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ABSTRACT Maize is an important cereal that is grown and consumed all over the world. Among the selection methods that contribute to increasing the frequency of favorable alleles in native maize populations, selection between and within and stratified mass selection in half-sibling families has proven efficient. This study aimed to conduct an individual selection between and within and stratified mass selection in ten half-sibling families of native maize and to estimate the variance components, genetic parameters, and selection gains for them. Ten half-brother families of families were evaluated. The experimental design was DBC, with two replications totaling 20 experimental units, evaluating four plants per plot. The spacing used was 0.8 by 0.3 m. The following were evaluated: stalk diameter (SD), ear length (EL), ear diameter (ED), number of rows (NF), number of grains per row (NGR), ear mass (EM), and total grain mass (TGM) were evaluated. Individual analyses were carried out for all the traits evaluated, selected to increase the original means with a selection intensity of 50% between/50% within. Stratified mass selection yielded higher selection gains than selection between and within families. The selection of the character’s ear mass and total grain mass showed the highest estimates of genetic gain, 54.45 and 48.37%, respectively.

Silver birch, a widely distributed deciduous tree native to Europe, is valued for its wood applications in construction, furniture making, and paper production. In Lithuania, silver birch ranks as the third most common forest-tree species, comprising 22% of the forested areas, and is an important species for tree breeding due to its potential and adaptability. This study was focused on assessing the mechanical properties of wood (sample and log hardness, wood density, dynamic modulus of elasticity (MOEdyn), static modulus of elasticity (MOE) and bending strength (MOR)) in silver birch (Betula pendula L. Roth.) trees from different half-sibling families. Two experimental plantations of the progenies of Lithuanian populations (half-sib families) of silver birch from different regions were analysed. From these plantations, four genetic families were selected for mechanical properties evaluation. The study findings revealed significant variability in various wood properties among different genetic families, although the static modulus of elasticity did not exhibit significant differences between the chosen genetic families. All measured wood properties decreased from the bottom to the top of the model trees. Wood hardness displayed a moderately negative correlation for wood density and weak correlations for MOE and MOR. Given the weak correlations between wood hardness and other wood mechanical properties, it is suggested that MOEdyn would be a more suitable trait for genetic studies. [ABSTRACT FROM AUTHOR]

Variation, variance, and correlation analyses and estimations of genetic parameters of traits related to chestnut blight resistance and growth in half-sibs of Castanea henryi were performed to screen for excellent families, individuals with good growth, and strong resistance to chestnut blight. The results showed that the average coefficient of variation (CV) of traits in 12 half-sib families was 20.19%, with the CV of the lesion area being the largest (39.76%) and that of the leaf shape index being the smallest (11.14%). Among the families, there were significant differences in lesion width, leaf area, leaf perimeter, leaf length, and vein number (P<0.05) and highly significant differences in infection rate, infection index, and leaf width(P<0.01). The seedling height showed a significant negative correlation with the infection rate (P<0.05) and a highly significant negative correlation with the infection index (P<0.01). The leaf length exhibited a highly significant negative correlation with the infection rate and index (P<0.01). Three excellent families were selected; namely, JO14 ('Bailuzi'), JO8 ('Youtongzi'), and JO2 (Dabaozhen'). Nine individuals (JO2-25, JO13-29, JO14-32, JO2-12, JO8-17, JO3-4, JO5-26, JO2-19, and JO12-20) with strong resistance and four individuals (JO2-5, JO7-16, JO8-17, and JO14-3) with good growth were selected, among which JO8-17 showed strong resistance and excellent growth. [ABSTRACT FROM AUTHOR]

Cumin (Cuminum cyminum L.) is an annual, outcross plant with medicinal properties. It is adapted to arid and semi-arid regions of the world. This research aimed to evaluate genetic parameters such as GCA and genetic distance based on molecular markers and important traits for parent selection among diverse genotypes of cumin. For this purpose, ISSR markers and a polycross assay were conducted. Forty-nine half-sib families were obtained from the polycross test and were evaluat ed for two years under normal and drought stress conditions. The measurements were aimed at 1000-seed weight, mechanized harvest height, and seed yield. The statistical analysis guided a selection of elite parents due to the high genetic diversity among half-sib families. An estimation of narrow sense heritability and general combining ability of the studied traits revealed the contribution of both additive and non-additive effects in genetically controlling the evaluated traits. According to the general combining ability, drought tolerance indices and genetic distance of 49 genotypes, the top 10 candidates were selected for the production of drought-tolerant seeds. From a molecular perspective, the banding patterns obtained from ISSR markers showed significant genetic diversity among all genotypes and indicated a proper distance among ten selected parents. The findings of this experiment provided a starting point for cumin breeding. It is likely that a breeding program would proceed with random pollinations among the ten select genotypes under controlled conditions to produce high-yield drought-to lerant varieties. [ABSTRACT FROM AUTHOR]

