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Abstract I -S-U-M-M-A-R-Y The present investigation was planned to study the V21’iabilit:yamong different isolates of Botrytii!.ill1i ilunn to induce onion neck rot disease. Also their ebilities to produce chemical changes on onion bulbs owing t c infection were studied. The effect of gro\’!thregulat0~ S or fungicides on disease incidence Bnd the chemical ChSDC8S in the bulbs in field and durins storage was elsa studied. ReEults obtained could be 8lli~~arizedas follows: 1. Eight isolates .of B. allii were isolated from diseased onion plants, i.e. transplants, bulbs, saecs and seed pro(..\ucinbeu;l bs collected from different localities of cifferent Governorates of ARE. The isolates varied III their linear growth and culture coloul’ on PDA see-im-D.. All the tested isolates proved to be pathogenic to all tested onion cultivars. _ 6 Isolate No.2 (Assiut) was more virulent y;hcl’€’es isolate !,O. 3 (hlalla,,,,\·,rais) the lea st virul ent both in greenhOllse oLd in vitro experiments. ~. The fungi associated with onion seeds ~ere as follows: i.soer[dllUs niger and Penicillium spp- were isolated - 109 - f iom both sterilized [lYH) ul1sterilized seeds. A1ternari~~ spp. and Rhizopus spp. were isolated fl’om the unsterilized seeds only. Botrytis a11ii ViaE isolated f rom the sterilized seeds only. :”. In Cl”eenhouse, experiments the percentage of in! ection incTe8sec1 v.Lth the incre8sine of ino,~u1um potential 2fter 60 , 3no 120 days in spore suspe1sion method and (:lfte:r 30 arid 60 days, in the infestetion with fUllC;US grOVil1 on sorghum medium method. 6. All the five tested onion cu1tivars ~ere susceptible to infection ~ith B. a11ii except GJzs-6 which was Grsue X hybrid 33 was highly suscep~ib1e after 60 days in spore-suspension and disc method3. 7. In vitro, both GibhEr~11in(GA3) and Allar (B9) increased the linEar Growth of B. a111i on rLh, v-h i.Le 1n601e acetic acid (IAA) decreased it. Also, it was noticed th2t all the three growth reguleto18 enhanced the spoYQlation of B. 811ii. 5. ’:’:oakingonion transplants in di.f f e:’ent concentrations of GA’:l.’ IAA and Bo before transp181tine:: for different ~ -’ periods decreased the percentage oC infection with neck ~ot disease under greenhouse conditions except . in case of soaking in IAA for 6 hours at concentrations of 100 and 200 ppm (after 120 days). - lIe - 9” As for the growth regulator IAA, the hl.gie st perc entaG8 of infection after 60 days was 50 % at cone entration 200 ppm for 2 hours and after 120 days it bc~- 8’re 95 % (more than the control) at concentrations of 100 and 200 pp~ for 6 hours. ~hile the lowest percentage of infection wa s after 60 dn:’8 20 % at concentration of 50 ppm for 2 hours (in the first season) and 200 ppm for 4 hours (in the second seacon). After 120 days it became 60 % at the concentration of 100 ppm for 6 hrs. ~~. As for Allar (B 9 ) the highest percentaCJ of infection 2fter 60 days V:38 50 % at eoncent1’etioll of 100 ppm for 4 hr-s . and after 120 days it reached 90 ’IS at ooncen- ”~:’3tioDS 50 ppm for 6 nr s, and 100 ppm for 2 and 6 hr s, Tespee. ~hile the lowest percentBge of infection after 60 cays ~8S 20 % at concentration 100 ~pm for 6 hrs. and after 120 days it