الفهرس 
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Abstract
Four Egyptian varieties of cowpea seeds, Vigna unguiculata (L.) namely:
Cream 7, Kaha 1, Dokki 331 and Kafr El-Shekh 1 were used in the present
investigation to test their relation (to cowpea weevil, Callosobruchus
maculatus, a major pest of stored pulses. The whole seed from each variety
was examined and several physical (phenotypic) characteristics were
measured. Seeds from each variety were analyzed to characterize some of
its nutritional and non-nutritional chemical contents and their correlation to
the seed resistance. A bioassay using natural seeds was performed, and
results have demonstrated that seeds expressed varied degrees of
resistance, and the physicochemical properties of cowpea seeds did not
seem to exert an overriding influence on pest susceptibility but may
influence the oviposition behavior of C. maculatus females. When C.
maculatus was provided with these cowpea varieties, the number of eggs
per seed, the weight loss of seed, the developmental time and the
percentage adults emerging were differed with seed variety. Clearly the
differences between varieties were significant biologically as well as
statistically and seeds of Cream 7 variety was found to be the highly
susceptible (which referred to as susceptible variety) and Kafr El-Sheikh 1
the least susceptible (which referred to as resistant variety). Subsequently,
these two varieties were selected for the purpose of studying the chemical
bases of resistance. Larvae developing within the grain do the largest
damage of stored seeds. By investigation of the feeding patterns of bruchid
larvae living and growing within cowpea seeds, it was observed that larvae
have feeding patterns in resistant seeds which are varied compared to
susceptible ones. Larvae feeding in resistant seeds did not penetrate deeply
into the seed cotyledons as those feeding on susceptible seeds. Results
presented evidence that an interior zone in resistant seeds, in each
cotyledon adjacent to the air space separating the two seed halves, is
responsible for the high mortality and developmental delays experienced
by bruchid larvae. It appears that the resistance factor is most concentrated
in such zone. In order to study the biochemical basis of cowpea resistance
to C. maculatus, Seed proteins were analyzed qualitatively and
quantitatively to study the chemical basis of resistance to bruchid
infestation. Higher amounts of proteins (albumins and globulins) were
found in susceptible seeds. Seven protein bands found in resistant seeds
and not visualized in the susceptible ones, which could be correlated with
the resistance. Variant vicilins (storage globulins) were found in resistant
seeds and were found to react with the polyclonal antibody used. These
proteins were found in internal organs such as midgut, Malpighian tubules,
fat body and haemolymph of larval C. maculatus and were considered as
the main resistance factor. It has been suggested that the toxic properties of
vicilins may be related to their recognition and interaction with
glycoproteins and other membrane constituents along the digestive tract of
the insect. Histological and histochemical characteristics of C. maculatus
as affected by feeding upon the resistant seeds of V. unguiculata. The
rearing of larvae on the resistant seeds resulted in several histopathological
lesions in the larval tissue including all their internal organs and systems.
The major histopathological lesions which could be recorded were:
Cyplasmic vacuolation, nuclear pyknosis, apical degeneration of epithelia,
disruption of junctional complexes, rupture and finally necrosis. The
histochemical studies confirmed the recorded histopathological lesions at
the sub-cellular level as follows:
1-The total carbohydrate content of larval tissue exhibited a marked
decrease which recorded a statistically significant value.
2-The total protein content of the cells of the variant larvae exhibited also a
marked decrease confirmed by the image analysis by a non- significant
value.
3-The total DNA content of the cells of the variant larvae in its turn
exhibited an obvious decrease. This decrease was statistically nonsignificant.