In Poland, the tree improvement programme was initiated in 2004, but the trials for European larch (Larix decidua Mill.) did not start until 2021. Our aim is to present certain aspects of the methodological approach of progeny testing for this species. The European larch, known for its rapid growth among native coniferous trees in Europe, holds great promise for forest breeding. Unfortunately, its natural range in Poland is limited, with rare but well-known valuable provenances. In 2023, six progeny tests were established using the same 130 open-pollinated families, derived from plus trees originating from valuable seed regions (Md51, Md61, Md71) and areas below 52° N latitude. After a decade of growth, the results will be used to identify valuable genotypes and establish advanced-generation seed orchards. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Guangxi Normal University - Natural Science Edition is the property of Gai Kan Bian Wei Hui 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.)

Growth and survival of 123 grafted and half-sib Scots pine (Pinus sylvestris L.) progenies have been investigated in a 1st generation seed orchard and progeny tests of variousages. It was found that during the first decade after planting the survival rate of the progeny tests was going slightly down, with a simultaneous decrease in the share of progeniessuperior to the control, and in the degree of superiority (height difference). We observed a moderate statistically significant correlation between the heights of maternal clones and their half-sib progenies, with its positive trend (from r = 0.28 in 2014 up to r = 0.33 in 2018) during the entire study period. Older progeny tests (30 years old) showed a moderate significant correlation (r = 0.36) in the ratio of stem faults (forked,multistem) between clones and half-sib progenies. It was confirmed that selection based on growth rate should have the highest priority for Scots pine plus trees provided thatthe habit and seed productivity of their clones are taken into account. The results reported here testify to the statement that reliable preliminary assessments of half-sib familiescan be obtained starting at the age of 7, with the tests lasting 25–30 years at maximum. As a result of the breeding and selection assessment, a set of 20 plus trees (clones)had been formed fulfilling minimum requirements for an advanced-value seed orchard of the I,5 generation.

Copyright of Revista Chapingo Serie Horticultura is the property of Universidad Autonoma Chapingo 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 prediction accuracy of multi-environment prediction models can be affected by the complexity of the genotype by environment interaction (G×E). Moreover, depending on the trait genetic architecture, accounting for non-additive effects, such as dominance effects, may increase the prediction accuracy of genomic models. Hence, we aimed to verify empirically: (i) the impact of the genotype by environment complexity on the prediction accuracy of grain yield in maize hybrids; (ii) the advantage of dominance effects modeling for the prediction of maize hybrids in multi-environment trials; (iii) how parent information impacts on the prediction accuracy of hybrids in multi-environment genomic models. We used a dataset comprising 614 maize hybrids evaluated during two growing seasons, under two nitrogens regimes at two locations in Brazil. The prediction accuracies were obtained using four different validation systems (hybrids and half-sib families based sampling). Our results suggest that sampling entire half-sib families or individual hybrids can achieve similar accuracy estimates in multi-environment prediction models. Moreover, modeling dominance deviations in a multi-environment prediction model can significantly increase the prediction accuracy, mainly under high G×E complexity. Also, we found a linear relationship between prediction accuracy and G×E complexity. Furthermore, we observed significant increases in prediction accuracy of lowly correlated environments when information of a linking trial/environment was included in the prediction model. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the parent–offspring genetic structure of the pedunculate oak (Quercus robur L.), sessile oak (Q. petraea [Matt.] Liebl.) and their hybrids. Forty half-sib Quercus families and their maternal trees originating from one tree stand in southern Lithuania were analyzed using SSR and RAPD markers. Based on a preliminary study of leaf morphological traits, the individuals separated into six groups. The studied half-sib oak families were also compared for allelic diversity, including group variations; genotypic structure; genetic diversity; and the degree of genetic subdivision and differentiation. The level of genetic variation and subdivision was lower in the hybrid families than in the families of the parental species. Genotypic analysis of the half-sibling offspring showed the asymmetric nature of interspecific hybridization processes of pedunculate and sessile oaks in mixed stands. [ABSTRACT FROM AUTHOR]

