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conn s 43 Connecticut A New Scantic, Fusarium-Wilt Resistant Broadleaf Tobacco Cultivar BY JAMES LAMONDIA A. Digitized by the Internet Archive in 2011 with funding from LYRASIS members and Sloan Foundation http://www.archive.org/details/scanticnewfusariOOIamo A New Scantic, Fusarium-Wilt Resistant Broadleaf Tobacco Cultivar BY JAMES LAMONDIA A. A newcultivar ofConnecticutbroadleafcigarwrapper allowedto self-pollinate (inbreed) and resultingprogenyare tobacco (Nicotiana tabacum L.) resistantto Fusariumwilt, mixedtogetherin equalproportions (bulked) priorto causedbythefungus Fusarium oxysporum Schlechtend.:Fr. seeding forthe nextgeneration. Selectionfortraits suchas f. sp. nicotianae (J. Johnson) W.C. Snyder& H.N. Hans., disease resistance and agronomictype are madefromthe hasbeendeveloped atThe ConnecticutAgricultural second (F2) generationonuntil plants are inbredfor sixto Experiment Station's ValleyLaboratory. This cultivar, eight generations (F6-F8). The greatestvariationoccursin 'Scantic', allowsbroadleaftobaccoproductioninsoils theF2 generationand selectionreducesvariationand infested withthe Fusariumwiltpathogen. Yields and increases thefrequencyofdesirable traits overtime. After sortingqualityofScantic are equalto orbetterthanthe the F6-F8 generations, eachplant represents agenetically current standard wilt-resistant cultivar 'C9' or similarwilt- uniform homozygous inbred lineand apotentialnew susceptible cultivars. Limited quantities ofseed are cultivar. availableto growers and scientists. The F2 generationofacomposite ofthree crosses Fusariumwilt hasbeenthe mostpersistentand betweenwilt-susceptible Connecticutbroadleaftobacco important disease ofbroadleaftobacco inthe Connecticut lines andthewilt-resistantcultivar'C2' (C2 x 'Winn'; C2 x River Valley overthe lasttwo decades. The most effective 'Gogulski'; and C2 x'Gradowski') was selectedfor control ofFusariumwilt hasbeenachieved through the resistanceundergreenhouse conditions. Onethousand development anduse ofwilt-resistantbroadleaftobacco seedlings oftheF2 compositewere eachinoculated with cultivars (LaMondia andTaylor, 1991; Lucas, 1975). One 1.0 x 107 microconidiaofF. oxysporum perplantin wilt-resistantcultivar, C9, was released in 1991 andhas greenhousetrays. Twenty-fiveofthe most resistantand beenwidelygrown (up to 80%ofthe total acreageannually) vigorous seedlings were selectedand selfed. Eachyear, an throughout the Valley. Wilt-resistant cultivars are not additional 1,200 F3 to F8 progenywereplantedannually immune toFusarium infectionandwill developwilt into Merrimacfine sandyloamfield soil (71.8% sand, symptoms under high inoculum potential (LaMondia and 23.0%silt, 5.2%clayand2.2%organic matter, pH6.2) Taylor, 1987). Resistance toF. oxysporum is conferredby naturally infestedwithhighlevels omf/7, oxysporum.m an unknown number ofsmall-effectgenes (quantitatively Transplants wereplaced inrows 1 apart and0.3 apart inherited) (Gritton et al., 1965). Continuous growth ofa withinrows. Twenty-five superiorwilt-resistantplants out single cultivar such as C9 overa numberofyears may oftheapproximately 1,200 individualsplantedwere eventually selectfor isolates ableto cause disease onthat selected, selfed, and seedwasbulkedeachyearfrom 1988 cultivar. The development andproduction ofadditional (F3) to 1993 (F8). Plants werealso selectedforgrowth wilt-resistant cultivars, likely withdifferentnumbers or habit, traits, and reduced sensitivityto weatherfleckcaused types ofresistance genes, is desirable as it mayprolongthe byozone. TwentysuperiorF8 inbredlines wereself effectiveuse ofplantresistance overtime. pollinated in 1993 (giventhe designations A-l to A-20) and evaluated as inbred lines in 1994 andthereafter. BREEDINGAND SELECTION EVALUATIONAND PERFORMANCE Scantic is aninbred