Cajanus cajan
Enable an agent to identify Cajanus cajan, assess its growth and reproductive condition, and select evidence-based cultivation, conservation or harvest actions.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an agent to identify Cajanus cajan, assess its growth and reproductive condition, and select evidence-based cultivation, conservation or harvest actions.
Cajanus cajan, commonly called pigeon pea, is a woody perennial legume in the family Fabaceae, widely cultivated as an annual crop for its edible seeds and for forage, fuelwood and soil improvement.
It can be Identify and document a plant using linked vegetative and reproductive evidence.; Compare planting material and local growing conditions before scheduling establishment.; Track flowering and pod development to distinguish green-pod and dry-seed harvest opportunities.; Inspect roots and soil conditions when evaluating poor growth or nodulation.; Scout damaged plants and pods, then route unresolved causes for diagnosis.; Assess whether pruning, seed retention or stand replacement fits the plant's observed condition..
Distinguishing features
Check for an erect, branching shrub with woody stem development; ordinary climbing pea or bean habit does not match.
Check for alternate, trifoliate leaves with elongated, hairy leaflets and paler undersides; this combination differs from the tendrilled leaves of garden pea and the many small leaflets of chickpea.
Inspect reproductive material for yellow pea-type flowers and hairy, elongated pods containing multiple seeds; neither flower colour nor seed colour alone confirms identity.
Use the combined habit, leaf, flower and pod characters as an identification screen, supported by [NParks](https://www.nparks.gov.sg/florafaunaweb/flora/6/9/6971); distinguish close Cajanus relatives or suspected hybrids through an appropriate taxonomic key or verified accession record.
Scope
+ Species identification using vegetative and reproductive characters
+ Cultivar or accession relationships and planting-material provenance
+ Establishment, growth, flowering, pod development and regeneration
+ Root-zone conditions, nodulation and responses to environmental stress
+ Plant health, reproductive damage and suitability for intended harvest
- Other Cajanus species and their independent biological models
- Cultivars as separately managed breeding or commercial entities
- Harvested grain lots, processed dal and food preparation
- Rhizobial organisms, insect pests and pathogens as independent things
- Farm enterprises, field management plans and agricultural machinery
Characteristics
- Identification confidence
- unresolved | provisional | confirmed, with evidence and identifier Common names and trifoliate leaves cannot independently establish species identity.
- Cultivar or accession
- Named cultivar, accession identifier or unknown Links observed performance to planting material without treating it as universal for the species.
- Growth habit
- Erectness, branching pattern and degree of basal woodiness Supports identification and assessment of harvest or pruning access.
- Plant height
- cm above soil surface, with age and observation date Makes growth and canopy comparisons interpretable.
- Reproductive stage
- Vegetative | budding | flowering | green pods | drying pods | mature seed; multiple stages allowed Determines relevant scouting and harvest decisions.
- Observed flowering time
- Days from sowing to a stated flowering criterion, with location and sowing date Supports local crop scheduling without imposing one maturity duration.
- Root-zone water condition
- Dry | moist and aerated | saturated | waterlogged, with method and duration Separates water shortage from poor drainage when assessing stress.
- Root nodulation
- Nodules per sampled plant, with root recovery method and internal appearance Documents the symbiosis while keeping nodule presence distinct from measured nitrogen fixation.
- Pod damage incidence
- % examined pods damaged, with sample size, stage and damage type Quantifies reproductive injury without presuming its cause.
- Regrowth after cutting
- Surviving plants (%) and new shoot count per plant at stated days after cutting Tests whether the observed material supports continued biomass production.
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 20 findings · 32 questions.
Pigeonpea identity Establish which organism the registry entry denotes and how observed material is identified.
A familiar crop name can conceal uncertain species identification or undocumented planting material.
Species boundary
Keep species identity separate from common names, cultivars and crop products.
Botanical name and common name
Pigeonpea is identified as Cajanus cajan (L.) Millsp. in the [USDA plant guide](https://plants.sc.egov.usda.gov/DocumentLibrary/plantguide/pdf/pg_caca27.pdf).