In order to find SNPs and genes affecting shank traits, we performed a GWAS in a chicken F2 population of eight half‐sib families from five hatches derived from reciprocal crosses between an Arian fast‐growing line and an Urmia indigenous slow‐growing chicken. A total of 308 birds were genotyped using a 60K chicken SNP chip. Shank traits including shank length and diameter were measured weekly from birth to 12 weeks of age. A generalized linear model and a compressed mixed linear model (CMLM) were applied to achieve the significant regions. The value of the average genomic inflation factor (λ statistic) of the CMLM model (0.99) indicated that the CMLM was more effective than the generalized linear model in controlling the population structure. The genes surrounding significant SNPs and their biological functions were identified from NCBI, Ensembl and UniProt databases. The results indicated that 12 SNPs at 12 different ages passed the LD‐adjusted 5% Bonferroni significant threshold. Two SNPs were significant for shank length and nine SNPs were significant for shank diameter. The significant SNPs were located near to or inside 11 candidate genes. The results showed that a number of significant SNPs in the middle ages were higher than the rest. The MXRA8 gene was related to the significant SNP at week 1 that promotes proliferation of growth plate chondrocytes. A unique SNP of Gga_rs16689511 located on chicken Z chromosome within the LOC101747628 gene was related to shank length at three different ages of birds (weeks 8, 9 and 11). The significant SNPs for shank diameter were found at weeks 4 and 7 (four and five SNPs respectively). The identifications of SNPs and genes here could contribute to a better understanding of the genetic control of shank traits in chicken. [ABSTRACT FROM AUTHOR]

Since the plus trees are selected based on phenotype, it is necessary to evaluate them in progeny test. The aim of this study is an indication of selecting elite mother trees based on the results from half-sib progeny test trials. As study sites, two Scots pine half-sib progeny tests were selected. During evaluation, the progenies had reached the age of 38 and 40 years, respectively. In both progeny trials, quantitative parameters and qualitative traits of Scots pine half-sib progenies were investigated. Based on these data, complex evaluation of half-sib families was carried out. We concluded that, Scots pine progenies at the age of 38 and 40 years in fresh and moist mixed forests are characterised by acceptable quality, with the survival being 25%–33% per progeny test trial. Based on a complex evaluation of 38- and 40-year-old half-sib progenies of plus trees, we proposed to select 31% of tested plus/mother trees as candidates for elite trees. Further, the list of candidates for elite trees was created with five plus trees from the Volyn region (26% of the total tested from the region) and four plus trees from the Lviv region (40% of the total tested from the region). With age, the share of the best and undesirable trees decreases, while the proportion of intermediate trees increases in both control trees and half-sib progenies. At the age of 38 and 40 years, the proportion of fast-growing offspring was from 0% to 36%, while the declining trend that was observed in previous years was being continued. Thus, due to the declining trend in the proportion of fast-growing offspring observed at the age of 38 and 40 years, we propose to select candidate trees for an elite group not early than after 40 years of test their progenies. [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the genetic variability between red clover half-sib families in terms of yields of dry forage mass during regrowing, as well as seasonal yield stability and years of use. Ten red clover elite plants selected in the past by one or more breeding criteria underwent a re-pollination in 2014. Their polycross progeny (HSFs) were examined by cuts from the first to the fourth vegetation (2015-2018) for the following indicators: green matter yield, dry matter content, dry matter yield, time for cuts formation. 'Nika 11' and 'Sofia' 52 cultivars were used as a control for high summer productivity and adaptability. In early spring growth, the polycross progeny of elite genotypes did not significantly differ in dry forage mass. In contrast, as in late spring and summer regrowing, the effect of the family was significant (P<0.05). Genotypic effects are also observed in terms of growth rate. A genetic potential for increasing the yield of dry forage mass for both late-spring and summer regrowing was found for family 2 and 3. Valuable genotypes for the breeding in relation to yield stability over seasons and age of plants, respectively years of use, can be selected in family 7, which originated from a local wild-type germplasm. The high expression in the level and stability of the observed characteristics, as well as the high estimates of general combination ability, determined 'Nika 11' as an important genetic source in the breeding for high forage productivity in regrowing. According to these results, 'NIKA 11' is used as a major component in the formation of polycross groups with the selected families. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department 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.)

This study aimed to evaluate the effect of recurrent selection on the genetic variability of UENF-14 population after six selections. Two hundred and ten half-sib families were evaluated in two environments in the state of Rio de Janeiro, using incomplete randomized blocks design with treatments arranged in replication within “Sets”. There was significant effect for Families within the “Set” (F)/S, proving that there is enough genetic variability to be exploited in the popcorn breeding program of UENF. The significance for the source of variation Environment (E) shows that the environments were distinct enough to promote differences between the evaluated characteristics. It was found that for both characteristics of greatest interest, GY and PE, the magnitude of the additive variance remains with close values in advanced cycles of UENF-14 population, indicating that variability remains, with no evidence of decreases in advanced cycles. This is concluded by the longevity of UENF breeding program.

Eucalyptus cladocalyx F. Muell is a tree endemic to southern Australia and is distributed across four isolated regions: Kangaroo Island, southern Flinders Ranges, and two geographical zones in Eyre Peninsula. E. cladocalyx is capable of growing under extreme environmental conditions, including dry and saline soils. The objective of this study was to analyze genetic diversity in 45 half-sib families planted in northern Chile that are distributed across five different zones (provenances). Genetic variability was assessed using ISSR (Inter Simple Sequence Repeat) molecular markers. The results showed low levels of genetic diversity within populations (He = 0.113 to 0.268) in contrast with other Eucalyptus species. In addition, there was a significant genetic differentiation among provenances (Φst = 0.14); populations from the Kangaroo Island provenance showed more differentiation than any other population. These results are in agreement with previous studies of the species. Our study revealed that Chilean resources are a representative sample of Australian populations; therefore, the germplasm planted in northern Chile would be sufficient for the development of improvement programs. ISSR-Marker technology could be an alternative to identify genotypes of interest in material selection.

