الفهرس 
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Abstract
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SUMLlARY
The findings obtained in the pr8sent investigation
can be summarized as follows:
1- A survey o~ the stalk-rot diseases of grain
sorghum revealed the occuren~e of these diseases in most
of the sorghum-growing areas of the country. The incidence
of stalk-rots, in fields selected at random in the visited
Governorates, ranged from 0 to 20% with an average of
about 9%.
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2- Three conditions of the stalk-rot complex were
observed. Of these, Cephalosporium wilt disease caused
by Cephalosporium acremoniwn was the most prevalent.
Charcoal stalk-rot due to Macrophomina plmseolina WaS
sometimes observed. A third wet stalk-rot condition, frequently
encountered, was apparently a modified form of the
wilt disease due to infection by secondary invadors •
.3- Different local, commercial and exotic cultivars
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of grain sorghum were tested against- infection with stalk-
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rots in naturally intestedfield at Shandawell. It was
found that cultivarsG) and NESI007 were highly susceptible
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to infection, whereas, G54, L 31/62, L 109/67, L 132/67,
L 162/67, NES 635, NES 786, Gl14 and hybrid 113 were
hig~ly resistant.
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4- The pathoeenic1ty t~sts, were artificially confirmed
using both the soil-infestation and the stalk-inoculation
techniques, showed that Q.acremon1um was highly pathogenic
producing typical wilt symptoms on grain sorghum plants.
Macrophomina phaseo1ina was found to be pathogenic producing
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charcoal stalk-rot symptoms. Fusarium Doniliforme was shown
to cause severe root and foot-rot in plants.
5- Studying pathogenic variation in five Q.acremonium
isolates demonstrated that all tested isolates were pathoeenic
and produced premature Withering of plants. Fayoum isolate
was the most Virulent one, whereas Beni-Suef isolate was the
least pathogenic one.
6- Cross inoculation of’C.acremonium isolates whether
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obtained from maize or from sorghum were more virulent to
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the sorghum varieties than to Q8ize varieties. It was found
that all the funeal isolates which were isolated from grain
sorghum were able to infect maize PUults producing typical
,
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signs of tlaclc- bundIe. Likewis e, the grain sorc;hum cultivaxs
were shown to be affected with fungal isolates
which ’:Jere isolated- from maize, where plant a shoned the
wilt symptoms. HO”Jever, no speciali:::~D.tion in pathoeenicity
was found in Q.acremonium isolat.es obtained neither fror.l
maize hor from sorghum.
7- The resu.lts of varietal resistance to Q.acremo.uiwJ1
showed that infection % by soil-infestation method rax\:::eu
frOill 10 to 80 ?~ between thi2 tested cnltJ.’1:.irs. The local
variety 31/62, J.J 109/61 and L 132/67 were hiGhly reDhltonL J
whereas, local 102/67, L 129/67 and G3 VJCl’C highly sU8ceptible
varieties.
Toot hpick-inocl.11a tion technique J on the other hellO.,
showed that culi;~;-”e’l:’s NES 1818, nES 1324 and UES 635 we.re
hi~~ly resistant to infection a~d L 102/67, L 129/67,
!~brid 113, hyb~id,119, L 2S/62,.;G123, L 109/67, L 162/67.
)rES 786 wer e hiChly auacep t LbLe to in:r(~(~tion.
8- Stutlyinc lTe1ation of :,lant nee to infection with
-C.a--cr~noniu.m•.....-. revcnld that infection increasod with the
increase of plant age 1.U1t 11 t he th:LX’d \”:eek o\: sowinc·
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9- Root injury appeared to faci litata Lnf’ec t ion, in
par t Ic uIur at t he late stages of p’ln nt gro’.’Jth.
10- Infection percentage. increased with the tncr ee se
of -C. -a-c-r-e-moniurn inocu.lum level t ill it l’ eUcIH” 1 t:18 :naxirnw.l •...
when 100 gm Lnocu’Lum per Ho.25 pot were user] and tlten dec-
Itned VJi th the inc rease of LnocuLum pot ent :ia 1..
11- Using the sen!’ pLat e modificatiou of carnbr’ i.dGe
Iilethod, it has b ee n shown that £.~E~19n5.l!!11has n moder.ate
degr ee of comp eta t tv e sn.prophytic aldlity.
by soil mieroorganis!il!’;.
13- Ro inhititory effect of culture filt~0t0
acrem9.!!i.~ to the tested fungi was f’ound , ’FW1’SBS the
nafllely; Bacill .•’U..! id.uhtli s, StaJl~.l2.s.occus. ~qureus and
14- C.~~~~BS not active to secr~te pectolytic
enzyI,le s ,
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15- -C.ac.remoniwn was able to hydrolyze otnrch and
to Crow on wediurn contuining starch as D. sole source of
carbon.
Follmving 1~e1son’ s method (1944) for estimating
redl”l.cins sugar s , it could be able to find a relation
between the variation of pathoeenic:tty of Q.acFemonium
and efficjYfloy in starch hydrolysis. It has been shown
that Fayoum isolate (the most pathoeenic isolate) g£\ve
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thu hiehest results followed by Giza isolate.
