Genotypic effects on callus induction and plant regeneration in callus, suspension and protoplast... more Genotypic effects on callus induction and plant regeneration in callus, suspension and protoplast culture, and their correlations with both phenotypic and GCA-values for anther culture response, were studied using 21 genotypes of perennial ryegrass. Differences between genotypes accounted for approximately 40% of the total variation for callus induction and initial callus growth, and 59 and 83% of the variation in callus culture for regeneration percentage and percentage of green plants. Effects of genotypes were less pronounced in suspension culture, where suspensions from the same genotype often behaved differently. Some suspension cultures retained their capacity for green plant regeneration for almost two years, repeatedly producing 80-100% green regenerants during this period. Genotypes with high regeneration percentage and a large proportion of green plants from callus culture were also superior in suspension culture for both regeneration performance and longevity. Regeneration percentage and percentage of green plants were uncorrelated, and probably under different genetic control. While capacity for green plant formation from the different genotypes showed no correlation between anther culture and somatic in vitro culture, a positive correlation was observed between the regeneration percentages in somatic in vitro culture and anther culture (r = 0.44*-0.85***), suggesting some common genetic control of the two systems .
Current plant science and biotechnology in agriculture, 1995
Replicated experiments with callus, suspension and protoplast cultures of perennial ryegrass were... more Replicated experiments with callus, suspension and protoplast cultures of perennial ryegrass were performed to quantify the genetic component of plant regeneration parameters. In callus culture genotype has by far the greatest influence on plant regeneration. In suspension culture, however, the effect of genotype is less pronounced and the random variation due to uncontrollable variation is larger. Regeneration pattern for protoplasts parallels that of the source suspension. The study shows a positive correlation between plant regeneration in anther culture and in somatic tissue cultures, with upto 30–50 per cent of the genotypic variation for plant regeneration in callus and suspension culture being explained by the correlation with anther culture response parameters. Long-term regenerable suspension cultures can be established in ryegrass, since finely dispersed cell suspensions, maintained for more than 36 months, have retained the ability to regenerate high yield of green plants. In protoplast nurse culture, upto 10 per cent plating efficiency and upto 40.000 green protoplast-derived plantlets per ml sedimented suspension cells was obtained. Such nurse cultures have a stronger positive effect than conditioned medium.
Accurate assessments of genetic gains ensuing from plant breeding for the most important agronomi... more Accurate assessments of genetic gains ensuing from plant breeding for the most important agronomic characteristics in Nordic spring barley (Hordeum vulgare L.) are not available. Hence this research was aimed to determine the rate of genetic improvement in the Nordic barley breeding pool. This study included 90, 2-row spring barley cultivars released (1942-1988) and 29, 6-row spring barley cultivars released (1930-1991) adopted by Nordic farmers that were tested in four Nordic locations for three consecutive years. Relative genetic gain owing to plant breeding was 13% in 2-row barley and 34% in 6-row barley for grain yield. The absolute gain for this characteristic was 13 ± 3 kg ha −1 year −1 in 2-row barley, and 22 ± 3 kg ha −1 year −1 in 6-row barley. Improved yield was achieved in Nordic barley by reducing plant height (0.20 ± 0.04 cm year −1 for 2-row barley and 0.16 ± 0.06 cm year −1 for 6-row cultivars), thereby reducing significantly lodging (0.5 ± 0.1% year −1 and 0.4 ± 0.1 year −1), and increasing significantly the harvest index (0.0008 ± 0.0002 year −1 and 0.0018 ± 0.0002 year −1). Additionally, in 2-row spring barley cultivars resistance to powdery mildew (0.19 ± 0.08% year −1) and thousand-kernel weight (0.07 ± 0.03 g year −1) were also significantly enhanced, whereas hectoliter weight was improved (0.06 ± 0.02 kg year −1) in 6-row barley cultivars in the period investigated.
