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The present experiment was conducted in bhindi / okra to observe the extent of heterosis for eight characters of plant and fruit yield traits through diallel analysis. The characters consist of plant height (cm), number of primary branches per plant, node at which 1st flower appears, number of nodes on main stem, internodal length, days to 50% flowering, pod yield per plant (g) and pod yield per hectare (q/ha). The experimental material comprised of 66 F1 hybrids developed from crossing 12 okra genotypes in diallel crossing excluding reciprocals. Out of eight characters studied, plant height, number of branches per plant and number of nodes on main stem are growth determining features. They generally decide the fruit/pod bearing surface of the okra plant. Therefore, Positive heterosis is desirable for plant height, number of branches per plant, number of nodes on main stem including fruit yield per plant and fruit yield per hectare but negative heterosis is profitable for node at which 1st flower appears, intermodal length and days to 50% flowering. Out of 66 F1, 50, 32 and 38 hybrids showed significant heterosis positively over mid parent, better parent and standard check respectively for fruit yield per plant and fruit yield per hectare and the highest was reported in hybrids IC-45831 ×IC-43733 subsequently IC-45831 ×Pusa A-4. [ABSTRACT FROM AUTHOR]

This study was aimed to determine some genetic parameters of summer squash (cucurbita pepo L.), half diallel cross among eight inbred lines carried out in summer season 2021 at field of College of Agricultural Engineering Sciences, University of Duhok. The experiment lay out using randomized complete block design with three replications. The results revealed that the mean square for all genotypes was highly significant effect in all studied traits. The inbred lines LBL2 and CNS2881 was superior in yield plant-1 obtained 9.67 kg and 10.94 kg, the crosses (CNS2881 x PEP1670) and (PEP1670 x N33133) recorded the highest value 13.83 and 13.53 respectively. The crosses (PEP512 x, CNS2881), (CNS2881 x PEP1670) and (PEP1670 x N33133) revealed significant heterosis for most traits. The heritability in broad sense was higher than narrow sense heritability in all traits ranged between 0.949 and 0.827 for fruit diameter and fruit weight. The average degree of dominance was higher than one in all traits except fruit length and fruit diameter. [ABSTRACT FROM AUTHOR]

IntroductionWheat performance is always affected by climate change and environmental stresses such as drought stress. Development of high-yielding cultivars requires genetic diversity. Awareness about heritability of traits can be helpful in determining the appropriate breeding strategy for any environmental conditions. By progeny trial after a diallel crossing, the function of genes and inheritance of quantitative traits can be estimated. This increases the ability to select parental lines, to participate in crosses, and determines the management of generations in the segregating populations. Materials and methodsIn order to understand the genetic structure of grain yield and some morphological traits of bread wheat under normal and drought stress conditions, eight bread wheat cultivars including Star; Tirgan; Ehsan; Shirodi; Bam; Tajan, Yang and Akbari were planted in the crossing block and direct crosses were performed among the eight cultivars to produce F1 generation. This research carries out in Gorgan agricultural research station in 2020-2021 cropping season, under normal and drought stress conditions. The progenies of the crosses with their parents were evaluated based on a randomized complete block design (RCBD) with three replications. Imposing stress by terminating irrigation was initiated at the Zadoks 60 (full heading emergence) stage. Results and discussionCombined analysis of variance under normal and drought stress conditions showed that the simple effects of genotype and environment were statistically significant in all traits. Also, the interaction effects of genotype×environment was statistically significant for grain yield, biological yield and 100-kernel weight. In fact, for these traits the response of genotypes was different under normal and stress conditions. Analysis of variance of Griffing's diallel method showed a statistically significant difference between genotypes in all studied traits. Therefore, among the progenies of the crosses it is possible to select superior genotypes. In biological yield and grain yield under both normal and drought stress conditions, Tirgan cultivar had the highest general combining ability, while Star cultivar showed the lowest general combining ability. Tirgan cultivar can be used to increase grain yield and biological yield under both conditions. In plant height, peduncle length and harvest index, Tajan×Yang, Ehsan×Shirodi and Bam×Yang crosses had the maximum specific combining ability, respectively. In other traits, in each condition, an individual cross had the highest specific combining ability. Under normal conditions, Tajan×Akbari cross had the highest specific combining ability in grain yield. Under drought stress conditions, Bam×Akbari cross had the highest specific combining ability in biological yield and grain yield, it simultaneously had a high specific combinability in 100-grain weight, harvest index and number of grains per spike. Therefore, Bam×Akbari cross was determined as the best cross in genetic improvement of desirable agronomic traits with high specific combining ability in yield and yield components, under drought stress conditions. The ratio of additive variance from genetic variance for plant height and peduncle length was greater than dominance variance. Subsequently, the highest narrow-sense heritability in both normal and drought stress conditions was related to plant height and peduncle length. In both normal and drought stress conditions, the highest degree of dominance was related to harvest index traits and number of grains per spike, respectively. Therefore, in these traits the lowest narrow-sense heritability, the lowest Baker's genetic ratio and the highest ratio of dominance variance from genetic variance were observed in both normal and drought stress conditions. In grain yield, a high ratio of dominance variance from genetic variance was assigned under normal (84%) and drought stress (88%) conditions, hence low narrow-sense heritability was observed under normal (8%) and drought stress (5%) conditions. In general, in grain yield, biological yield and 100-kernel weight, narrow-sense heritability was lower under drought stress conditions, compared to normal conditions, which indicates a greater ratio of non-additive effects under drought stress conditions. ConclusionThe results of this study showed that under both conditions, Tirgan cultivar had the highest general combining ability in grain yield and biological yield. Tajan×Akbari and Bam×Akbari crosses were determined as the best cross in genetic improvement of desirable agronomic traits with high specific combining ability in yield and yield components, under normal and drought stress conditions, respectively. In grain yield, biological yield and 100-kernel weight, narrow-sense heritability was lower under drought stress conditions, compared to normal conditions. Based our results under both conditions in the progenies of the crosses, genetic improvement can be done in plant height and peduncle length in the initial generations, but for other traits including grain yield and its components, selection should be postponed to more advanced generations.

