of troublesome weed species that currently contaminate the crop postharvest. The extent to which snap bean tolerates pyroxasulfone is poorly documented. The objective of this research was to quantify the extent to which pyroxasulfone tolerance exists in a large collection of snap bean cultivars. A snap bean diversity panel of 277 entries was screened for tolerance to sulfentrazone at a rate of 420 g ai ha−1 in a field trial in 2019 and 2020 near Urbana, IL. Snap bean cultivars exhibited variation in tolerance to pyroxasulfone. While a handful of cultivars were tolerant across variable environments, most cultivars were sensitive in the year that had 30% more water supply (rainfall plus sprinkler irrigation) within 3 wk of planting. Low estimates of broad-sense heritability reflect a large influence of the environment on seedling emergence and growth. With a few exceptions, currently, the margin of crop safety across diverse germplasm is insufficient for registration of pyroxasulfone use on snap bean crops.

Screening Spring Wheat Genotypes for TaDreb-B1 and Fehw3 Genes under Severe Drought Stress at the Germination Stage Using KASP Technology.

Drought stress is a major yield-limiting factor throughout the world in wheat (Triticum aestivum L.), causing losses of up to 80% of the total yield. The identification of factors affecting drought stress tolerance in the seedling stage is especially important to increase adaptation and accelerate the grain yield potential. In the current study, 41 spring wheat genotypes were tested for their tolerance to drought at the germination stage under two different polyethylene glycol concentrations (PEG) of 25% and 30%. For this purpose, twenty seedlings from each genotype were evaluated in triplicate with a randomized complete block design (RCBD) in a controlled growth chamber. The following nine parameters were recorded: germination pace (GP), germination percentage (G%), number of roots (NR), shoot length (SL), root length (RL), shoot-root length ratio (SRR), fresh biomass weight (FBW), dry biomass weight (DBW), and water content (WC). An analysis of variance (ANOVA) revealed highly significant differences (p < 0.01) among the genotypes, treatments (PEG25%, PEG30%) and genotypes × treatment interaction, for all traits. The broad-sense heritability (H2) estimates were very high in both concentrations. They ranged from 89.4 to 98.9% under PEG25% and from 70.8 to 98.7% under PEG30%. Citr15314 (Afghanistan) was among the best performing genotypes under both concentrations for most of the germination traits. Two KASP markers for TaDreb-B1 and Fehw3 genes were used to screen all genotypes and to study the effect of these on drought tolerance at the germination stage. All genotypes with Fehw3 (only) showed a better performance for most traits under both concentrations compared to other genotypes having TaDreb-B1 or having both genes. To our knowledge, this work is the first report showing the effect of the two genes on germination traits under severe drought stress conditions.

DUS descriptors based morphometric characterization to analyze genetic variability in gladiolus

Abstract Present investigation involved phenotypic characterization of 84 gladiolus genotypes based on 18 DUS descriptors to estimate genetic variation and identify desirable genotypes for hybridization. Considerable variability was observed among the genotypes for most of the traits and principal component analysis revealed that the first two principal components explained most of the existing variation (&gt;98%) in the germplasm. Genotypic coefficient of variation exhibited a wide range from 7.80% (androecium length) to 37.11% (duration of flowering) while, phenotypic coefficient of variation ranged from 8.12% (androecium length) to 37.61% (duration of flowering). Strong broad sense heritability estimates (&gt;95%) were observed for the characters viz., bract length, flower width, tepal length, tepal width, style length, time of beginning of flowering and duration of flowering. Seventy four pair wise inter-trait combinations showed significant and positive genotypic and phenotypic correlations among 153 possible trait combinations. Mahalanobis D2 statistic analysis revealed that genotypes of the cluster II and V to be highly distinct and hybridization between them might have better chance to obtain desirable recombinants. Ward’s cluster analysis confirmed that the cv. Victor and cv. Malaviya Shatabdi to be highly diverse for the selected traits. It is concluded that the above genotypes may be utilized in crossing programme to obtain better progenies. Characterized data of gladiolus germplasm would assist the breeders in varietal identification, conservation and their sustainable utilization during breeding programme.

