Effect of Hhydrogen Peroxide Foliar Spraying on Tuber's Quality of Three Potato Cultivars

Two field experiments concerning potato (Solanum tuberosum L.) crop werecarried out during two successive winter seasons of 2009/2010 and 2010/2011 in a private farm ata newly reclaimed area, in El-Amria region, Alexandria governorate, Egypt. The experiment wasperformed to study the effect of hydrogen peroxide (H2O2) on the potato processing quality and theeconomical characters. The split-plot design in three replicates was used, where potato cultivarswere placed in the main plots, while doses of foliar spraying with hydrogen peroxide were occupiedthe sub-plots. Three potato cultivars were tested in this investigation; Lady Rossetta, Valor andMondial. Four doses of hydrogen peroxide were used as zero, 25, 50 and 75 mM in the first year.Two higher doses, 100 and 125 mM of hydrogen peroxide were added in the second year. Potatoplant stem diameter was positively affected with the increasing of H2O2 concentrations from zero up to 125 mM. The results showed that the 25, 50 and 75 mM of H2O2 concentrations did not affect thepotato tuber yield. The other two high levels (100 and 125 mM) of H2O2 resulted in lower potatoyields. The number of tubers/ 10 Kg weight trait seemed to be affected with H2O2 concentrations, inwhich it was above the accepted number during the second year (more than 112 tubers/10 Kgweight).In the first year, the data indicated that spraying potato plants with 75 or 50 mM of H2O2significantly increased dry matter percentage compared with the control treatment. Both treatmentsof 75 and 50 mM of H2O2, produced the highest levels of tuber starch content in the first year , whilethe treatment 75 mM of H2O2, produced the highly tuber starch content with significant differencesamong the other tested treatment in the second year of the study. The effect of hydrogen peroxideon parenchyma cell diameter trait differed from year to another. The treatment of 50 mM of H2O2possessed the highest value for parenchyma cell diameter trait, whereas, the treatments of both 25and 125 mM of H2O2 increased the parenchyma cell diameter trait. The lowest chipping defectswere produced when potato plants sprayed with 50 mM H2O2. The control treatment gave thelowest mean value (result) where this treatment produced highly significant level of tuber chippingdefects.