Weed Tehnology. 24. Volume :3 396 Eonomi Evlution of Glyphoste-Resistnt nd Conventionl Sugr Beet ANDREW R. KNISS, ROBERT G. WILSON, ALEX R. MARTIN, PAUL A. BURGENER, nd DILLON M. FEUZ 2 Astrt: Field experiments were onduted ner Sottsluff, NE, in 2 nd 22 to ompre eonomi spets of glyphoste pplied to different glyphoste-resistnt sugr eet ultivrs with tht of onventionl heriide progrms pplied to ner-equivlent, non glyphoste-resistnt onventionl ultivrs. Glyphoste pplied two or three times t 2-wk intervls, eginning when weeds were m tll, provided exellent weed ontrol, yield, nd net eonomi return regrdless of the glyphoste-resistnt sugr eet ultivr. All onventionl heriide tretments resulted in similr net eonomi returns. Although the onventionl sugr eet ultivrs HM 64 nd Bet 446 responded similrly to heriide tretments with respet to surose ontent, Bet 446RR produed roots with % more surose thn HM 64RR. When verged over heriide tretments, produer plnting Bet 446RR ould fford to py US $/h more for glyphoste-resistnt tehnology s ould produer plnting HM 64RR. When verged over ultivrs nd heriide tretments, it is estimted tht produer ould fford to py n dditionl US $3/h for glyphoste-resistnt tehnology without deresing net return. Nomenlture: Glyphoste; sugr eet, Bet vulgris (L.) Bet 446, Bet 446RR, HM 64, HM 64RR. Additionl index words: Heriide-tolernt rops, tehnology fee, weed mngement, lopyrlid, desmediphm, ethofumeste, phenmediphm, triflusulfuron. Arevitions: DES, desmediphm; f, followed y; PHEN, phenmediphm; R G, gross return; TRIF, triflusulfuron; Y, root yield. INTRODUCTION Sugr eet is n importnt eonomi rop of the stte of Nersk nd the United Sttes. Over 6,7 h were hrvested in Nersk in 2, resulting in surose prodution of more thn 23, Mg (Hmlin nd Groskurth 22). In Nersk, nnul prodution osts n exeed US $,4/h (Burgener 2). Ntionwide, verge net eonomi returns hve een negtive for 4 of the lst 6 yr (Ginessi et l. 22). Weed ontrol is ostly nd neessry prt of sugr eet prodution. In the sene of hemil weed ontrol, the hnd lor required to weed nd thin sugr eet ould exeed h/h (Dwson 974). Beuse of the high ost of hnd lor for weed removl, most weed ontrol progrms rely on severl POST heriide tretments with or without PRE heriide pplied t plnting. Cultivtion nd hnd lor ply diminishing role Reeived for pulition My, 23, nd in revised form June 27, 23. A ontriution of the University of Nersk Agriulturl Reserh Division, Linoln, NE 63. Journl Series 46. 2 Former Grdute Reserh Assistnt, Professor, nd Professor, Deprtment of Agronomy nd Hortiulture, nd Reserh Anlyst nd Assoite Professor, Deprtment of Agriulturl Eonomis, University of Nersk, Sottsluff, NE 6936. Corresponding uthor s E-mil: kniss@uwyo.edu. in most weed ontrol progrms. In the sene of weeds, ultivtion of sugr eet does not inrese yield, nd there is evidene tht ultivtion my hve negtive effet on surose yield (Dexter et l. 9). Although redued-rte heriide pplitions, or mirortes, redue input osts, their effiy n e vrile. Miller nd Mesh (2) found tht rodlef weed ontrol ws less nd grss ontrol etter with mirorte tretments ompred with stndrd rte progrms, nd Wilson (9) found tht three mirorte pplitions did not ontrol redroot pigweed (Amrnthus retroflexus L. # 3 AMARE) or ommon lmsqurters (Chenopodium lum L. # CHEAL) s well s two pplitions t onventionl rtes. The introdution of trnsgeni sugr eet resistnt to glyphoste ould give produers the pility of rodspetrum weed ontrol using only one POST heriide, pplied two or more times during the growing seson. One pplition of glyphoste is not dequte for sesonlong weed ontrol in glyphoste-resistnt sugr eet 3 Letters following this symol re WSSA-pproved omputer ode from Composite List of Weeds, Revised 99. Aville only on omputer disk from WSSA, Est th Street, Lwrene, KS 6644-97. 3
