Search

Pod shatter susceptibility was investigated in Brassica napus germplasm and shatter resistant species of B. juncea and Sinapis alba. The comparisons were made by measuring seed yield in field plots, detached pod rupture energy (RE) and the half-life of pod-opening. Pod shatter resistance was significantly greater in B. napus lines derived from interspecific hybridizations of B. napus with B. rapa, B. carinata and B. juncea, than common B. napus cultivars. While these lines exhibited no significant difference in resistance to pod shatter than B. juncea, an entry of S. alba had no yield loss caused by pod shatter. Resistance to pod shatter was characterized in the field as little or no yield loss after full maturity, delayed shattering in time, and stable yield performance under variable climatic conditions during pod maturity. Yield loss caused by pod shatter ranged from a low of 4% for the B. juncea cv. ‘AC Vulcan’ to a high of 61% for the black seeded B. napus line DH12075 in 2-year field trials after 1 month maturity. Pod shatter resistance was not significantly associated with specific plant and pod morphological traits, except pod length (P = 0.005) in tested materials. Field visual scores of pod shatter through inspections of average pod shatter per plant within plots were highly correlated with plot yield loss. Indoor quantitative evaluations of pod strength using a pendulum machine to measure pod RE and random impact test to measure half-life of pod-opening resistance were highly correlated with field yield loss. Multiple evaluations of pod shatter in method and in time after pod maturity are recommended for reliable evaluation of pod shatter resistance. [ABSTRACT FROM AUTHOR]

By intergeneric sexual hybridization between Sinapis alba and Brassica oleracea, F1, F2 and BC1 progeny plants were produced. S. alba plants (genome SS, 2n = 24) were pollinated with B. oleracea (genome CC, 2n = 18), and the fertile F1 plants were pollinated with B. oleracea to obtain BC1 plants. GISH analysis showed that 10 out of 12 F1 plants had 12 S. alba chromosomes (one full S chromosome set) and nine B. oleracea chromosomes (one C chromosome sets), representing the expected hybrids. However, two F1 plants had 12 S chromosomes and 18 C chromosomes (two C chromosome sets), indicating unexpected hybrids. A maximum of three trivalents between C and S chromosomes were identified at metaphase I of semi-fertile F1 pollen mother cells (PMCs), which indicates homology and chromosome pairing between these two genomes. The C genome had obviously been doubled in two F2 plants from selfed semi-fertile F1 plants. BC1 plants consisted of 18 C chromosomes and different numbers of one, five and six additional S chromosomes, respectively. Monosomic alien addition lines developed in the present study can be used for B. oleracea breeding and Sinapis alba gene mapping. [ABSTRACT FROM AUTHOR]

Increasing protein content is an important objective in breeding high protein oilseed yellow mustard ( Sinapis alba L). The objectives of this research were to increase meal protein content, study population variation during three cycles of selection for increased meal protein content, and quantify the relationships of protein with oil and 1000-seed weight. Recurrent selection was employed with half-sib family evaluation in replicated field trials. Meal protein content increased by an average of 1% per cycle. The correlation between meal protein and seed oil content was negative ( r = −0.49 to −0.58). The population shifts, with selection, reflected successful increase of average meal protein content, and an increased frequency of genotypes with high meal protein content. Furthermore, simultaneous selection for meal protein and seed oil content was possible. The correlation between meal protein content and seed weight was positive ( r = 0.29–0.39) and thus selecting for increased meal protein content posed no risk of decreasing seed weight in this yellow mustard germplasm. [ABSTRACT FROM AUTHOR]

Somatic hybrids between Sinapis alba (2n = 24) and Brassica oleracea (2n = 18) have been backcrossed with the B. oleracea parent. Whereas backcrosses with the diploid B. oleracea parent were unsuccessful, 344 BC1 seeds could be obtained from inter-valence crosses with tetraploid B. oleracea (2n = 4x = 36). The investigated 96 BC1 plants segregated for morphological traits and for fertility. They were backcrossed with diploid B. oleracea or self-pollinated, depending on their male fertility. The BC1F2 and BC2 progenies segregated well for the morphological traits. Disturbances were observed especially in the generative phase (flower development and pollen fertility). Both male fertile and male sterile BC1F2 and BC2 plants were obtained and backcrossed or self-pollinated with the B. oleracea parent. The presence of either one of the parental or the cybrid organelle genomes was detected. In the progenies, a stable maternal inheritance of the organelle genome patterns was observed. Isozyme analyses revealed polymorphism for the leucine aminopeptidase (LAP) which was used for the identification of S. alba genes in the progenies. Cytological investigations showed a clear differentiation between the BC1F2 and BC2 plants. Whereas the BC1F2 plants possess large numbers of chromosomes ranging from 34 to 40, the BC2 material was strongly reduced to chromosome numbers ranging from 20 to 22. Preliminary investigation of the meiosis suggests the possibility of introgressions of S. alba-DNA into the B. oleracea genome. [ABSTRACT FROM AUTHOR]

Somatic hybrids of Sinapis alba + Brassica juncea (Sal Sal AABB) were synthesized by protoplast electrofusion. They were true genomic allopolyploids since they possessed 60 chromosomes, i.e. the sum of S. alba (2n = 24) and B. juncea (2n = 36) chromosomes. Chromosome pairing was predominantly bivalent with the occasional occurrence of multivalents in the pollen mother cells at diakinesis and metaphase I. Hybrids were completely pollen-sterile, but produced seeds on backcrossing with B. juncea and B. campestris. A total of 37 BC1 plants were raised from two somatic hybrids (JS-1 and JS-2) and 24 of these were analysed cytologically. The 22 plants originating from the pollinations of somatic hybrids with B. juncea showed a chromosome configuration of 18II+12I and had 42-86% pollen fertility. Two plants from the backcrosses of the somatic hybrid with B. campestris formed 10II + 20I, and had 0-4% fertile pollen. Total DNA analysis by probing with pTA71 carrying a full-length 18S-25S rDNA fragment of the wheat nuclear genome revealed that the two somatic hybrids possessed all the characteristic bands of both the species, confirming their hybridity. Probing with the mitochondrial coxI and atp9 genes indicated mitochondrial genome recombination in the hybrids. Hybridization with chloroplast-specific psbD indicated that both the somatic hybrids possessed the cp genome of S. alba origin. [ABSTRACT FROM AUTHOR]

The method of in-vitro fertilization of ovules can be successfully applied to various species of Brassitcaceae. Mature embryos and plants were obtained after in-vitro pollinating the ovules of Arabis caucasica, Brassica napus, B. oleracea var. sabellica (kale), B. oleracea var. italica (broccoli), Diplotaxis tenuifolia, Moricandia arvensis and Sisymbrium Loeselli. In the case of Sinapis alba fertilization and embryo development did not occur. The same method has been successfully used for obtaining hybrid immature embryos at different stages of development from crosses between B. napus × D. tenuifolia, B. napus × M. arvensis, B. oleracea var. italica × D. tenuifolia, D. tenuifolia × B. napus, D. tenuifolia × M. arvensis and D. tenuifolia × S. Loeselli. The present findings show that in-vitro pollination of ovules of various species of Brassicaceae makes it possible to (a) perform the whole process of fertilization and embryogenesis; and (b) obtain intergeneric hybrid embryos. [ABSTRACT FROM AUTHOR]