Effect of hot-water and cold treatments on reducing contamination in almond tissue culture

Abstract: In this study, hot-water and cold treatments were used for eradication of explant contamination, and also the effect of plant growth regulators on shoot proliferation was evaluated. The explants were nodal segments of a late flowering almond cultivar 'Sharood 7'. Experiments were carried out in a complete randomized design with 25 replications. All hot-water treatments eliminated fungal contamination. The best hot-water treatment was 50?C in which 88% of explants were both free of contamination and necrosis followed by 76% at 47.5?C and 56% at 45?C. The best proliferation rate obtained in 1.5 mg L^-1 BA in combination with 0.1 mg L^-1 IBA (5.25 shoots per explant) which was significantly higher than 1 mg L^-1 (2.65 shoots per explant). Cold treatments only (2 and 4 days in 4?C) delayed fungal contaminations for 7 days, so it was impossible to assess bacterial contamination.