According to the difference of selection criteria, methods of marker-assisted selection (MAS) of quantitative traits can be divided into genotype-based selection (GS) and genotypic value-based selection (GVS). By mean...According to the difference of selection criteria, methods of marker-assisted selection (MAS) of quantitative traits can be divided into genotype-based selection (GS) and genotypic value-based selection (GVS). By means of computer simulation, potentials of the two methods were compared. Results showed that the two methods had similar basic laws and their efficiencies were not significantly different except that GS behaved better in the case where the number of QTLs was large and QTL effects were equal. From the application point of view, combination of GS and GVS should be the development direction of MAS research in the future.展开更多
We study the steady state properties ofa genotype selection model in presence of correlated Gaussian whitenoise. The effect of the noise on the genotype selection model is discussed. It is found that correlated noise ...We study the steady state properties ofa genotype selection model in presence of correlated Gaussian whitenoise. The effect of the noise on the genotype selection model is discussed. It is found that correlated noise can breakthe balance of gene selection and induce the phase transition which can makes us select one type gene haploid from agene group.展开更多
This paper investigates a genotype selection model subjected to both a multiplicative coloured noise and an additive coloured noise with different correlation time τ1 and τ2 by means of the numerical technique. By d...This paper investigates a genotype selection model subjected to both a multiplicative coloured noise and an additive coloured noise with different correlation time τ1 and τ2 by means of the numerical technique. By directly simulating the Langevin Equation, the following results are obtained. （1） The multiplicative coloured noise dominates, however, the effect of the additive coloured noise is not neglected in the practical gene selection process. The selection rate μ decides that the selection is propitious to gene A haploid or gene B haploid. （2） The additive coloured noise intensity and the correlation time τ2 play opposite roles. It is noted that α and τ2 can not separate the single peak, while can make the peak disappear and ^-2 can make the peak be sharp. （3） The multiplicative coloured noise intensity D and the correlation time τ1 can induce phase transition, at the same time they play opposite roles and the reentrance phenomenon appears. In this case, it is easy to select one type haploid from the group with increasing D and decreasing τ1.展开更多
In 1994, Grove, Kocic, Ladas, and Levin conjectured that the local stability and global stability conditions of the fixed point -y= 1/2 in the genotype selection model should be equivalent. In this article, we give an...In 1994, Grove, Kocic, Ladas, and Levin conjectured that the local stability and global stability conditions of the fixed point -y= 1/2 in the genotype selection model should be equivalent. In this article, we give an affirmative answer to this conjecture and prove that local stability implies global stability. Some illustrative examples are included to demonstrate the validity and applicability of the results.展开更多
An isolate of the Spodoptera frugiperda multiple nucleopolyhedrovirus comprises a stable proportion of deletion genotypes （e.g., SfNIC-C）, that lack pifl and pif2 rendering them noninfectious per os, and that surviv...An isolate of the Spodoptera frugiperda multiple nucleopolyhedrovirus comprises a stable proportion of deletion genotypes （e.g., SfNIC-C）, that lack pifl and pif2 rendering them noninfectious per os, and that survive by complementation with a complete genotype （SfNIC-B） in coinfected cells. To determine whether selection for particular ratios of complete and deletion genotypes occurs mainly during the establishment of the primary infection in insect midgut cells or during subsequent systemic infection, we examined genotype frequencies in insects that fed on OBs comprising different co-occluded mixtures of genotypes. Dramatic changes in genotype frequencies were observed between the OB inoculum and budded virus （BV） samples taken from larvae inoculated with OBs comprising 10% SfNIC-B ＋ 90% SfNIC-C indicating that a marked reduction of SfNIC-C genotype had occurred in the insect midgut due to the immediate elimination of all OBs that originated from cells that had been infected only by SfNIC-C. In contrast, immediate changes were not observed in OBs comprising mixtures of 50% SfNIC-B ＋ 50% SfNIC-C or those comprising 10% SfNIC-B ＋ 90% SfNIC-C as most of the OBs in these mixtures originated from cells that had been infected by both genotypes. Subsequent changes in genotypic frequencies during five days of systemic infection were fairly small in magnitude for all genotypic mixtures. We conclude that the prevalence of defective genotypes in the SfNIC population is likely determined by a balance between host selection against OBs produced in cells infected by SfNIC-C alone and within-host selection for fast-replicating deletion genotypes. The strength of intra-host selection is likely modulated by changes in MOI during the infection period.展开更多