Morphological data recorded from field trials using Citrullus lanatus germplasm collected in Nami... more Morphological data recorded from field trials using Citrullus lanatus germplasm collected in Namibia were used to analyse and compare the various morphotypes of this species. The experiment comprised wild types and local landraces as well as commercial cultivars. Cluster analysis supported the indigenous classification system used in Namibia, in which Citrullus types are distinguished based on gross morphology, ecology and
Current Plant Science and Biotechnology in Agriculture, 1997
Both Lolium perenne and L. multiflorum are strong outbreeders that exhibit severe inbreeding depr... more Both Lolium perenne and L. multiflorum are strong outbreeders that exhibit severe inbreeding depression (Bean & Yok-Hwa, 1972; Matzk, 1974) and possess a strict gametophytic self-incompatibility system which involves two major gene loci with modification by the genetic background (Lawrence et al., 1983).
A phenotypic diversity index (PDI) was calculated using 10 agronomiccharacteristics recorded in 9... more A phenotypic diversity index (PDI) was calculated using 10 agronomiccharacteristics recorded in 90 accessions of 2-row spring barleys and 29accessions of 6-row spring barleys grown in the Nordic Region. The PDIranged from 0.0308 to 0.6245 in 2-row barley accessions and from0.0314 to 0.7016 in 6-row barley accessions. The average PDIs were0.2178 and 0.2438 in 2-row and 6-row barley germplasm, which confirmsthat some older cultivars were parents of newer cultivars. The lowest PDIwas between accessions with the same name, which suggest that irrespectiveof their market source, they were the same cultivars. The largest PDI rangesin 2-row barley cultivars within the same country or release decade werecorrelated to the number of accessions in the respective cluster, whichsuggests that phenotypic diversity in this germplasm depends on the numberof cultivars included in the cluster. However, this association was not alwaysobserved in 6-row barley cultivars. The most distinct 2-row cultivars ...
An efficient nurse culture system was established for perennial ryegrass protoplast culture which... more An efficient nurse culture system was established for perennial ryegrass protoplast culture which allowed up to 59 000 protoplast-derived green plants to be regenerated from 1 ml of sedimented suspension cells. Nurse cultures improved plating efficiency, vitality of the protoplast-derived colonies and the frequency of green plants (number of green plants/100 plants), while regeneration frequency (number of plants/100 colonies) was determined mainly by the protoplast donor suspension. Conditioned medium taken from the embryogenic protoplast-donor suspension (self-conditioning) increased the plating efficiency and frequency of green plants, while conditioned media harvested from 6 other suspensions on average had a negative effect on colony formation and colony vitality. Concentrated self-conditioned medium resulted in a higher plating efficiency than self-conditioned medium diluted 1:1 with protoplast culture medium. Nurse culture was more efficient than conditioned medium at normal protoplast density and was also superior for compensating suboptimal protoplast density. There is evidence that the conditioning effect was reduced to 50% when the conditioned medium was stored for 2 days, suggesting involvement of unstable chemical factors and that the superiority of nurse cultures may be due to a continuous supply of conditioning compounds.
An efficient Agrobacterium-mediated transformation procedure for barley was developed for immatur... more An efficient Agrobacterium-mediated transformation procedure for barley was developed for immature embryos. Factors considered crucial for the delivery and integration of transgenes, such as type of growth regulator, duration of preculture period, plasmolysis and micro wounding were evaluated for their effect on frequencies of transient expression and stable integration. Dicamba in the callus induction and maintenance media was generally superior to 2,4-D in promoting transient expression and subsequent stable transformation. Plasmolysis generally reduced the level of transient expression although transgenic plants were recovered when 1-day precultured embryos were plasmolysed and grown on 2,4-D containing media. Micro wounding by particle bombardment did not change the level or localisation of transient expression events after Agrobacterium infection. Transgenic plants were generated with five out of 12 different procedures with transformation efficiencies ranging from 1.7 to 6.3%. Integration of bar and uidA coding sequences was confirmed by PCR for 75 plants representing 42 independent transgenic lines. Expression of the uidA gene was detected in 74% of primary transformants while 91% of them expressed the bar gene. Southern analysis proved integration of the transgenes with copy numbers ranging from one to six. Most transgenic lines that expressed both marker and reporter genes showed simple integration patterns and Mendelian inheritance of the transgenes in T1 progeny.