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department 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.)

Guava (Psidium guajava L.) is one of the most valuable cultivated fruit species of the Myrtaceae family; however only a few researches related to the estimation of genetic parameters has been done in populations of this specie. It is important for the plant breeder to continually consider the heritability of the trait under selection, the type of individuals selected, the associations between traits, and the resources available to develop an effective selection strategy. The objective of this work was estimate the heritability in narrow sense, and the genetic and phenotypic correlations, for quantitative traits evaluated in three guava populations. Parent-offspring regression analysis was used to estimate heritability in narrow sense. Parent-offspring covariance analysis was used to estimate the genetic correlation coefficients whereas phenotypic correlation was calculated by Pearson correlation coefficient. These analyses were made using SPSS program. The relatively high values of heritability were found for plant height and fruit length. Most of the traits showed significance genetic and phenotypic correlations between them. Both coefficients values were different in magnitude but they had the same sign in most of the traits. The results indicated that genetic correlations were superior to phenotypic correlations. These results have practical importance in the genetic breeding selection process of this specie. [ABSTRACT FROM AUTHOR]

When hundreds of cross-pollinated trees planted in The National Gene Bank of Populus tomentosa blossom and bear fruit, in theory, half-sib progeny should originate from hundreds of combinations. Paternity testing was performed on the superior half-sib progeny with outstanding performance using microsatellite markers, a process that can be used to rapidly screen for superior cross combinations and significantly improve the efficiency and effectiveness of genetic improvements. Based on the comprehensive evaluation of the eight main growth traits of 2292 plants of 30 half-sib families, 77 plants consisting of 43 triploid and 34 diploid plants were selected as superior. We used 14 pairs of highly polymorphic SSR primers to identify the male parents of the 77 superior plants. Our results identified 29 male trees as the pollen parents of 59 superior plants from 49 cross combinations. The probabilities of 2-14, 3-48-1, 1903, 2-1, 4234, 5099, and 4114 as male parents were significantly higher than those of other males, suggesting that these male parents have potential for applications in breeding strategies of P. tomentosa. Thus, this study used SSR molecular markers to identify the male parents of superior individuals in a P. tomentosa population, laying a foundation for the application of maternal efficiency and construction of optimal hybrid parent groups. [ABSTRACT FROM AUTHOR]

Potato late blight is a common name for the mostimportant and destructive disease caused by Phytophthorainfestans (Mont. de Bary) in potato crops. Resistance genesfor the disease have been found in Solanum phureja, and areof great importance in implementing important tools such asplant breeding in disease management The aim of this studywas to estimate the heritability of resistance to P. infestansin a population of S. phureja. This research was carried outin potato cultivations in two locations in the municipality of LaUnión (Antioquia, Colombia). Pathogen severity was evaluatedin leaves using a diagrammatic scale. Heritability was measured between families and within families by stratified mass and simple mass selection. There were no statistically significant differences among the heritabilities from the methods of selection; however, significant differences were found between locations. For the first location, heritability estimations were in the range of 0.35 and 0.54, while values obtained in the second location were between 0.05 and 0.08. / El tizón tardío o gota de la papa producido porPhytophthora infestans (Mont. de Bary), es la enfermedadmás limitante del cultivo. El mejoramiento genético, conla obtención de variedades resistentes es un componenteimportante del manejo integrado del patógeno; en la especieSolanum phureja se han encontrado genes de resistencia a laenfermedad. La heredabilidad permite estimar la proporción de la variabilidad total debida al efecto de los genes; y esta depende de la población en estudio y de la unidad de selección que se utilice. El objetivo de este estudio fue estimar la heredabilidad de la resistencia a la gota de la papa en una población de S. phureja. Esta investigación, se desarrolló en dos localidades del municipio de La Unión (Antioquia, Colombia), en la cual se evaluó la severidad de la enfermedad utilizando una escala diagramática de severidad para hoja. La heredabilidad se evaluó bajo los métodos de selección entre familias, entre y dentro de familia, masal estratificada y masal simple; sin encontrar diferencias estadísticamente significativas entre la heredabilidadobtenida para los diferentes métodos de selección, pero sí entre las localidades; así, en la vereda La Cabaña, la estimación de la heredabilidad varió entre 0,35 a 0,54, y en la vereda San Juan la estimación de la heredabilidad varió entre 0,05 a 0,08.