Development of stable crops cultivars adapted to environmental constraints is very important for food security. Safflower, an oilseed crop which tolerates environmental abiotic stresses, is suitable for marginal lands...Development of stable crops cultivars adapted to environmental constraints is very important for food security. Safflower, an oilseed crop which tolerates environmental abiotic stresses, is suitable for marginal lands relatively dry and deprived from fertilizer inputs or irrigation. A set of Moroccan and introduced cultivars as well as international accessions were conducted at Oujda （Eastern of Morocco） during 2009-2010 for late and conventional sowing under two water regimes, in a field experiment using a completely randomized design, with three replications. The objective was to evaluate the effect of genotype and contrasting environment on safflower behavior and to select genotypes with large adaptation to the contrasted environmental conditions. Morphological, physiological and agronomic traits, as well as the stress susceptibility index （SSI）, were recorded in this study. Results showed significant effect of genotype, year （sowing time）, water regime and their interaction on most of the studied parameters. Late sowing and drought affected negatively all the parameters except seed oil which lightly increased under drought stress. Number of heads per plant （NHP） had the strongest association with seed yield under both drought and non-drought conditions, and hence could be taken as selection criterion for safflower seed yield improvement. Five accessions showed the highest overall mean seed yield （~ 1,000 kg/ha） and four accessions exhibited the highest overall mean seed oil content （〉 310 g/kg）. For late sowing, the accessions P1262421 and PI537604 produced the highest seed yield （〉 800 kg/ha） and the highest seed oil content （〉 290 g/kg）. For conventional sowing, the accessions PI250076 and PI250523 were the most performant, with a seed yield 〉 1,300 kg/ha and a seed oil content 〉 330 g/kg. Based on their mean productivity across environments, their SSI and their MDA, P1271073 and P1250076 could be selected and used as promising germplasm in safflower breeding program in Morocco as well as other dry areas throughout the world.展开更多
Background： Consuming moderate amounts of lean red meat as part of a balanced diet valuably contributes to intakes of essential nutrients, in this study, we merged phenotypic and genotypic information to characterize...Background： Consuming moderate amounts of lean red meat as part of a balanced diet valuably contributes to intakes of essential nutrients, in this study, we merged phenotypic and genotypic information to characterize the variation in lipid profile and sensory parameters and to represent the diversity among 15 cattle populations. Correlations between fat content, organoleptic characteristics and lipid profiles were also investigated. Methods： A sample of 436 largely unrelated purebred bulls belonging to 15 breeds and reared under comparable management conditions was analyzed. Phenotypic data -including fatness score, fat percentage, individual fatty acids （FA） profiles and sensory panel tests- and genotypic information from 11 polymorphisms was used. Results： The correlation coefficients between muscle total lipid measurements and absolute vs. relative amounts of polyunsaturated FA （PUFA） were in opposite directions. Increasing carcass fat leads to an increasing amount of FAs in triglycerides, but at the same time the relative amount of PUFAs is decreasing, which is in concordance with the negative correlation obtained here between the percentage of PUFA and fat measurements, as well as the weaker correlation between total phospholipids and total lipid muscle content compared with neutral lipids. Concerning organoleptic characteristics, a negative correlation between fiavour scores and the percentage of total PUFA, particularly to n-6 fraction, was found. The correlation between juiciness and texture is higher than with flavour scores. The distribution of SNPs plotted by principal components analysis （PCA） mainly reflects their known trait associations, although influenced by their specific breed allele frequencies. Conclusions： The results presented here help to understand the phenotypic and genotypic background underlying variations in FA composition and sensory parameters between breeds. The wide range of traits and breeds studied, along with the genotypic information on polymorphisms previously associated with different lipid traits, provide a broad characterization of beef meat, which allows giving a better response to the variety of consumers＇ preferences. Also, the development and implementation of low-density SNP panels with predictive value for economically important traits, such as those summarized here, may be used to improve production efficiency and meat quality in the beef industry.展开更多