WEED TECHNOLOGY (Wilson et l. 22). Two or three pplitions of glyphoste pplied to glyphoste-resistnt sugr eet ontrolled 9% or more of the totl weed popultion (Guz et l. 22; Wilson et l. 22). Glyphoste-resistnt systems in other rops suh s soyen (Glyine mx L.) nd orn (Ze mys L.) produe eonomi returns greter thn or similr to those of onventionl systems (Johnson et l. 2; Nolte nd Young 22, 22; Reddy nd Whiting 2). Although the ost of glyphoste is often less thn onventionl heriides, input osts re sometimes greter in glyphoste-resistnt systems euse of n dditionl fee produers must py for glyphoste-resistnt seed (Johnson et l. 2). The fee vries y rop. Beuse glyphoste-resistnt sugr eet re not yet sold ommerilly, this fee hs not een estlished. One estimte hs pled the dditionl ost of glyphoste-resistnt sugr eet seed t US $ per unit of, seeds (Rie et l. 2). In 6-m rows t seed sping of 7. m, this would equte to US $4/h. By ssemling gronomi dt from severl different field studies, Burgener et l. (2) predited tht net returns would e equl etween glyphoste-resistnt nd onventionl systems if glyphoste-resistnt seed osts pproximtely US $24/h more thn onventionl seed. Forty-six perent of Burgener et l. s figure ws ttriuted to n inrese in root yield (Y) in the glyphoste-resistnt system, wheres redution in input osts ounted for the remining 4%. For produers to py suh lrge perentge of totl weed-ontrol osts t the time of seed purhse, finnil inentive eyond rek-even senrio will e required. For this reson, Burgener et l. (2) predited tht n dditionl seed ost in exess of US $23/h will prohiit doption of the tehnology. Assuming n dditionl ost of US $2/h for glyphoste-resistnt seed, Ginessi et l. (22) estimted tht glyphoste-resistnt sugr eet would result in n verge US $4/h svings in totl input osts if the tehnology is epted. My (23) pproximted tht frmers in the U.K. ould sve over US $24/h y plnting genetilly modified heriide-tolernt sugr eet, even fter pying US $4/h more for glyphosteresistnt seed. However, Ginessi et l. (22) ssume no differene in surose prodution etween the two systems, wheres My (23) only ounts for differenes in yield etween the two systems due to weed eet in the onventionl system. Few refereed rtiles hve een pulished diretly ompring eonomis of the glyphoste-resistnt weed mngement system with onventionlly used weed mngement progrms pplied to onventionl sugr eet ultivrs (My 23). Most eonomi nlyses of heriide-tolernt sugr eet to dte hve omined dt from reserh onduted independently, often t different lotions nd times (Burgener et l. 2; Ginessi et l. 22; My 23). Beuse of deresing profit mrgins fed y most sugr eet produers, it is impertive tht mngement deisions re sed on eonomi dt generted from side-y-side omprisons. The ojetive of this reserh ws to ompre eonomi spets of glyphoste pplied to glyphoste-resistnt sugr eet ultivrs with tht of onventionl heriide progrms pplied to ner-equivlent onventionl ultivrs. MATERIALS AND METHODS Field studies were onduted t four sites ner Sottsluff, NE (the Sott nd Mithell in 2, nd the Sott nd Sottsluff in 22). Soil t ll sites ws Tripp very fine sndy lom (Typi Hplustolls) with ph of 7.6, 7., nd 7.6 nd orgni mtter ontent of.2,., nd.% t Mithell, the Sott, nd Sottsluff, respetively. The experimentl design ws split-plot with min plots rrnged in rndomized omplete loks with four replitions. Twelve whole-plot ftors inluded n untreted; glyphoste-resistnt nd non glyphoste-resistnt hnd weeds; glyphoste pplied POST one, twie, or three times; onventionl weed ontrol progrms onsisting of desmediphm (DES) plus phenmediphm (PHEN) plus triflusulfuron (TRIF) plus lopyrlid pplied POST two or three times with or without ethofumeste PRE; nd mirorte tretment of DES plus PHEN plus TRIF plus lopyrlid plus methylted seed oil djuvnt pplied POST three times with or without ethofumeste PRE (Tle ). Sugr eet ultivrs