became 55 % at 1”cnrentl’atiOl.l of 50 :JP~·!1for 6 hr s , ,~. As for Gibberellin (GA)) the highest r(rcentage of infection after 60 days was 55 % at COlcentrations of 125 ppm for 2 and 4 hr s , (first sea::on) and 250 pp~ for 4 hrs. (secona season), and af;er 120 days it became 135 % at concentration ·of 500 PI’ n for 2 hr s , ~hile ~he lOTIest percentage of infectiJn after 60 jays vas 25 % at concentration of 250 Jpm for - 111 - 6 hours and after 120 days it be cerae (5 % at the conc en t.ratioD of 500 pvn for 4 hours. 12. The total sugars in Giza-6 cv. bulbs.yielded from tn’lnsplants soaked in grm’!th r egu La t or sv!ere hLgh er’ in the uninfected bulbs then in the irfected ones~ for all used growth regulators. The feme trend was noticed in case of non-reducing sugarf • As fOT GA 3 , the highest amount of totll sugars was obtained from the uninfected bulbs so:ked in 250 ppm for 2 hours and the Love st amount was obtained from ::-:i’ec’ceb(ull bs y i.e Ld ed f r-orn soaking i: - 125 ppm for 6 hours. Also, the highest and 10....es eT!ounts of rec1ucing end non-reducing SUg8TS V:€Te o btn Ln ed from the sa:ne previous treatments. 14. For IAA, totel, reducing and non-redu~ine sugars were higher in the uninfected bulbs than il infected ones. T~€ highest amount of total and reducinG sugars was obtained from uninfected bulbs soaked in 50 ppm for 2 hrs. AlSO, the highest 8~ounts of non-reducing sugars ~as obtained from bulbs soake( in 50 ppm for 2 hI’S. 1he lowest amounts obteired from uninfe~- ted. ouI bs for total and reducing sup IS from bulbs -\’;8.8 obtained from soaking in 100 ppm for 2 hours s~c free soaking in 50 ppm for 2 hrs for infected DU.l”. QS. r - 112 - 15~ For Allar (Bo)’ total, reducinG ond non-reducing sugars were higher in uninfected bulbs than in infected ones. The uninfected bulbs soaked jn 25 ppn for 2 hCU.TS gave the highest amounts of tot~ll and reducing 8l1;;::n.’ 8 , wni Le tbe uninfec-ted bul be sonl~?d in lOC ppm cav’e t r;e hie;hest amounts IJf non-rec1uciL3 sugal’s. On tbe other hand~ the lOwEst 8mount~ of total, redand non-reducing sugSTS Vier-s obtninecl from infected buL b s ao ak e d in 100 ppm f or 2 hours, ~,CO ppm for 6 hOUTS and 100 ppm for 6 tours, respectively. .i_ .•• -’ c-’ GcLcI’elly, total and free phenols inCl’C!0sed in dieeas€c1 bu’bs previously tleeted with ~rowth rEGulators. As for :’8cul to of tl-e8ting plan~~s with GA3, most treatments S8ve hicner amounts of total, fJ’ee and conjugatc~ phe~o18 then in tbe untreated (plants) faT both the uninfcct<:.C ,one} infected culbs. The hjyhest amourrt a of Ts:sl, free and conjuG2ted phenols in infected C flOUTS, 125 pprn for 2 hours and 500 I prn , respectivcly. ~hcreas the lo~est emounts wer(’ obtained from 500 ppm for 2 hours. As for IAA, tte highest amounts of to-~81 Bnd free phenols ~ontent were presented in inf~cted bulbs t:estAd with 50 ppm for 6 houro. While the highest conjugetec phenols were presented in il’lfected bulbs - 113 - treated with 50 ppm for 4 ~ourH and tte lowest amounts at 100 ppm for 2 hours • • )8 for Aller (80) the highest amounts of total, free -’ sud conjuG2tcd phenols content were fJc~ infected bu I be t.r-e a t ed wi, th 50 ppm for 2 hours, 50 ppm for 2 hours, 50 ppm for 2 hours end 100 ppm for 4 hOUTS l’(:’specti vely. V,hile the 1ov:est amounts \”fere’ obtained from n rri ntect ed bulbs treated ’;:ith100 ppm fOT 2 hOUTD Dt ;25 ppm f02:’ 6 hOUTD arrd 100 ppm for 2 hours, respectively. jc::, :0’:’ the totsl ami.n o D.cids in the b!JJ.