Crop seeds are important sources of protein, oil, and carbohydrates for food, animal feeds, and industrial products. Recently, much attention has been paid to quality and functional properties of crop seeds. However, ...Crop seeds are important sources of protein, oil, and carbohydrates for food, animal feeds, and industrial products. Recently, much attention has been paid to quality and functional properties of crop seeds. However, seed traits possess some distinct genetic characteristics in comparison with plant traits, which increase the difficulty of genetically improving these traits. In this study, diallel analysis for seed models with genotype by environment interaction （GE） effect was applied to estimate the variance-covariance components of seed traits. Mixed linear model approaches were used to estimate the genetic covariances between pair-wise seed and plant traits. The breeding values （BV） were divided into two categories for the seed models. The first category of BV was defined as the combination of direct additive, cytoplasmic, and maternal additive effects, which should be utilized for selecting stable cultivars over multi-environments. The three genetic effects, together with their GE interaction, were included in the second category of BV for selecting special lines to be grown in specific ecosystems. Accordingly, two types of selection indices for seed traits, i.e., general selection index and interaction selection index, were developed and constructed on the first and the second category BV, respectively. These proposed selection indices can be applied to solve the difficult task of simultaneously improving multiple seed traits in various environments. Data of crop seeds with regard to four seed traits and four yield traits based on the modified diallel crosses in Upland cotton （Gossypium hirsutum L.） were used as an example for demonstrating the proposed methodology.展开更多
Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding re...Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding research of families of the species has not been reported previously.Based on diameter at breast height(DBH),height and volume of 25 families on four experimental sites,we calculated variance components,genetic parameters,juvenile and mature trait correlations and made genotype main effect plus genotype×environment interaction effect(GGE)biplot based on the breeding values estimated using the method of best linear unbiased prediction(BLUP).Compared with height,DBH and volume had higher heritability and larger variation coefficients,making them the more suitable traits for family selection and evaluation.Based on these,GGE biplots containing 20 combinations of site×age were drawn using data at 13 to 17 years when the interactions between family and location were strong.Test sites classifications based on DBH,and volume were inconsistent,with two categories for DBH and one for volume.The Guyuan site was the most suitable with strong discriminating ability,high representativeness and stability among tree ages.Integrating the ranking results of DBH and volume,families 66,76,82 and 111 were high-yielding and stable,families 78 and96 were high-yielding with above average stability,families72 and 79 were high-yielding with below average stability,whereas stability of family 100 was inconsistent between DBH and volume.Early selection based on DBH was convenient and reliable,and can be made at seven years.This study provides support for the selection of Larix gmelinii var.principis-rupprechtii families in Hebei province and an example for the application of stem analysis data from multiple sites in tree breeding.展开更多
The aim of this experimental work is to select wheat progenies tolerant high levels of salinity. Studies were conducted to determine the realized response in salt tolerance of some selected progeny （F3） through one ...The aim of this experimental work is to select wheat progenies tolerant high levels of salinity. Studies were conducted to determine the realized response in salt tolerance of some selected progeny （F3） through one cycle of screening and selection and the extent of variability for salt tolerance among selected progeny （F3） of wheat. All the selected progeny （F3） derived from （F2） populations after exposure are to high salinity level, were tested for salt tolerance during all growth stages in sand cultures salinized with 0, 100, 175 mM NaCI as compared with the unselected progeny （F2）. Results showed that the selected progeny （F3） were in all cases except one, superior in yield at maturity and in most cases significantly so, both at 100 and 175 mM NaCl, to the yield of the unselected progeny （F2） controls. In this study, some selected progeny exhibited more than twice the seed yield compared with that obtained from unselected progeny at 175 mM NaCl, and their seed yield was also significantly higher than that at 0 mM NaCl. Results also indicated that the highest value percentage of realized response in salt tolerance was in （F3AS1） and （F3AS2） at 175 mM NaCI. It is important to bear in mind that the significant improvement in selected progeny was achieved just in a single cycle of selection. There is then a strong possibility that further increases in tolerance may be obtained through further cycles of selection till reaching F6 or F7 where would show genetics stability.展开更多