ville with nd without glyphoste-tolerne trit were hosen. All non glyphoste heriide tretments were pplied to onventionl sugr eet ultivrs ( Bet 446 4 or HM 64 ), wheres glyphoste tretments were pplied to glyphoste-resistnt ultivrs ( Bet 446RR 4 or HM 64RR ) for totl of two split-plot ftors. Eh onventionl ultivr nd its ner-equivlent mde up one split-plot ftor. Bet 446RR ontins trnsgeni event onferring glyphoste-tolerne tht t the time of this pulition is not registered for use in the United Sttes. HM 64RR ontins the trnsgeni event GTSB77 nd hs reeived 4 Betseed In., 7 Mrshll Rod, P.O. Box 9, Shkopee, MN 379. Syngent, 939 Sugrmill Rod, Longmont, CO. Volume, Issue 2 (April June) 24 39
KNISS ET AL.: GLYPHOSATE-RESISTANT SUGAR BEET Tle. Weed ontrol tretment pplition rtes nd timings. Tretment nme Heriides Rte growth stge Sugreet Averge weed height Hnd weed PRE Conventionl 2 Mirorte d Conventionl 3 Glyphoste Glyphoste 2 Glyphoste 3 Ethofumeste PHEN DES TRIF CLOP PHEN DES TRIF CLOP PHEN DES TRIF CLOP Glyphoste Glyphoste Glyphoste Glyphoste Glyphoste Glyphoste kg/h.2.9.9.2..4.4..2.9.9.2..4.4.4.4.4.4 Throughout seson PRE Cot, 2-4 TL Cot, 2 TL, 4TL Cot, 2-4 TL, 4-6 TL m 4 DAFT 4 DAFT 2 DAFT Arevitions: PHEN, phenmediphm; DES, desmediphm; TRIF, triflusulfuron; CLOP, lopyrlid; COT, otyledon; 2-4 TL, two to four true-lef; 2 TL, two true-lef; 4 TL, four true-lef, 4-6 TL, four to six true-lef; DAFT, dys fter first tretment. Glyphoste rtes re given in e, ll other heriide rtes re given in i. When tretment ws initited. d Mirorte lso inluded the ddition of methylted seed oil t.% y volume. nonregulted sttus for use in the United Sttes (USDA 9). Split plots were six rows, sped 6 m prt. Plot length ws 9. m in 2, 2.2 m in 22. Sugr eet ws plnted to stnd on prepred eds in mid- to lte April (Tle 2) t depth of 2. m nd rte of four seeds per 3 m of row. Heriides were pplied rodst with trtor-mounted spryer in 2 nd kpk spryer in 22. Spry volume delivered ws 9 L of wter/h t 27 kp pressure with Tee-Jet 2 nozzles. 6 Heriide pplition dtes re given in Tle 2. Hnd-weeded ontrols were kept weed free eginning on June, 2, nd My, 22, through August 2 in oth yers. Plots were furrow irrigted nd ultivted s needed t ll lotions, with the exeption of Mithell in 2, whih ws not ultivted, nd Sottsluff in 22, whih ws irrigted with n overhed sprinkler system. All plots were irrigted soon fter plnting to id sugr eet emergene nd inorportion of PRE ethofumeste. All weeds etween the enter two rows in the entire length of eh plot were ounted pproximtely 4 d fter finl glyphoste pplition. Perent weed ontrol ws lulted y dividing numer of weeds in eh treted plot y the men from untreted ontrols. Visul sugr eet injury ws oserved to 4 d following finl glyphoste pplition nd rted on -point sle, with no visile injury nd deth of ll sugr eet plnts. The enter two rows of eh plot were mhine hrvested, weighed, nd nlyzed for sugr ontent 6 Sprying Systems Co., P.O. Box 79, Wheton, IL 69. t the Western Sugr 7 tre lortory. A seprte lortory nlyzed ll roots from this reserh to ensure tht trnsgeni sugr eet remined out of ommeril proessing filities. Yield dt olleted inluded Y nd surose ontent. Gross surose prodution ws lulted y multiplying the Y y the perent surose. Eonomi returns were lulted from yield dt. Gross returns (R G ) were lulted for eh plot on the sis of the Western Sugr grower ontrt pyment shedule. Prie per ton is dependent on the surose ontent nd the verge prie of sugr from the pyment shedule. Gross returns were lulted with the following formul: where R ((Y-tre) % surose ontent)p [] G Y root yield in kg/h P prie of sugr in $/kg An djustment for tre ws inorported into Eqution to reflet more urtely the pyment grower would reeive. Tre dt were not ville from trnsgeni reserh plots, so tre dt gthered from other reserh plots in the sme field were verged, nd the resulting vlue used in the lultion. Net return is defined in this nlysis s the eonomi return on investment nd mngement. All osts of prodution other thn weed ontrol were derived from Burgener (2) nd were equl ross tretments. Additionl osts of huling sugr eet roots to the pile were 7 Western Sugr Corporte Hedqurters, 7 Est Hmpden Avenue, Suite 6, Denver, CO 23. 39 Volume, Issue 2 (April June) 24