In this article we compared two approaches: one is Griffing approach for numerical components and other is Hyman's approach for graphical representation of the components through the mating design of Complete Diallel Cross design for p=5 parental lines. Griffing (1956) approach was a numerical approach based on the estimates of combining ability effects. Here use his fourth method. Hayman (1954) approach also have four components namely (i) complete, (ii) partial, (iii) over-dominance and (iv) no dominance. Hayman's approach based on the estimation of parts of variation. We use three mutually orthogonal Latin squares design of order 5 for the construction of mating designs. ANOVA and estimates of combining ability derived and analyzed. We demonstrate the numerical accuracy of the proposed design Griffing method I and Hayman's method by using Turnip data of 5x5 crosses of plant height. [ABSTRACT FROM AUTHOR]

Developing adapted chili pepper genotypes to Egyptian conditions offering both high yield and quality is crucial particularly under the current fast-growing population and abrupt climate change. Thereupon, this study aimed to investigate the general (GCA) and specific (SCA) combining abilities for yield and quality traits, develop hybrids adapted to Egyptian conditions with high yield and quality, and elucidate the type of gene action governing these traits in chili pepper. This study was carried out at a private farm in DakahlyiaGovernorate, Egypt during the two successive autumn seasons 2021 and 2022 applying half-diallel mating scheme (5×5) without reciprocals. Five diverse parental genotypes of chili pepper were used for this study; i.e., P4, P5, P7, P8, and P11. The results reflected highly significant variation among the tested parental genotypes and crosses in all studied traits. The best combiner based on GCA was P8 for most tested traits. It recorded significant positive GCA values all studied traits except for number of fruits per plant and fruit wall thickness showed insignificant medium GCA effect. In addition, all evaluated parental genotypes were good for improving fruit length and fruit diameter. The results reflected the role of non-additive gene action on offspring for total yield was confirmed. The relationship among the tested characters could provide useful information for screening pepper genotypes and breeding programs. [ABSTRACT FROM AUTHOR]

Cassava breeding is a critical aspect of sustainable agriculture to address the challenges of food security and climate change. The present study aimed to assess the combining ability of six Thai cassava elite varieties for four key traits, including fresh root yield (FRY), fresh shoot yield (FSY), harvest index (HI) and starch content (SC) through an analysis of the diallel mating design over two years. Parental lines HB80 and R5 showed significant positive general combining ability (GCA) effects for high SC; R1 and HB80 for low FSY; and R1 for high FRY and HI. The genetic effects for FSY, SC and HI were primarily influenced by the GCA of the progenitors, while specific combining ability (SCA) was more important for the FRY than the other three traits. Cultivation conditions were also found to impact the evaluation of genetic effects, with a poor growing environment affecting the expression of the genotype. This study provides a useful basis for the selection of parental lines for cassava breeding programs and insights into the genetic control of yield and related traits in the Thai elite cassava germplasm. [ABSTRACT FROM AUTHOR]

The present study was to determine the nature of gene action and combining ability of six quantitative traits related to productivity of five varieties and ten hybrid combinations of durum wheat. Five modern durum wheat varieties were used in diallel crosses as parents. The study includes three F1 and two F2 generations. The experiments were done in a randomized block design in three replications during three years. Significant differences between the genotypes in both generations was found for all the traits. The general combining ability and specific combining ability showed reliability in both generations. Obtained results suggests that breeding schemes should include both types of genetic effects in order to improve productivity components. The ratio of variances showed that general combining ability has a greater influence on the inheritance of plant height, spike length and thousand kernels weight. For productivity tillering capacity, number of spikelets per spike and kernels weight per spike, specific combining ability has a great impact in inheritance. For thousand kernels weight a redetermination of the genetic formula was established in both generations. Durum wheat varieties Deni, Superdur and Progres were found to be the best general combinators for studied productivity elements. The most valuable cross combinations were Deni × Superdur, Superdur × Predel and Progres × Predel. Parental wheat varieties and progenies from these crosses can be used for improving productivity components and for increasing yields in durum wheat breeding programs.

Context: Establishment of true heterotic pattern in maize germplasm can increase the efficiency of hybrid breeding. Heterosis is dependent on the genetic diversity of parents and the extent of dominance at different loci. Estimation of genetic diversity through use of molecular markers is routine practice in maize breeding. Aims: The present study was designed to test whether simple sequence repeat (SSR) markers linked to yield-contributing traits are more reliable for heterotic grouping than random SSRs. Methods: Diallel crosses developed among 19 inbred lines were evaluated at multi-locations. The genotypes were also grouped using polymorphic random (50) and linked (47) SSRs. Key results: The crosses generated with lines belonging to different heterotic groups of linked SSR markers did not reveal any superiority over the crosses of the diallel set. By contrast, mean performance of inter-heterotic group crosses generated on the basis of random markers was superior to that of intra-heterotic crosses. Specific combining ability effects did not reveal any significant association with genetic distance of random or linked markers. Conclusions: The lack of improved efficiency of linked markers over random markers can be attributed to factors including the quantitative nature of the trait, genotype × environment interactions, genetic background of germplasm in which the markers are expressed, and multiple alleles. Implications: Markers linked to yield-contributing traits are no more reliable for heterotic grouping than random markers. Establishment of true heterotic pattern in maize germplasm can increase the efficiency of hybrid breeding, and therefore, it is useful to compare efficiency of SSRs linked to yield-related traits with that of random SSRs for heterotic grouping. Mean performance of inter-heterotic group crosses generated on the basis of random markers was superior to that of intra-heterotic crosses. Specific combining ability effects did not reveal significant association with genetic distance of random or linked markers. [ABSTRACT FROM AUTHOR]