To investigate the genetic resistance to northern corn leaf blight (Exserohilum turcicum) disease in the UENF-14 popcorn population and the inclusion of this trait in the analysis, two hundred ten popcorn half-sib families were evaluated using an incomplete block design with treatments arranged in replicates "Sets". Regarding the Families within "Set" (F/S) source of variation, enough genetic variability was found for northern corn leaf blight disease resistance to be explored in the next cycles of the UENF popcorn breeding program. The open-pollinated UENF-14 variety has a source of resistance to this disease in its genetic basis, given that it originated from crossing with an American cultivar with yellow grains that is resistant to disease. These results strengthen the possibility of selecting resistant families across the cycles, so it is concluded that the selection was effective at maintaining the balance in the occurrence of the disease in the study population and that the source of resistance is not lost with advancing cycles. The addition of the foliar disease variable in the analysis is of the utmost importance for the improvement of popcorn as it makes it possible to aggregate genes for resistance to this disease along with agronomic traits of interest.

Three methods of red clover (Trifolium pratense L.) breeding for forage yield in two harvest years on locations in Bredelokke (Denmark), Hladké Životice (Czech Republic) and Les Alleuds (France) were compared. Three types of 46 candivars1, developed by A) recurrent selection in subsequent generations (37 candivars, divided into early and late group), B) polycross progenies (4 candivars) and C) ge­no-phe­no­ty­pic selection (5 candivars) were compared. The trials were sown in 2005 and cut three times in 2006 and 2007; their evaluation is based primarily on total yield of dry matter. The candivars developed by polycross and geno-phenotypic selections gave significantly higher yields than candivars from the recurrent selection. However, the candivars developed by the methods B and C did not differ significantly. The candivars developed by these progressive methods were suitable for higher yielding and drier environment in Hladké Životice (where was the highest yield level even if averaged annual precipitation were lower by 73 and 113 mm in comparison to other locations, respectively); here was ave­ra­ge yield higher by 19 and 13% for B and C in comparison to A method. Highly significant interaction of the candivars with locations was found. It can be concluded that varieties specifically aimed to different locations by the methods B and C should be bred; also the parental entries should be selected there.

The objectives of this work were to analyze theoretical genetic gains of maize due to recurrent selection among full-sib and half-sib families, obtained by Design I, Full-Sib Design and Half-Sib Design, and genotypic variability and gene loss with long term selection. The designs were evaluated by simulation, based on average estimated gains after ten selection cycles. The simulation process was based on seven gene systems with ten genes (with distinct degrees of dominance), three population classes (with different gene frequencies), under three environmental conditions (heritability values), and four selection strategies. Each combination was repeated ten times, amounting to 25, 200 simulations. Full-sib selection is generally more efficient than half-sib selection, mainly with favorable dominant genes. The use of full-sib families derived by Design I is generally more efficient than using progenies obtained by Full-Sib Design. Using Design I with 50 males and 200 females (effective size of 160) did not result in improved populations with minimum genotypic variability. In the populations with lower effective size (160 and 400) the loss of favorable genes was restricted to recessive genes with reduced frequencies.Os objetivos deste trabalho foram analisar ganhos genéticos teóricos de milho como resultado da seleção entre famílias de irmãos completos e de meios-irmãos, obtidas pelos Delineamentos I, de Irmãos Completos e de Meios-Irmãos, e a variabilidade genotípica e perda de genes com seleção a longo prazo. Os delineamentos foram avaliados por simulação, com base nos ganhos médios estimados após dez ciclos de seleção. O processo de simulação considerou sete sistemas gênicos com dez genes (com distintos graus de dominância), três classes de populações (com diferentes freqüências gênicas), sob três condições de ambiente (valores de herdabilidade), e quatro estratégias de seleção. Cada combinação foi repetida dez vezes, totalizando 25.200 simulações. Seleção entre famílias de irmãos completos é geralmente mais eficiente do que seleção com base em progênies de meios-irmãos. Empregar famílias de irmãos completos obtidas pelo Delineamento I é geralmente mais eficiente que usar progênies derivadas do Delineamento de Irmãos Completos. O Delineamento I, com 50 machos e 200 fêmeas (tamanho efetivo de 160), não determinou população melhorada com variabilidade genotípica mínima. Nas populações melhoradas com menor tamanho efetivo (160 e 400), a perda de genes favoráveis é restrita àqueles recessivos em baixa freqüência.

Copyright of Acta Scientiarum: Agronomy is the property of Universidade Estadual de Maringa 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.)

