YIELD ESTIMATE USING SPECTRAL INDICES IN EGGPLANT AND BELL PEPPER GROWN UNDER DEFICIT IRRIGATION

The objective of this research was to estimate eggplant (Solanurn melongena cv. "Aydin Siyahi') and bell pepper (Capsicum annuum L. "California Wonder") yield using spectral indices. The experiments were conducted in the growing season of 2011 in Canakkale, Turkey. The following eight spectral indices were used (1) Simple Ratio Index (SR), (2) Normalized Difference Vegetation Index (NDVI), (3) Green Normalized Difference Vegetation Index (GNDVI), (4) Water Band Index (WBI), (5) Photochemical Reflectance Index (PRI), (6) Wide Dynamic Range Vegetation Index (WDRVI), (7) Enhanced Vegetation Indices (EVI) and (8) Red Edge Normalized Difference Vegetation Index (RENDVI). In addition to these indices the six following spectral bands were also used; (1) R-645, (2) R-663, (3) R-970, (4) R-940, (5) R-970/940 and (6) R-940/970. Four irrigation levels, including 0% (SO, non-irrigated), 33% (S33), 66% (S66) and 100% (S100, control) of field capacity were applied throughout three growth stages (vegetative (V), flowering (F) and fruit growth (FG)). Regression models were obtained between spectral indices and yield of both plants. The correlation coefficients (r) were between 0.921 and 0.997 for eggplant and between 0.857 and 0.900 for bell pepper at different growth stages. The research results showed that spectral indices and bands have a good potential to estimate the yield of eggplant and pepper plants.