Effect of Foliar spraying with Yeast Extract and Hydrogen Peroxide on Yield and Quality of Sweet Potato

The present investigation was carried out during the two summer seasons of 2015 and 2016 at sharnoob vilage,Damanhur city, Behera governorate, Egypt, to study the effect of foliar application of yeast extract , hydrogen peroxide(H2O2) and combination of them on growth, yield and quality of sweet potato tuberous roots, using two sweet potatocultivars, Abees and Mabrouka. Generally, the results indicated that Abees cv. recorded maximum values of number ofshoots/ plant in the second season, plant length in the first season , foliage fresh weigh/ plant, total sugar %, reducingsugar %, carotene %, dry matter % and starch% contents of roots. Results showed also that spraying of yeast extract gavethe highest means values for all studied traits of vegetative characters of two cultivars; in both seasons. Moreover,spraying of yeast extract gave the highest significant means values for total yield of roots/plant, weight of marketableroots/plant, number of marketable roots/plant, total sugar %, reducing sugar %, carotene %,dry matter of roots % andstarch% contents in roots compared with other treatments in both seasons. The treatment combination of growing Abeescultivar and yeast extract recorded the highest mean values of the most studied characters compared with other treatments.