derived from abulk systemof modified single seed descent. Inthisbreeding system, the Scantic (evaluatedas line A-7 incommercialfieldtrials) best individuals (approximatelytwopercent in this case) are was selected as a superioradvanced inbred. Agronomic Connecticut Agricultural Experiment Station Bulletin 974 characteristics and cured leafquality were evaluated inboth (Elgersma, etal., 1972; Gordon etal., 1990; LaMondia and experimental plots and undercommercial conditions with Taylor, 1987). Wilt-resistantbroadleaftobacco cultivars cooperatingfarmers. Yields and sorting characteristics of appearto minimize increases inF. oxysporum population Scanticwere compared to the wilt-resistant standard C9 on densities in soil (LaMondia, 1995). These results are similar a commercial farmin South Windsor, CTin 1995, 1997, to the effects ofwilt-resistant watermelon, pea ortomato on and 1998. Cured leaves were commercially graded into one densities ofpathogenicF. oxysporum in soil (Larkin etal., ofsix grades representing wrapper, binder, orfillerquality. 1993; Reyes and Mitchell, 1962). Thepercent ofthe totalyield in each gradewas determined Wilt-resistant tobacco, while not providing a means of andvalueperacre calculated (Table 1). Economic return eliminating the pathogen from soil, continues to allowthe peracre for Scantic was significantly higherthanfor C9 in successful production ofbroadleaftobacco in fields infested 1995 and 1997 and similarto C9 in 1998. Curedleaf withF. oxysporum (LaMondia andTaylor, 1991). Thewilt- weightperacrewas higher ineachyearandpercent resistant cultivar C9 has beenwidely grown in wrapper gradeswere higherintwo ofthethreeyears. In F. oxysporum-infested soils. Scantic is an additional MA 1999, anadditional commercial fieldtrial in Whately, Fusariumwilt-resistant cultivaravailable forcommercial concluded that Scantic had 14.5%higherweightperacre productionwitha similar level ofresistance and the than C9 andthat 64.6% ofthecured leaves ofScantic were advantage ofincreased curedweightyield peracre wrapperquality, while 25%werebinderand 10.4%were compared to C9. filler. Leafyields, wilt incidence and wilt severitywere ACKNOWLEDGMENTS determined infieldplots atthe ValleyLaboratoryin 1996. Scantic, C9 andthe wilt-susceptible cultivar Gogulski were The authorwishesto thank S. Waldron. W. Dunn, and comparedin soils eitherinfestedoruninfested withthewilt FairviewFarmforexcellent cooperationincommercial pathogenF. oxysporum. Each cultivarwastransplantedto scale field trials and cured leafquality analysis, and J. sixreplicate two-rowplots of20 plants perplotineach Canepa-Morrison, S. Lamoureux, and R. Horvath for F. oxysporum-'infested oruninfestedfield. Plants were rated technical assistance. for diseaseincidence (numberof20 plants symptomatic) and severity (ratedona scale of - 4 where = healthy, REFERENCES 1 = stunted or off-color, 2 = one leafsymptomatic, 3 = more than one leafsymptomatic, and 4 = plantdead) on Elgersma, D.M., MacHardy, W.E., and Beckman, C.H. August 5, 1996. Tenplants perplotwere harvested on 1972. Growthand distribution ofFusarium oxysporum fsp. August 16, 1996 andweighed. Wiltincidence and severity lycopersica in near-isogenic lines oftomato resistant or were lowforboth Scantic and C9 (Table 2). Scantic resulted susceptibletowilt. Phytopathology62:1232-1237. inover 20% freshweightyield increases in comparisonto C9, regardless ofwhether soilswere infestedwiththe Gordon, T.R., Jacobson, D.J., MayD.M., Tyler, K.B., and pathogenornot. Yieldincreases overthe susceptible Zink, F.W. 1990. Fruityield, disease incidence, and root cultivarwere approximately 5%inthe absence ofdisease colonization ofhybrid muskmelons resistantto Fusarium and dramatically different inF. oxysporum-infested soil. wilt. PlantDis. 