Seven varieties of flax were used as parents in this study and were planted in the 2018-2019 season. Through the flowering period, all possible diallel crosses were made among these parents according to the second method of Griffing. In mid-November, the plants of the F1 generation consisting of twenty-one crosses were harvested, and in the following season, the parents and the hybrids were planted in mid-November using a Randomized complete block design (RCBD) with three replications. The results showed that the variety Sakha 3 was surpassed for most studied traits, including grain yield. The two varieties, Sakha 2 and Sakha 5, showed a general combining ability for most studied traits. As for the hybrids, the hybrid (Sakha 2 x Syrian) was surpassed tin in the specific combining ability for most studied traits. The heterosis was significant in the hybrids (Sakha 1 x Sakha 2), (Sakha 2 x Sakha 3), and (Sakha 3 x Giza 8) for most studied traits. The additive variance was significant from zero for plant height, which amounted to 29.411, and in the number of capsules per plant, which amounted to 210,198 and the number of seeds per capsule, which amounted to 4.386, and 1000 seeds weight was 1.401, while the values of H1 and H2 were significant for most traits, including the biological yield as it reached 3.497, and the values of narrow-sense heritability and the expected genetic advance were low for most traits. [ABSTRACT FROM AUTHOR]

Magnitude and type of gene actions in a specific population are the main criteria for the parents' selection that will develop the best recombinants after hybridization. Information about the genetic control of complex traits is useful for the further development of efficient breeding programs. In order to identify action of genes for grain yield plant-1 and its correlation with main yield components, incomplete diallel crossing was applied. The field trial was conducted at the experimental field of the Agricultural Advisory Service in southeastern Europe, during season 2012-2013. Mean values of F1 generation showed that crosses Apache × Prima had the highest value of grain yield plant-1 and Jackson × Balkan had the lowest. Common type of inheritance for grain yield plant-1 was over dominance. The ANOVA revealed that this trait was controlled by additive and non-additive effects. The best general combiner for grain yield plant-1 was Apache, and two crosses (Dragana × Jackson; Balaton × Nevesinjka) showed significant SCA effects. Components of genetic variance showed that dominant was more important than additive component, and the total number of dominant genes were in excess over the number of recessive genes in all parents. Furthermore, moderately low value of narrow sense heritability (h2=31.96%) was observed for grain yield plant-1 . Parent Sana contained maximum dominant genes, whereas parent Jackson had maximum recessive genes. Grain yield plant-1 was significantly correlated with tillers numbers plant-1 at genotypic level (rg=0.494). The results from this study might be helpful for creating new wheat cultivars with highyielding potential.

Abstract Theory predicts that the ability of selection and recombination to purge mutation load is enhanced if selection against deleterious genetic variants operates more strongly in males than females. However, direct empirical support for this tenet is limited, in part because traditional quantitative genetic approaches allow dominance and intermediate‐frequency polymorphisms to obscure the effects of the many rare and partially recessive deleterious alleles that make up the main part of a population's mutation load. Here, we exposed the partially recessive genetic load of a population of Callosobruchus maculatus seed beetles via successive generations of inbreeding, and quantified its effects by measuring heterosis—the increase in fitness experienced when masking the effects of deleterious alleles by heterozygosity—in a fully factorial sex‐specific diallel cross among 16 inbred strains. Competitive lifetime reproductive success (i.e., fitness) was measured in male and female outcrossed F1s as well as inbred parental “selfs,” and we estimated the 4 × 4 male‐female inbred‐outbred genetic covariance matrix for fitness using Bayesian Markov chain Monte Carlo simulations of a custom‐made general linear mixed effects model. We found that heterosis estimated independently in males and females was highly genetically correlated among strains, and that heterosis was strongly negatively genetically correlated to outbred male, but not female, fitness. This suggests that genetic variation for fitness in males, but not in females, reflects the amount of (partially) recessive deleterious alleles segregating at mutation‐selection balance in this population. The population's mutation load therefore has greater potential to be purged via selection in males. These findings contribute to our understanding of the prevalence of sexual reproduction in nature and the maintenance of genetic variation in fitness‐related traits.

Cassava breeding is a critical aspect of sustainable agriculture to address the challenges of food security and climate change. The present study aimed to assess the combining ability of six Thai cassava elite varieties for four key traits, including fresh root yield (FRY), fresh shoot yield (FSY), harvest index (HI) and starch content (SC) through an analysis of the diallel mating design over two years. Parental lines HB80 and R5 showed significant positive general combining ability (GCA) effects for high SC; R1 and HB80 for low FSY; and R1 for high FRY and HI. The genetic effects for FSY, SC and HI were primarily influenced by the GCA of the progenitors, while specific combining ability (SCA) was more important for the FRY than the other three traits. Cultivation conditions were also found to impact the evaluation of genetic effects, with a poor growing environment affecting the expression of the genotype. This study provides a useful basis for the selection of parental lines for cassava breeding programs and insights into the genetic control of yield and related traits in the Thai elite cassava germplasm.

