The environmental stability of breadmaking quality of wheat flours i.e. the absence of fluctuatio... more The environmental stability of breadmaking quality of wheat flours i.e. the absence of fluctuation across environments and genotype! environment interactions is as important as their performance in milling and baking. Many statistical approaches have been used to assess cultivar stability parameters across environments. Quality stability parameters were studied using a set of eleven bread wheat cultivars and five hybrid wheats grown in France at eight locations in two consecutive years. Three different statistical variances: ecovalence Wi, environmental variance S 2 Xi and genotypic stability were used to assess the stability of quality parameters measured on wheat kernels at harvest, on the technological properties of their flours and on the molecular weight distribution of total endosperm proteins extracted using 2% SDS in phosphate buffer with sonication. Asymmetrical flow field-flow fractionation coupled with a multi-angle laser light scattering photometer allowed the molar masses of polymeric glutenins to be measured without size limits. Marked variation in the quality parameters was observed due to genetic and environmental effects. The three stability values calculated for protein content were not significantly correlated to the stability of the polymeric fraction, the bread loaf volume (LV) or the bread quality score (BQS). The three stability values of LV and BQS were significantly correlated to the stability of the weight-average (hMiw) molecular weight of the polymeric fraction. Multiple regressions showed that 60-84% of the stability values of LV and BQS were explained by the stability of only few quality parameters among which the hMiw of polymers played the major role.
ABSTRACT Abstract: The Green Revolution genes considerably increased the yield potential of moder... more ABSTRACT Abstract: The Green Revolution genes considerably increased the yield potential of modern wheat varieties, but also rendered them more susceptible to Fusarium head blight (FHB) causing problems with mycotoxin contamination. In order to study the association of “reduced height” (Rht) genes and FHB resistance, Rht-B1b, Rht-D1b and Rht8 genes were introduced in tall high-yielding wheat cultivars expressing a good level of Fusarium head blight (FHB) resistance via marker-assisted selection (MAS). The F1 plants of five crosses were backcrossed twice and 189 BC1 lines were genotyped. MAS was performed with Rht-B1b and Rht-D1b specific markers, with SSR Xgwm261 being diagnostic for Rht8, and with a Ppd-D1 specific marker. During the first phase of selection corresponding chromosomes were screened with 48 SSRs for polymorphisms followed by the use of 3 to 5 polymorphic SSRs for the detection of recombination around these loci. Based on this procedure a total of 42 lines were selected for the selection phase two. 152 genome-wide SSRs had been screened among the parent lines, and from these a set of 80 polymorphic SSRs (4 per chromosome) was chosen for background fingerprinting of the 42 lines. This process is ongoing. We expect that Rht alleles will be quickly integrated into tall and high-yielding cultivars with excellent quantitative FHB resistance carrying only small chromosomal fragments of the Rht donor lines. Finally, in multi-location field trials these new lines will be tested to analyse the association of the three Rht genes and FHB susceptibility.
National audienceThe discovery that fungal effector proteins are important for infection represen... more National audienceThe discovery that fungal effector proteins are important for infection represents a novel opportunity for controlling plant diseases. Use of fungal effectors for resistance breeding is a game-changing technology creating opportunities and innovative methods to identify novel resistances to fungal diseases in plants. These methods are amenable to high throughput phenotyping. The recent availability of high-density genetic marker coverage of the wheat genome allows the mapping of novel resistances identified through such high throughput phenotyping. We are using necrotrophic protein effectors from Parastagonospora nodorum (Pn) and toxic proteins from Fusarium graminearum (Fg) and Zymoseptoria tritici (Zt) to detect resistance genes/QTLs in wheat. Complementary strategies will be used to detect a large array of resistance mechanisms to fungal effectors. Recombinant necrotrophic protein effectors and toxic proteins are produced in yeast and the purified proteins are de...