Abstract QTL detection experiments in livestock species commonly use the half-sib design. Each male is mated to a number of females, each female producing a limited number of progeny. Analysis consists of attempting to detect associations between phenotype and genotype measured on the progeny. When family sizes are limiting experimenters may wish to incorporate as much information as possible into a single analysis. However, combining information across sires is problematic because of incomplete linkage disequilibrium between the markers and the QTL in the population. This study describes formulæ for obtaining MLEs via the expectation maximization (EM) algorithm for use in a multiple-trait, multiple-family analysis. A model specifying a QTL with only two alleles, and a common within sire error variance is assumed. Compared to single-family analyses, power can be improved up to fourfold with multi-family analyses. The accuracy and precision of QTL location estimates are also substantially improved. With small family sizes, the multi-family, multi-trait analyses reduce substantially, but not totally remove, biases in QTL effect estimates. In situations where multiple QTL alleles are segregating the multi-family analysis will average out the effects of the different QTL alleles.

Although linkage disequilibrium, epistasis and inbreeding are common phenomena in genetic systems that control quantitative traits, theory development and analysis are very complex, especially when they are considered together. The objective of this study is to offer additional quantitative genetics theory to define and analyze, in relation to non-inbred cross pollinating populations, components of genotypic variance, heritabilities and predicted gains, assuming linkage disequilibrium and absence of epistasis. The genotypic variance and its components, additive and due to dominance genetic variances, are invariant over the generations only in regard to completely linked genes and to those in equilibrium. When the population is structured in half-sib families, the additive variance in the parents' generation and the genotypic variance in the population can be estimated. When the population is structured in full-sib families, none of the components of genotypic variance can be estimated. The narrow sense heritability level at plant level can be estimated from the parent-offspring or mid parent-offspring regression. When there is dominance, the narrow sense heritability estimate in the in F2 is biased due to linkage disequilibrium when estimated by the Warner method, but not when estimated by means of the plant F2-family F3 regression. The bias is proportional to the number of pairs of linked genes, without independent assortment, and to the degree of dominance, and tends to be positive when genes in the coupling phase predominate or negative and of higher value when genes in the repulsion phase predominate. Linkage disequilibrium is also cause of bias in estimates of the narrow sense heritabilities at full-sib family mean and at plant within half-sib and full-sib families levels. Generally, the magnitude of the bias is proportional to the number of pairs of genes in disequilibrium and to the frequency of recombining gametes.

The seedling height and ground diameter of 42 half-sib families of biennial Cyclobalanopsis glauca were investigated and compared. The results showed that there were extremely significant differences between different families in the terms of seedling height and ground diameter. According to the seedling height and ground diameter, families 39, 27, 28 and 19 of C. glauca were superior to other families at the seedling stage. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum: Agronomy is the property of Universidade Estadual de Maringa 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.)

Melilotus officinalis is an important forage and green manure crop. There is a high degree of genetic diversity within species of M. officinalis. Despite the forage potential and the ability of nitrogen fixation, it has not been propagated in recent years because its high coumarin content. As a forage crop, the breeding goal of M. officinalis was mainly focused on improving forage yield and quality and reducing coumarin content. In this study, 25 superior half sib (HS) families of M. officinalis were used to carry out the second cycle recurrent selection, and genotypic variation of key traits (yield, quality and coumarin content) at two locations during 2018 and 2019 seasons were evaluated. Significant genotypic variation existed for the key traits: plant height (PH), dry biomass (DB), crude protein (CP), acid detergent fiber, neutral detergent fiber and coumarin. Also, significant genotype × location interactions were observed for the traits: DB, PH, CP, stem diameter, acid detergent lignin and acid insoluble ash (P < 0.05). Coumarin was negatively correlated with DB and PH, and positively correlated with CP. Genetic gain of all the traits of the second cycle recurrent selection were lower than that of the first cycle recurrent selection, except for PH and leaf/stem ratio (LSR). After the second cycle recurrent selection, the genetic gains of coumarin and LSR were higher than for other traits. Furthermore, new breeding lines generated by polycrossing superior HS families were evaluated. The polycrossing improved the yield and in vitro rumen fermentation characteristics and reduced the coumarin content. Our work provides new breeding lines of M. officinalis, beneficial for a sustainable grassland-based livestock industry. • Genotype × environment interactions affect yield and quality traits. • Recurrent selection process is useful to obtain plant materials with low coumarin content and high yield. • Superiority of new M. officinalis lines over currently grown demonstrated on fields and in vitro rumen fermentation. • We developed new breeding lines of M. officinalis beneficial for livestock industry. [ABSTRACT FROM AUTHOR]

Approximately, 20% of arable land worldwide, as well as nearly half of irrigated land, is subjected to salt stress. Osmotic stress and ion toxicity due to saline soils cause low crop yields. In this study, we introduced 18 families of salt-tolerant birch (Betula pendulaRoth.,Betula kirghisorumSav.-Ryczg., andBetula pubescensEhrh) into five high-salinity locations in northeastern China and evaluated their survival abilities. We also analyzed variation and stability of genotype–environment interactions of the different families under an additive main effect and multiplicative interaction model. Survival rate analysis indicated that the introduced families were well adapted to the high-salinity environments, whereas native families died. Variation analysis revealed significant differences between location × family interaction mean values for height and basic stem diameter (BSD), suggesting that most genotypes responded differently to different sites. The heritability of tree height and BSD at different sites varied from 0.416 to 0.940, with the coefficient of phenotypic variation ranging from 9.88% to 35.53%. Stability analysis indicated that some families had high tree heights but were sensitive to environmental conditions, whereas others were resistant but had average tree heights. These results suggest that families should be bred in various habitats to assess growth under favorable and unfavorable environments. [ABSTRACT FROM AUTHOR]