Marker-trait association analyses revealed major novel QTLs for grain yield and related traits in durum wheat.

The growing global demand for wheat for food is rising due to the influence of population growth and climate change. The dissection of complex traits by employing a genome-wide association study (GWAS) allows the identification of DNA markers associated with complex traits to improve the productivity of crops. We used GWAS with 10,045 single nucleotide polymorphism (SNP) markers to search for genomic regions associated with grain yield and related traits based on diverse panels of Ethiopian durum wheat. In Ethiopia, multi-environment trials of the genotypes were carried out at five locations. The genotyping was conducted using the 25k Illumina Wheat SNP array to explore population structure, linkage disequilibrium (LD), and marker-trait associations (MTAs). For GWAS, the multi-locus Fixed and Random Model Circulating Probability Unification (FarmCPU) model was applied. Broad-sense heritability estimates were high, ranging from 0.63 (for grain yield) to 0.97 (for thousand-kernel weight). The population structure based on principal component analysis, and model-based cluster analysis revealed two genetically distinct clusters with limited admixtures. The LD among SNPs declined within the range of 2.02-10.04 Mbp with an average of 4.28 Mbp. The GWAS scan based on the mean performance of the genotypes across the environments identified 44 significant MTAs across the chromosomes. Twenty-six of these MTAs are novel, whereas the remaining 18 were previously reported and confirmed in this study. We also identified candidate genes for the novel loci potentially regulating the traits. Hence, this study highlights the significance of the Ethiopian durum wheat gene pool for improving durum wheat globally. Furthermore, a breeding strategy focusing on accumulating favorable alleles at these loci could improve durum wheat production in the East African highlands and elsewhere.

Genetic diversity, heritability, correlation coefficient, and path analysis of forage yield components in Iranian Phalaris aquatica L. genotypes

Twenty-six selected genotypes of Phalaris aquatica L. from Iranian germplasm were evaluated to evaluate the genetic diversity of some agromorphological characteristics. Each selected genotype was cloned and planted as spaced single plants according to a randomized complete block design (RCBD) with four replications in 2016 and 2017. Large and significant (p < 0.01) differences among genotypes were found for all traits. The estimates of broad sense heritability were low to high (h$^{2}$$_{b}$ = 0.16 - 0.75) for studied traits. High heritability estimates for dry matter yield (DMY) indicate a sufficient genetic variability for further improvement. There was the highest heritability rate and genetic advance for plant height and DMY. Selection for traits with high heritability and genetic advance can be successful. The dry matter yield cut 1 (DMY1) correlation with the number of days to flowering, number of days to pollination, plant height, and crown diameter cut 2 was positive and significant. In stepwise multiple linear regression, the plant height, number of stems per plant, and spike length explained more than 84% of the total variation of DMY1. The plant height was the most crucial component of DMY1. The path analysis showed that plant height positively affected DMY1 (0.83). The highest negative indirect effects on DMY1 were observed for plant height via the number of stems per plant (-0.238). Axes 1 and 2 of the principal coordinate analysis explained 40.94% and 18.48% of the variation, respectively, and, although not entirely separated, general groupings can be determined. In factor analysis, component 1 was positively associated with the traits dry matter yield cut 2 (DMY2) (0.855), dry matter yield (0.821), and plant height (0.755). Therefore, the first component can be called the biomass component. Finally, selection would be more effective in improving forage yield based on yield components. In conclusion, the results indicated appropriate genetic variability in the studied genotypes. However, the studied genotypes will deliver a valuable germplasm to employ in breeding programs for forage cultivar production. This progress is crucial in introducing these selected genotypes to develop a core collection of Phalaris aquatica germplasm in Iran.

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.