WEED TECHNOLOGY Tle 2. Plnting, heriide pplition, nd hrvest dtes. Site Tretment or opertion Timing Mithell 2 Sott 2 22 Sottsluff 22 Plnt PRE Conventionl 2 nd 3 Conventionl 2 nd 3 Conventionl 3 Mirorte Mirorte Mirorte Glyphoste, 2, nd 3 Glyphoste 2 nd 3 Glyphoste 3 Hrvest PRE COT 2-4 TL 4-6 TL COT 2TL 4TL -m weeds 4 DAFT 2 DAFT April 23 April 27 My 4 My 2 My 3 My 4 My 2 My 3 My 3 June June 27 Otoer 3 April 23 April 27 My 6 My 23 My 3 My 6 My 23 My 3 My 3 June June 27 Otoer 4 April April 23 My 4 My 3 June My 4 My 2 My 2 June 3 June 7 July Otoer April 22 April 23 My 4 My 23 June 3 My 4 My 2 My 2 My 2 June June 24 Otoer 4 Arevitions: COT, sugreet otyledon stge; 2-4 TL, sugreet two to four true-lef stge; 4-6 TL, sugreet four to six true-lef stge; 2 TL, sugreet two true-lef stge; 4 TL, sugreet four true-lef stge; DAFT, dys fter first tretment. lulted y multiplying the fresh weight y the ustom hrge for huling. Weed ontrol osts were lulted using heriide pries listed (University of Nersk 22). Although ll heriide pplitions were pplied rodst, osts for ethofumeste nd onventionl rte pplitions of PHEN plus DES plus TRIF plus lopyrlid were lulted in 2-m nd to reflet more urtely pries ssoited with ommon grower prties. Sugr eet growers in Nersk generlly nd onventionl rtes of sugr eet heriides over the rop row nd then ultivte to remove weeds from etween the rows to sve on heriide osts. All sites exept Mithell were ultivted two to three times during the growing seson. Cultivtion removed weeds etween the rop row, thus negting ny weed ontrol enefit of rodsting vs. nding the heriides. A dithing opertion t the Mithell site produed similr effet. Beuse ll weeds outside the lulted nd re were removed mehnilly, it is ssumed tht no weed ontrol differenes would e oserved etween nd nd rodst pplitions. Beuse of its low ost, it is ntiipted tht growers will pply glyphoste rodst to glyphoste-resistnt sugr eet. Costs of prodution inluding weed mngement nd huling were sutrted from R G to otin net return for eh plot. All dt were sujet to ANOVA. Weed ontrol nd rop injury dt were rsine squre root trnsformed; euse no enefit from the trnsformtion ws oserved, tul dt re presented. No yer y tretment intertion ws present, so yield nd eonomi dt were verged over yers for nlysis. When omining dt, the MIXED proedure in SAS (2) ws used, treting yer s fixed effet nd lotions s rndom effets. Men seprtion ws performed using Fisher s proteted LSD. Where pproprite, single degree of freedom ontrsts were onstruted to ompre groups of glyphoste tretments with groups of onventionl heriide tretments, nd the estimtes ssoited with these ontrsts re reported s rek-even osts of the dditionl fee tht will likely ompny glyphoste-resistnt sugr eet seed. RESULTS AND DISCUSSION Weed Control nd Crop Injury. No weed ontrol tretment y ultivr intertion ws present with respet to rop injury or weed ontrol, so tretment dt were verged over ultivrs for nlysis. Dt re presented seprtely y site euse of differing environmentl onditions nd weed popultions influening rop injury nd weed ontrol (Tle 3). One pplition of glyphoste provided vrile weed ontrol. Two or three pplitions of glyphoste provided t lest 9% weed ontrol t ll sites exept the Sott site in 22. Beuse of drought onditions t this site, weed popultions were extremely low erly in the seson. Even fter sugr eet hd een irrigted severl times to id in emergene nd stnd estlishment, weed density remined reltively low. However, it is importnt to note tht euse of low weed densities erly in the seson, high degree of ontrol ws not neessry to void sugr eet yield loss. Although weed ontrol ppers to e worse t the Sott in 22 thn t the other sites, most weeds present were not of eonomi onsequene. Mny weeds tht were ounted on July germinted fter the rop nd did not grow ove the sugr eet nopy thus voiding sugr eet yield loss. Three POST pplitions of PHEN plus DES plus Volume, Issue 2 (April June) 24 39