Black poplar ( Populus nigra) is a potential feedstock for cellulosic ethanol production, although breeding for this specific end use is required. Our goal was to identify associations between single nucleotide polymorphism ( SNP) markers within candidate genes encoding cellulose and lignin biosynthetic enzymes, with chemical wood property phenotypic traits, toward the aim of developing genomics-based breeding technologies for bioethanol production., Pyrolysis molecular beam mass spectrometry was used to determine contents of five- and six-carbon sugars, lignin, and syringyl : guaiacyl ratio. The association population included 599 clones from 17 half-sib families, which were successfully genotyped using 433 SNPs from 39 candidate genes. Statistical analyses were performed to estimate genetic parameters, linkage disequilibrium ( LD), and single marker and haplotype-based associations., A moderate to high heritability was observed for all traits. The LD, across all candidate genes, showed a rapid decay with physical distance. Analysis of single marker-phenotype associations identified six significant marker-trait pairs, whereas nearly 280 haplotypes were associated with phenotypic traits, in both an individual and multiple trait-specific manner., The rapid decay of LD within candidate genes in this population and the genetic associations identified suggest a close relationship between the associated SNPs and the causative polymorphisms underlying the genetic variation of lignocellulosic traits in black poplar. [ABSTRACT FROM AUTHOR]

Copyright of Ciência Florestal (01039954) is the property of Ciencia Florestal 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 Revista Chapingo Serie Ciencias Forestales is the property of Universidad Autonoma Chapingo 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 Revista Chapingo Serie Horticultura is the property of Universidad Autonoma Chapingo 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 experiment was conducted to ascertain narrow-sense heritability (h²) and the family-within-provenance variation in shoot die-back, taproot length and root biomass of half-sib Pterocarpus angolensis families from Malawi, Namibia and Zambia. Provenances differed significantly in shoot die-back for both shoot die-back seasons. A within provenance family effect was not significant in the first shoot die-back season but was significant in the second shoot die-back season. An increase in proportion of seedlings dying back, to 91%, for a Malawi family was observed in the second shoot die-back season. Provenance and within provenance family effects may be due to latitudinal differences between the provenances. The h 2 of shoot die-back was 0.07 (SE = 0.07) in the first shoot die-back season and 0.42 (SE = 0.27) in the second shoot die-back season. Narrow-sense heritability for root biomass was 0.81 (SE = 0.45). The h² for the second die-back season and root biomass suggest the traits are heritable. Random selection of individual families for assessing shoot die-back is important since this trait is only restricted to seedlings and saplings and not mature trees. Within provenance family effects for root biomass were significant, indicating differences between families. Two families from the most northerly provenances of Phalombe and Skull Rock in Malawi were significantly different from other southern families. Non-significant phenotypic correlation between shoot die-back and root biomass shows that shoot die-back is not likely to be determined by root size nor taproot depth. Although a non-significant negative phenotypic correlation (-0.15) between the second shoot die-back season and root biomass was obtained, a family from Malawi that had the highest mean shoot die-back in the second shoot die-back season had the smallest root biomass. Half-sib families with post shoot die-back growth potential, in the first shoot die-back season, are likely to have a better chance of post shoot die-back growth later. [ABSTRACT FROM AUTHOR]

Abstract: Phenogenetic response of silver birch populations and half-sib families to separate and combined elevated ozone (O3) concentrations and ultraviolet-B (UV-B) radiation dozes was studied at juvenile age in the climatic chambers. Significant population and family effects were found for seedling height, lamina width, and leaf damage. The exposure to UV-B radiation decreased genetic variation at the stage of seed germination. Complex exposure to UV-B and O3 caused an increase of genetic variation at the stage of intensive seedling growth: seedling height genetic variation in separate treatments increased from 23.7–38.6 to 33.7–65.7%, the increase for lamina width was from 10.2–13.9 to 13.6–31.8%. Different populations and families demonstrated differing response to elevated complex UV-B and O3 exposure. Changes of genetic intra-population variation were population-specific. Such changes in genetic variation under the impact of stressors can alter adaptation, stability, and competitive ability of regenerating populations in a hardly predictive way. [Copyright &y& Elsevier]