16- On f’i It er paper t Q.acremoniur.l showed hieh c ellulose
decomposine ability.
Colorimetric <letermination of cellulose decomposition
as reducing sw~ars revealed that Fayama isolnte
was rather active cellulose decomposer and Beni-Suef
Lso Lat e was rather P90r in this respect.
17- Colonization of buried, sorghum stalk pieces
apparently increased with the increase in the amount of
inoculum in the inoculum-&oil mixtures. A decrease in
the colonization with the increase of incubation time
WU:3 noticed.
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18- The effeet of two soil factors on the survival
of Q.f!.cremOnilUTI in d ecornpos ing Lnf’ec t ed sorghum stalk
pieces was studied: ;:
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(i) Temperature: Decomposition was $lower at 20°C than
at 30 and 35°0. Survival of the fitngus was greatest
at 3D and 35°C than at 20°0.
(ii) Moisture: Under four soil moisture levels; air dry,
36.J50 and 100% saturation, it was found that decomposition
of infected sorghlli~stalk pieces waS generally faster than
that of healthy stalk pieces. Decompos LtLon was greatest
at 50% saturation. Q.acremonium survived most effectively
in stalk pieces buried in soil containing 30 and 50% water
saturation in which the fungus showed increasing act ivi ty
after two. montbs and then this activity decLtne d gradually
up to 4 months. However, in air dry soil and at 100% ,
water saturation activity decline4., rather sharpl¥ • -’
19- On stalk inoculation with Q.acremoni~t deterrnination
of sugar content revealed a remarkable decrease in
total and non-reducing sugars due to infection. A
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notico.able increase in the percentage of reducing sugars
occur ed in the inoculated stalks with the increase of time
from 15 to 45 daY:s ~f ino~ulation.
” 20- Protein cont ent was higher in inoculat ed stalks
than that of uninoculated one~.
21- The rate of amino acids was higher in the case
of inoculated stalks with .C-..acremonium than that of
’.!uninoculated ones. Total and free amino acids increased
as a result of infection after 15 days to reach the maximum
at JO days then decreased slightly after 45 days
from inoculation.
22- Total phenol contents increased in inoculated
stalks compared with uninoculated ones. Amounts of free
phenols were markedly high in the inocnlat ed stalks
than those of uninoculated ones. conjugated phenols were ,
high in uninoculated stalks tnan those of inoculated stalks
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particularly in the later stages of disease development.
23- Orthodihydroxyphenol contents were higher in
inoculated stalks compared with uninoculated ones.
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24- A noticQ.able increase in titratable acidity in
tissues infected with C~acremonium was observed. This
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was mar e clear at 15 days after inoculation.
25- The amount of total soluble solids (r.s.s.)
increased in stalks inoculated with Q.~~~c=r~em~o_na_fit_eurm~
15 days of incubation followed by considerable decline.
but amount s of T.S.S. were still higher than those in
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uninoculntes stalks.
26- Inoculation of grain sorghum stalks with g.
acremonium caused an 0 bvious decrease in chlo:r.phylls a
and b as well as the carotenoids content of leaves developed
from infected plants.
27- StudyinB the activity of oxidative enzymes in
tissue extracts revealed that infection ,nth -C.acremonium
increased the activity of phenoloxidase, peroxidase •
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catalase and ascorbic acid oxidase.
28- Infection with stalk-rots caused a considerable
r~uction in the weight or kernels (about 50% reduction)
on the basia of dry weit;ht. However, the bulk and true
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densities were higher in kernels of infected plante than
in those of healthy ones.
29- Infection with stalk-rot s caus ad increase in
kernel endosperm and reduction in germ Qnd pericarp if
compared with those of kernels obtained from healthy
plants.
30- A positive corxelation between moistl~e, ash
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and suear contents in whole kernel was observed. Infection
decreased all these cant ent s to a level lower than
that in kernels of healthy plants.
,31- Protein cOlltent was generally higher in whole
kernel, endosperm and germ of grain of infected plants
than that of grain ot non-infected plants. However, ’
results in case of pericarp fluctuated.
,32- Study or protein fractio,ns in seeds of both
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healthy and infected plants with stalkrots exhibited that
kaferin fraction was generally higher in whole kernel of
infected plants than that in kernel of healthy ones on
contrast with glutelin fraction. The albumins and globulins
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were lower in the kernels of infected plants than in those
of Wl-infected pl~nt·s. The insoluble proteins were always
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higher in kernels of infect’ed plants then those of healthy
ones. ,.
JJ- Both of Lysine and Tryptophane were lower in whole
kernels of infected plants than those in kernels of uninfected
one s ,
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in their
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Determination of crude fats revealed a decrease
contents in grains of infected plants comparable
to fat contents in healthy plant seeds.
35- Determination of minerals content showed an
obvious increase in lis, K, Ca, I~ and Fe contents, on
contrast with Zn and Cu in kernel flour due to infection.
No difference was founl in Mana.gane•.s. e cent e.nt of kernel
flour of healthy and infected plants.
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