The effect of iron and zinc fertiliser dosage on yellow rust in durum wheat (Triticum durum L.)

This study aimed to assess the impact of dosage of iron (Fe) and zinc (Zn) on the incidence and severity of yellow rust (Puccinia striiformis f. sp. tritici) in durum wheat (Triticum durum), utilizing vegetation indices derived from multispectral data for precise analysis. For this purpose, freshly collected yellow rust spores were homogenized in volatile minerals and applied to all durum test materials (K & imath;z & imath;ltan 91, Eminbey, Mirzabey 2000, & Ccedil;e & scedil;it-1252) under artificial epidemic conditions in two periods, heading (Zadoks 45) and flowering (Zadoks 50), one week apart. In addition, each of the blocks, which were arranged in three replicates and four durum wheat cultivars, received different doses of iron (Fe), zinc (Zn) and Fe + Zn. Mineral fertilizers were applied in six phenological periods (Zadoks13-Zadoks21, Zadoks 22-Zadoks37 and Zadoks41-Zadoks49) starting from the tillering period (Zadoks 13-21). The effects of mineral fertilizer applications on the disease were evaluated by converting the reflectance values obtained from multispectral data into vegetation index values for each phenological period. Iron (Fe) applications used for durum cultivars decreased disease severity in the early period (Zadoks 13-21) but increased it in the late period (Zadoks 41-49). Zinc (Zn) applications reduced disease severity in early and late phenological growth periods. Iron (Fe) + Zinc (Zn) applications reduced disease severity in all phenological periods. The vegetation indices for monitoring disease severity were LCCI, SIPI, PSRI, NDVI, NBNDVI, MSR, GNDVI, NLI, and YRI (Table 1). These indices were used for disease detection for all phenological periods. Iron, zinc and iron+zinc applications resulted in a decreasing disease severity reflected in the GNDVI and LCCI indices in the early-mid period (Zadoks17), and in the NBNDVI and LCCI indices for all other durum varieties.