Potential of the Brassica oleracea gene pool for the improvement of spring B. napus canola
Notice bibliographique
Résumé
Canola (Brassica napus L.) is an amphidiploid or allotetraploid (AACC, 2n = 4x = 38) crop plant and it is one of the most important oilseed crops in the world. The narrow genetic base of this crop, especially in its C genome, is not only a major impediment for its continued improvement but also for mapping and identification of all loci and alleles for a trait that could be found in the Brassica genomes. Currently, hybrid canola cultivars have taken the majority of market share in different countries including Canada. To increase the yield of hybrid canola, there is a need for increasing the level of heterosis or hybrid vigor in this type of cultivar for which presence of adequate genetic diversity in hybrid parental lines is needed. In this study, the value of the C genome of six B. oleracea L. (CC, 2n = 18) accessions belonging to four variants of this species, viz. vars. alboglabra, botrytis, capitata and italica, was investigated for broadening the genetic base of spring B. napus canola. Six B. napus canola inbred populations developed from six B. napus × B. oleracea interspecific crosses and two breeding methods (F2- and BC1-derived inbred lines) were used. Test hybrids were produced by crossing the inbred lines to the B. napus canola line and the inbred and test hybrid populations were evaluated in replicated field trials for different agronomic and seed quality traits including yield. Inbred lines were also analyzed by SSR and SNP markers to assess genetic diversity of the inbred populations and the effect of the C genome alleles in the inbred and hybrid populations as well as for QTL mapping of different traits. Analysis of the parents and the inbred populations using 95 SSR markers showed the existence of wide diversity among the B. oleracea accessions; several canola lines derived from the six crosses tended to group together with their B. oleracea parent demonstrating that the diversity of the B. oleracea gene pool can be exploited for broadening the genetic base of the C genome of B. napus canola. However, loss of some B. oleracea alleles occurred in the inbred populations during the development of these lines and this loss occurred to a greater extent in the F2-derived population as compared to the BC1-derived population, which might be due to a stronger selection by breeders for the two canola quality traits (zero erucic acid in seed oil and low glucosinolate in seed meal) in the F2-derived population. Evaluation of the inbred populations in 10 field trials showed that the population derived from the cross involving var. italica gave the greatest yield, while the population derived from the cross with var. botrytis had the highest seed oil content; this population also gave high seed yield. In regard to the performance of the test hybrids, population derived from the cross involving var. alboglabra gave the greatest mid-parent heterosis (MPH) (11.1 ± 2.2 S.E. %) while the population derived from the cross involving var. italica gave the lowest MPH (4.0 ± 2.2 S.E. %); however, individual test hybrid exhibiting upto 82.7% MPH was found in this population. Multivariate analysis showed that inbred lines or test hybrids with high seed yield and oil content, and earliness of flowering and maturity with longer grain-filling period can be obtained from this population. A genome-wide association study using the above-mentioned inbred populations and 3,131 SNP markers detected 18 QTLs for three agronomic and seed quality traits; this included the QTLs located on chromosome C2, C3, C5 and C6 affecting days to flowering, QTLs on C1, C3, C5, C7 and C8 affecting seed oil content and QTLs on C1, C2, C3, C5 and C6 affecting seed glucosinolate content. Novel QTLs and alleles, which have not been reported previously, were also identified in this study, e.g. the C5 QTL affecting days to flowering; in this case, the alternative allele was derived from B. oleracea var. capitata cv. Bindsachsener and this allele improved the earliness flowering. Thus, the results from this study provided substantial evidence that the B. oleracea gene pool can be used to broaden the genetic base of B. napus canola for the improvement of inbred and hybrid cultivars of this crop as well as for identification of novel QTLs and alleles for different traits.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».