Improving Metribuzin Tolerance in Lentil (Lens culinaris)
Notice bibliographique
Résumé
Weeds are a major limitation to lentil (Lens culinaris Medik.) production worldwide with grain yield losses of up to 87% from weed competition. In broad-acre mechanized lentil production systems, weed control relies on herbicide application; however, limited options exist. This study identified, characterised and validated novel tolerance in lentil to the photosystem II (PSII) inhibitor herbicide, metribuzin. Field research involving variable sowing dates, induced shade treatments and metribuzin rate were conducted to understand soil and weather factors responsible for herbicide phytotoxicity in lentil. Analysis of soil and weather factors around the time of herbicide application to the cultivar PBA Flash suggested a combination of factors were involved. Heavy rainfall within 10 days of application, particularly on light textured soils or where soil moisture was low, was most strongly linked to plant damage. A higher level of selective tolerance to metribuzin than that currently present in commercial lentil cultivars is required. Two methods, germplasm screening using a hydroponic sand assay and field screening of a large mutated population of PBA Flash, were used to identify lines with improved tolerance to metribuzin compared to current cultivars. Dose response experiments found germplasm line SP1333 had GR50 (the rate required to reduce dry weight (DW) 50%) values up to four-fold that of PBA Flash. However, GR50 values were greater than 25-fold that of PBA Flash in mutant selections M009 and M043. A field study in Canada with 20 Canadian and Australian genotypes confirmed the improved tolerance level of the mutants. Dose response analysis of five PSII inhibiting herbicides and DNA sequencing of the psbA chloroplast gene was undertaken to quantify the spectrum and mechanism of herbicide tolerance in M009 and M043. Compared to PBA Flash, metribuzin tolerance was increased 33-fold in M043 and 10-fold in M009, but no additional tolerance to other herbicides. Nucleotide sequencing of the psbA gene of both mutants identified a substitution at position 751 compared to PBA Flash. The resulting deduced amino acid sequence indicated an Ala251Thr substitution as responsible for the metribuzin tolerance. The substitution is unique in mutagenised higher plants and is the first report of an induced psbA target site mutation in higher plants. Reciprocal F1, F2 and F3 populations developed from M009 and M043 with PBA Flash identified a maternal inheritance pattern, but with paternal leakage in approximately 20% of F1 phenotypes. Reciprocal BC1F2 and BC1F3 populations were developed to identify any fitness cost associated with the tolerance. Field experiments identified reductions in net assimilation rate, DW and grain yield (GY) in tolerant lines with a fitness cost of 20 to 40%. This finding is comparable with the fitness cost measured in triazine tolerant (TT) canola due to tolerance to the PSII inhibiting triazine herbicides. Agronomic field experiments over two years at contrasting sites in South Australia compared the plant growth and GY of M009 and M043 with PBA Flash and SP1333 to post-emergent metribuzin. Clear differences existed in the responses of M009 and M043 compared with PBA Flash and SP1333 to metribuzin rate across sites. This finding confirmed that the mutant genotypes have an agronomically useful level of tolerance to metribuzin in southern Australia. However, DW was generally reduced linearly with metribuzin rate in both M043 and M009 suggesting a level of herbicide sensitivity at higher rates on some soil types. All three lentil genotypes with improved metribuzin tolerance are in use as parents in Australian breeding programs. The higher level of tolerance and superior agronomic performance of M043 makes it the genotype of choice. Knowledge of the genetic controls of inheritance and associated fitness cost of the target site provided by this study will aid plant breeders in rapid and effective incorporation of the tolerance into agronomically accepted plant types. The potential of developing a metribuzin tolerant lentil industry in Australia, similar to that which has occurred in TT canola, now exists.
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 machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| 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 | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 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 source (Gemma direct ou Codex distillé), 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 ».