The aim of this research is to study phenotypic correlations and establishing the genetic distance between parents and their hybrids by cluster analysis. Experiments were conducted in three consecutive years in the experimental field of the Field Crops Institute - Chirpan, Bulgaria. The trials were performed in a randomized block design in three replications. Nine quantitative traits were observed, seven related to productivity and two related to grain quality. Significant differences between genotypes were established for all studied traits. The traits grains number per spike and grains weight per spike had a high positive correlation. This relationship was of great importance in determining the right strategy for leading a selection for productivity. At the first level the cluster analysis revealed two clusters genetically distant from each other. The bigger cluster was divided into two clusters with significant distance. Three clusters with a significant distance between them were observed. Parents and their hybrids fall into different clusters, indicating that hybrid combinations are genetically distant from their parents. [ABSTRACT FROM AUTHOR]

Eight parental inbred lines and their 28 crosses through the half diallel cross were used for estimation of general (GCA) and specific (SCA) combining abilities to select the best crosses for grain yield, earlier and lower ear placement. Half diallel cross mating design was carried out during the summer season of 2015 in BENI HEDER research farm of the Egyptian Agricultural Company for seed production (EGAS) Company to produce 28 yellow maize hybrids. At 2016 season, 28 hybrids (F1) and eight parents were tested in a trial using randomized complete block design with four replications, and also at 2017 season the same trial was repeated. The data was collected for ten different characters. A Griffing's method ΙΙ model ΙΙ was used to calculate the GCA and SCA effect and to estimate the genetic components. Inbred lines were evaluated, and then inbred 711 significantly contributed to the good performance of the hybrids for grain yield trait. [ABSTRACT FROM AUTHOR]

Simple Summary: Diallel crosses are breeding schemes used to estimate combining ability and the effects of reciprocal crosses among strains or varieties. Using this diallel cross scheme, we produced a crossbred population of Ariza labeo (Labeo ariza), a newly potential aquaculture species in Bangladesh. The improved performances of this crossbreed were observed phenotypically (growth performances) and genetically (variation at selected microsatellite loci) and manifested through myofiber histology. Captive breeding of this species in carp hatcheries of Bangladesh could be initiated and facilitated through maintaining the gene pool of the L. ariza of Kangsha and the Atrai River. Conservation could also be considered for advancing the better performer crossbred (G4K♀A♂) as the reference diallel crossbred. The simple yet efficient breeding technique and the manifestation of growth performances using histological and phenotypical observations will encourage the hatchery operators of Bangladesh and elsewhere to initiate the induced breeding of L ariza in large scale aquaculture. The objective of the present study was to evaluate the growth performance and genetic variation in diallel crosses of Ariza labeo (Labeo ariza) originating from three geographically separated rivers (Atrai, Jamuna and Kangsha) in Bangladesh. Intra (G1K♀K♂, G2J♀J♂, and G3A♀A♂) and inter (G4K♀A♂, G5K♀J♂, G6A♀K♂, G7A♀J♂, G8J♀K♂, and G9J♀A♂) stocks were produced following diallel cross (sex ratio—1:1 and n = 48; 16 from each river). Reproductive and growth performance, muscle cellularity and genetic variation following genotyping of eight microsatellite markers (Lr1, Lr2, Lr3, Lr22, Lr24, Lr27, Lr28 and Lr29) and analysis of all crossbreeds was performed. The fertilization (95% ± 2.11%), hatching (88% ± 1.03%), and survival rates (82% ± 1.88%) of G4K♀A♂ were higher compared to other groups. With respect to length and weight gains (2.67 ± 0.4 cm and 3.39 ± 0.2 g), SGR (3.23% ± 0.20%), and heterosis (8.87% and 24.74%) G4K♀A♂ was the superior group. A higher number of hyperplastic muscle fibers, mean number of alleles (2.75) and mean observed heterozygosity (0.417) from G4K♀A♂ could be interpreted to mean that G4K♀A♂ comprise better performance efficiency compared to others and are considered for continuing the L. ariza stock improvement program. [ABSTRACT FROM AUTHOR]

Five varieties of bread wheat (Triticum aestivum L.) Tamuz-3 Adnaniya, Abu-Greebe-3, IPA-99 and Sham-6 and their half diallel crosses were used to study general and specific combining ability for plant height, number of tillers per plant, number of spikes per plant, spike length , number of grains per spike, 100 grains weight and grain yield per plant. The result of the analysis of variance showed that the mean square of genotypes, (GCA) and (SCA) were highly significant for all studied characters. The ratio between the component variance of (GCA) and the component of variance (SCA) was less than one for all studied characters except for plant height which was more than one this indicate the importance of additive and dominance gene effects for all characters, but the dominance gene effects is more important for determining these characters. The largest and positive value for (GCA) effect was in the following parental varieties : Abu- Ghreeb-3 for plant height and number of grains per spike, IPA-99 for number of tillers and number of spikes per plant, Adnaniya for spike length and 100 grains weight and grain yield per plant. The (SCA) effects value in some hyprids was positive with desirable direction, but other hyprids showed negative with undesirable direction for all studied characters therefor heterosis can be utilized for improve these characters. The hyprids (1x3), (1x4), (2x3),(2x4),(2x5),(4x5) revealed desirable and high significant heterosis for all studied characters. The broad sense heritability were high for all studied, however the narrowsense heritability were high for plant height and medium to remained characters. There were over dominance for all characters except partial dominance for plant height.