·’~f;yi~lded from tent incl’O:”-[Jsec1 in t he infected t.h an in the u:linfected bu..l b s , ~~.• As for GA-:<,’the highest amoun t of totel ami no acids ’” c~teined from infected bulbs treated ~j.th 125 ppm ·jL’.l~)S tI’ec,ted\’.’1th 250 ppm for 6 houl’s”, While as for IAA -’.;.:·lC hi chest arnou n t was from infected bu Lbs tJ:’eated ~ith 100 ppm for 4 hOUTS~ and the lowe3t amount was fr03 uninfected bulbs treatEa ~ith 200 ppm for 4 hours, eid as for Aller (So) the highest amount of tc:e:l 22:’~iDO acids wa s f’r-ori infected bulbs at 100 ppm Ie::’ 4- ncur-s, ’{,bile the lOFest amount Y;3S from un- ~n~ected bulbs treated TIith 100 pp~ fer 6 hOUTs. - 114 - the effec~ of tre8tin~ Giz8-20 transplants before transplanting and spraying the plants before h2YVesting with Benlete 50 % TIP and Sumisclex 50 % ~p on the phenolic compounds content wos studied at harvesting time and during storage. It was found that Sumisclex ;’jave the highest amourrt e from total 2nd freE phe~ols after 60 days storage for most concer: tr-stions. As for Benlate, come tTe8t~’lents gav e the hiehest amounts after GO days Bnd the other gave the highest amounts after 90 days storr~e. \’f28 effective than Ronilan 50 :~ \’P arid Sumisclex 50 % VIP (s::/stemicfune;icides). ’\’,~:.ile Allison 50 :;’j was effective t han l’O\C1’81 50 ,% (~lOn-SY2temic fUI1E;icides) on the liI18<’F’ grcJVlth of •....• , . ~. 2...L.Lll. C__ ’ Ir:.~, Be::-rlate 50 % ViJ? ’1’:28 effectiv’) than Sumiscle:r.: 50 1 ;p ~hen used for dipping the transplants Giza-20 (Eehe~y) at the rates of 2 giL and 20 giL, respecti7ely, under field conditions. Whereas the treatment ~ith Bcnlete 50 % gave less infection (4.17 %) end nore yield (2.4 kg/25 bulbs) than ~:;ul’1i::;clex 50 %. ~~. =reatirg bulbs for seed yield by diff£rent methods of application of Benlate 50 % WP, Po~ilan 50 % WP, Ro~ilan dust 5 % and S~lisclex 50 % WP decreased the percentage of infection with neck rot disease and increased the seed yieldr It ~as foun~ thnt - 115 - 0ulbs dipping in Benlate 50 % WP gave the beut resulto whi Le the least resul ts as regards in case of c~pr8ying wi th SULlisclex 2g/L in the two ~:easons. ~L:be effect of treating with Benlate 50 ;S ViP and Sumisclcx 50 %.WP before and after transplentine of Giz2-20 (Dehery cv.) in field on the yield and infectioD during storage, showed that Benlate was effective for increasing yield of bulbs while it became less effective after 150 days during storace. Spraying et 4 weeks before harvesting at the rate of 2 gm/L ~ave tbe je~t results for the two fungicides on the yield. 2~1~ lJ2dng Benlete 50 ’X’ \’IP and Sumisclex 50 )-; before and after transplanting of Giza-6 cv. decrensed the infection in both the field and storaS8 and increased tje yield. In this respect, Sumisclex was effective theE Benlate- Cn the other hand, spr2y:ln~ at 4 weeks befo~e harvesting at the rete of 2 giL was the best tree.tQent for the two fungicides .on the yield and •. ~ .J.,.