The environmental stability of breadmaking quality of wheat flours i.e. the absence of fluctuatio... more The environmental stability of breadmaking quality of wheat flours i.e. the absence of fluctuation across environments and genotype×environment interactions is as important as their performance in milling and baking. Many statistical approaches have been used to assess cultivar stability parameters across environments. Quality stability parameters were studied using a set of eleven bread wheat cultivars and five hybrid wheats grown
ABSTRACT Six genetically different inbred genotypes of spring-type rye Secale cereale with differ... more ABSTRACT Six genetically different inbred genotypes of spring-type rye Secale cereale with differences in the average number and in the positional distribution of chiasmata were used in this study. The line with the lowest chiasma frequency was chosen as the female parent and crossed with the other five lines. Parental, F1, and F2 data were collected on chiasma number and on chiasma distribution between and within bivalents. Evidence for a polygenic control of both phenomena was found. Chiasma distribution between bivalents within pollen mother cells obviously follows a binomial distribution. This is effected by a mechanism that prevents the formation of a second chiasma on a chromosome arm as long as chromosome arms without chiasma remain; i.e., with 14 chiasmata seven ring bivalents will generally be formed. This mechanism causes a very strong negative correlation between frequency and between-cell variance of chiasmata. The number of chiasmata is independent of their position within the bivalents. A very close correlation between the number of pollen mother cells without univalents and the number of fertile pollen grains was found.
ABSTRACT An inbred genotype of cultivated rye was found that produces unreduced gametes in a very... more ABSTRACT An inbred genotype of cultivated rye was found that produces unreduced gametes in a very regular fashion. In the cross progeny of this line with another inbred line, which did not show unreduced gametes, the inheritance of this phenomenon was studied. The formation of unreduced gametes appears to be a recessive trait controlled by more than one gene. Chiasma frequency in 4n PMCs is exactly twice that in 2n PMCs. In first metaphase of 4n PMCs only bivalents (no multivalents) were seen. The possible mechanism leading to unreduced gametes and its evolutionary implications are discussed.
The environmental stability of breadmaking quality of wheat flours i.e. the absence of fluctuatio... more The environmental stability of breadmaking quality of wheat flours i.e. the absence of fluctuation across environments and genotype! environment interactions is as important as their performance in milling and baking. Many statistical approaches have been used to assess cultivar stability parameters across environments. Quality stability parameters were studied using a set of eleven bread wheat cultivars and five hybrid wheats grown in France at eight locations in two consecutive years. Three different statistical variances: ecovalence Wi, environmental variance S 2 Xi and genotypic stability were used to assess the stability of quality parameters measured on wheat kernels at harvest, on the technological properties of their flours and on the molecular weight distribution of total endosperm proteins extracted using 2% SDS in phosphate buffer with sonication. Asymmetrical flow field-flow fractionation coupled with a multi-angle laser light scattering photometer allowed the molar masses of polymeric glutenins to be measured without size limits. Marked variation in the quality parameters was observed due to genetic and environmental effects. The three stability values calculated for protein content were not significantly correlated to the stability of the polymeric fraction, the bread loaf volume (LV) or the bread quality score (BQS). The three stability values of LV and BQS were significantly correlated to the stability of the weight-average (hMiw) molecular weight of the polymeric fraction. Multiple regressions showed that 60-84% of the stability values of LV and BQS were explained by the stability of only few quality parameters among which the hMiw of polymers played the major role.
