Etude de caracteres morphologiques et iso-enzymatiques sur des plantes issues de culture d'antheres chez le chou-fleur (Brassica oleracea var botrytis)

Des embryons ont été obtenus par culture d’anthères d’un génotype issu d’une variété-population de chou-fleur (Brassica oleracea L botrytis), type automne. Une étude cytologique, l’établissement de profils isoenzymatiques et l’analyse de certains caractères morphologiques ont permis de mieux définir les particularités des plantes obtenues à partir de ces embryons. Soixante-quatre pour cent des plantes étudiées se sont avérées tétraploïdes alors que 26% seulement sont diploïdes et 6% triploïdes. Aucun haploïde n’a été observé. Une bonne corrélation (r = 0,973 p < 0,01) a été notée entre le nombre de chloroplastes dans les cellules de garde des stomates et le niveau de ploïdie déterminé par dénombrement chromosomique. Certains critères morphologiques, comme la longueur des boutons avant l’anthèse ou la longueur des pétales à l’anthèse, se sont avérés être également de bons outils d’estimation du niveau de ploïdie. Le polymorphisme observé pour les 2 systèmes iso-enzymatiques, ACO et PGM, chez la plante mère a permis de mettre en évidence la ségrégation des allèles dans la descendance obtenue par culture d’anthères ce qui atteste de l’origine gamétophytique du matériel et de l’homozygotie des lignées issues de ces travaux. Aucun phénomène d’embryogenèse somatique n’a été observé.Anther culture derived embryos were obtained from an autumn type cauliflower (Brassica oleracea L botrytis). Cytological, morphological (table I) and electrophoretic analyses of the regenerated plants were undertaken. A high frequency of tetraploids (64%) was observed. Only 26% of the plants were diploid, and 6% triploid. No haploids were obtained. A good correlation (r = 0.973 p < 0.01) (table III) was noted between the number of chloroplasts in the stomatic guard cells and the ploidy level determined by chromosome counting (fig 2). A few morphological characteristics (length of the buds just before anthesis, petal length) may also be taken into account to estimate the ploidy level (table IV). The mother plant was analysed by starch gel electrophoresis and was found to be homozygous for most of the studied enzyme loci except for ACO and PGM for which polymorphism was observed (fig 1). This polymorphism allowed the verification of the gametophytic origin of the plants obtained by anther culture in which no more polymorphism was detected and segregation of the alleles could be studied (table II). No somatic embryos were observed

Étude de caractères morphologiques et iso-enzymatiques sur des plantes issues de culture d'anthères chez le chou-fleur (Brassica oleracea var botrytis)

Des embryons ont été obtenus par culture d'anthères d'un génotype issu d'une variété-population de chou-fleur (Brassica oleracea L botrytis), type automne. Une étude cytologique, l'établissement de profils isoenzymatiques et l'analyse de certains caractères morphologiques ont permis de mieux définir les particularités des plantes obtenues à partir de ces embryons. Soixante-quatre pour cent des plantes étudiées se sont avérées tétraploïdes alors que 26% seulement sont diploïdes et 6% triploïdes. Aucun haploïde n'a été observé. Une bonne corrélation (r = 0,973 p < 0,01) a été notée entre le nombre de chloroplastes dans les cellules de garde des stomates et le niveau de ploïdie déterminé par dénombrement chromosomique. Certains critères morphologiques, comme la longueur des boutons avant l'anthèse ou la longueur des pétales à l'anthèse, se sont avérés être également de bons outils d'estimation du niveau de ploïdie. Le polymorphisme observé pour les 2 systèmes iso-enzymatiques, ACO et PGM, chez la plante mère a permis de mettre en évidence la ségrégation des allèles dans la descendance obtenue par culture d'anthères ce qui atteste de l'origine gamétophytique du matériel et de l'homozygotie des lignées issues de ces travaux. Aucun phénomène d'embryogenèse somatique n'a été observé.Study of morphological and electrophoretic traits of anther culture derived cauliflower plants (Brassica oleracea var botrytis). Anther culture derived embryos were obtained from an autumn type cauliflower (Brassica oleracea L botrytis). Cytological, morphological (table I) and electrophoretic analyses of the regenerated plants were undertaken. A high frequency of tetraploids (64%) was observed. Only 26% of the plants were diploid, and 6% triploid. No haploids were obtained. A good correlation (r = 0.973 p < 0.01) (table III) was noted between the number of chloroplasts in the stomatic guard cells and the ploidy level determined by chromosome counting (fig 2). A few morphological characteristics (length of the buds just before anthesis, petal length) may also be taken into account to estimate the ploidy level (table IV). The mother plant was analysed by starch gel electrophoresis and was found to be homozygous for most of the studied enzyme loci except for ACO and PGM for which polymorphism was observed (fig 1). This polymorphism allowed the verification of the gametophytic origin of the plants obtained by anther culture in which no more polymorphism was detected and segregation of the alleles could be studied (table II). No somatic embryos were observed

Étude de caractères morphologiques et iso-enzymatiques sur des plantes issues de culture d'anthères chez le chou-fleur (Brassica oleracea var botrytis)

International audienc

Etude de caracteres morphologiques et iso-enzymatiques sur des plantes issues de culture d'antheres chez le chou-fleur (Brassica oleracea var botrytis)