~ l.n~ ec :”lOD. I SUMMARY The present investigation was planned to study the V21’ iabili t: yamong different isolates of Bot ryt j j I .illl i ilunn to induce onion neck rot disease. Also their ebili ties to produce chemical changes on onion bulbs owing t c infection were studied. The effect of gro \ ’ ! thregulatO~ S or fungicides on disease incidence Bnd the chemical ChSDC SS in the bulbs in field and durins storage was elsa studied. ReEul ts obtained could be 81li ~~arizedas follows: 1. Eight isolates . of B. allii were isolated from diseased onion plants, i. e. transplants, bulbs, saecs and seed pro ( .. \ucinhB.Jlbs collected from different localities of cifferent Governorates of ARE. The isolates varied III their linear growth and culture coloul’ on PDA see-im-D .. All the tested isolates proved to be pathogenic to all tested onion cu l ti vars . 6 Isolate No.2 (Assiut) was more virulent y;hcl’€’es isolate !,o. 3 (hlalla”, ~”fciJs) the lea st virul ent both in greenhOllse oLd in vitro experiments. The fungi associated with onion seeds ~ere as follows: i. soer [dllUs niger and Penicillium spp- were isolated - 109 - f iom both sterilized [IYH) ull steriIi zed seeds. AJternarj~~ spp. and Bbj zaP]]5 spp. were isolated fl ’om the unsterilized seeds only. Botrytjs a J J j j ViaE isolated from the sterilized seeds only. .” In CI”eenhouse, experiments the percentage of in! ection incTe8seci v.Lth the incre8sine of 2fter 60 3no 120 days in spore (:Ifte:r 30 arid 60 days, in the infestetion suspe1Sion ino.e-u lum potential method and with fUllC;US grOVill Oll sorghum medium method. 6. All the five tested onion cu1ti vars ~ere susceptible to infection < i th B. alljj except GJzs-6 which was t ,h_an G.’.;..za-20 (T\ehery), wh i L e Grsue X hybrid 33 was highly suscep~ib1e after 60 days In spore-suspension and disc method3. 7. In vitro. both GibhEr~11in(GA3) and Allar (B9) increased the linEar Growth of B. alllj on rLh, v-hi.Le In60le acetic acid (IAA) decreased it. Also , it was noticed th2t all the three growth reguleto18 enhanced the spoYQlation of B. 8JJjj. 5. ’:’ :oakin~nion transplants in di.f f e: ’ent concentrations of GA’:1. I IAA and B before transp181 tine 0, for different periods decreased the percentage oC infection with neck ~ot disease under greenhouse conditions except in case of soaking in IAA for 6 hours at concentrations of 100 and 200 ppm (after 120 days). - lIe - 9” As for the growth regulator IAA, the hl.gie st perc entaGS of infection after 60 days was 50 % at cone entra tion 200 ppm for 2 hours and after 120 days i t bc~- 8’re 95 % (more than the control) at concentrations of 100 and 200 pp-: for 6 hours. ~hile the lowest percentage of infection wa S after 60 dn:’8 20 % at concentration of 50 ppm for 2 hours (in the first season) and 200 ppm for 4 hours (in the second seacon). After 120 days it became 60 % at the concentration of 100 ppm for 6 hrs. As for Allar (B 9 ) the highest percentaCJ 2fter 60 days V:38 50 % at eoncentl’etioll of infection of 100 ppm for 4 hr-s. and after 120 days it reached 90 ’IS at oonc en- ”~:’3tioDS 50 ppm for 6 nr s, and 100 ppm for 2 and 6 hr s , Tespee. ~hile the lowest percentBge of infection after 60 cays ~8S 20 % at concentration 100 ~pm for 6 hrs. and after 120 days it became 55 % at 1”cnrentl’atiOl.l of 50 :JP~·!1for 6 hr s , .