- Which taxonomic authority and record support the scientific name used for this material? provenance
- Does the supplied name denote the species, a cultivar, a living plant or a harvested product? boundary
Identification evidence
Connect identification decisions to observable plant characters.
Combined morphological check
Trifoliate foliage, erect shrub habit, yellow pea-type flowers and hairy pods provide a combined identification screen. [NParks](https://www.nparks.gov.sg/florafaunaweb/flora/6/9/6971)
- Which leaf, stem, flower and pod characters were observed on the same plant? measurement
- What evidence excludes locally occurring Cajanus relatives or suspected hybrids? boundary
Planting material and establishment Represent the origin and establishment performance of pigeonpea planting material.
A species label alone cannot explain differences in emergence, maturity or suitability for a planting window.
Accession context
Preserve the relationship between observed plants and their seed source.
Traceable seed origin
Record seed-source identity and cultivar claims as evidence-bearing relationships rather than inferred attributes.
- Which supplier, saved-seed population or accession produced these plants? provenance
- Which evidence supports the claimed cultivar identity and seed-generation history? provenance
Seedling establishment
Assess emergence and early competition under the actual sowing conditions.
Emergence and early competition
Early establishment can be slow, making weed competition relevant. [USDA plant guide](https://plants.sc.egov.usda.gov/DocumentLibrary/plantguide/pdf/pg_caca27.pdf)
- What proportion of sown seeds emerged, and over how many days under the recorded soil conditions? measurement
- Does stand inspection support weed control, further observation or re-establishment? action
Flowering and seed production Track reproductive timing and the provenance of retained seed.
Harvest scheduling and seed maintenance require more than a generic annual crop calendar.
Reproductive timing
Interpret flowering and maturity against planting material and environment.
Conditional flowering calendar
Maturity varies with planting material, temperature and photoperiod; a single species-wide flowering deadline is inappropriate. [USDA plant guide](https://plants.sc.egov.usda.gov/DocumentLibrary/plantguide/pdf/pg_caca27.pdf)
- When were first flowering, the specified population flowering threshold and mature pods observed? measurement
- Which local trials support the expected flowering response of this accession at this sowing date? provenance
Retained seed integrity
Assess whether seed collected from the stand can support its intended identity claim.
Crossing context
Cross-pollination can occur, so retained seed should not automatically inherit a parental cultivar identity claim. [USDA plant guide](https://plants.sc.egov.usda.gov/DocumentLibrary/plantguide/pdf/pg_caca27.pdf)
- Which other pigeonpea accessions flowered nearby during the seed-parent flowering period? provenance
- What isolation, controlled pollination or progeny verification supports retaining this seed for the intended purpose? action
Roots, water and nodulation Connect below-ground condition to growth and possible management responses.
Drought tolerance and legume status do not establish adequate water supply or effective nitrogen fixation in an observed plant.
Root-zone suitability
Distinguish moisture stress from limitations imposed by drainage or rooting depth.
Drought and drainage
Pigeonpea has a deep taproot and drought tolerance, but prolonged drought can reduce production and waterlogging is unsuitable. [USDA plant guide](https://plants.sc.egov.usda.gov/DocumentLibrary/plantguide/pdf/pg_caca27.pdf)
- What rootable depth, compaction and duration of soil saturation were observed? measurement
- Does the evidence support irrigation, drainage improvement or a different planting location? action
Symbiotic nitrogen context
Keep observed nodulation distinct from quantified nitrogen contribution.
Nodules and fixation evidence
Root nodulation is documented for pigeonpea; the model requires separate evidence for any nitrogen-fixation estimate. [USDA plant guide](https://plants.sc.egov.usda.gov/DocumentLibrary/plantguide/pdf/pg_caca27.pdf)
- What nodule abundance and internal appearance occur on a representative root sample? measurement
- Which measurement method and biomass accounting support a claimed nitrogen contribution? provenance
Health and harvest decisions Evaluate plant injury, harvest stage and the consequences of biomass removal.
Grain, green-pod and biomass objectives require different observations and actions on the same species.
Damage and diagnosis
Record symptoms and reproductive damage before assigning causes.