KNISS ET AL.: GLYPHOSATE-RESISTANT SUGAR BEET Tle 3. Sugreet injury nd weed ontrol s influened y weed ontrol tretment t four sites ner Sottsluff, NE, in 2 nd 22. Tretment Crop injury Mithell 2 Weed ontrol Crop injury Sott 2 Weed ontrol Crop injury Sott 22 Weed ontrol Sottsluff 22 Crop injury Weed ontrol % Untreted Hnd weed Glyphoste Glyphoste 2 Glyphoste 3 Hnd weed d PRE onventionl 2 d Conventionl 2 d PRE mirorte d Mirorte d PRE onventionl 3 d Conventionl 3 d LSD (.) 4 2 2 7 6 3 9 76 77 93 9 3 2 4 7 7 6 3 7 4 9 67 76 9 2 3 3 6 34 44 3 34 2 3 9 2 39 2 9 9 9 9 9 9 93 6 Rted to 4 d fter finl glyphoste pplition. Control of totl weed popultion pproximtely 4 d fter finl glyphoste pplition. Applied to sugreet ultivrs HM 64RR nd Bet 446RR. Dt re verged over ultivrs. d Applied to sugreet ultivrs HM 64 nd Bet 446. Dt re verged over ultivrs. TRIF plus lopyrlid t onventionl rtes generlly gve the gretest weed ontrol mong onventionl or mirorte heriide tretments. No weed ontrol enefit ws oserved y pplying ethofumeste PRE efore this tretment. The pplition of ethofumeste PRE followed y (f) three onventionl rte POST pplitions used greter rop injury thn POST-only tretments t the Sottsluff site in 22 (Tle 3). Freezing tempertures on April 2 ( 7 C)ndMy2( 4 C), strong winds on My 2 nd 22, nd ethofumeste PRE f three POST pplitions of the onventionl heriides omined to use 39% injury nd 4% redution of lef re (dt not shown) ompred with the hnd-weeded ontrol. This my e in prt euse of irrigtion the dy efore freezing tempertures ourred. Greter heriidl tivity of ethofumeste in wet soils ompred with dry soils hs een doumented previously y MAuliffe nd Appley (9, 94). Irrigtion wter sturted the soil ner the surfe, whih would inrese the onentrtion of ethofumeste in the soil solution (MAuliffe nd Appley 94). Ethofumeste tken up y sugr eet roots nd hypootyls is rpidly trnsloted into folige (Eshel et l. 97). Inresed heriide in the folige t the time of the freeze proly ontriuted to intensified rop response. Hnd weeding in 2 did not egin until weeds were pproximtely m tll. This erly-seson ompetition in ddition to injury from weed removl resulted in rop injury tht ws greter thn expeted t oth lotions. Hnd weeding ws egun erlier in 22, thus using less injury to the rop. Cultivr Differenes in Surose Content. Lotions were treted s rndom effets, nd no yer y tretment intertion ws present, so dt were omined over lotions nd yers for nlysis. Heriide tretment y ultivr intertions were present with respet to surose ontent, so simple effets of surose dt re presented. The intertions resulted from differenes in surose ontent etween trnsgeni nd onventionl ultivrs. No signifint differenes existed etween Bet 446 nd HM 64 with respet to surose ontent regrdless of weed ontrol tretment (Tle 4). Conversely, ll dif- Tle 4. Surose ontent s ffeted y ultivr nd weed ontrol tretment verged over four sites ner Sottsluff, NE, in 2 nd 22. Tretment Untreted Hnd weed Glyphoste Glyphoste 2 Glyphoste 3 Hnd weed PRE onventionl 2 Conventionl 2 PRE mirorte Mirorte PRE onventionl 3 Conventionl 3 Bet 446 or Bet 446RR 4.32 d.97.96. 6.23.7.3.2..3 4.4.34 Surose ontent % HM 64 or HM 64RR 2.6 4.9.6 4.76 4.6.6.36.32 4.92.4..67 P t..69.6...6.632.9.3.663.6623.379 P vlues orrespond to ultivr omprisons within row. Applied to sugreet ultivrs HM 64RR nd Bet 446RR. Applied to sugreet ultivrs HM 64 nd Bet 446. d Lest squre mens within olumn followed y the sme letter re not signifintly different (.). 392 Volume, Issue 2 (April June) 24
