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Seed meal amendments rich in glucosinolates are of interest for soil pest and disease control. The Ethiopian mustard (Brassica carinata A. Braun) line N2-6215, with very high levels of seed glucosinolates (160 μmol/g), was developed from the line C-101 (116 μmol/g) following mutagenesis. The objective of this research was to study the inheritance of very high seed glucosinolate content. Plants of N2-6215 were reciprocally crossed with plants of the line C-101. The F 1 , F 2 , and BC 1 F 1 plant generations were evaluated in two environments and seeds from individual plants were analysed for total glucosinolate content. The very high glucosinolate content in N2-6215 seeds was largely subject to maternal control. No cytoplasmic effects were detected. The trait was found to be oligogenic and determined by at least two or three genes. The estimates of broad-sense heritability were 0.45 and 0.58 in both environments, whereas the estimates of narrow-sense heritability were 0.35 and 0.50. The moderate heritability and oligogenic control of the trait suggest the feasibility of breeding for increased seed glucosinolate content in Ethiopian mustard.

Oils rich in polyunsaturated fatty acids linoleic acid and linolenic acid have important industrial applications, both as drying oils in the manufacture of paints and coatings as well as in formulation of pharmaceuticals and nutraceuticals. However, no oil types with high levels of polyunsaturation have been developed so far in Brassica oilseed crops. The objective of the present research was to select for high levels of linoleic acid and linolenic acid in Ethiopian mustard (Brassica carinata A. Braun). Selection started from the F3 (S0) seed generation of crosses involving the high oleic acid, high erucic acid line N2-3591, the low linolenic, high erucic acid line HF-186, and the zero erucic acid line 25X-1. The analysis of individual S0 seeds showed ranges of variation with maximum levels of 68.9% linoleic acid and 36.4% linolenic acid. Selection for increased levels of linoleic acid resulted in a S1:2 high linoleic acid line BC-HL that showed average linoleic acid contents of 62.5%, 58.3%, and 59.6%, respectively in three contrasting environments, compared to 47.8%, 45.8%, and 52.1%, respectively in a high linoleic acid check line. Selection for increased levels of linolenic acid resulted in a S1:2 high linolenic acid line BC-HLN that showed average linolenic acid contents of 27.1%, 25.8%, and 26.3%, respectively in the mentioned environments, compared to 23.9%, 21.2%, and 19.4%, respectively in a high linolenic acid check line. Both lines developed in the present research possess novel fatty acid profiles not available so far in Brassica oilseed crops and they may contribute to broaden the potential of Brassica oils for industrial applications.

The presence of high levels of sinigrin in the seeds represents a serious constraint for the commercial utilisation of Ethiopian mustard (Brassica carinata A. Braun) meal. The objective of this research was the introgression of genes for low glucosinolate content from B. juncea into B. carinata. BC1F1 seed from crosses between double zero B. juncea line Heera and B. carinata line N2-142 was produced. Simultaneous selection for B. carinata phenotype and low glucosinolate content was conducted from BC1F2 to BC1F4 plant generations. Forty-three BC1F4 derived lines were selected and subject to a detailed phenotypic and molecular evaluation to identify lines with low glucosinolate content and genetic proximity to B. carinata. Sixteen phenotypic traits and 80 SSR markers were used. Eight BC1F4 derived lines were very close to N2-142 both at the phenotypic and molecular level. Three of them, with average glucosinolate contents from 52 to 61 micromoles g−1, compared to 35 micromoles g−1 for Heera and 86 micromoles g−1 for N2-142, were selected and evaluated in two additional environments, resulting in average glucosinolate contents from 43 to 56 micromoles g−1, compared to 29 micromoles g−1 for Heera and 84 micromoles g−1 for N2-142. The best line (BCH-1773), with a glucosinolate profile made up of sinigrin (>95%) and a chromosome number of 2n = 34, was further evaluated in two environments (field and pots in open-air conditions). Average glucosinolate contents over the four environments included in this research were 42, 31 and 74 micromoles g−1 for BCH-1773, Heera and N2-142, respectively. These are the lowest stable levels of glucosinolates reported so far in B. carinata.