... Genetic control of the capacity to respond to anther culture in perennial ryegrass was studie... more ... Genetic control of the capacity to respond to anther culture in perennial ryegrass was studied in F, offspring from crosses between 11 clones selected for anther-culture ... x Chantal ' Clone 175 is selected from the cultivar 'Sisu' and clones 245 and 255 from 'Verna' (Olesen et al. ...
A Peruvian quinoa core collection, containing 103 chosen ecotypes or landraces, was defined on a ... more A Peruvian quinoa core collection, containing 103 chosen ecotypes or landraces, was defined on a geographically stratified non-overlapping sampling procedure. The objective was to determine whether this protocol was correct. Hence, a phenotypic distance matrix among 76 accessions from this core collection was created by calculating the difference between each pair of accessions for each characteristic. These 76 accessions were
Suspension culture performance in commercial varieties of perennial ryegrass was studied to asses... more Suspension culture performance in commercial varieties of perennial ryegrass was studied to assess the effect of variety on suspension culture response and plant regeneration. 179 suspension cultures were established from embryos of mature seeds of 21 varieties and one breeding population. Of these, 123 suspensions were morphogenic (21 varieties) and 66 suspensions (18 varieties) regenerated green plants. A number of suspension lines, originating from two different suspensions, retained the capacity for green plant formation for almost four years. Replicates performed with seed lots of different ages indicated that suspensions initiated from young seeds (1 year) were of better quality than suspensions initiated from older seeds (2-4 years). Varieties differed in their capacity to form morphogenic suspensions and suspensions capable of regenerating green plants, although the effect of variety was relatively small. It was concluded that responsive genotypes can be found within most varieties of Lolium perenne.
Acta Agriculturae Scandinavica, Section B - Soil & Plant Science, 2001
Phenotypic diversity for agronomic characteristics was determined in an experiment without fertil... more Phenotypic diversity for agronomic characteristics was determined in an experiment without fertilizer in 1998 in 41 two-row and 21 six-row winter barley accessions, provided by the Nordic Gene Bank, at Højbakkegård (Denmark). There were significant differences among ...
The accuracy of the Content should not be relied upon and should be independently verified with p... more The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content.
Genotypic effects on callus induction and plant regeneration in callus, suspension and protoplast... more Genotypic effects on callus induction and plant regeneration in callus, suspension and protoplast culture, and their correlations with both phenotypic and GCA-values for anther culture response, were studied using 21 genotypes of perennial ryegrass. Differences between genotypes accounted for approximately 40% of the total variation for callus induction and initial callus growth, and 59 and 83% of the variation in callus culture for regeneration percentage and percentage of green plants. Effects of genotypes were less pronounced in suspension culture, where suspensions from the same genotype often behaved differently. Some suspension cultures retained their capacity for green plant regeneration for almost two years, repeatedly producing 80-100% green regenerants during this period. Genotypes with high regeneration percentage and a large proportion of green plants from callus culture were also superior in suspension culture for both regeneration performance and longevity. Regeneration percentage and percentage of green plants were uncorrelated, and probably under different genetic control. While capacity for green plant formation from the different genotypes showed no correlation between anther culture and somatic in vitro culture, a positive correlation was observed between the regeneration percentages in somatic in vitro culture and anther culture (r = 0.44*-0.85***), suggesting some common genetic control of the two systems .
Current plant science and biotechnology in agriculture, 1995
Replicated experiments with callus, suspension and protoplast cultures of perennial ryegrass were... more Replicated experiments with callus, suspension and protoplast cultures of perennial ryegrass were performed to quantify the genetic component of plant regeneration parameters. In callus culture genotype has by far the greatest influence on plant regeneration. In suspension culture, however, the effect of genotype is less pronounced and the random variation due to uncontrollable variation is larger. Regeneration pattern for protoplasts parallels that of the source suspension. The study shows a positive correlation between plant regeneration in anther culture and in somatic tissue cultures, with upto 30–50 per cent of the genotypic variation for plant regeneration in callus and suspension culture being explained by the correlation with anther culture response parameters. Long-term regenerable suspension cultures can be established in ryegrass, since finely dispersed cell suspensions, maintained for more than 36 months, have retained the ability to regenerate high yield of green plants. In protoplast nurse culture, upto 10 per cent plating efficiency and upto 40.000 green protoplast-derived plantlets per ml sedimented suspension cells was obtained. Such nurse cultures have a stronger positive effect than conditioned medium.