WEED TECHNOLOGY Tle. Cultivr differenes in surose ontent verged over four sites ner Sottsluff, NE, in 2 nd 22. Comprison Differene in surose ontent P t HM 64RR hnd weed vs. HM 64 hnd weed Bet 446RR hnd weed vs. Bet 446 hnd weed All HM 64RR tretments vs. ll HM 64 tretments (inluding hnd weed) All Bet 446RR tretments vs. ll Bet 446 tretments (inluding hnd weed) HM 64RR heriide tretments vs. HM 64 heriide tretments Bet 446RR heriide tretments vs. Bet 446 heriide tretments Untreted dt re not inluded in this nlysis. * Denotes signifine (.). ** Denotes signifine (.). %.6.26.44*.6**.43.66**.232.64.22.73.39.23 ferenes etween Bet 446RR nd HM 64RR were signifint whether treted with glyphoste, hnd weeded, or no tretment ws pplied. This suggests the differenes re not euse of differentil tolerne to the heriide. No differenes were pprent etween heriide tretments within ultivr (Tle 4). When ompring hnd-weeded ontrols, differenes in surose ontent etween trnsgeni ultivrs nd their ner-equivlent onventionl ultivrs were not sttistilly signifint (Tle ). However, when verged over tretments, greter surose ws produed y Bet 446RR thn Bet 446 nd trend for lower surose ws oserved in HM 64RR ompred with HM 64. The geneti kgrounds of Bet 446 nd Bet 446RR re quite similr, nd for ll prtil purposes the ultivrs re equivlent with the exeption of the glyphoste-tolerne trit (J. R. Stnder, personl ommunition). 4 Beuse of the similr genetis of these ultivrs, we onlude tht greter weed ontrol nd redued rop injury re responsile for the greter surose ontent in Bet 446RR. Greter weed ontrol nd redued rop injury were lso hieved in HM 64RR when ompred with HM 64, ut trend for lower surose ontent ws oserved in HM 64RR (Tle ). Approximtely 7 to 7.% of the HM 64 genotype is shred y HM 64RR (R. Mrtens, personl ommunition). Although the ultivrs re visully indistinguishle, the genetis my llow for onsiderle differenes etween the ultivrs side from glyphoste-tolerne. Surose prodution in sugr eet is inherited in omplex fshion (Shneider et l. 22), so 2 to 2% genotypi differene etween HM 64 nd HM 64RR ould explin the trend for lower surose ontent. Sugr eet Yield. When verged over sites, three pplitions of glyphoste pplied to Bet 446RR produed greter Y thn ll onventionl nd mirorte heriide tretments exept ethofumeste PRE f the mirorte nd greter gross surose prodution thn ll onventionl nd mirorte heriide tretments when pplied to Bet 446 (Tle 6). One pplition of glyphoste to Bet 446RR produed similr gross surose to tht of ll onventionl heriide tretments pplied to Bet 446. These differenes suggest ovious yield enefits from swith to glyphoste use on glyphosteresistnt sugr eet (Bet 446RR) from onventionl sugr eet (Bet 446) using onventionl heriides. Three pplitions of glyphoste pplied to HM 64RR resulted in greter Y thn ethofumeste PRE f two or three pplitions of the onventionl tretment, two POST pplitions of the onventionl tretment, nd the mirorte without ethofumeste PRE pplied to HM 64 (Tle 6). However, euse of the redued surose ontent of HM 64RR, only the mirorte nd two pplitions of the onventionl progrm pplied to HM 64 produed less gross surose thn three POST pplitions of glyphoste pplied to HM 64RR. Eonomis of Glyphoste-Resistnt nd Conventionl Sugr eet. Glyphoste pplied three times to Bet 446RR resulted in greter gross eonomi return thn onventionl or mirorte tretments pplied to Bet 446 (Tle 7). Greter R G in omintion with lower tretment osts mke differenes in net returns etween glyphoste-resistnt nd onventionl systems sustntil. Glyphoste pplied two or three times to Bet 446RR resulted in greter net return thn ll onventionl or mirorte tretments pplied to Bet 446. Two pplitions of glyphoste to Bet 446RR resulted in $43/h greter net return thn ny onventionl or mirorte tretment. All onventionl nd mirorte tretments resulted in similr net returns s one pplition of glyphoste. Differenes in tretment osts explin Volume, Issue 2 (April June) 24 393
