Hermaphroditism in Marijuana (Cannabis sativa L.) Inflorescences – Impact on Floral Morphology, Seed Formation, Progeny Sex Ratios, and Genetic Variation
Notice bibliographique
Résumé
Cannabis sativa L. (hemp, marijuana) produces male and female inflorescences on different plants (dioecious). In commercial production, marijuana plants are all genetically female and male plants are undesired. On occasion, spontaneously occurring hermaphroditic inflorescences, which are pistillate flowers accompanied by spontaneous production of anthers, can lead to undesired seed formation. We studied hermaphroditism in marijuana strains with the objective of describing the morphological features of this unique phenotype. We also hypothesized that hermaphroditism would impact progeny sex ratios and affect genetic diversity. Anthers were collected from hermaphroditic inflorescences that were observed in three commercial female strains (genotypes). The morphological features, pollen production and germination were compared to staminate inflorescences on male plants using light and scanning electron microscopy. Seeds from hermaphroditic plants were harvested, germinated and seedlings were tested for gender using a PCR-based assay. The genetic variation among seedlings derived from hermaphroditic seeds was also compared to that derived from cross-fertilized seeds using six ISSR primers. Nei’s index of gene diversity and Shannon’s Information index were calculated for hermaphroditic and cross-fertilized populations. The morphology of anthers in hermaphroditic inflorescences was found to be similar to that in staminate flowers. In PCR assays, female and male seedlings both produced a 540 bp size fragment, while a 390 bp band was present only in male plants. Seedlings from hermaphroditic seeds, as well as anther tissues, were all observed to have the female banding pattern. In comparison, seedlings derived from cross-fertilized seeds yielded a male:female expression ratio of approximately 1:1 in two different strains of marijuana. The percentage of polymorphic loci ranged from 44% to 72% in hermaphroditic and cross-fertilized populations. Nei’s index of gene diversity and Shannon’s Information index were similar for both populations. Uniquely, hermaphroditic inflorescences produce seeds which give rise only to genetically female plants. The extent of genetic variation after one generation of selfing was similar to that among progeny from cross-fertilized seeds. The presence of Copia-like retrotransposons within the C. sativa genome was established through sequence comparisons of the 540 bp fragment. Their functions or association with the expression of male or female phenotype requires further study.
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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 | 0,001 | 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 ».