Theory predicts that the ability of selection and recombination to purge mutation load is enhanced if selection against deleterious genetic variants operates more strongly in males than females. However, direct empirical support for this tenet is limited, in part because traditional quantitative genetic approaches allow dominance and intermediate‐frequency polymorphisms to obscure the effects of the many rare and partially recessive deleterious alleles that make up the main part of a population's mutation load. Here, we exposed the partially recessive genetic load of a population of Callosobruchus maculatus seed beetles via successive generations of inbreeding, and quantified its effects by measuring heterosis—the increase in fitness experienced when masking the effects of deleterious alleles by heterozygosity—in a fully factorial sex‐specific diallel cross among 16 inbred strains. Competitive lifetime reproductive success (i.e., fitness) was measured in male and female outcrossed F1s as well as inbred parental "selfs," and we estimated the 4 × 4 male‐female inbred‐outbred genetic covariance matrix for fitness using Bayesian Markov chain Monte Carlo simulations of a custom‐made general linear mixed effects model. We found that heterosis estimated independently in males and females was highly genetically correlated among strains, and that heterosis was strongly negatively genetically correlated to outbred male, but not female, fitness. This suggests that genetic variation for fitness in males, but not in females, reflects the amount of (partially) recessive deleterious alleles segregating at mutation‐selection balance in this population. The population's mutation load therefore has greater potential to be purged via selection in males. These findings contribute to our understanding of the prevalence of sexual reproduction in nature and the maintenance of genetic variation in fitness‐related traits. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In a diallel cross between four maternal lines of rabbits, the four maternal lines and the corresponding crossbred females (does) were evaluated concerning functional longevity, estimating their crossbreeding components. Sixteen genetic groups were produced by using four maternal lines of rabbit (A, V, H and LP (L)). The groups were distributed over 4 Spanish farms. In all farms, the V line was present as the reference group. A total of 7,211 does' longevity records were recorded. Using a Cox proportional hazard model of fixed effects, survival analysis was performed to study longevity analysing the hazard of death or culling. Does from lines A, H and V had similar risks of death or of being culled, and they were more susceptible compared with those from line L. The lowest hazard was associated with L line does. No significant differences were found between the average of all crosses and the V line except when comparing the V line to the cross between A and H lines, favouring the former (1.30 higher risk of replacement for AH animals). Significant differences between reciprocal crosses were observed between VH and HV, in favour of HV (0.72 of relative risk of replacement) and between LH and HL, in favour of HL (0.76 of relative risk). Line V had the highest risk due to the direct genetic effects, and these differences were significant with the lines H (1.40 of relative risk) and L (1.43 of relative risk). The differences in maternal genetic effects were small and not significant except between lines H and V in favour of V line (0.75 of relative risk). The estimated direct heterosis effects do not always follow the same trend but they showed the importance of the crossing between specialized lines to produce crossbred does for intensive meat rabbit production. [ABSTRACT FROM AUTHOR]

Several strains of pearl oysters (Pinctada fucata) are distributed in the coastal areas of South China. To explore strategies for genetic improvement, additive genetic, heterotic, and strain reciprocal effects on growth traits were estimated by performing a full 3 × 3 diallel cross of three pearl oyster strains that are local to Beihai, Guangxi Province; Xuwen, Guangdong Province; and Sanya, Hainan Province. The simultaneous production of progeny for all crosses was achieved using mass spawning in Lingshui, Hainan Province. For body weight, the Beihai strain showed the highest additive genetic effect (+ 5.7%) and the Sanya strain showed the lowest (− 4.3%), with similar additive genetic effect patterns for shell length, shell height, and shell width. The averaged heterotic outcomes were significant (P < 0.01) for all growth traits, varying from + 6.1% for shell length to + 19.1% for body weight. Reciprocal cross effects were determined for growth traits, with a relatively high correlation for all traits between strain additive performance and total performance (r2 = 0.72 to 0.85). These findings reveal the potential to exploit strain additive variation to improve P. fucata culture stock using direct selection methods for increased productivity of pearl oyster cultivation in China. [ABSTRACT FROM AUTHOR]

Copyright of Egyptian Journal of Agronomy is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Iberian pig is one of the pig breeds that has the highest meat quality. Traditionally, producers have bred one of the available varieties, exclusively, and have not used crosses between them, which has contrasted sharply with other populations of commercial pigs for which crossbreeding has been a standard procedure. The objective of this study was to perform an experiment under full diallel design among three contemporary commercial varieties of Iberian pig and estimate the additive genetic variation and the crossbreeding effects (direct, maternal and heterosis) for prolificacy. The data set comprised 18 193 records for total number born and number born alive from 3800 sows of three varieties of the Iberian breed (Retinto, Torbiscal and Entrepelado) and their reciprocal crosses (Retinto × Torbiscal, Torbiscal × Retinto, Retinto × Entrepelado, Entrepelado × Retinto, Torbiscal × Entrepelado and Entrepelado × Torbiscal), and a pedigree of 4609 individuals. The analysis was based on a multiple population repeatability model, and we developed a model comparison test that indicated the presence of direct line, maternal and heterosis effects. The results indicated the superiorities of the direct line effect of the Retinto and the maternal effect of the Entrepelado populations. All of the potential crosses produced significant heterosis, and additive genetic variation was higher in the Entrepelado than it was in the other two populations. The recommended cross for the highest yield in prolificacy is a Retinto father and an Entrepelado mother to generate a hybrid commercial sow.

The objective of the present study was to evaluate the growth performance and genetic variation in diallel crosses of Ariza labeo (Labeo ariza) originating from three geographically separated rivers (Atrai, Jamuna and Kangsha) in Bangladesh. Intra (G1K♀K♂, G2J♀J♂, and G3A♀A♂) and inter (G4K♀A♂, G5K♀J♂, G6A♀K♂, G7A♀J♂, G8J♀K♂, and G9J♀A♂) stocks were produced following diallel cross (sex ratio—1:1 and n = 48; 16 from each river). Reproductive and growth performance, muscle cellularity and genetic variation following genotyping of eight microsatellite markers (Lr1, Lr2, Lr3, Lr22, Lr24, Lr27, Lr28 and Lr29) and analysis of all crossbreeds was performed. The fertilization (95% ± 2.11%), hatching (88% ± 1.03%), and survival rates (82% ± 1.88%) of G4K♀A♂ were higher compared to other groups. With respect to length and weight gains (2.67 ± 0.4 cm and 3.39 ± 0.2 g), SGR (3.23% ± 0.20%), and heterosis (8.87% and 24.74%) G4K♀A♂ was the superior group. A higher number of hyperplastic muscle fibers, mean number of alleles (2.75) and mean observed heterozygosity (0.417) from G4K♀A♂ could be interpreted to mean that G4K♀A♂ comprise better performance efficiency compared to others and are considered for continuing the L. ariza stock improvement program.

