Narrow Leaflet Index

Narrow Leaflet Index (NLI) refers to cannabis plants expressing characteristically thin, elongated leaflets—a measurable morphological trait often associated with sativa-type genetics and certain equatorial landrace populations. This phenotypic marker reflects the ratio of leaflet length to width and is commonly documented in breeding records and germplasm catalogs. Breeders tracking NLI observe variation across hybrid lines; some modern cultivars trend toward wider leaflets (indica-type), while others retain narrow proportions from heritage sativa parentage. The trait has no inherent correlation with cannabinoid or terpene profiles, though certain breeding programs have maintained narrow-leaflet plants as visual markers of specific lineage backgrounds. Understanding leaflet morphology helps geneticists map parentage and regional adaptation patterns in historical and contemporary breedin

Breeders use narrow leaflet index as a phenotypic descriptor for strain documentation and pedigree tracking. The trait serves as a visual reference point when maintaining or crossing lines derived from sativa-dominant or equatorial genetic backgrounds.