Accurate assessments of genetic gains ensuing from plant breeding for the most important agronomi... more Accurate assessments of genetic gains ensuing from plant breeding for the most important agronomic characteristics in Nordic spring barley (Hordeum vulgare L.) are not available. Hence this research was aimed to determine the rate of genetic improvement in the Nordic barley breeding pool. This study included 90, 2-row spring barley cultivars released (1942-1988) and 29, 6-row spring barley cultivars released (1930-1991) adopted by Nordic farmers that were tested in four Nordic locations for three consecutive years. Relative genetic gain owing to plant breeding was 13% in 2-row barley and 34% in 6-row barley for grain yield. The absolute gain for this characteristic was 13 ± 3 kg ha −1 year −1 in 2-row barley, and 22 ± 3 kg ha −1 year −1 in 6-row barley. Improved yield was achieved in Nordic barley by reducing plant height (0.20 ± 0.04 cm year −1 for 2-row barley and 0.16 ± 0.06 cm year −1 for 6-row cultivars), thereby reducing significantly lodging (0.5 ± 0.1% year −1 and 0.4 ± 0.1 year −1), and increasing significantly the harvest index (0.0008 ± 0.0002 year −1 and 0.0018 ± 0.0002 year −1). Additionally, in 2-row spring barley cultivars resistance to powdery mildew (0.19 ± 0.08% year −1) and thousand-kernel weight (0.07 ± 0.03 g year −1) were also significantly enhanced, whereas hectoliter weight was improved (0.06 ± 0.02 kg year −1) in 6-row barley cultivars in the period investigated.
Morphological data recorded from field trials using Citrullus lanatus germplasm collected in Nami... more Morphological data recorded from field trials using Citrullus lanatus germplasm collected in Namibia were used to analyse and compare the various morphotypes of this species. The experiment comprised wild types and local landraces as well as commercial cultivars. Cluster analysis supported the indigenous classification system used in Namibia, in which Citrullus types are distinguished based on gross morphology, ecology and
Current Plant Science and Biotechnology in Agriculture, 1997
Both Lolium perenne and L. multiflorum are strong outbreeders that exhibit severe inbreeding depr... more Both Lolium perenne and L. multiflorum are strong outbreeders that exhibit severe inbreeding depression (Bean & Yok-Hwa, 1972; Matzk, 1974) and possess a strict gametophytic self-incompatibility system which involves two major gene loci with modification by the genetic background (Lawrence et al., 1983).
A phenotypic diversity index (PDI) was calculated using 10 agronomiccharacteristics recorded in 9... more A phenotypic diversity index (PDI) was calculated using 10 agronomiccharacteristics recorded in 90 accessions of 2-row spring barleys and 29accessions of 6-row spring barleys grown in the Nordic Region. The PDIranged from 0.0308 to 0.6245 in 2-row barley accessions and from0.0314 to 0.7016 in 6-row barley accessions. The average PDIs were0.2178 and 0.2438 in 2-row and 6-row barley germplasm, which confirmsthat some older cultivars were parents of newer cultivars. The lowest PDIwas between accessions with the same name, which suggest that irrespectiveof their market source, they were the same cultivars. The largest PDI rangesin 2-row barley cultivars within the same country or release decade werecorrelated to the number of accessions in the respective cluster, whichsuggests that phenotypic diversity in this germplasm depends on the numberof cultivars included in the cluster. However, this association was not alwaysobserved in 6-row barley cultivars. The most distinct 2-row cultivars ...