To determine the gene action and nominate good combinators for the wet gluten content of grain in durum wheat, a diallel cross was performed. Five modern durum wheat varieties were included in the half diallel combination - Victoria (BG), Deni (BG), Superdur (AT), Progress (BG) and Predel (BG). The experiments were conducted in the experimental field of the Field Crops Institute in Chirpan by block method in three replications in the period 2014-2016. The necessary technological analyses were performed in laboratory conditions according to the relevant standard for measuring the wet gluten content. Statistical data processing shows that the dominance and over dominance effects have a very important role in inheritance. Both the additive (GCA) and the non-additive (SCA) gene effects have reliable significance in inheritance of the trait, with the preponderance of the non-additive ones (SCA). Significant combinators that increase the value of the trait and ones that reduce it have been nominated. Two crosses with significant SCA effects: Superdur × Progress and Progress × Predel were identified. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Kirkuk University for Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study aimed to evaluate the performance of hybrids and their parents for identify promising hybrids and the objectives to develop single cross hybrids in addition to estimate inbreeding depression , some genetic parameters , phenotypic and genotypic correlation for the studied characters. An experiment was conducted by using four varieties of faba bean (Vicia faba L.) viz., 1- French (Aguadulce) 2- Syrian (Shami) 3- Spain and 4- Holland , were Full diallel crossing carried out according to (Griffing 1956) first method (Model I) to produce F2-Hybrids of twelve single hybrid from self pollination of F1 hybrid during the growing season 2009/2010. The parents and F2 hybrid were planted by using Randomized Complete Block Design (R.C.B.D.) with three replications at vegetable field of the Horticulture and landscape design department , College of Agriculture and Forestry , Mosul University , during the growing season 2010/2011. Results showed that parents and F2S were significantly different for all the studied characters , parent 1- French (Aguadulce) was found to be the best for green , dry pods yield , seeds yield and biological yield , whereas the hybrid (2×3) for the green , dry pods yield and seeds yield , while the hybrid (2×1) for the biological yield. F2 hybrid exhibited a significant inbreeding depression for all the studied characters. A significant additive variance were found for all studied characters except date flowering and no.of seeds per pod. Narrow sense heritability was higher for: Plant height , no.of branches/plant , pod length , 100 seed weight , green , dry pods yield and seeds yield , which indicated an additive gene action for these characters. Over dominance were found for: flowering , maturity date , no.of pods/plant , no.of seeds per pod and biological yield. Genetic advance expectant in F3 hybrid were found for most studied characters , which indicates the importance of selection for improving these characters. The higher phenotypic and genotypic correlation were found between dry pods yield and seeds yield.

Used in this study Four varieties of faba bean (Vicia faba L.) viz., 1- French (Aguadulce) 2- Syrian (Shami) 3- Spain and 4- Holland were Full diallel crossing carried out according to (Griffing 1956) first method (Model I) to produce F2 hybrids , of twelve single hybrid from self pollination of F1 hybrid during the growing season 2009/2010. The parents and F2 hybrid were planting by using Randomized Complete Block Design (R.C.B.D.) with three replications at vegetable field of the Horticulture and landscape design department , College of Agriculture and Forestry , Mosul University , during the growing season 2010/2011 , for evaluate the performance of full diallel hybrids and parents , to determine the best parental combinations through general and specific combining abilities analysis and estimating their effects and reciprocal effect of the yield and its components. Analysis of variance results showed that mean squares of general combining ability was significant for all the studied characters except biological yield , and that of specific combining ability was significant for most studied characters , the reciprocal effects was significant for all studied characters except no. of pods per plant and seeds yield. The results showed that variance compound of general combining ability was higher than that of specific combining ability for pod length , 100 seed weight, green pods yield and seeds yield , indicating that an additive gene action control the inheritance of these characters. Estimation of general combining ability effects showed that the parents French (Aguadulce) and Syrian (Shami) was significant and good combiners for most of the studied characters , indicating that the contains desired gene , the hybrids varied for their specific combining ability effects , the hybrid 1×4 have a good significant specific combining ability effects for the most desirable characters , and this due to the wide genetic diversity between their parents and their abilities to inherit their characters to their hybrids.

The Iberian pig is one of the pig breeds that has the highest meat quality. Traditionally, producers have bred one of the available varieties, exclusively, and have not used crosses between them, which has contrasted sharply with other populations of commercial pigs for which crossbreeding has been a standard procedure. The objective of this study was to perform an experiment under full diallel design among three contemporary commercial varieties of Iberian pig and estimate the additive genetic variation and the crossbreeding effects (direct, maternal and heterosis) for prolificacy. The data set comprised 18 193 records for total number born and number born alive from 3800 sows of three varieties of the Iberian breed (Retinto, Torbiscal and Entrepelado) and their reciprocal crosses (Retinto × Torbiscal, Torbiscal × Retinto, Retinto × Entrepelado, Entrepelado × Retinto, Torbiscal × Entrepelado and Entrepelado × Torbiscal), and a pedigree of 4609 individuals. The analysis was based on a multiple population repeatability model, and we developed a model comparison test that indicated the presence of direct line, maternal and heterosis effects. The results indicated the superiorities of the direct line effect of the Retinto and the maternal effect of the Entrepelado populations. All of the potential crosses produced significant heterosis, and additive genetic variation was higher in the Entrepelado than it was in the other two populations. The recommended cross for the highest yield in prolificacy is a Retinto father and an Entrepelado mother to generate a hybrid commercial sow. [ABSTRACT FROM AUTHOR]