KNISS ET AL.: GLYPHOSATE-RESISTANT SUGAR BEET Tle 6. Root yield nd gross surose prodution s ffeted y weed ontrol tretment verged over four sites ner Sottsluff, NE in 2 nd 22. Bet 446 or Bet 446RR HM 64 or HM 64RR Tretment Root yield Gross surose Root yield Gross surose kg/h Hnd weed Untreted Glyphoste Glyphoste 2 Glyphoste 3 Hnd weed PRE onventionl 2 Conventionl 2 PRE mirorte Mirorte PRE onventionl 3 Conventionl 3 3,6, d 43,7,6 7,,4 46,6 44,6 49,7 47,7 46,6 44,,,7 d 6,9, 9,3, 7,2 6,9 7, 7,3 6,9 6,9 46,, d 46,2,3 3, 4,9 44,9 4, 47, 4,4 43,7 4,7 7,,6 d 6,9 7, 7, 7,7 7, 6,3 7,2 6, 6, 7, Applied to sugreet ultivrs HM 64RR nd Bet 446RR. Lest squre mens within olumn followed y the sme letter re not signifintly different (.). Applied to sugreet ultivrs HM 64 nd Bet 446. only frtion of the differenes in net return, whih re primrily euse of inresed surose prodution. Gross eonomi returns for HM 64 nd HM 64RR were similr etween ll heriide tretments (Tle 7). Differenes were evident etween net returns of two or three pplitions of glyphoste nd the mirorte without ethofumeste PRE nd ethofumeste PRE f three POST pplitions of the onventionl tretment euse of differenes in surose prodution in omintion with the lower ost of glyphoste tretments. Tretment osts explin greter perentge of the differenes in net returns etween HM 64 nd HM 64RR. It is possile tht if the ost of onventionl sugr eet heriides were redued euse of ompetition, ptent expirtion, et., the eonomi enefit of swithing to the glyphoste-resistnt HM 64RR from HM 64 might eome negligile. It is ntiipted tht n dditionl fee will e dded to the sle prie of glyphoste-resistnt seed s is the se in other rops. By ompring net returns in glyphoste tretments with net returns of onventionl heriide tretments, rek-even vlue for this dditionl ost n e lulted (Tle ). A fee less thn the rek-even vlue will e ssumed to enefit produer who dopts glyphoste-resistnt tehnology, wheres fee greter thn the rek-even vlue would e detrimentl to the dopting produer. Assuming these estimtes re sed on medin prodution onditions, in % of the yers tul rek-even osts will e greter nd in % of the yers tul rek-even osts will e less. To inrese the proility tht the tehnology will e profitle, the mount produer is willing to py should e somewht less thn the rek-even ost. For eh estimte, the stndrd error nd lower limit of the Tle 7. Gross nd net return s influened y heriide tretment nd sugreet ultivr verged over four sites ner Sottsluff, NE in 2 nd 22. Tretment Tretment ost Bet 446 or Bet 446RR HM 64 or HM 64RR Gross return Net return Gross return Net return $/h Untreted Glyphoste Glyphoste 2 Glyphoste 3 PRE onventionl 2 Conventionl 2 PRE Mirorte Mirorte PRE onventionl 3 Conventionl 3 3 69 4 232 7 2 39 2 39 e,6 d 2,2 2,26,77 d,63 d,6 d,742 d,69 d,646 d 44 d 332 77 36 64 66 22 233 9 7 37,646,72,,69,3,72,46,7,72 72 292 3 43 44 3 26 74 3 Glyphoste tretments were pplied to sugreet ultivrs HM 64RR nd Bet 446RR while nonglyphoste tretments were pplied to HM 64 nd Bet 446. Net return defined s return to investment nd mngement. Lest squre mens within olumn followed y the sme letter re not signifintly different (.). 394 Volume, Issue 2 (April June) 24
