Abstract
Hot weather can substantially reduce pod production by cowpea [ Vigna unguiculata (L.) Walp.]. The objectives were to characterize and classify cowpea based on their responses to heat during reproductive development. Diverse cowpea accessions were grown over six summers in Imperial Valley, CA under hot temperatures (mean daily max/min 41/24 °C) and long days (14 h, 51 min decreasing to 12 h, 18 min). Selected genotypes were grown at Riverside, CA, under more optimal temperatures (35/17 °C) and the same daylengths. At Imperial Valley, genotypic variation was observed for duration to first macroscopic floral bud and extent of floral bud abortion, peduncle elongation, flower production, and podding. At Riverside, similar genotypic variation occurred for days to first floral bud, but subsequent reproductive development was normal. Controlled environment studies in growth chambers showed that the detrimental effects induced in sensitive genotypes by high temperature were enhanced by long photoperiods. Based on these differing reproductive responses, the accessions were classified into eight groups. Heat‐tolerant accessions in Group I exhibited normal peduncle elongation, early flowering, and produced many flowers and pods. Accessions in Groups II and III performed similarly but set few pods (Group II) or no pods (Group III). Accessions in Groups IV through VII differed in duration to first floral bud, with Group VII being the latest and exhibiting substantial bud abortion, suppressed peduncle elongation, and no flowers. Group VIII accessions produced no visible floral buds. Cowpea developed in different regions and for specific seasons within a region fell into discrete classification groups, indicating that the system has a genetic and ecological basis. This classification system is useful for characterizing the types of heat responses present in cowpea genotypes and for selecting appropriate combinations of parents for breeding heat‐tolerant cultivars for different production zones and seasons.
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Claims 13
Claim · model-written summary
At Imperial Valley, cowpea genotypes varied in timing of first floral bud and floral bud abortion.
- Taxon
- cowpea
Vigna unguiculatat0 - Outcome
- duration to first macroscopic floral bud and extent of floral bud abortione0
- Setting
- Imperial Valleye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At Imperial Valley, genotypic variation was observed for duration to first macroscopic floral bud and extent of floral bud abortion”
t0“Cowpea”
Claim · model-written summary
At Imperial Valley, genotypes varied in peduncle elongation, flower production, and podding.
- Taxon
- cowpeaVigna unguiculatat0
- Outcome
- peduncle elongation, flower production, and poddinge0
- Setting
- Imperial Valleye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At Imperial Valley, genotypic variation was observed for duration to first macroscopic floral bud and extent of floral bud abortion, peduncle elongation, flower production, and podding”
t0“Cowpea”
Claim · model-written summary
At Riverside, genotypes varied in days to first floral bud.
- Taxon
- cowpeaVigna unguiculatat0
- Outcome
- days to first floral bude0
- Setting
- Riversidee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At Riverside, similar genotypic variation occurred for days to first floral bud”
t0“Cowpea”
Claim · model-written summary
Subsequent reproductive development at Riverside was normal.
- Taxon
- cowpeaVigna unguiculatat0
- Outcome
- subsequent reproductive development was normale0
- Setting
- Riversidee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At Riverside, similar genotypic variation occurred for days to first floral bud, but subsequent reproductive development was normal”
t0“Genotypic Variation and Classification of Cowpea for Reproductive Responses to High Temperature under Long Photoperiods”
Claim · model-written summary
Long photoperiods enhanced high temperature damage in sensitive genotypes.
- Taxon
- cowpeaVigna unguiculatat0
- Treatment
- long photoperiodse0
- Outcome
- detrimental effects induced in sensitive genotypes by high temperaturee0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the detrimental effects induced in sensitive genotypes by high temperature were enhanced by long photoperiods”
t0“Cowpea”
Claim · model-written summary
The accessions were classified into eight reproductive-response groups.
- Taxon
- cowpeaVigna unguiculatat0
- Outcome
- classified into eight groupse0
- Value
- eight groupse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the accessions were classified into eight groups”
t0“Cowpea”
Claim · model-written summary
Group I accessions had normal peduncle elongation, flowered early, and made many flowers and pods.
- Taxon
- cowpeaVigna unguiculatat0
- Material
- Group Ie0
- Outcome
- normal peduncle elongation, early flowering, and produced many flowers and podse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Heat‐tolerant accessions in Group I exhibited normal peduncle elongation, early flowering, and produced many flowers and pods”
t0“Cowpea”
Claim · model-written summary
Group II accessions set few pods.
- Taxon
- cowpeaVigna unguiculatat0
- Material
- Group IIe0
- Outcome
- few podse0
- Direction
- fewe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“set few pods (Group II)”
t0“Cowpea”
Claim · model-written summary
Group III accessions set no pods.
- Taxon
- cowpeaVigna unguiculatat0
- Material
- Group IIIe0
- Outcome
- no podse0
- Direction
- noe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no pods (Group III)”
t0“Cowpea”
Claim · model-written summary
Group VII was latest to form first buds, with substantial abortion, suppressed peduncle elongation and no flowers.
- Taxon
- cowpeaVigna unguiculatat0
- Material
- Group VIIe0
- Outcome
- substantial bud abortion, suppressed peduncle elongation, and no flowerse0
- Direction
- suppressede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Group VII being the latest and exhibiting substantial bud abortion, suppressed peduncle elongation, and no flowers”
t0“Cowpea”
Claim · model-written summary
Group VIII accessions formed no visible floral buds.
- Taxon
- cowpeaVigna unguiculatat0
- Material
- Group VIIIe0
- Outcome
- no visible floral budse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Group VIII accessions produced no visible floral buds”
t0“Cowpea”
Claim · model-written summary
Regional and seasonal origins fell into discrete reproductive classes.
- Taxon
- CowpeaVigna unguiculatae0
- Outcome
- discrete classification groupse0
- Setting
- different regionse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cowpea developed in different regions and for specific seasons within a region fell into discrete classification groups”
Claim · model-written summary
The authors consider the classification useful for characterizing heat responses and selecting breeding parents.
- Taxon
- cowpeaVigna unguiculatae0
- Outcome
- selecting appropriate combinations of parents for breeding heat‐tolerant cultivarse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This classification system is useful for characterizing the types of heat responses present in cowpea genotypes and for selecting appropriate combinations of parents for breeding heat‐tolerant cultivars”