>, As for Gibberellin (GA)) the highest r (rcentage of infection after 60 days was 55 % at COlcentrations of 125 ppm for 2 and 4 hr s, (first sea: :on) and 250 pp~ for 4 hrs. (secona season), and af;er 120 days it became 135 % at concentration ·of 500 PI’ n for 2 hr s, ~hile ~he IOTIest percentage of infectiJn after 60 jays vas 25 % at concentration of 250 Jpm for 111 - 6 hours and after 120 days it be cerae (5 % at the conc en t.ratioD of 500 pvn for 4 hours. 12. The total sugars in Giza -6 cv. bulbs. yielded from tn’lnsplants soaked in grm’! th r egu La tor sv! ere h Lgh er’ in the uninfected bulbs then in the irfected ones - for all used growth regulators. The feme trend was noticed in case of non-reducing sugarf • As fOT GA , the highest amount of totll sugars was 3 obtained from the uninfected bulbs so: ked in 250 ppm for 2 hours and the Love st amount was obtained from ::-:i’ec’cEb(il bs yi.eLded fr-om soaking 1:- 125 ppm for 6 hours. Also, the highest and 10...es eT! aunts of reclucing end non-reducing SUg8TS V:€Te 0 btn Lne d from the sa:ne previous treatments. 14. For IAA, totel, reducing and non-ir edu-d ne sugars were higher in the uninfected bulbs than il infected ones. T~€ highest amount of total and reducinG sugars was obtained from uninfected bulbs soaked in 50 ppm for 2 hrs. AlSO, the highest 8~ounts of non-reducing sugars ~as obtained from bulbs soake ( in 50 ppm for 2 hI’S. 1he lowest amounts obteired from uninfe~- ted. ouI b s for total and reducing sup IS from bulbs -\’;8.8 obtained from soaking in 100 ppm for 2 hours S~C free soaking in 50 ppm for 2 hrs for infected DU.l~ os, - 112 i s- For Allar (Bo ) I total, reducinG ond non-reducing sugars were higher in uninfected bulbs than in infected ones. The uninfected bulbs soaked j n 25 ppn for 2 hCD.TS gave the highest amounts of tot~ 11 and reducing 811;;::n.’ 8, wni Le tbe uninfec-ted bul be sonl-vd ill laC ppm cav’e t r;e hie;hest amounts IJf non-recl uci L3 sugal’s. On tbe other hanri- the lOwEst 8mount~ of total, reducillC; and non-reducing sugSTS Vier-s obtninec1 from infected buLb s ao ak e d in 100 ppm f or 2 hours, ~,CO ppm for 6 hOUTS and 100 ppm for 6 tours, respectively. GcLcI’e1ly, o! total and free phenols inCl’C!Osed ill dieeasf’c l bu’bs previously tleeted with ~rowth rEGulators. As for :’8cul to of tl-e8ting p.l an-v-s with GA3, most treatments S8ve hicner amounts of total, fJ I ee and conj uqat.cphe- vo l B then in tbe untreated (plants) faT both the uninfcct<:.C .one} infected culbs. The hjyhest amourrt a of Ts: sl, free and conjuG2ted phenols in infected in bu L o s tlE’eteo ”i1·tl;.1 500 ppm for hulhs TIe~e noticed C flOUTS, 125 pprn for 2 hours and 500 I prn, respectivcly. ~hcreas the lo~est emounts wer(’ obtained from 500 ppm for 2 hours. As for IAA, tte highest amounts of t.o-v-B’l Bnd free phenols ~ontent were presented in Lnf vct.ed bulbs t:estAd with 50 ppm for 6 houro. While the highest conjugetec phenols were presented in il’lfected bulbs 113 - treated with 50 ppm for 4 <our H and tte lowest amounts at 100 ppm for 2 hours • ·)8 for Aller (8q) the highest amounts of total, free sud conjuG2tcd phenols content were fJc~ infected bu I be t.r-e at ed wi, th 50 ppm for 2 hours, 50 ppm for 2 hours, 50 ppm for 2 hours end 100 ppm for 4 hOUTS l’(:’specti ve1y. V, hile the lov:est amounts \”fere’ obtained from nrrintected bulbs treated ’;:ithlOO ppm ror 2 hOUTDDt ;25 ppm f02:’ 6 hOUTD arrd 100 ppm for 2 hours, respectively. jc::, :0’:’ the totsl ami.n a D.cids m the b!JJ.