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Abstract 1. ~e present investigations represent an attempt to study the genetic behaviour at the .reaction to Fusarium w:Ut. as well as some other qualitative and quantitative eharaoters in some Tomato orosses grO\Vnin the three suooess1ve years (1964,1965,1966). 2. The study was based on the data of’ F 1 , F 2 and Bel progenies of fourteen orosses including seven Varieties of tomatoes; Red Cherrr, San Marzano, Pearl Harbor, Ame.r1oan. Genome, Pearson 107 and Orange. 3. !Z!heinbentanoe of Fusarium wilt was studied in eight crosses 1coluding the resistant varieti.es Red Cherry. San Marzano and Amerioan. The F plants showed dom1nanoe at resis tanee in all orosses including tim variety AmeZ!ican. and dominanoe of susoeptibility in crosaes 1acluding the varieties Red Cherry and San Marzano. The F2 and Bel generations showed that this character was controlled by four dominant genes for resistanoe and two domioant gsnes for susceptibility. The genes suggested for ra sistanoe were (R) in the variety American. and was epistatic to gene (81) for susoeptibility in Orangetgene(R in Red Cber;rJ and the two ·comp~emanta.;eygene s ( ~ ~ R.5 ) for ~sistance in San Marzano, which we~ hypostatic to ei ther genes (81 or 82 ) for susoeptibil.ity carried by the varieties Orange aod Pearson 107. The recessive @Bues ( r. r1• r2 t 81 ’ ’82 ) for susoeptibility wexe carried by Pear~ Harbor. 4. The genetic behaviour of fruit shape was studied as a qualitative eharaoter in ten crosses inoluding three fruit shapes; roundish oblate, round, and. oval. The F1 plants showed the domi.nanoeof roundish oblate over oval shape. It appeared :from the F2 and baokorosses segregations that fNit shape chD.moter was governed by three pairs of genes, where gene (E) oont:roJJac1 equatorial expansion of fruit I (P) polar expansion, and ( Lc) few 10cule nwnber. and these genes interacted together to give di.fferent fruit shapes. The recessive gene ( 10 ) .for many looule s modified frui t shape to be oblate when present with either genes ( E orP ). The round fruit shape appeared in genotfl)es (E P 10 ) as i.n the varie ty .Amerlcan or (e p 10 ) as in the varia tY’Oranget the roundish oblate sbape was developed in the presence of the three dominant genes (E P La) as in Red Cherry and Genomeor in the presence of two dominant genes (E La P ) as in Pearl Harbor and Pearson. 1.07. The oval f.ru1 t shape was fouad in the presence of tiwo dominant genes ( e P La) as in the variety San Mo.rzanf”. 5. Assooiation studies between :fruit shape and number of locules per fruit showed significant associations in five orosses. These associations might be probably due to the presenoe of a linkage between one o;fiJthegene or genes for Looul.e number and one of the froit shape genes, being on the same ohromosome. 6. The iaheri banoe of fruit colour was studied in eleven orosses iooluding red and orange fruited varieties. Red flesh oolour showed to be dominant to orange .flesh colour in Fl- It appeared from F2 and BOl progenies that this charaoter was controlled by five pairs of genes , where the two oo~J..ementary genes ( R1 , ~ ) for red flesh oolour located in the variet)’ .American and were epistatic over gene (T) for orange flesh colour in the variety orange • The f.1JP nes ( R3 ) in Genone, (R 4 and R 5 ) in Pearl Harbor, we.re all duplicate gs nea :for red f.ruit flesh oolour epistatioto gene (T) for orange flesh colour. The reoessive alleles for all these genes caused yellow fle sh colour. 7. PZ’Ui.t size showed to be quanti ta tively lnheri ted character in eight orosses. The F1 plants were intermediate between pa.renal fruit sizes, showing partial. dominance at small frUit size. The F2 distribution covered the ranges of both panencs or beyond the range o£ the largo fmited parent. The number of genes for fruit si.ze varied greatl}” fJ:’Om (1”:’12)pairs of genes with multiplioative gene aotd.on, However, this value reaohed (25-33) pairs of genes in the cross Red Cherry x Genome. Heritability values were high in all cases ronging from (62.12% _ 96.91% ) t showing e:ff’eotiveness of selection :for fJ:\lit weight. 8. In the crosses belonging to the large x large .fruit group inolud1ng the two crosses, San Marzano x (Pearl Harbor and Genome), there was a oha.raoter1stic shift in fruit s1.ze. The meanfruit weight of F plants was very muchlowQr than the comparatively am.all er fruited parent. This pbenomenonoontinued in F2 of the cross San Marzano x Pearl Harbor onJ.y. This phenomenon was suggested to be reJ.ated either to negative heterosis or to effeot of acoumulation of dominant genes for small fmited size existed in both large fmited parents. 9. Plant height was lnheri ted as a quanti.tative character in two orosses. The F1 plants .represented the dom1nanoe Of long stem accompanied by heterosis in the oross Pearl Harbor-x Orange and showed partial dominance :for long stalked plant in the CroBS American x San Marzano. Number~ genes governing plant height showed to be limited ranging from (1-2) pairs. The heritability for th1s ohamoter was high. enough ( ranging from 62.95% _ 92.89%) to indicate the effectivenoss of selection for this oha.raoter. 10. The inheritance of ascorbic acid content in fruits was studied in the arOSB .Pearson 107 x San Marzano. The F1 plant showed intermedia.te values between parents t and F2 plants showed partial dominance (]f high vitamin C in the variety Pearson 107. Simple monogenic inheritance. was observed in F2 distribution with some modifiers having additive effeot. The heritability far this cll.aracter was very high ranging ( 92.71% .;. 93.43%)t indicating effectiveness 0:£ seleotion for high vitamin C contents. |