Two field experiments were carried out in summer seasons of 2003 and 2004
at the Experimental Farm of Faculty of Agriculture. Suez Canal University. Ismailia
Governorate to study the effect of spraying potato plants with different concentrations
of vitamins B, (thiamin) and C (L.ascorbic acid) on growth parameters, yield and its
contents and chemical composition of potato under sandy soil conditions.
Results indicated that plant height was significantly increased with the
concentrations of 100 and 200 ppm of vito B, and 100 of viI. C. however the other
concentrations of the two vitamins decreased it compared with the control. Spraying
plants with each of vito 8, or vit. C increased number of stems I plant. The increments
were only significant among control and 200 ppmof each vitamin. Number of leaves
numberl plant. average leaf area and Iota I dry weight was increased with increasing
vitamins concentrations. Vitamin 8, seemed to be more effective than vitamin C on
Ihe previous growth parameters. Relative growth rate (RGR). crop growth rate (CGR).
specific leaf weight (SLW), speciflc leaf area (SlA), leaf weight ratio (lWR) and net
assimilation rate (NAR). all these parameters significantly increased in sprayed plants
with each vit. B, or viI. C over the control. The increments were corresponded with the
increase in vitamins concentration.
Number of tubers! plan! and tuber weight was significantly increased with
spraying plants with 200 and 300 ppm from each of vit. 8, and vit. C comparing with
conirot Tuber grading showed that spraying with vitamins signfican!ly increased the
weigh I of medium and large lubers and the total yield. Regarding U.S. grade one as
percentage of total yield. viI. B, at 300 ppm occupied the first rank in the two seasons
While control plants came in the last rank. The other treatments were in between
Tuber quality had been affected by vitamins spraying. dry matter per cent, starch
content as well as specific gravity were significantly increased in the tubers of the
treated plants. Moreover, nitrogen % in the tubers. phosphorus % and potassium %
were increased insignificantly with vitamins application.