No information is available on the transferability and amplification quality of microsatellite (SSR) markers of the public domain in Brassica carinata A. Braun. The objective of the presented research was to study the amplification of a set of 73 SSRs from B. nigra (L.) Koch and B. napus L. in B. carinata, and to compare the results with those obtained in the amplification of the same markers in other Brassica species of the U triangle. This set of SSRs from B. nigra (B genome) and B. napus (AC genome) allows the identification of the 3 basic genomes of the Brassica species tested. 94.3% of the SSR markers from B. nigra and 97.4% of those from B. napus amplified SSR-specific products in B. carinata. Very high-quality amplification with a strong signal and easy scoring in B. carinata was recorded for 52.8% of the specific loci from B. nigra SSRs and 59.3% of the specific loci from B. napus SSRs, compared to 66.7% in B. nigra and62.8%in B. napus. Genome specificity and amplification quality of B. nigra and B. napus SSR markers in the 6 species under study is reported. High-quality transferable SSR markers provide an efficient and cost-effective platform to advance in molecular research in B. carinata., The research was supported by grant no. MCYT AGL2001-2293 from the Spanish Government.

La mostaza etíope (Brassica carinata A. Braun) es una especie oleaginosa que tiene gran potencial agronómico como cultivo en zonas de clima semiárido. Sin embargo, B. carinata no se utiliza en la actualidad como cultivo oleaginoso debido al elevado contenido de compuestos tóxicos denominados glucosinolatos, presentes principalmente en sus semillas. Hasta la fecha no se ha descrito la obtención de líneas de B. carinata con niveles bajos y estables de glucosinolatos en semillas. La presente Tesis se enmarca en una línea de investigación dirigida al desarrollo de líneas de B. carinata con niveles reducidos de glucosinolatos en semillas y al estudio genético de la síntesis de glucosinolatos en esta especie. Los objetivos específicos de la Tesis fueron: (1) el estudio genético del contenido en glucosinolatos en semillas en una línea de B. carinata con niveles elevados de estos compuestos, (2) la evaluación de la transferibilidad de marcadores microsatélites (SSRs) desarrollados en B. nigra (BB) y B. napus (AACC) a B. carinata (BBCC) para su aplicación en programas de mejora genética de esta especie, (3) el estudio comparativo de varias líneas de B. carinata con niveles reducidos en glucosinolatos en semillas y selección de segregrantes transgresivos para éste carácter, y (4) reducción del contenido en glucosinolatos en semillas de B. carinata mediante hibridación interespecífica. En esta Tesis se ha determinado que el contenido elevado en glucosinolatos en semillas de la línea N2-6215 presenta una moderada heredabilidad (0.45 £ h2b £ 0.58; 0.35 £ h2n £ 0.50), y está controlado por un reducido número de genes, estimado entre dos y tres. Se ha puesto de manifiesto la buena transferibilidad y capacidad discriminatoria de los marcadores SSR de B. nigra (L.) Koch (genoma B) y B. napus L. (genoma AC) para su aplicación a la mejora de B. carinata (genoma BC). Como consecuencia de los cruzamientos realizados, se han generado nuevas líneas de B. carinata con niveles reducidos y estables en glucosinolatos totales en semillas que no habían sido obtenidos hasta ahora en esta especie. Así, mediante un programa de cruzamientos intraespecíficos se han identificado líneas segregantes con niveles de glucosinolatos en semillas inferiores al nivel mínimo encontrado en sus respectivos parentales (52 µmoles g-1 frente a 73 µmoles g-1), y se ha realizado mediante hibridación interespecífica la transferencia de genes para bajo contenido en glucosinolatos desde B. juncea doble cero (< 30 µmoles g-1 en semillas) a B. carinata, dando lugar a una línea de B. carinata (BCH-1773) con niveles reducidos de glucosinolatos en semillas (42 µmoles g-1) y tipo de planta B. carinata, determinado tanto mediante descriptores fenotípicos como mediante los marcadores SSR transferidos a B. carinata en el transcurso de esta Tesis.

International audience; The success of the first meiotic division relies (among other factors) on the formation of bivalents between homologous chromosomes, the monopolar orientation of the sister kinetochores at metaphase I and the maintenance of centromeric cohesion until the onset of anaphase II. The meiotic cohesin subunit, Rec8 has been reported to be one of the key players in these processes, but its precise role in kinetochore orientation is still under debate. By contrast, much less is known about the other non-SMC cohesin subunit, Scc3. We report the identification and the characterisation of AtSCC3, the sole Arabidopsis homologue of Scc3. The detection of AtSCC3 in mitotic cells, the embryo lethality of a null allele Atscc3-2, and the mitotic defects of the weak allele Atscc3-1 suggest that AtSCC3 is required for mitosis. AtSCC3 was also detected in meiotic nuclei as early as interphase, and bound to the chromosome axis from early leptotene through to anaphase I. We show here that both AtREC8 and AtSCC3 are necessary not only to maintain centromere cohesion at anaphase I, but also for the monopolar orientation of the kinetochores during the first meiotic division. We also found that AtREC8 is involved in chromosome axis formation in an AtSPO11-1-independent manner. Finally, we provide evidence for a role of AtSPO11-1 in the stability of the cohesin complex.