Abstract
This study investigates the environmental regulation of sex expression and seed yield stability in four Thai dioecious hemp (Cannabis sativa L.) cultivars (RPF1, RPF2, RPF3, and RPF4) under different seasonal conditions to optimize seed production. The experiment was conducted across two planting periods (in-season and off-season) to evaluate the effects of varying day lengths and temperatures on growth, reproductive development, and yield. The results showed that shorter day lengths and lower temperatures during the off-season led to an increased proportion of female plants across all cultivars, except RPF3, which exhibited a stable female-to-male ratio. RPF4 had the highest increase in female plants (16%), followed by RPF1 and RPF2 (10%). Seed yield was significantly influenced by seasonal changes, with RPF3 and RPF4 consistently outperforming the other cultivars. In the in-season, RPF3 and RPF4 produced the highest seed yields, reaching 83.4 g/plant and 81.6 g/plant, respectively. During the off-season, both cultivars experienced a decline in seed yield (by 24–26%), primarily due to a reduction in seed production in secondary inflorescences. However, RPF3 compensated for this loss with a 31% increase in seed production at main inflorescences, ensuring yield stability. RPF4 maintained its high yield potential by increasing the proportion of female plants, offsetting the decline in seed yield per plant. Additionally, cumulative growing degree days (CGDD) at harvest were comparable between seasons, with values of 2434 °Cd (in-season) and 2502 °Cd (off-season), indicating that temperature accumulation remained within an optimal range for seed maturation. The study highlights the importance of cultivar selection based on yield component stability and adaptability to seasonal variations. These findings provide valuable insights for improving hemp seed production strategies in Thailand’s diverse agro-climatic conditions.
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Claims 13
Claim · model-written summary
Off-season conditions raised female plant proportion in RPF1, RPF2 and RPF4.
- Taxon
- Cannabis sativa L.
Cannabis sativae1 - Treatment
- shorter day lengths and lower temperatures during the off-seasone0
- Outcome
- proportion of female plantse0
- Direction
- increasede0
- Qualifier
- except RPF3e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shorter day lengths and lower temperatures during the off-season led to an increased proportion of female plants across all cultivars, except RPF3”
e1“hemp (Cannabis sativa L.) cultivars”
Claim · model-written summary
RPF3 retained a stable female-to-male ratio.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Material
- RPF3e0
- Outcome
- stable female-to-male ratioe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RPF3, which exhibited a stable female-to-male ratio”
e1“hemp (Cannabis sativa L.) cultivars”
Claim · model-written summary
RPF4 showed a 16% increase in female plants.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Material
- RPF4e0
- Treatment
- off-seasone2
- Outcome
- female plantse0
- Direction
- increasee0
- Value
- 16%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RPF4 had the highest increase in female plants (16%)”
e1“hemp (Cannabis sativa L.) cultivars”
e2“during the off-season”
Claim · model-written summary
RPF1 and RPF2 each showed a 10% increase in female plants.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Material
- RPF1 and RPF2e0
- Treatment
- off-seasone2
- Outcome
- female plantse3
- Direction
- increasee3
- Value
- 10%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“followed by RPF1 and RPF2 (10%)”
e1“hemp (Cannabis sativa L.) cultivars”
e2“during the off-season”
e3“increase in female plants”
Claim · model-written summary
Seasonal changes significantly influenced seed yield.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Treatment
- seasonal changese0
- Outcome
- Seed yielde0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seed yield was significantly influenced by seasonal changes”
e1“hemp (Cannabis sativa L.) cultivars”
Claim · model-written summary
RPF3 yielded 83.4 g/plant in season.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Material
- RPF3e0
- Outcome
- seed yieldse0
- Direction
- higheste0
- Value
- 83.4 g/plante0
- Qualifier
- in-seasone2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RPF3 and RPF4 produced the highest seed yields, reaching 83.4 g/plant and 81.6 g/plant, respectively”
e1“hemp (Cannabis sativa L.) cultivars”
e2“In the in-season”
Claim · model-written summary
RPF4 yielded 81.6 g/plant in season.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Material
- RPF4e0
- Outcome
- seed yieldse0
- Direction
- higheste0
- Value
- 81.6 g/plante0
- Qualifier
- in-seasone2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RPF3 and RPF4 produced the highest seed yields, reaching 83.4 g/plant and 81.6 g/plant, respectively”
e1“hemp (Cannabis sativa L.) cultivars”
e2“In the in-season”
Claim · model-written summary
Secondary inflorescence seed production was reduced off season.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Treatment
- off-seasone2
- Outcome
- seed production in secondary inflorescencese0
- Direction
- reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reduction in seed production in secondary inflorescences”
e1“hemp (Cannabis sativa L.) cultivars”
e2“During the off-season”
Claim · model-written summary
RPF3 main inflorescence seed production increased 31%.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Material
- RPF3e0
- Treatment
- off-seasone2
- Outcome
- seed production at main inflorescencese0
- Direction
- increasee0
- Value
- 31%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RPF3 compensated for this loss with a 31% increase in seed production at main inflorescences”
e1“hemp (Cannabis sativa L.) cultivars”
e2“During the off-season”
Claim · model-written summary
RPF4 offset per-plant yield decline by increasing female plant proportion.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Material
- RPF4e0
- Outcome
- high yield potentiale0
- Qualifier
- increasing the proportion of female plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RPF4 maintained its high yield potential by increasing the proportion of female plants, offsetting the decline in seed yield per plant”
e1“hemp (Cannabis sativa L.) cultivars”
Claim · model-written summary
In-season CGDD at harvest was 2434 °Cd.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Outcome
- cumulative growing degree days (CGDD) at harveste2
- Value
- 2434 °Cde0
- Qualifier
- in-seasone0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“2434 °Cd (in-season)”
e1“hemp (Cannabis sativa L.) cultivars”
e2“cumulative growing degree days (CGDD) at harvest”
Claim · model-written summary
Off-season CGDD at harvest was 2502 °Cd.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Outcome
- cumulative growing degree days (CGDD) at harveste2
- Value
- 2502 °Cde0
- Qualifier
- off-seasone0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“2502 °Cd (off-season)”
e1“hemp (Cannabis sativa L.) cultivars”
e2“cumulative growing degree days (CGDD) at harvest”
Claim · model-written summary
Authors recommend cultivar selection based on yield component stability and seasonal adaptability.
- Taxon
- Cannabis sativa L.Cannabis sativae1
- Outcome
- cultivar selection based on yield component stability and adaptability to seasonal variationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“importance of cultivar selection based on yield component stability and adaptability to seasonal variations”
e1“hemp (Cannabis sativa L.) cultivars”