The evaluation of rice （Oryza safiva L.） cultivars assists breeders in identifying useful trait relationships and in selecting parents as donors of specific traits. This study was conducted to compare long-grain ric...The evaluation of rice （Oryza safiva L.） cultivars assists breeders in identifying useful trait relationships and in selecting parents as donors of specific traits. This study was conducted to compare long-grain rice cultivars using genotype x trait （GT） biplot analysis and determine potential donors of traits related to grain yield and quality. Seventeen cultivars in the 2005 and 2006 Uniform Regional Rice Nursery in Beaumont, Texas, USA were analyzed for 20 traits using GT biplot analysis. The GT biplots showed the diversity among cultivars with regards to yield-related traits. Cultivars recommended as donor parents were： Trenasse, Spring, Presidio, and Cocodrie for high grain yield and head rice rate Trenasse and Presidio for semi-dwarfness; Banks for tall plant height; Wells for high flag leaf area, panicle weight, and number and mass of filled grains per panicle; Hidalgo for high tiller density; Francis for high number of spikelets per panicle; Spring and Trenasse for short flowering duration; Cheniere for more days to heading and maturity and Spring for less days; and Spring and Hidalgo for high grain weiqht. Breeders can use these cultivars with specific traits to increase qrain yield and quality.展开更多
Cyclocarya paliurus, an economically valuable tree species, has traditionally been used as a nutraceutical food or medicine in China. However, limited information is available on its genotype selection and cultivation...Cyclocarya paliurus, an economically valuable tree species, has traditionally been used as a nutraceutical food or medicine in China. However, limited information is available on its genotype selection and cultivation under a wide range of environmental conditions for growth and targeted health-promoting substances. We studied the effects of genotype and environment, and their interaction on leaf triterpenoid content and tree growth for 12 genotypes of C. paliurus grown at four sites. We quantified the correlation between leaf triterpenoid accumulation and tree growth. The contents of cyclocaric acid B, cyclocarioside I, and arjunolic acid ranged from 0.06 to 3.89, 0 to 3.71, and 0.65 to 8.86 mg g^-1, respectively. Three individual triterpenoids were primarily influenced by genotype (variation ranged from 53.7 to 68.0%), while environment accounted for most of the variation in total triterpenoid content and tree growth (71.3–89.5%). Most tested environmental parameters were significantly correlated to total triterpenoid content, but not to the contents of the individual triterpenoids measured. Growth in tree height and diameter at breast height were significantly negatively correlated with total triterpenoid content but were non-significantly correlated with individual triterpenoid contents. We conclude that genotypic selection, manipulation of environmental conditions, and implementation of appropriate silvicultural operations would be important strategies for increasing the accumulation of health-promoting phytochemicals.展开更多
A study was carried out to evaluate the development of 12 tetraploid alfalfa cultivars exposed to Al toxicity in nutrient solution. Newly germinated seedlings of cultivars Alfa 200, Alto, Araucana, Costera, Crioula, E...A study was carried out to evaluate the development of 12 tetraploid alfalfa cultivars exposed to Al toxicity in nutrient solution. Newly germinated seedlings of cultivars Alfa 200, Alto, Araucana, Costera, Crioula, Esmeralda, Falcon, F-708, Rio, Romagnola, Valley Plus, and Victoria, were exposed to either 0, 4, 8 or 12 mg·L-1 Al3+. Plants were analyzed regarding root length (RL) and dry matter (RDM), aerial part length (APL), and dry matter (APDM), hypocotyl length (HypL) and dry matter (HypDM), epicotyl length (EpiL) and dry matter (EpiDM), and petiole length (PetL), and dry matter (PetDM). Results indicated that, although all genotypes exhibited detectable sensitivity to such a stress, cvs. Crioula, Victoria and Alpha-200 were tolerant to 4 mg·L-1 Al3+ toxicity. It was also concluded that Al3+ levels up to the 4 mg·L-1 will be effective for screening tetraploid alfalfa genotypes regarding this type of stress, when evaluations are made in nutrient solution. Finally, RL is the most suitable variable for conducting such evaluations, but all variables related to dry matter in the aerial part are also recommended.展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant No. 39893350).