· ’~f;yi~lded from tent inc1’O:”-[Jsecl III the infected t.h an III the u:linfected bu.l b s , ~--- As for GA-:<,’ the highest amoun t of tote1 arm no acids c -t.e i ned from infected bulbs trea ted ~j. th 125 ppm -jL’.I~)S tI’ ec, ted’.’! th 250 ppm for 6 haul’s”, While as for IAA -’.;.:·lC hi chest amou n t was from infected buLbs tJ:’eated < i t.h 100 ppm for 4 hOUTS~ and the lowe3t amount was frO 3 uninfected bulbs tre atEa < i t.h 200 ppm for 4 hours, eid as for Aller (So) the highest amount of tc:e:l 22:’~iDO acids wa s f’r-ori infected bulbs at 100 ppm Ie::’ 4- ncur-s, ’{,bile the lOFest amount Y;3S from un- ~n~ected bulbs treated TIith 100 pp~ fer 6 hOUTs. - 114 - the ef f ec- of t re Sr i n- Giz8-20 transplants before transplanting and spraying the plants before h2YVesting with Benlete 50 % TIP and Sumisclex 50 % ~p on the phenolic compounds content wos studied at harvesting time and during storage. It was found that Sumisc1ex ;Jave the highest amourrt e from total 2nd freE phe-o l s after 60 days storage for most concer: tr-stions. As for Benlate, come tTe8t~’ lents gave the hiehest amounts after GO days Bnd the other gave the highest amounts after 90 days s t or r ve , 111 than Ronilan 50 :~ \’P arid Sumisclex 50 % VIP (s:: / stemicfune;icides). ’\’,~:.ile Allison 50 >,j was effective than I’O\el’81 50 ,% (~lOn-SY2temic fUll E;icides) on the liIl8<’F’ grcJVlth of 2’ L uj If’ ~ Be: : -rla~ % ViI? ’1’:28 effectiv’) than Sumiscle: r. : 50 1 ;p ~hen used for dipping the transplants Giza-20 (Eehe-ry) at the rates of 2 giL and 20 giL, respecti 7ely, under field conditions. Whereas the treatment ~i th Bcnlete 50 % gave less infection (4.17 %) end nore yield (2.4 kg/25 bulbs) than ~:;ul’li::;clex 50 %. =reatirg bulbs for seed yield by diff£rent methods of application of Benlate 50 % WP, Po~ilan 50 % WP, Ro-v i l an dust 5 % and S~lisclex 50 % WP decreased the percentage of infection with neck rot disease and increased the seed y i e l d It ~as f oun-: thnt - 115 - Ou1bs dipping in Benlate whi Le the least resul ts c-vpt’Sying wi th SULlisc1ex 50 % WP gave as regards 2g/L III the the beut resul to in case of two ~:easons. -iibe effect of treating with Benlate 50;S ViP and Sumisclcx 50 %. WP before and after transplentine of Giz2-20 (Dehery cv.) in field on the yield and infectioD during storage, showed that Benlate was effective for increasing yield of bulbs while it became less effective after 150 days during storace. Spraying et 4 weeks before harvesting at the rate of 2 gm/L ~ave tbe j e~t results for the two fungicides on the yield. 2~1~ lJ2dng Benlete 50 ’X’ \’/P and Sumisclex 50 )-; before decrensed the and after transplanting infection in both of Giza-6 cv. the field and storaS8 and increased tj e yield. In this respect, Sumisclex was effective theE Benlate- Cn the other hand, spr2y: Lri- at 4 weeks be f o-ie harvesting at the rete of 2 giL was the best tree. tQent for the two fungicides .on the yield and l.n~ ect-ioo. |