Abstract
Willd.) is increasingly cultivated in marginal environments; however, early-season frosts pose a major constraint to successful stand establishment. Despite evidence of genotypic variation in cold tolerance, the effects of short, occasional frost events occurring at specific germination stages remain poorly understood. We evaluated the impact of single, occasional frost events (0, -2, and -4 °C) applied during distinct germination phases: Phase I (imbibition, 4 h), Phase II (absorption, 2 h), and Phase III (radicle protrusion, 6 h), in two Chilean quinoa cultivars (Roja and Amarilla). Across four replicates (50 seeds per cultivar per treatment), we quantified germination percentage and rate, imbibition rate, osmotic potential (Φ), and proline content under controlled conditions. The main results were: Frost exposure during Phases I and II markedly reduced final germination, frequently causing reductions greater than 70% relative to the control, with the strongest inhibition observed at -4 °C during Phase I. In contrast, when frost was applied during Phase III, germination was less affected and generally remained above 50%, indicating clear phase-dependent tolerance. Frost conditions reduced imbibition rate and induced a more negative osmotic potential, accompanied by increased proline accumulation, particularly at -4 °C during Phases II and III. Amarilla showed higher germination than Roja when frost was applied during Phase III, revealing cultivar-specific responses. These findings demonstrate that the first hours following sowing constitute a critical sensitivity window to occasional frost in quinoa. Phase-specific physiological responses, including osmotic adjustment, appear to play a protective role under freezing stress. The observed cultivar differences highlight exploitable genetic variation and provide valuable information for improving sowing management and breeding strategies under increasing climatic variability.
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Claims 7
Claim · model-written summary
Frost in phases I and II reduced final germination, often by over 70% against control.
- Taxon
- quinoa (Chenopodium quinoa Willd.)
Chenopodium quinoat0 - Treatment
- Frost exposure during Phases I and IIe0
- Outcome
- final germinatione0
- Direction
- reducede0
- Value
- greater than 70%e0
- Comparator
- the controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“quinoa (Chenopodium quinoa Willd.)”
e0“Frost exposure during Phases I and II markedly reduced final germination, frequently causing reductions greater than 70% relative to the control”
Claim · model-written summary
The strongest germination inhibition occurred at -4 °C in phase I.
- Taxon
- quinoa (Chenopodium quinoa Willd.)Chenopodium quinoat0
- Treatment
- -4 °C during Phase Ie0
- Outcome
- inhibitione0
- Direction
- strongeste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“quinoa (Chenopodium quinoa Willd.)”
e0“the strongest inhibition observed at -4 °C during Phase I”
Claim · model-written summary
Phase III frost affected germination less, leaving it generally above 50%.
- Taxon
- quinoa (Chenopodium quinoa Willd.)Chenopodium quinoat0
- Treatment
- frost was applied during Phase IIIe0
- Outcome
- germinatione0
- Direction
- less affectede0
- Value
- above 50%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“quinoa (Chenopodium quinoa Willd.)”
e0“when frost was applied during Phase III, germination was less affected and generally remained above 50%”
Claim · model-written summary
Frost reduced imbibition rate.
- Taxon
- quinoa (Chenopodium quinoa Willd.)Chenopodium quinoat0
- Treatment
- Frost conditionse0
- Outcome
- imbibition ratee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“quinoa (Chenopodium quinoa Willd.)”
e0“Frost conditions reduced imbibition rate”
Claim · model-written summary
Frost made osmotic potential more negative.
- Taxon
- quinoa (Chenopodium quinoa Willd.)Chenopodium quinoat0
- Treatment
- Frost conditionse0
- Outcome
- osmotic potentiale0
- Direction
- more negativee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“quinoa (Chenopodium quinoa Willd.)”
e0“Frost conditions reduced imbibition rate and induced a more negative osmotic potential”
Claim · model-written summary
Frost increased proline accumulation, particularly at -4 °C in phases II and III.
- Taxon
- quinoa (Chenopodium quinoa Willd.)Chenopodium quinoat0
- Treatment
- Frost conditionse1
- Outcome
- proline accumulatione0
- Direction
- increasede0
- Qualifier
- particularly at -4 °C during Phases II and IIIe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“quinoa (Chenopodium quinoa Willd.)”
e0“increased proline accumulation, particularly at -4 °C during Phases II and III”
e1“Frost conditions reduced imbibition rate and induced a more negative osmotic potential”
Claim · model-written summary
Amarilla germinated more than Roja under phase III frost.
- Taxon
- quinoa (Chenopodium quinoa Willd.)Chenopodium quinoat0
- Material
- Amarillae0
- Treatment
- frost was applied during Phase IIIe0
- Outcome
- germinatione0
- Direction
- highere0
- Comparator
- Rojae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“quinoa (Chenopodium quinoa Willd.)”
e0“Amarilla showed higher germination than Roja when frost was applied during Phase III”
The same questions in other papers
cold · growth · Chenopodium quinoa (quinoa)Positive and negative results
1 in the opposite direction
- negative
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.