The objective of this work was to propose an algorithm (HAPROB) to estimate haplotype probabilities for genotyped members of half-sib families for which parents lacked genotypic information. The algorithm had 2 basic steps. First, a Monte Carlo-based approach was used to estimate haplotype probabilities for sires conditional upon offspring genotypes and population allelic frequencies, and then offspring-haplotype probabilities were estimated conditional upon sire probabilities and population frequencies. The 2 steps were alternated iteratively until estimates of population frequencies were essentially unchanged. Simulation was used to evaluate effects of the number of Monte Carlo cycles on the accuracy of the reconstructed haplotypes. Fifty thousand cycles was found to be sufficient for the haplotype configurations considered. Accuracy of the algorithm was compared with that obtained by the public domain SIMWALK2 software. Predictions of the most likely haplotype configurations are produced by SIMWALK2, but no estimates of probability are given. The accuracy of the current approach was comparable to that obtained from SIMWALK2. The proportions of times that haplotypes were reconstructed correctly were 87.0 and 92.4% (sires and offspring) for HAPROB vs. 87.5 and 91.5% for SIMWALK2. Effects of family size on accuracy of reconstruction were examined. Accuracy of reconstruction was only about 4% for sires with 2 offspring, but accuracy among the offspring themselves was 65%. Accuracy increased quickly as family size increased and reached 100% for sires with 30 offspring. Maximum accuracy for offspring was about 96%. Estimates of haplotype probabilities produced can be used in regression analyses to estimate effects of haplotypes on quantitative phenotypes. [ABSTRACT FROM AUTHOR]

The purpose of the study was to estimate among- and within-population variation for juvenile growth and for growth rhythm traits, bud flushing and leaf colouring, in open-pollinated families of Quercus robur L. from six Lithuanian populations under different environmental conditions. Assessments were done in the nursery up to 4 yrs, and after replanting in three field trials at the age of 6 yrs. A highly significant population effect was found for bud flushing. Large family variance components were estimated for bud flushing and height. The family×site interaction was significant and more pronounced for growth cessation and height than for bud flushing. Depending on the trait, from 13 to 33% of families contributed significantly to the family×site interaction. Strongly significant site×population interaction was estimated only for bud flushing. Families with early bud flushing were taller, although the correlation was weak. Correlations between family means in bud flushing and bud flushing of parent trees varied from 0.53 to 0.60. Large CV A estimates for the adaptive traits suggest that species have a potential to adapt to environmental changes that may occur from global warming and indicate good perspectives for gene conservation and tree breeding when using Multiple Population Breeding System. [ABSTRACT FROM AUTHOR]

We tested a hypothesis that elevated ozone was an eliciting or contributing factor in outbreaks of the 'top dying' (or 'subtop dying') syndrome in Norway spruce (Picea abies). Progeny were used from open-pollinated trees within a stand with the 'top dying' syndrome, The mother trees were classified in relation to the expression of the 'top dying' syndrome, and progeny from the healthiest and least healthy thirds of the population were exposed to high and low concentrations of ozone for three seasons. Elevated ozone did not affect height growth of the trees. It did not measurably affect net photosynthesis, stomatal conductance or instantaneous water use efficiency. Chlorophyll and carotenoid contents were also not significantly affected by ozone concentration. In the first year, instantaneous water use efficiency was lower in the progeny of the unhealthy mother trees than in the healthy mother trees. Furthermore, the unhealthy mother trees tended to produce longer annual shoots and showed more winter damage at the end of the experiment. None of these parameters were related to ozone concentration in the atmosphere. These results do not support a hypothesis that elevated ozone is a significant contributory factor or an eliciting factor in the development of the syndrome. [ABSTRACT FROM AUTHOR]

Effects of water stress on production of ethylene and its precursor, 1‐aminocyclopropane‐1‐carboxylic acid (ACC), by loblolly pine (Pinus taeda L.) seedlings from a Texas drought‐hardy and a Virginia Coastal Plain source were investigated. Ethylene production rates in needles from the Virgnia source increased slightly with initial stress (‐1.3 MPa), declined until water potential reached ‐1.6 MPa and then increased sharply at ‐2.5 MPa. The ethylene production rates in needles from the Texas also increased slightly with initial stress, then decreased with decreasing water potential. Ethylene production by root tissue was two to three times higher than needle tissue and decreased with decreasing water potential. ACC concentrations in needles of both seed sources decreased as water potential began decreasing. Below ‐1.4 MPa, ACC levels started increasing (Texas source) or remained constant until ‐2.8 MPa (Virginia source) at which time its level increased three‐fold. Mean ACC levels in root tissue [122 nmol (g dry weight)−1] were slightly higher than the mean levels in the needle tissue [92 nmol (g dry weight) −1]; roots apparently were more efficient in converting it to ethylene since ethylene production was two to three times higher than needle tissue. The modulation of ethylene synthesis by ACC synthase and ethyleneforming enzyme appeared to be influenced by stress level, organ and seed source. [ABSTRACT FROM AUTHOR]