文摘According to the difference of selection criteria, methods of marker-assisted selection (MAS) of quantitative traits can be divided into genotype-based selection (GS) and genotypic value-based selection (GVS). By means of computer simulation, potentials of the two methods were compared. Results showed that the two methods had similar basic laws and their efficiencies were not significantly different except that GS behaved better in the case where the number of QTLs was large and QTL effects were equal. From the application point of view, combination of GS and GVS should be the development direction of MAS research in the future.
文摘We study the steady state properties ofa genotype selection model in presence of correlated Gaussian whitenoise. The effect of the noise on the genotype selection model is discussed. It is found that correlated noise can breakthe balance of gene selection and induce the phase transition which can makes us select one type gene haploid from agene group.
基金Project supported by the Natural Science Foundation of Yunnan province of China (Grant No 2006A0002M)the Science Foundation of Baoji University of Science and Arts of China (Grant No Zk0697)
文摘This paper investigates a genotype selection model subjected to both a multiplicative coloured noise and an additive coloured noise with different correlation time τ1 and τ2 by means of the numerical technique. By directly simulating the Langevin Equation, the following results are obtained. （1） The multiplicative coloured noise dominates, however, the effect of the additive coloured noise is not neglected in the practical gene selection process. The selection rate μ decides that the selection is propitious to gene A haploid or gene B haploid. （2） The additive coloured noise intensity and the correlation time τ2 play opposite roles. It is noted that α and τ2 can not separate the single peak, while can make the peak disappear and ^-2 can make the peak be sharp. （3） The multiplicative coloured noise intensity D and the correlation time τ1 can induce phase transition, at the same time they play opposite roles and the reentrance phenomenon appears. In this case, it is easy to select one type haploid from the group with increasing D and decreasing τ1.
基金the Deanship of Scientific in King Saud University and Centre of Research in Faculty of Science for their encouragements and their support
文摘In 1994, Grove, Kocic, Ladas, and Levin conjectured that the local stability and global stability conditions of the fixed point -y= 1/2 in the genotype selection model should be equivalent. In this article, we give an affirmative answer to this conjecture and prove that local stability implies global stability. Some illustrative examples are included to demonstrate the validity and applicability of the results.
基金This study was funded by MEC projects numbers AGL2005-07909-CO3-01 and AGL2008-05456-CO3-01/AGR
文摘An isolate of the Spodoptera frugiperda multiple nucleopolyhedrovirus comprises a stable proportion of deletion genotypes （e.g., SfNIC-C）, that lack pifl and pif2 rendering them noninfectious per os, and that survive by complementation with a complete genotype （SfNIC-B） in coinfected cells. To determine whether selection for particular ratios of complete and deletion genotypes occurs mainly during the establishment of the primary infection in insect midgut cells or during subsequent systemic infection, we examined genotype frequencies in insects that fed on OBs comprising different co-occluded mixtures of genotypes. Dramatic changes in genotype frequencies were observed between the OB inoculum and budded virus （BV） samples taken from larvae inoculated with OBs comprising 10% SfNIC-B ＋ 90% SfNIC-C indicating that a marked reduction of SfNIC-C genotype had occurred in the insect midgut due to the immediate elimination of all OBs that originated from cells that had been infected only by SfNIC-C. In contrast, immediate changes were not observed in OBs comprising mixtures of 50% SfNIC-B ＋ 50% SfNIC-C or those comprising 10% SfNIC-B ＋ 90% SfNIC-C as most of the OBs in these mixtures originated from cells that had been infected by both genotypes. Subsequent changes in genotypic frequencies during five days of systemic infection were fairly small in magnitude for all genotypic mixtures. We conclude that the prevalence of defective genotypes in the SfNIC population is likely determined by a balance between host selection against OBs produced in cells infected by SfNIC-C alone and within-host selection for fast-replicating deletion genotypes. The strength of intra-host selection is likely modulated by changes in MOI during the infection period.