74:778-781. ResistancetoF. oxysporum is quantitativelyinherited (Grittonet al., 1965). Previous observationsinfield and Gritton, E.T., Jones, G.L., Powell, N.T., andMatzinger, greenhouse experiments as well as in commercial D.F. 1965. Inheritanceofresistance to Fusariumwilt in production have shownthatwilt expressiononwilt-resistant flue-curedtobacco. Crop Sci. 5:547-550. plants is oftenmild andthatplants often outgrowearly symptoms (LaMondiaand Taylor, 1987; LaMondia and LaMondia, J.A. 1995. Influence ofresistanttobacco and Taylor, 1991). Differences inwilt severitybetween Scantic tobacco cyst nematodes on rootinfection and secondary and C9 werenot significantlydifferent. Fusariumwilt inoculum ofFusarium oxysporum fsp. nicotianae. Plant severity, as determinedbyratings ofvisible symptoms, was Disease 79:337-340. much greaterforthe wilt-susceptible Gogulskithanwilt- resistant Scantic or C9 tobacco. LaMondia, J.A., and Taylor, G.S. 1987. Influence ofthe Wilt-resistanttobacco is not immunetoFusarium tobacco cystnematode (Globodera tabacum) on Fusarium oxysporum infection. F. oxysporum hasbeen isolated wiltofConnecticutbroadleaftobacco. PlantDis. 71:1129- repeatedlyfromwilt-resistantbroadleaftobacco (LaMondia 1132. andTaylor, 1987). ResistancetoF. oxysporum in other crops hasbeencorrelatedwith alackofinfection, orwith reducedinfection, ofvasculartissues abovethe soil line Scantic. A New Fusarium-Wilt Resistant BroadleafTobacco Cultivar LaMondia. J.A., andTaylor. G.S. 1991. New Fusarium wilt-resistant Connecticutbroadleaftobaccovarieties. Conn. Agricultural Experiment Station Bull. 891. Larkin. R.P.. Hopkins. D.L., and Martin. F.N. 1993. Effect ofsuccessive watermelon plantings on Fusarium oxysporum and other microorganisms in soils suppressive and conducive to Fusarium wilt ofwatermelon. Phytopathology 83:1097-1105. Lucas. G.B. 1975. Diseases ofTobacco. 3rd ed. H.E. Parker and Sons. Fuquay-Varina, N.C. Reyes. A.A., and Mitchell, J.E. 1962. Growth response of several isolates ofFusarium in rhizospheres ofhost and nonhost plants. Phytopathology 52:1196-1200. Connecticut Agricultural Experiment Station Bulletin (>74 Table 1. Percent leafgrades, cured leafyields and value peracre ofSemitic and C9 broadlcaftobacco over three sears under commercial production conditions (South Windsor. CT). 1995 1997 1998 Leaf Scantic C9 Scantic C9 Scantic C9 Grade (%) (%) (%) (%) (%) ("») Wrapper 65.6 57.9 59.0 23.0 44.0 50.0 Binder 21.9 25.4 28.0 51.0 30.0 39.0 Filler 12.5 14.8 13.0 26.0 26.0 11.0 Yield andvalue Yield and value Yield andvalue Pounds/acre* 2304 2016 2486 2373 2232 2000 Value/acre+ $13,202 $10,231 $13,171 $8,130 $9,812 $10,032 * Cured weight leafyield per acre. + Weight in each grade multipliedby price per pound for each grade. Table 2. Fusarium wilt incidence, severity, and shoot fresh weight ofwilt-resistant C9 and Scantic and wilt-susceptible Gogulski broadleaftobacco in wilt-infested oruninfested fields. Cultivar Wilt Status Field Wilt Incidence* Wilt Severity+ Yield' Scantic resistant Infested 0.7 1.0 29.5 Scantic resistant Uninfested 0.0 0.0 34.0 C9 resistant Infested 0.2 0.2 24.3 C9 resistant Uninfested 0.0 0.0 27.8 Gogulski susceptible Infested 17.0 3.6 4.0 Gogulski susceptible Uninfested 0.5 1.0 32.4 * Numberof20 plants perplot with wilt symptoms evident. + Disease rating (0=healthy, 4=dead) ofplants. A Freshweight (lb) per 10 plants. The Connecticut Agricultural Experiment Station (CAES) prohibits discrimination in all its programs and activities on the basis of race, color, ancestry, national origin, sex, religious creed, age, political beliefs, sexual orientation, criminal convictionrecord, genetic information, learning disability, present or past history ofmental disorder, mental retardation or physical disability including but not limited to blindness, or marital or family status. 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