ABSTRACT Abstract: The Green Revolution genes considerably increased the yield potential of moder... more ABSTRACT Abstract: The Green Revolution genes considerably increased the yield potential of modern wheat varieties, but also rendered them more susceptible to Fusarium head blight (FHB) causing problems with mycotoxin contamination. In order to study the association of “reduced height” (Rht) genes and FHB resistance, Rht-B1b, Rht-D1b and Rht8 genes were introduced in tall high-yielding wheat cultivars expressing a good level of Fusarium head blight (FHB) resistance via marker-assisted selection (MAS). The F1 plants of five crosses were backcrossed twice and 189 BC1 lines were genotyped. MAS was performed with Rht-B1b and Rht-D1b specific markers, with SSR Xgwm261 being diagnostic for Rht8, and with a Ppd-D1 specific marker. During the first phase of selection corresponding chromosomes were screened with 48 SSRs for polymorphisms followed by the use of 3 to 5 polymorphic SSRs for the detection of recombination around these loci. Based on this procedure a total of 42 lines were selected for the selection phase two. 152 genome-wide SSRs had been screened among the parent lines, and from these a set of 80 polymorphic SSRs (4 per chromosome) was chosen for background fingerprinting of the 42 lines. This process is ongoing. We expect that Rht alleles will be quickly integrated into tall and high-yielding cultivars with excellent quantitative FHB resistance carrying only small chromosomal fragments of the Rht donor lines. Finally, in multi-location field trials these new lines will be tested to analyse the association of the three Rht genes and FHB susceptibility.
National audienceThe discovery that fungal effector proteins are important for infection represen... more National audienceThe discovery that fungal effector proteins are important for infection represents a novel opportunity for controlling plant diseases. Use of fungal effectors for resistance breeding is a game-changing technology creating opportunities and innovative methods to identify novel resistances to fungal diseases in plants. These methods are amenable to high throughput phenotyping. The recent availability of high-density genetic marker coverage of the wheat genome allows the mapping of novel resistances identified through such high throughput phenotyping. We are using necrotrophic protein effectors from Parastagonospora nodorum (Pn) and toxic proteins from Fusarium graminearum (Fg) and Zymoseptoria tritici (Zt) to detect resistance genes/QTLs in wheat. Complementary strategies will be used to detect a large array of resistance mechanisms to fungal effectors. Recombinant necrotrophic protein effectors and toxic proteins are produced in yeast and the purified proteins are de...
The environmental stability of breadmaking quality of wheat flours i.e. the absence of fluctuatio... more The environmental stability of breadmaking quality of wheat flours i.e. the absence of fluctuation across environments and genotype×environment interactions is as important as their performance in milling and baking. Many statistical approaches have been used to assess cultivar stability parameters across environments. Quality stability parameters were studied using a set of eleven bread wheat cultivars and five hybrid wheats grown
ABSTRACT Six genetically different inbred genotypes of spring-type rye Secale cereale with differ... more ABSTRACT Six genetically different inbred genotypes of spring-type rye Secale cereale with differences in the average number and in the positional distribution of chiasmata were used in this study. The line with the lowest chiasma frequency was chosen as the female parent and crossed with the other five lines. Parental, F1, and F2 data were collected on chiasma number and on chiasma distribution between and within bivalents. Evidence for a polygenic control of both phenomena was found. Chiasma distribution between bivalents within pollen mother cells obviously follows a binomial distribution. This is effected by a mechanism that prevents the formation of a second chiasma on a chromosome arm as long as chromosome arms without chiasma remain; i.e., with 14 chiasmata seven ring bivalents will generally be formed. This mechanism causes a very strong negative correlation between frequency and between-cell variance of chiasmata. The number of chiasmata is independent of their position within the bivalents. A very close correlation between the number of pollen mother cells without univalents and the number of fertile pollen grains was found.
ABSTRACT An inbred genotype of cultivated rye was found that produces unreduced gametes in a very... more ABSTRACT An inbred genotype of cultivated rye was found that produces unreduced gametes in a very regular fashion. In the cross progeny of this line with another inbred line, which did not show unreduced gametes, the inheritance of this phenomenon was studied. The formation of unreduced gametes appears to be a recessive trait controlled by more than one gene. Chiasma frequency in 4n PMCs is exactly twice that in 2n PMCs. In first metaphase of 4n PMCs only bivalents (no multivalents) were seen. The possible mechanism leading to unreduced gametes and its evolutionary implications are discussed.
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