National audienceAnther culture derived embryos were obtained from an autumn type cauliflower (Brassica oleracea L botrytis). Cytological, morphological (table I) and electrophoretic analyses of the regenerated plants were undertaken. A high frequency of tetraploids (64%) was observed. Only 26% of the plants were diploid, and 6% triploid. No haploids were obtained. A good correlation (r = 0.973 p < 0.01) (table III) was noted between the number of chloroplasts in the stomatic guard cells and the ploidy level determined by chromosome counting (fig 2). A few morphological characteristics (length of the buds just before anthesis, petal length) may also be taken into account to estimate the ploidy level (table IV). The mother plant was analysed by starch gel electrophoresis and was found to be homozygous for most of the studied enzyme loci except for ACO and PGM for which polymorphism was observed (fig 1). This polymorphism allowed the verification of the gametophytic origin of the plants obtained by anther culture in which no more polymorphism was detected and segregation of the alleles could be studied (table II). No somatic embryos were observed.Des embryons ont été obtenus par culture d’anthères d’un génotype issu d’une variété-population de chou-fleur (Brassica oleracea L botrytis), type automne. Une étude cytologique, l’établissement de profils isoenzymatiques et l’analyse de certains caractères morphologiques ont permis de mieux définir les particularités des plantes obtenues à partir de ces embryons. Soixante-quatre pour cent des plantes étudiées se sont avérées tétraploïdes alors que 26% seulement sont diploïdes et 6% triploïdes. Aucun haploïde n’a été observé. Une bonne corrélation (r = 0,973 p < 0,01) a été notée entre le nombre de chloroplastes dans les cellules de garde des stomates et le niveau de ploïdie déterminé par dénombrement chromosomique. Certains critères morphologiques, comme la longueur des boutons avant l’anthèse ou la longueur des pétales à l’anthèse, se sont avérés être également de bons outils d’estimation du niveau de ploïdie. Le polymorphisme observé pour les 2 systèmes iso-enzymatiques, ACO et PGM, chez la plante mère a permis de mettre en évidence la ségrégation des allèles dans la descendance obtenue par culture d’anthères ce qui atteste de l’origine gamétophytique du matériel et de l’homozygotie des lignées issues de ces travaux. Aucun phénomène d’embryogenèse somatique n’a été observé

Effect of combining two genes for partial resistance to Barley yellow dwarf virus-PAV (BYDV-PAV) derived from Thinopyrum intermedium in wheat

In this study two Sources of resistance to Barley yellow dwarf virus (BYDV), both originating from Thinopyrum intermedium, were combined in a single genotype, line ZT, using GISH (genomic in situ hybridization) and a new molecular marker of the partial resistance gene Bdv2. Susceptible wheat cv. Sunstar, the translocation line TC14 carrying Bdv2, the addition line ZH with the group-2 chromosome arm carrying resistance, and line ZT with both resistances were inoculated with five strains of Barley yellow dwarf virus-PAV. The tests confirmed the resistance of TC14 and ZH and revealed an additive effect of the two sources of resistance in ZT. The resistance of line ZT was characterized by 1 proportion of infected plants significantly lower than the parental lines TC14 and ZH (42% vs. a mean of 76% for the parents) and a very low virus titre (area under the virus concentration progress curve of 1.2 vs. a mean on 6.3 for the parents)

Genetic control of oil content in oilseed rape (Brassica napus L.)

International audienceIn oilseed rape (Brassica napus L.) like in most oleaginous crops, seed oil content is the main qualitative determinant that confers its economic value to the harvest. Increasing seed oil content is then still an important objective in oilseed rape breeding. In the objective to get better knowledge on the genetic determinism of seed oil content, a genetic study was undertaken in two genetic backgrounds. Two populations of 445 and a 242 doubled haploids (DH) derived from the crosses "Darmor-bzh" x "Yudal" (DY) and "Rapid"" x "NSL96/25" (RNSL), respectively, were genotyped and evaluated for oil content in different trials. QTL mapping in the two populations indicate that additive effects are the main factors contributing to variation in oil content. A total of 14 and 10 genomic regions were involved in seed oil content in DY and RNSL populations, respectively, of which five and two were consistently revealed across the three trials performed for each population. Most of the QTL detected were not colocalised to QTL involved in flowering time. Few epistatic QTL involved regions that carry additive QTL in one or the other population. Only one QTL located on linkage group N3 was potentially common to the two populations. The comparisons of the QTL location in this study and in the literature showed that: (i) some of the QTL were more consistently revealed across different genetic backgrounds. The QTL on N3 was revealed in all the studies and the QTL on N1, N8 and N13 were revealed in three studies out of five, (ii) some of the QTL were specific to one genetic background with potentially some original alleles, (iii) some QTL were located in homeologous regions, and (iv) some of the regions carrying QTL for oil content in oilseed rape and in Arabidopsis could be collinear. These results show the possibility to combine favourable alleles at different QTL to increase seed oil content and to use Arabidopsis genomic data to derive markers for oilseed rape QTL and identify candidate genes, as well as the interest to combine information from different segregating populations in order to build a consolidated map of QTL involved in a specific trait