Boron seed treatments induce germination and seedling growth by reducing seed-borne pathogens in safflower (Carthamus tinctorius L.)

Abstract

The objective of this study was to determine the effects of seed treatments with boron on germination, seedling growth, and disinfection of seed-borne pathogens in safflower. Safflower seeds of the Balci cultivar were treated with solutions of 0, 5, 10, and 20 ppm boron for 6 hours or surface treated with powdery sodium borate (Na2B8O13.4H2O). The experiment was a completely randomized design with eight replications and 25 seeds per replicate. Treated or untreated seeds were germinated between papers and germination characteristics, emergence, seedling growth, and infected seed rate were investigated. The results showed that the peak germination percentage (96.5%) was achieved in seeds primed with 5 ppm B. The mean germination time was significantly reduced, and the germination index reached the maximum value (23.5) in seeds primed with 5 ppm boron. Emergence percentage improved from 76.5% in the control to 87.5% in the seed dressing. The root and shoot length of the primed seeds increased fourfold. Seedling fresh weight was positively affected by the boron treatments, and seeds primed with 20 ppm boron produced the heaviest fresh seedlings. All boron treatments significantly reduced the infection rate by about 73%, but the lowest infection rate (11.5%) was observed in seeds primed with 5 ppm boron. It was concluded that safflower seeds should be primed with 5-10 ppm boron or at least undergo seed dressing with boron to reduce the negative effects of seed-borne pathogens and promote germination and seedling growth.