Hybridization is an important breeding method to improve productive traits in aquaculture. The Manila clam Ruditapes philippenarum , a worldwide cultured bivalve, has achieved the great commercial success owing to a global appreciation of its delicious taste and affordable price. In order to evaluate the aquaculture potential of clam hybridization, a complete diallel cross between two geographical populations (Shandong and Guangdong) was performed in the present study. Two intra-population mating groups LL (L♀ × L♂) and ZZ (Z♀ × Z♂) and two crossbreeding groups ZL (Z♀ × L♂) and LZ (L♀ × Z♂) were established to investigate the potential heterosis of growth and survival in the clams. Three full-sib families were constructed in each mating group to calculate the growth and survival heterosis. During the larval stage (2 ∼ 10d), no significant difference was detected in averaged shell length between reciprocal hybrids and inbred groups. In contrast, hybrid spats after 15d cultivation showed a significantly larger size (shell length and shell height) than that of inbred spats. For the reciprocal hybrids, the greatest growth heterosis of shell length and height (33.42% and 33.13%) was detected from 20 days after fertilization in ZL. After 40d cultivation, ZL displayed the most growth potential in shell length and height, reaching maximum values of 0.900 and 0.858 mm, respectively. The hybrids had 25% ∼ 40% higher survival rates than those of the inbred groups, with the highest survival heterosis in ZL. The positive values for the general combining ability (GCA) were consistently detected in the Zhanjiang population. At day 40, the special combining ability (SCA) in ZL was approximately two-fold higher than that in LZ. These findings indicate that the hybrids produced by Laizhou males and Zhanjiang females have the greater aquaculture potential, providing a useful crossbreeding strategy for clam genetic improvement in aquaculture. • Intraspecific crossbreeding of clams produced hybrids with great growth potential. • The growth and survival heterosis were found in larvae and spats. • The greatest growth heterosis was detected at 20d after fertilization. • Crossbreeding of Laizhou males and Zhanjiang females has the great aquaculture potential. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Kirkuk University for Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Identifying elite inbred parent lines that produce high-performing hybrid Pacific oyster seed requires diallel or factorial test crosses among lines, each acting as both a male and a female parent. Previously, we used the generalized linear model with fixed effects (i.e. GLM) to partition variance in yield, among hybrid families produced by a diallel cross, into causal genetic components—principally, general combining ability (GCA), specific combining ability (SCA), and reciprocal effect (R). However, GLM is extremely sensitive to missing information, which arises from loss of hybrid families for random environmental causes or from variation in the reproductive success of parent lines. To resolve this issue, we apply a Bayesian hierarchical model, which partitions yield variance into the familiar causal genetic components, while providing Bayesian shrinkage estimates incorporating the uncertainty of missing data. Our study suggests that correlation between observed yields and those predicted by the Bayesian model is high (r 2 ≥ 0.99), for observed offspring, regardless of diallel completeness. Additionally, in analyses of complete diallel crosses, line-specific GCA rankings from GLM and Bayesian models are consistent for parent lines. Finally, comparing simulated complete and incomplete diallel datasets, we show the accuracy of predicted yield for families that are present and of parent-line ranking by GCA and the reliability of parent-line selection for double-cross hybrids, especially when non-parental lines (i.e. the four hybrid parents used to predict the yield of double-cross hybrids) are present. Our study demonstrates that the Bayesian hierarchical model performs as well as GLM in analyzing complete diallel crosses and can properly deal with incomplete diallel crosses for which GLM does not work. Therefore, the Bayesian hierarchical model is powerful in diallel analysis to select superior parent lines for producing high-yielding, hybrid, Pacific oyster seed. • The Pacific oyster shows dramatic hybrid vigor for yield and potential for rapid improvement through crossbreeding. • Traditional statistical methods for diallel analysis are sensitive to missing information, which is common in practice. • We use simulation to test the ability of a Bayesian hierarchical model to predict offspring and to rank parent lines. • This model accurately predicts yield of offspring present in incomplete diallels and helps identify superior parent lines. [ABSTRACT FROM AUTHOR]

Tomato leaf curl virus is a serious threat to an autumn-winter crop of tomato in North India, causing yield losses up to 90-100%. Therefore, nine resistant and one susceptible line (Punjab Chhuhara) of tomato were crossed in half-diallel fashion to develop 45 F1 hybrids. Parents and their hybrids were evaluated for yield and quality traits under natural epiphytotic field conditions. There were extensive differences in the performance of parental lines carrying similar and different resistance genes (Ty-X). Of three parental lines carrying Ty-2 gene, CLN 17 performed better than 2123D and 2123C in respect of mean and general combining ability (GCA) for total yield and fruit weight. Likewise, out of three parental lines incorporating two resistance genes (Ty-1 and Ty-2), the line CLN 138B had better mean values and GCA for total yield and fruit weight than CLN 138A and CLN 104. However, the parental line CLN 154 with three different resistance genes (Ty-1, Ty-2, Ty-3) showed the best GCA for total yield, and it was followed by genotype CLN 138B comprising of two resistance genes (Ty-1 and Ty-2). However, the parental lines carrying Ty-2 gene alone produced three useful hybrids expressing 19 to 28% heterosis over top parent for total yield. Four highly significant cross-combinations can be recommended for pedigree selection to develop superior inbred lines. The top parent CLN 154 yielding significantly higher than released varieties along with seven F1 hybrids manifesting 16 to 31% top parent heterosis for total yield can be recommended after multi-location evaluations. Overall, this study provides useful information on the successful leaf curl virus resistant gene combinations under the north-Indian conditions. [ABSTRACT FROM AUTHOR]

A half diallel set of five- parents of pea (Pisum sativum L.) was used to study the inheritance of four seed quality traits in addition to the differences in soluble protein patterns. The studied traits included 100 green seed weight, sugar percentage, starch percentage and protein content. The variances of SCA were higher in magnitude than those of GCA for total sugar and starch contents which indicated that non-additive effects were higher than the additive effects for these characters. Both additive and non-additive effects were important in controlling protein content. Meanwhile, the variance of GCA exceeded SCA by 50 folds in 100 green seed weight indicated the predominance of additive effects in the inheritance of such trait than non-additive effects. The cultivars Lincoln and Victory Freezer displayed the highest significant “gi” positive values for total sugar and 100 green seed weight. Both Master B and Dwarf Gray Sugar followed by Alaska were the best combiners for starch and protein contents. Dominance effects due to specific crosses and/or epistasis were found for all studied characters. Negative and significant correlations were observed between total sugar content and each of starch and protein contents. The electrophoretic analysis of protein profiles revealed genetic differences among the tested parents as well as among their F1 crosses. Most of these noticeable variations were the existence of high numbers of protein bands in the hybrids as compared with their parents. The relationships among the five garden pea varieties were studied using the UPGMA cluster analysis based on data recorded from their protein profiles and the four seed traits. [ABSTRACT FROM AUTHOR]