文摘Development of stable crops cultivars adapted to environmental constraints is very important for food security. Safflower, an oilseed crop which tolerates environmental abiotic stresses, is suitable for marginal lands relatively dry and deprived from fertilizer inputs or irrigation. A set of Moroccan and introduced cultivars as well as international accessions were conducted at Oujda （Eastern of Morocco） during 2009-2010 for late and conventional sowing under two water regimes, in a field experiment using a completely randomized design, with three replications. The objective was to evaluate the effect of genotype and contrasting environment on safflower behavior and to select genotypes with large adaptation to the contrasted environmental conditions. Morphological, physiological and agronomic traits, as well as the stress susceptibility index （SSI）, were recorded in this study. Results showed significant effect of genotype, year （sowing time）, water regime and their interaction on most of the studied parameters. Late sowing and drought affected negatively all the parameters except seed oil which lightly increased under drought stress. Number of heads per plant （NHP） had the strongest association with seed yield under both drought and non-drought conditions, and hence could be taken as selection criterion for safflower seed yield improvement. Five accessions showed the highest overall mean seed yield （~ 1,000 kg/ha） and four accessions exhibited the highest overall mean seed oil content （〉 310 g/kg）. For late sowing, the accessions P1262421 and PI537604 produced the highest seed yield （〉 800 kg/ha） and the highest seed oil content （〉 290 g/kg）. For conventional sowing, the accessions PI250076 and PI250523 were the most performant, with a seed yield 〉 1,300 kg/ha and a seed oil content 〉 330 g/kg. Based on their mean productivity across environments, their SSI and their MDA, P1271073 and P1250076 could be selected and used as promising germplasm in safflower breeding program in Morocco as well as other dry areas throughout the world.
文摘Background： Consuming moderate amounts of lean red meat as part of a balanced diet valuably contributes to intakes of essential nutrients, in this study, we merged phenotypic and genotypic information to characterize the variation in lipid profile and sensory parameters and to represent the diversity among 15 cattle populations. Correlations between fat content, organoleptic characteristics and lipid profiles were also investigated. Methods： A sample of 436 largely unrelated purebred bulls belonging to 15 breeds and reared under comparable management conditions was analyzed. Phenotypic data -including fatness score, fat percentage, individual fatty acids （FA） profiles and sensory panel tests- and genotypic information from 11 polymorphisms was used. Results： The correlation coefficients between muscle total lipid measurements and absolute vs. relative amounts of polyunsaturated FA （PUFA） were in opposite directions. Increasing carcass fat leads to an increasing amount of FAs in triglycerides, but at the same time the relative amount of PUFAs is decreasing, which is in concordance with the negative correlation obtained here between the percentage of PUFA and fat measurements, as well as the weaker correlation between total phospholipids and total lipid muscle content compared with neutral lipids. Concerning organoleptic characteristics, a negative correlation between fiavour scores and the percentage of total PUFA, particularly to n-6 fraction, was found. The correlation between juiciness and texture is higher than with flavour scores. The distribution of SNPs plotted by principal components analysis （PCA） mainly reflects their known trait associations, although influenced by their specific breed allele frequencies. Conclusions： The results presented here help to understand the phenotypic and genotypic background underlying variations in FA composition and sensory parameters between breeds. The wide range of traits and breeds studied, along with the genotypic information on polymorphisms previously associated with different lipid traits, provide a broad characterization of beef meat, which allows giving a better response to the variety of consumers＇ preferences. Also, the development and implementation of low-density SNP panels with predictive value for economically important traits, such as those summarized here, may be used to improve production efficiency and meat quality in the beef industry.
