DOI: 10.12688/f1000research.189197.1 ISSN: 2046-1402

Maize Canopy Architecture and Chili Shade Tolerance in Tropical Intercropping Systems: A Systematic Review of Microclimate Modification, Genetic Adaptation, and Breeding Targets

Brayen Patandean, Maria Pascalia Kasih Bere Leki, Boby Yesprapto Pa, Novita Ndandarmana, Efrilian Abadi, Ramot Christian, Efer Simon Masela, Andrey Navaro, Abd Rahman Yusuf, May Munah Purba, Asha Aliya Ridwan, Rahmat Rivai Lubis
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Background Intercropping benefits are strongly context-dependent, shaped by physiological compatibility between component species rather than spatial arrangement alone. In maize-chili systems, this compatibility is governed by two historically separate literatures: maize canopy architecture, which determines shading, and chili shade tolerance, which determines companion-crop response. This review synthesizes both bodies of evidence within a single mechanistic framework linking canopy-driven light and microclimate modification to chili morphology, physiology, genetics, pest and disease dynamics, and postharvest quality. Methods Following PRISMA 2020 and ROSES guidance, we searched Scopus (maize block, n=692; chili block, n=60) and PubMed as a complementary source for molecular mechanisms (n=91), yielding 843 records (828 after deduplication). Screening followed a single documented pass against pre-defined criteria: 129 records were excluded at title/abstract screening, 24 were retained for contextual citation only, and 107 more were excluded at secondary screening, yielding a working corpus of 566 records. Findings were synthesized narratively (SWiM) across five thematic lenses. Results Maize canopy architecture is genetically characterized at the single-gene level ( lac1 , loci linked to lg1 ), but rarely designed for companion shading. Chili shade tolerance is strongly genotype-dependent, with up to 17-fold differences in capsaicinoid content among cultivars under identical shade. Direct evidence combining both commodities remains scarce, concentrated within one research cluster. Canopy-modified microclimate alters pest/disease dynamics asymmetrically (e.g., Pepper veinal mottle virus incidence fell from 75% to <17% under intercropping), while postharvest quality follows a shade-optimum curve rather than a linear response. Conclusions The maize canopy-architecture and chili shade-tolerance literatures are mechanistically convergent, sharing a common photoreceptor-mediated signaling pathway, yet remain rarely integrated experimentally. We define ideotype targets for both commodities and argue that intercropping-adapted breeding should treat genotype × genotype compatibility rather than independent single-species optimization as its primary selection unit, a reframing with direct implications for maize and chili breeding programmes targeting tropical intercropping systems.

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