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The Brassica B-genome species possess many valuable agronomic and disease resistance traits. To transfer traits from the B genome of B. carinata into B. napus, an interspecific cross between B. napus and B. carinata was performed and a doubled haploid (DH) population was generated from the [BC.sub.3][S.sub.3] generation. Successful production of interspecific DH lines as identified using B-genome microsatellite markers is reported. Five percent of DH lines carry either intact B-genome chromosomes or chromosomes that have deletions. All of the DH lines have linkage group J13/B7 in common. This was further confirmed using B. nigra genomic DNA in a fluorescent in situ hybridization assay where the B-genome chromosomes were visualized and distinguished from the A- and C-genome chromosomes. The 60 DH lines were also evaluated for morphological traits in the field for two seasons and were tested for resistance to blackleg, caused by Leptosphaeria maculans, under greenhouse conditions. Variation in the DH population followed a normal distribution for several agronomic traits and response to blackleg. The lines with B-genome chromosomes were significantly different (p < 0.01) from the lines without B-genome chromosomes for both morphological and seed quality traits such as days to flowering, days to maturity, and erucic acid content. Key words: Brassica napus, Brassica carinata, B genome, introgression, SSR markers, cytogenetics, GISH, agronomic traits. Les especes a genome B au sein du genre Brassica possedent plusieurs caracteristiques agronomiques et resistances a des maladies utiles. Pour transferer ces caracteristiques du genome B du B. carinata a celui du B. napus, un croisement interspecifique entre le B. napus et le B. carinata aete realise et une population d'haploides doubles (HD) a ete genereea partir de la generation [BC.sub.3][S.sub.3]. Le succes dans la production de lignees HD interspecifiques a ete; veerifie en employant des microsatellites specifiques du genome B. Cinq pourcent des lignees HD portaient soit des chromosomes intacts du genome B ou des chromosomes ayant des deletions. Toutes les lignees HD avaient en commun J13/B7. Ceci a ete; confirme en employant l'ADN geenomique du B. nigra lors d'une hybridation in situ en fluorescence ou les chromosomes du genome B ont etee visualises et distinguees de ceux des genomes A et C. Ces 60 ligneees HD ont eegalement ete eevalueees pour leurs caracteristiques morphologiques au champ pendant deux saisons de meeme qu'en serre pour leur resistance a la jambe noire, causeee par Leptosphaeria maculans. La variation au sein de la population de ligneees HD presentait une distribution normale pour plusieurs des caracteristiques agronomiques et la resistance a la jambe noire. Les ligneees avec des chromosomes du genome B eetaient significativement differentes (p < 0,01) des lignees sans chromosome du genome B tant pour les caracteres morphologiques (floraison, maturite;) que les proprieetees des graines (contenu en acide erucique). Mots-cles: Brassica napus, Brassica carinata,g^nome B, introgression, marqueurs SSR, cytogeenetique, GISH, caracteres agronomiques. [Traduit par la Redaction], Introduction One of the goals of Brassica oilseed research programs is the stable introgression of novel traits from wild or closely related species into cultivated canola plants (Brassica napus) through [...]

The dominance of the diploid state in higher organisms, with haploidy generally confined to the gametic phase, has led to the perception that diploidy is favored by selection. This view is highlighted by the fact that no known female organism within the Metazoa exists exclusively (or even for a prolonged period) in a haploid state. We used fluorescence microscopy and variation at nine microsatellite loci to show that the false spider mite, Brevipalpus phoenicis, consists of haploid female parthenogens. We show that this reproductive anomaly is caused by infection by an undescribed endosymbiotic bacterium, which results in feminization of haploid genetic males., It is commonly thought that no female organism within the Metazoa exists exclusively in a haploid state, because selection favors diploidy in higher organisms (1, 2). There are several theories [...]

It is of fundamental importance in evolutionary genetics to partition the sources of phenotypic variation into environmental and genetic portions. The genetic component can be further partitioned into additive effects [...]

The relative duration of haploid and diploid phases during the sexual cycle varies greatly among organisms (Bold et al. 1980; Bell 1982, 1994; Klinger 1993), and yet, to date, we [...]

Only 7 nonrare haplotypes concerning Y-chromosome-specific TaqI fragments recognized by DNA probes p49f and p49a were encountered in 433 individuals belonging to 7 populations living in central Africa. Most of the haplotypes (77.7%) are characterized by the allelic combination A1,C0,D0,F1,I1 (haplotype IV). The degree of variability displayed by these sequences is low in the African population studied, compared with Europeans, probably because of the recent common origin of the Bantu-speaking populations studied and the common practice of male polygamy in Africa., Variations in sequences that are specific to the Y chromosome are particularly interesting from an evolutionary point of view. The probes p49f and p49a, located at Yq11.2 (Quack et al. [...]

In population improvement for combining ability, the use of selfed progenies increases genetic advance per cycle, but it can unduly increase the cycle length. Haplodiploidization (HD) can be very efficient because it induces complete homozygosity in a short period. We compared, from a theoretical approach, the potential of recurrent selection with a tester using doubled haploids (SDHT), with selection with testcrosses of [S.sub.0], [S.sub.1], or [S.sub.2] plants, with or without the use of off-season nurseries, for an annual plant like maize (Zea mays L.). With the same selection intensity, and without off-season nurseries, SDHT with a 4-yr cycle is the most efficient method. Efficiency increases with lower heritability, with an advantage in comparison to the test of [S.sub.0] plants ([S.sub.0]T) of 40 to 50% at low heritability ([h.sup.2] [is less than] 0.15) and 12% at high heritability ([h.sup.2] = 0.8). Use of off-season nurseries reduces the advantage of SDHT. With a 3-yr cycle, SDHT remains the best at low heritability with a gain of 27% (for [h.sup.2] = 0.1) in comparison to [S.sub.0]T with a 2-yr cycle. When using constant effective size, the advantage of SDHT is further reduced or suppressed at the benefit of [S.sub.0]T in 2 yr. The use of HD in recurrent selection for combining ability has its biggest advantage when heritability is low. Consideration of variety development will give more advantage to HD., FOR THE IMPROVEMENT by recurrent selection of the value of lines that can be derived from a population, haplodiploidization (HD) appears to be a very efficient process (Griffing, 1975; Gallais, [...]