基金supported by the National Basic Research Program of China (No. 2006CB101708)National Science and Technology Supporting Item of China (No. 2006BAD10A00).
文摘Crop seeds are important sources of protein, oil, and carbohydrates for food, animal feeds, and industrial products. Recently, much attention has been paid to quality and functional properties of crop seeds. However, seed traits possess some distinct genetic characteristics in comparison with plant traits, which increase the difficulty of genetically improving these traits. In this study, diallel analysis for seed models with genotype by environment interaction （GE） effect was applied to estimate the variance-covariance components of seed traits. Mixed linear model approaches were used to estimate the genetic covariances between pair-wise seed and plant traits. The breeding values （BV） were divided into two categories for the seed models. The first category of BV was defined as the combination of direct additive, cytoplasmic, and maternal additive effects, which should be utilized for selecting stable cultivars over multi-environments. The three genetic effects, together with their GE interaction, were included in the second category of BV for selecting special lines to be grown in specific ecosystems. Accordingly, two types of selection indices for seed traits, i.e., general selection index and interaction selection index, were developed and constructed on the first and the second category BV, respectively. These proposed selection indices can be applied to solve the difficult task of simultaneously improving multiple seed traits in various environments. Data of crop seeds with regard to four seed traits and four yield traits based on the modified diallel crosses in Upland cotton （Gossypium hirsutum L.） were used as an example for demonstrating the proposed methodology.
基金supported by the Key Research and Development Program of Hebei Province[20326333D]Science and Technology Promotion Demonstration Project of forestry and grassland in Hebei Province[Hebei TG[2019]001]Science and Technology Promotion Demonstration Project of forestry and grassland in Hebei Province[Hebei TG[2020]013]。
文摘Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding research of families of the species has not been reported previously.Based on diameter at breast height(DBH),height and volume of 25 families on four experimental sites,we calculated variance components,genetic parameters,juvenile and mature trait correlations and made genotype main effect plus genotype×environment interaction effect(GGE)biplot based on the breeding values estimated using the method of best linear unbiased prediction(BLUP).Compared with height,DBH and volume had higher heritability and larger variation coefficients,making them the more suitable traits for family selection and evaluation.Based on these,GGE biplots containing 20 combinations of site×age were drawn using data at 13 to 17 years when the interactions between family and location were strong.Test sites classifications based on DBH,and volume were inconsistent,with two categories for DBH and one for volume.The Guyuan site was the most suitable with strong discriminating ability,high representativeness and stability among tree ages.Integrating the ranking results of DBH and volume,families 66,76,82 and 111 were high-yielding and stable,families 78 and96 were high-yielding with above average stability,families72 and 79 were high-yielding with below average stability,whereas stability of family 100 was inconsistent between DBH and volume.Early selection based on DBH was convenient and reliable,and can be made at seven years.This study provides support for the selection of Larix gmelinii var.principis-rupprechtii families in Hebei province and an example for the application of stem analysis data from multiple sites in tree breeding.
文摘The aim of this experimental work is to select wheat progenies tolerant high levels of salinity. Studies were conducted to determine the realized response in salt tolerance of some selected progeny （F3） through one cycle of screening and selection and the extent of variability for salt tolerance among selected progeny （F3） of wheat. All the selected progeny （F3） derived from （F2） populations after exposure are to high salinity level, were tested for salt tolerance during all growth stages in sand cultures salinized with 0, 100, 175 mM NaCI as compared with the unselected progeny （F2）. Results showed that the selected progeny （F3） were in all cases except one, superior in yield at maturity and in most cases significantly so, both at 100 and 175 mM NaCl, to the yield of the unselected progeny （F2） controls. In this study, some selected progeny exhibited more than twice the seed yield compared with that obtained from unselected progeny at 175 mM NaCl, and their seed yield was also significantly higher than that at 0 mM NaCl. Results also indicated that the highest value percentage of realized response in salt tolerance was in （F3AS1） and （F3AS2） at 175 mM NaCI. It is important to bear in mind that the significant improvement in selected progeny was achieved just in a single cycle of selection. There is then a strong possibility that further increases in tolerance may be obtained through further cycles of selection till reaching F6 or F7 where would show genetics stability.