A complete diallel cross was made among nine Betula pendula trees growing in a natural population and a trial was planted on agricultural soil at one site. This exceptional trial has provided estimates of genetic parameters that can only be estimated in complete diallels. Traits measured were height and diameter during a period of 37 years, and assessments were made of bud burst, leaf abscission and rust infection at the early ages. All traits showed genetic variation and the variance components of general combining ability (GCA) effects were dominating, with heritability estimates of 0.16 and 0.23 for height and diameter at age six years. The best-growing families could be identified at that age. At age 37 years, when the trial had been thinned twice, the offspring from the highest and lowest ranked parent for growth contributed with 19% and 6% of the total volume of the stand, respectively. The GCA effects were also highly significant for the assessment traits, but with an interaction with year for bud burst. High values of estimates of genetic correlations proved that bud burst, leaf abscission and rust infection are interrelated, and also to some extent with growth traits. Families with an early bud burst were tallest, were less affected by the rust fungus and kept their leaves later in the autumn. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agricultural Chemistry & Biotechnology is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Six maize (Zea mays L.) open pollinated varieties (OPVS) viz; PSEV-3, Azam, Sarhad white, Jalal, Iqbal and Pahari were used in this experiment to determine their combining ability through 6 x 6 diallel mating design. The research was laid out in randomized complete block design with three replications at Cereal Crop Research Institute (CCRI) Pirsabak, Nowshehra (K.P.K) Pakistan during the year 2015. The results displayed highly significant (P≤0.01) variation among above six OPVS for days to germination, plant height, leaf area, number of grains ear-1, grains moisture % at harvest, grain yield and biological yield. Mean square values due to general combining ability were highly significant (P≤0.01) for all the experimental parameters except grain yield and biological yield. Highly significant specific combining ability for direct and reciprocal crosses shows highly significant differences for all the studied parameters. PSEV-3 proved best combiner for days to germination and grains moisture % at harvest while Azam for grain yield and biological yield. Sarhad White was the best combiner for grain yield. Reciprocal effects of Jalal x Iqbal exhibited best combination for leaf area and number of grains ear-1 while Pahari × Sarhad White for grain yield. [ABSTRACT FROM AUTHOR]

An experiment was carried out to estimate the genetic group effects and the crossbreeding genetic parameters of growth traits [body weight (BW), average daily gain (ADG), feed intake (FI) and feed conversion ratio (FCR)] in rabbits during fattening between 28 and 63 d. The rabbits were the progeny of does coming from a full diallel cross between 4 maternal lines (A, V, H and LP) mated to bucks of the paternal line R. On thousand fifty five rabbits were controlled and the traits were recorded weekly, with the cage as the experimental unit for FI and FCR (283 cages). The genetic group (V line) was present in all farms in order to connect records among them and to be used as reference group. Crossbreeding parameters were estimated according to the Dickerson model. Regarding dam effects between pure lines for BW at weaning, A line was the heaviest and showed significant differences with LP and V lines (61 and 30 g, respectively). Upon completion of the fattening period, the differences in favour of A line for BW at weaning were compensated. Throughout the fattening period, no significant differences were observed between the lines as dam lines. At the end of the fattening period, no significant differences were observed between the crossbred groups. Regarding the reciprocal effects, the most relevant results were the significances for FCR in favour of H as sire line. For all traits, the confidence intervals at 95% of all contrast and effects were large. The estimates of maternal heterosis were, in general, negative, which could be a consequence of the positive heterosis for litter size. The AH cross showed significant maternal heterosis for BW at 43 d (–53 g), ADG between 28 and 42 d (–3.5 g/d), FI between 28 and 63 d (–7 g/d) and FCR between 42 and 63 d (–0.15). The combination of direct and maternal effects of the V line was the worst for all growth traits, showing significant differences with the LP line for most of them, for instance 0.13 worse FCR between 28 and 63 d. Grand-maternal effects were less important than direct-maternal.

An experiment was carried out to estimate the genetic group effects and the crossbreeding genetic parameters of slaughter and carcass traits using data on the rabbits that were progeny of does coming from a full diallel cross between 4 maternal lines (A, V, H and LP) mated to bucks of the paternal line R. The rabbits of the 16 genetic groups, corresponding to the type of does of the diallel cross, were distributed in 4 Spanish farms and 1 genetic group (V line) was present in all farms in order to connect records among them and to be used as reference group. Crossbreeding parameters were estimated according to Dickerson’s model. 1896 rabbits were measured for slaughter traits and 950 for carcass traits. The A and LP lines had the lowest values for dressing percentage (–1.71 and –1.98 compared with H line and –1.49 and –1.75 with the V line, respectively). The A line was the heaviest for commercial carcass weight. No relevant differences were observed between the crossbred groups for all traits. Regarding the reciprocal effects, there were significant differences in favour of A line as sire line in the crossbred AV. Regarding the combination of direct and maternal effects, the A line showed significantly higher values for cold carcass weight (133 g., 71 g. and 142 g. compared to the H, LP and V lines). For the same parameter the H line showed significantly higher averages on dressing percentages than A and LP lines, 1.44 and 2.13%, respectively. Line A also showed, in general, better direct- maternal effects than the V line. Grand-maternal effects were less important than direct-maternal ones. The estimates of maternal heterosis were, in general, negative, which could be a consequence of the positive heterosis for litter size. However, despite this relationship between growth and litter traits, it has not been common to find negative maternal heterosis in growth traits. A diminution of dressing percentage was detected in some crossbreds (AL and LV) and care must be taken if these types are used.