Abstract:
A study was conducted during the spring seasons of 2001 and 2002 years
on potato tubers ( Solanum tuberosum L.) Desiree cv. (class-A). Potato seeds
were planted on Jan. 16 and 17 for the two seasons respectively .
The experiment included 21 treatments resulted from three times of
terminating irrigation which they were 12, 8 and 4 days before the date of lifting
tubers, beside seven vines desiccation methods: 8 days by hand, 8 days by
gramoxone, 4 days by hand, 4 days by gramoxone, 2 days by hand, 2 days by
gramoxone and by hand directly before tubers lifting as (control). Quantitative
characteristics were recorded after lifting tubers.
No significant effects of the times of terminating irrigation was detected
on each of the:- number of tubers / plant, individual plants yield, marketable
yield and total yield for both seasons, whereas terminating irrigation 8 days
before lifting potato tubers significantly reduced the percentage of skinning
tubers to 54.76%. However, terminating irrigation 4 days before tuber lifting
significantly increased this percentage to 66.07% for the first season.
As far as vines desiccation is concerned the results indicated that hand
cutting 4 days before tubers lifting caused a significant increased in the average
number of tubers/plant to 10.43, plant yield to 0.66 kg/plant, marketable yield to
7.58 ton/donum and the total yield to 8.28 ton/donum in a comparison with the
gramoxone desiccation 8 days before tuber lifting which resulted in a
significant decreased in the number of tubers/plant to 8.20, plant yield to 0.50
kg/plant, marketable yield to 5.74 ton/donum and the total yield to 6.25
ton/donum in the first season.
In the second season, on the other hand , cutting method of vines directly
before tuber lifting time significantly increased the plant yield to 1.25 kg/plant,
marketable yield to 14.77 ton/donum and total yield to 15.62 ton/donum. In the
contrast, the gramoxone killing method of vine 4 days before tubers lifting
significantly reduced the plant yield to 1.05 km/plant, marketable yield to 11.93
ton/donum and total yield to 13.17 ton/donum. It is important to say that the
vines cutting by hand 8 days before tubers lifting time, significantly decreased
the percentage of skinned tubers to 29.96% as compared with the hand vine
cutting 2 days before lifting time which was significantly increased this
percentage to 53.25%
