الفهرس 
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Abstract
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VI. S-.t0-0-4.A--R-YTomato
leaf curl is one ot tne most serious diseases
whioh greatly reduce tne ’tomato yield in Egypt. This work
is an attempt to study the inheritance ot resistance to
tbis disease. Tbree wild types ; ~. pimpinellifoliull,!!. b.1rsutUDl
and~. peruvlanum were included in crosses with tb.e eult1-
vated speoies t ~. esculentum. The genetic behaviour of plant
reaction to une viral agent was followed during tbe genera- -
tiona of parents, F1 and F2• Tbe inberitance of some quality
cnaracters and shedding was also ·studied.
The obtained resultS-OKD be-Bammarized as tollows :
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1. Only the followicg two crosses were successful : -L.eseu
len”tum variety PritonaL”Cl X~. EiIIlpinellifollp. U 121
and -L. esculentum variety Pritcb.ard X -L. birsutUil.
2. Pritohard variety sllowed ,to be susceptible while tbe
line belonging to ~. J3i!Jinell1folium LA.121 abowed also
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to be susceptible and tbe )11 plants ·ob’taloed fro.
the cross ~. ,sculentua Yarie1i7 Prltcbard X ~p!aPiDell
1tolium LA 121 did not show resistanoe’. ’.rue 1’2
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plants of tb.is cross bad segregated into 13 aUBcep”tible
to , res istan1i. Tb.is result may ,1Ddicate ttle presence
of two gene pairs one of tbem when domiDBnt t inbL,bi’ts
the effect of the dominant gene postulated for resistance.
So t the genetic constitution of these two parents was
postulated as follows : -rr1-1 for Pritchard aDd-UI-I :tor
Pimpine 11tic lium.
r
3. Plants of t he line belongiog to !- birsutalll had segregated
according to tb.e ratio 1 susceptible : 1resis1ian’t. ~h1s .
meanstbat gene(s) for resistance Qan not be found 1n
boaozygous state_ The results of tbe Pl obtained frolIl
the oross -L. esculentum variety Pritchard :I-L. hirsutulIl
gave segregation fi’t1;log the ratio 1 resis’tant : 1 susceptible
and in tbe P2 generation t he following three classes.
were obtained : 1 Beverly infeoted : 1 wl1ih mild ID.fea1ilon:’
, 1 s~tOlllesS. This queer .result was explalD&d b7 assumlag ,
a le1;bal gene closely liDkBd witt>. tt;le doalDaD’t geDe for
resistance. SOt ’thegeae1;ic CODS 11;u1;100 o~ 1;b.e two pareo’ts
was postulated as 1011oW8: -rl rL
1r tor Pritchard aDd
’-Rl 1.. for Hirsu’t •••
l’.L 1
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b. !BB!£1~~e~!_2!_!~!!_!£~!~-g~~~!~_~a~!~~!£!_!The inberitanoe of some fruit quality onaracters and
slledding was studied in tb.e oross betwe&D!!. esculentum variety
Pritchard and~. pimpinellUollum LA121; tlle obtained results
can be summarized as tollows :
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1. Prul’t length, diameter, size , 1I81gb:t and nwaber of 100ales
per fruit were inherited as quanti’tatlve c naracters and
showed partial or absence of dominance with alight teDdsDOy
toward tne lower parent. The natura ot gene act10n tor
these characters was cU1ll11atlve except in the case of
Dumberof locales per fruit where the gene aotion was
addltivg. However these cbaraoters see. to be oontrolled
by a low number ot genes. ~he aattaatea ot hetierosls
oo.pared with Ilid-par&nt and bettier parenti we” negative
and signifioant. High bari1iabl11ty values _re eattaated
tor these characters, augesting ’the possibility of
improving them. b,. selection.
2. Vitamin C oontent aDd 1;081 acidi’ty were lDurl1;ed also
as quaDtitatl” oharact;ea aDdsbowing the preseD08
of partial dominance. These cb.araoters seem to be
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controlled by 1-2 pair of genes for vitamin a and ,-4
pairs for aoidity. Tl1ese genes teDd to work e.dditively.
Positive-negative aDd signifioant values of heterosis for·
vitamin C and positive-negative insignificant values for
aoidity were obtained. Heritability estimate for ’lit_in
C and acidity were moderat, suggesting possibility of
increasing vitamin C oontent by seleotioD..
3. Total soluble solids was 1nberited as a quantitative
cbaracter and sbowed t be presenoe of over dominance.
Tbe nature of gene aot1o~ was additive. Heterosis .•.aloes
was positive and signifioant. Bigb beritabili~7 value
was obtained, suggestiog possibility of increasing total
soluble solids by selection.
4. Tbis study abo_ad partial doainan08 of the le88 sbedding
parentis, aDd tbiS oharaot:er .••••• to be OODt.roUe4 witb.
one to ’two pairs ot senese Sisni!loaDt beterosis was fOUDd
tor sbedding aDd be.r1;tabUlt7 Talae was mocUrat lDdt.oatiD8
tbe possibiliq ot etteatm •• 1801;100.
c. Q2rre11!-t129§tgd1e! :
1. Bighl7 significant aDdpositive phenotypio oorrelation 1I’&S
found between fruit length and each of fruit dl_e’t8r .
aDd size as we1.1as between fruit size aDd eaob. of tbe
cbaracters truit di_etar aDdweigb’t, in Pl, P2 aDd :r1
individuals and ’2population.
2. ~bera was bigbly signUicant positive partial oor.relatloD
be’tween fruit length aDd size 10 botb parents aDd1’2 popu1ation
wbile insignifioant value was obtained wltben the
,. Bigbly 81gD.l~loaDt arad positive oorrelatio”D v810 •• were
toaM between ~ru.lt dl.eter aDdtruit size wi:tbla ’tbe
P1,P2 aDd )11 individuals and 1’2 popula’tioa. • 81al1uo Nsalts
were also obtained b1’caloQlatlDg tb.8 partial oo.rralatloD.
4. !he .regression coerti01eDts wre high bet_eD fruit lepgth
aDd size, aDd be.•••een frat:t 81ze aDd _ish1i 11l P1,P2 aDd.
”1 lDdlvidl1als and 1’2 popal.~:tl0D.
5. ”.gatin-pGs ltive lns1ga1110....e correlation we” tOUM
betweeD sbeddlng aDd _.-11 ot ~rult 81. aDd-lsbt aa4
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positive correlation between fruit weigb.1;and shedding
was found.
6. Negative significant and insignificant correlati~on values
were found between vitemill 0 cOlltent and eacb of to1ial
acidity and fruit weight in P1,P2 and 1’1 individuals
and F
2
generation, except the positive and losignificant
correlation between vitamin C content and total ac 1d1t:1.
{ in P2 plants and J”2 generation. ’!be oorrelation between
vitamin C content aod total soluble solids were positive
and significant in pareats and the partial oorrelat:loo
between tbem was positive aDd significant io parents and
lr
l
individuals. Alsopositive and significant. partial
correlation was found between fruit weight aDd’total
soluble solids in 1’1 individuals suggesting ttle possibility
ot selection tor cbemical content.
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