An efficient nurse culture system was established for perennial ryegrass protoplast culture which... more An efficient nurse culture system was established for perennial ryegrass protoplast culture which allowed up to 59 000 protoplast-derived green plants to be regenerated from 1 ml of sedimented suspension cells. Nurse cultures improved plating efficiency, vitality of the protoplast-derived colonies and the frequency of green plants (number of green plants/100 plants), while regeneration frequency (number of plants/100 colonies) was determined mainly by the protoplast donor suspension. Conditioned medium taken from the embryogenic protoplast-donor suspension (self-conditioning) increased the plating efficiency and frequency of green plants, while conditioned media harvested from 6 other suspensions on average had a negative effect on colony formation and colony vitality. Concentrated self-conditioned medium resulted in a higher plating efficiency than self-conditioned medium diluted 1:1 with protoplast culture medium. Nurse culture was more efficient than conditioned medium at normal protoplast density and was also superior for compensating suboptimal protoplast density. There is evidence that the conditioning effect was reduced to 50% when the conditioned medium was stored for 2 days, suggesting involvement of unstable chemical factors and that the superiority of nurse cultures may be due to a continuous supply of conditioning compounds.
An efficient Agrobacterium-mediated transformation procedure for barley was developed for immatur... more An efficient Agrobacterium-mediated transformation procedure for barley was developed for immature embryos. Factors considered crucial for the delivery and integration of transgenes, such as type of growth regulator, duration of preculture period, plasmolysis and micro wounding were evaluated for their effect on frequencies of transient expression and stable integration. Dicamba in the callus induction and maintenance media was generally superior to 2,4-D in promoting transient expression and subsequent stable transformation. Plasmolysis generally reduced the level of transient expression although transgenic plants were recovered when 1-day precultured embryos were plasmolysed and grown on 2,4-D containing media. Micro wounding by particle bombardment did not change the level or localisation of transient expression events after Agrobacterium infection. Transgenic plants were generated with five out of 12 different procedures with transformation efficiencies ranging from 1.7 to 6.3%. Integration of bar and uidA coding sequences was confirmed by PCR for 75 plants representing 42 independent transgenic lines. Expression of the uidA gene was detected in 74% of primary transformants while 91% of them expressed the bar gene. Southern analysis proved integration of the transgenes with copy numbers ranging from one to six. Most transgenic lines that expressed both marker and reporter genes showed simple integration patterns and Mendelian inheritance of the transgenes in T1 progeny.
... Genetic control of the capacity to respond to anther culture in perennial ryegrass was studie... more ... Genetic control of the capacity to respond to anther culture in perennial ryegrass was studied in F, offspring from crosses between 11 clones selected for anther-culture ... x Chantal ' Clone 175 is selected from the cultivar 'Sisu' and clones 245 and 255 from 'Verna' (Olesen et al. ...
A Peruvian quinoa core collection, containing 103 chosen ecotypes or landraces, was defined on a ... more A Peruvian quinoa core collection, containing 103 chosen ecotypes or landraces, was defined on a geographically stratified non-overlapping sampling procedure. The objective was to determine whether this protocol was correct. Hence, a phenotypic distance matrix among 76 accessions from this core collection was created by calculating the difference between each pair of accessions for each characteristic. These 76 accessions were
Suspension culture performance in commercial varieties of perennial ryegrass was studied to asses... more Suspension culture performance in commercial varieties of perennial ryegrass was studied to assess the effect of variety on suspension culture response and plant regeneration. 179 suspension cultures were established from embryos of mature seeds of 21 varieties and one breeding population. Of these, 123 suspensions were morphogenic (21 varieties) and 66 suspensions (18 varieties) regenerated green plants. A number of suspension lines, originating from two different suspensions, retained the capacity for green plant formation for almost four years. Replicates performed with seed lots of different ages indicated that suspensions initiated from young seeds (1 year) were of better quality than suspensions initiated from older seeds (2-4 years). Varieties differed in their capacity to form morphogenic suspensions and suspensions capable of regenerating green plants, although the effect of variety was relatively small. It was concluded that responsive genotypes can be found within most varieties of Lolium perenne.
Acta Agriculturae Scandinavica, Section B - Soil & Plant Science, 2001
Phenotypic diversity for agronomic characteristics was determined in an experiment without fertil... more Phenotypic diversity for agronomic characteristics was determined in an experiment without fertilizer in 1998 in 41 two-row and 21 six-row winter barley accessions, provided by the Nordic Gene Bank, at Højbakkegård (Denmark). There were significant differences among ...
The accuracy of the Content should not be relied upon and should be independently verified with p... more The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content.
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