الفهرس 
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Abstract
SUMMARY
EVALUATION OF SOME AGRONOMIC CHARACTERS RELATED TO GROWTH AND YIELD OF CASSAVA
Manihot esculenta, (Crantz)
By
Mohamed Abdel Badea Helal El-Fieshawy
Cassava has many uses and represents about 14 to 56% of the total caloric intake in 14 countries. The starch rich tuberous roots of cassava are a traditional staple which is widely used in livestock and poultry
feed.
The introduction of cassava in Egypt will help in solving the cronic problems of livestock and poultry
feeding shortage.
The study was planned aiming at:
I-Evaluation of 12 varieties introduced by means of tissue culture technique.
II-Examining the possibility of the introduction of
cassava in Egypt as a new tuber crop which might
promote the expansion of desert land reclamation
by conducting a trial to study the yield responses
to cultural treatments.
III-Investigating the utilization of cassava tubers in human nutrition.
IV-Investigating the utilization of tubers, leaves and stems in livestock feeding.
To achieve these aims four groups of experi-ments were carried out. The summary of these experiments is given here.
I- Evaluation of 12 cassava varieties:
Fifty cassava varieties produced by tissue culture
were obtained from the International Plant Research Institute, San Carlos, California. from these, only twelve varieties were well adapted. Cuttings were obtained from 12 months old plants and were planted on ridges- Ten plants were grown for each variety at the Vegetable Research Institute, Agricultural Research
Center, Cairo.
Data on growth and yield characters at 8 months age were recorded. HCN content in fresh leaves and tubers were also determined. Simple correlations and
path coefficients were calculated.
The obtained results could be summarized as follows:
1. The tested varieties differed greatly in plant
height. Four varieties were tall, six medium and
two short. Branching levels ranged from zero to 3.
Three varieties were with no branching levels,
whereas the short varieties produced 2 or 3 levels.
Number of initial branches/plant showed great variation. Seven varieties beared one initial branch, four have two and one variety has 3 branches.
2.Number of leaves/plant varied from 105 to 565. Leaf area ranged from 147 cm2 to 467 cm2. Petiole length varied from 21 to 46 cm and petiole colour ranged from green, light green, green reddish to rose.
3.Tuber length ranged between 12 and 45 cm, tuber dia-meter between 2.5 and 6 cm, and number of marketable tubers/plant varied from zero to 11. Tuber colour ranged from white cream to dark brown.
4.Yield of leaves varied from 21.6 t/fad. for variety 10 to less than 5 t/fad for varieties 2, 3 and 4. Tuber yield/plant reached a maximum of 4.4 Kg for variety 12 and 4.2 Kg for variety 7. Inferior tuber yield of less than one Kg/ plant awes obtained with
varieties 1, 3, 4 and 5.
Varieties 7, 10 and 12 were the three leading varieties with an average of about 19 t /fad, and are
therefore recommended for further investigation.
5.Root to top ratio ranged from 0.015 in variety b to 1.11 in variety 10 showing a great variation.
64 HON content in tubers varied from 106 ppm in variety 8 to 218 ppm in variety 7. All tested varieties are
included in the poisonous category with a HON content of more than 100 ppm. It is disappoint-ing to see that 2 out of the 3 outstanding varieties (7 and 12) are grouped as highly
poisonous tubers.
HON in leaves showed considerable variation, ranging from 143 to 514 ppm. The three outstand-ing varieties (7, 10 and 12) contained high HON
content.
7. The correlation coefficients among the studied
varieties showed that plant height was negatively
and significantly correlated with branching levels,
number of branches, number of leaves, tuber length
and tuber diameter. Positive correlation
coefficients were found between plant height and
tuber yield, leaves yield, and root to top ratio.
Branching levels showed positive correlation with number of branches, and number of leaves.
Negative and significant correlation coefficients were recorded between branching levels and petiole
length and leaf area.
Number of initial branches was positively and
significantly correlated with leaves yield, and leaf area, and negatively correlated with tuber yield, tuber length and tuber diameter.