基金funded by the Texas Rice Research Foundation and by Lloyd T. WILSON through the Jack B. WENDT Endowed Chair
文摘The evaluation of rice （Oryza safiva L.） cultivars assists breeders in identifying useful trait relationships and in selecting parents as donors of specific traits. This study was conducted to compare long-grain rice cultivars using genotype x trait （GT） biplot analysis and determine potential donors of traits related to grain yield and quality. Seventeen cultivars in the 2005 and 2006 Uniform Regional Rice Nursery in Beaumont, Texas, USA were analyzed for 20 traits using GT biplot analysis. The GT biplots showed the diversity among cultivars with regards to yield-related traits. Cultivars recommended as donor parents were： Trenasse, Spring, Presidio, and Cocodrie for high grain yield and head rice rate Trenasse and Presidio for semi-dwarfness; Banks for tall plant height; Wells for high flag leaf area, panicle weight, and number and mass of filled grains per panicle; Hidalgo for high tiller density; Francis for high number of spikelets per panicle; Spring and Trenasse for short flowering duration; Cheniere for more days to heading and maturity and Spring for less days; and Spring and Hidalgo for high grain weiqht. Breeders can use these cultivars with specific traits to increase qrain yield and quality.
基金supported by the National Natural Science Foundation of China(Grant No.31470637)the Collaborative Innovation Plan of Jiangsu Higher Educationthe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Cyclocarya paliurus, an economically valuable tree species, has traditionally been used as a nutraceutical food or medicine in China. However, limited information is available on its genotype selection and cultivation under a wide range of environmental conditions for growth and targeted health-promoting substances. We studied the effects of genotype and environment, and their interaction on leaf triterpenoid content and tree growth for 12 genotypes of C. paliurus grown at four sites. We quantified the correlation between leaf triterpenoid accumulation and tree growth. The contents of cyclocaric acid B, cyclocarioside I, and arjunolic acid ranged from 0.06 to 3.89, 0 to 3.71, and 0.65 to 8.86 mg g^-1, respectively. Three individual triterpenoids were primarily influenced by genotype (variation ranged from 53.7 to 68.0%), while environment accounted for most of the variation in total triterpenoid content and tree growth (71.3–89.5%). Most tested environmental parameters were significantly correlated to total triterpenoid content, but not to the contents of the individual triterpenoids measured. Growth in tree height and diameter at breast height were significantly negatively correlated with total triterpenoid content but were non-significantly correlated with individual triterpenoid contents. We conclude that genotypic selection, manipulation of environmental conditions, and implementation of appropriate silvicultural operations would be important strategies for increasing the accumulation of health-promoting phytochemicals.
文摘A study was carried out to evaluate the development of 12 tetraploid alfalfa cultivars exposed to Al toxicity in nutrient solution. Newly germinated seedlings of cultivars Alfa 200, Alto, Araucana, Costera, Crioula, Esmeralda, Falcon, F-708, Rio, Romagnola, Valley Plus, and Victoria, were exposed to either 0, 4, 8 or 12 mg·L-1 Al3+. Plants were analyzed regarding root length (RL) and dry matter (RDM), aerial part length (APL), and dry matter (APDM), hypocotyl length (HypL) and dry matter (HypDM), epicotyl length (EpiL) and dry matter (EpiDM), and petiole length (PetL), and dry matter (PetDM). Results indicated that, although all genotypes exhibited detectable sensitivity to such a stress, cvs. Crioula, Victoria and Alpha-200 were tolerant to 4 mg·L-1 Al3+ toxicity. It was also concluded that Al3+ levels up to the 4 mg·L-1 will be effective for screening tetraploid alfalfa genotypes regarding this type of stress, when evaluations are made in nutrient solution. Finally, RL is the most suitable variable for conducting such evaluations, but all variables related to dry matter in the aerial part are also recommended.