Pod injury and wilt
Pod-feeding insects and Fusarium wilt are documented concerns; observed injury still requires case-specific diagnosis. [USDA plant guide](https://plants.sc.egov.usda.gov/DocumentLibrary/plantguide/pdf/pg_caca27.pdf)
- What proportions of plants show wilt and sampled pods show feeding injury? measurement
- Which specimen, field signs or diagnostic result support the proposed causal organism? provenance
- What locally supported response follows from the confirmed cause and observed severity? action
Harvest and continuation
Relate removal of pods or biomass to intended use and subsequent plant performance.
Harvest endpoint
Pigeonpea can supply green vegetable seed, dry pulse or forage; record the intended endpoint before assessing harvest readiness. [USDA plant guide](https://plants.sc.egov.usda.gov/DocumentLibrary/plantguide/pdf/pg_caca27.pdf)
- Is the intended output green pods, dry seed, planting seed or vegetative biomass? definition
- Which maturity observations justify harvest for that output? action
Post-cutting viability
Treat post-cutting survival and regeneration as observed outcomes, with cutting history attached.
- What cutting height, removed biomass and interval since the previous cut were recorded? measurement
- Does subsequent survival and shoot growth justify retaining, resting or replacing these plants? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This describes the plant species, not solely the harvested pulse or a particular cultivar.
- Height and maturity categories vary substantially with cultivar, environment and management.
- Cultivar registration, seed certification and phytosanitary requirements need jurisdiction-specific checking.
- Which of these check these first hold for the sense of Cajanus cajan this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Early-maturing cultivars
- Medium-duration cultivars
- Late-maturing cultivars
- Determinate growth forms
- Indeterminate growth forms
- Which of these kinds and varieties hold for the sense of Cajanus cajan this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Botanical nomenclature - Cajanus cajan (L.) Millsp. - Species name with author citation; pigeon pea is the common English name.
- Which of these identifiers and schemes hold for the sense of Cajanus cajan this model covers, and on what evidence? provenance
Standards and regulation
Recalled without web access and unsourced; every item is a lead to verify.
- The International Code of Nomenclature for algae, fungi, and plants governs botanical naming; revisions are adopted through International Botanical Congresses.
- Which of these standards and regulation hold for the sense of Cajanus cajan this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Dry seeds are cooked whole or split into dhal.
- Immature seeds and pods are consumed as vegetables.
- Leaves and crop residues provide livestock forage.
- Woody stems supply household fuel.
- Intercropping, hedgerows and green manure exploit its biomass production and symbiotic nitrogen fixation.
- Which of these real-world use hold for the sense of Cajanus cajan this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Plant height - Approximately 1-4 - m
- Which of these typical measurements hold for the sense of Cajanus cajan this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Fusarium wilt can kill plants and reduce yield.
- Sterility mosaic disease can prevent normal flowering and seed production.
- Pod-boring insects damage developing seeds.
- Waterlogging impairs roots and can cause severe crop losses.
- Drought during flowering or pod filling can reduce yield despite the crop's relative drought tolerance.
- Which of these failure modes and hazards hold for the sense of Cajanus cajan this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- In South Asia, dry split pigeon peas are widely used as toor or arhar dal.
- In parts of the Caribbean, pigeon peas are commonly eaten green or dried in rice dishes.
- Cultivar duration and flowering response vary with latitude, day length and local cropping systems.
- Which of these regional variation hold for the sense of Cajanus cajan this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Cicer arietinum - Chickpea is a separate species and genus, typically a smaller annual herb with inflated pods and distinctly beaked seeds.
- Vigna unguiculata - Cowpea is a separate species and genus, generally herbaceous rather than a woody shrub, with typically longer pods.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of Cajanus cajan this model covers, and on what evidence? provenance
What the second pass must settle
- Which current taxonomic treatment and diagnostic key best separate Cajanus cajan from relevant wild relatives and hybrids in the target region?
- Which accession-specific trials establish flowering response, maturity duration and yield for the intended latitude and sowing window?
- Which locally validated root-zone and nodulation measurements justify irrigation, inoculation or nutrient interventions?
- Which locally confirmed pests and pathogens warrant monitoring, and what evidence-based intervention thresholds apply?
- What harvest criteria, seed-isolation requirements and cutting regimes are validated for the intended cultivar and use?