WEED TECHNOLOGY Tle. Brekeven estimtes for the dditionl ost of glyphoste-resistnt sugreet seed. Comprison Brekeven estimte Stndrd error Lower limit 9% CI $/h Averged over ultivrs Glyphoste vs. onventionl heriides Glyphoste 2 or 3 vs. PRE onventionl 2 Glyphoste 2 or 3 vs. onventionl 2 Glyphoste 2 or 3 vs. PRE mirorte Glyphoste 2 or 3 vs. mirorte Glyphoste 2 or 3 vs. PRE onventionl 3 Glyphoste 2 or 3 vs. onventionl 3 Bet 446RR vs. Bet 446 Glyphoste vs. onventionl heriides Glyphoste 2 or 3 vs. PRE onventionl 2 Glyphoste 2 or 3 vs. onventionl 2 Glyphoste 2 or 3 vs. PRE mirorte Glyphoste 2 or 3 vs. mirorte Glyphoste 2 or 3 vs. PRE onventionl 3 Glyphoste 2 or 3 vs. onventionl 3 HM 64RR vs. HM 64 Glyphoste vs. onventionl heriides Glyphoste 2 or 3 vs. PRE onventionl 2 Glyphoste 2 or 3 vs. onventionl 2 Glyphoste 2 or 3 vs. PRE mirorte Glyphoste 2 or 3 vs. mirorte Glyphoste 2 or 3 vs. PRE onventionl 3 Glyphoste 2 or 3 vs. onventionl 3 3* 432* 477* 37* 44* 633* 472* 479* 63* 6* 494* 46* 796* 72* 294* 22 343* 24 42* 472* 24 7 4 4 4 4 4 6 7 6 7 6 6 94 6 6 6 63 6 6 24 23 24 232 3 227 39 336 326 27 262 9 42 4 2 79 2 4 2 2 Arevitions: CI, onfidene intervl. * Denotes signifint omprison (.). 9% onfidene intervl re reported. By not pying more thn the lower limit of the 9% onfidene intervl, it is ssumed tht the produer will e t lest s profitle s the onventionl system 9% of the time. The first rek-even estimte given in Tle orresponds to the verge net return of ll glyphoste tretments ompred with the verge net return of ll onventionl heriide tretments (inluding mirortes) when verged over ultivrs. Beuse one, two, nd three pplitions of glyphoste were inluded in this estimte, it is onsiderly less thn most vlues generted when only two or three pplitions of glyphoste re inluded. The inrese in net return of two or three pplitions of glyphoste is greter thn the ost of the extr tretments; hene, there is n inrese in net return nd onsiderle inentive for produers to pply glyphoste seond or third time. For this reson, rekeven vlues were lulted ompring these two tretments with eh onventionl heriide tretment. If produer usully plnts the ultivr HM 64 nd uses the mirorte progrm for weed ontrol, it would e ost effetive to swith to the glyphoste-resistnt ultivr s long s the dditionl ost of seed ws less thn US $42/h (Tle ). As result of inresed surose prodution, produer normlly plnting Bet 446 with the mirorte weed mngement progrm ould fford the glyphoste-resistnt Bet 446RR s long s the dditionl seed ost does not exeed US $46/h. When verged over heriide tretments, the rek-even vlue for HM 64RR is US $294/h, wheres the rek-even vlue for Bet 446RR is US $479/ h. If verged over heriide tretments nd ultivrs, the resulting rek-even vlue is US $3/h. The differenes etween these vlues serve s reminder of the importne of ultivr seletion to those who my e inlined to generlize out glyphoste-resistnt tehnology in sugr eet. It is essentil to differentite etween glyphoste-resistnt sugr eet ultivrs if they result in signifint differene in surose yield. The results of this reserh emphsize the need to ondut eonomi nlyses on dt generted from side-yside omprisons mde within single study. The lrge ultivr differenes presented here would hve likely een ttriuted to environmentl onditions nd verged if tken from independent studies. Side-y-side omprisons re lso required to disern differenes in prodution etween the two systems, whih hve een ignored y severl previous eonomi nlyses. The inorportion of trits into epted ultivrs n e time-intensive proess euse of the iennil nture of Volume, Issue 2 (April June) 24 39
KNISS ET AL.: GLYPHOSATE-RESISTANT SUGAR BEET sugr eet. The time involved is mplified when deling with trnsgeni trits. In the time it tkes reeders to produe trnsgeni ultivr tht is ommerilly eptle, newer, higher-yielding onventionl ultivrs will hve entered the mrket. For this reson future eonomi nlyses should inlude side-y-side omprisons of lolly dpted, top-yielding ultivrs regrdless of whether glyphoste-resistnt version of the ultivr is ville. Introdution of glyphoste-resistnt sugr eet into the U.S. mrket would llow sugr eet produers new weed mngement tool. If used properly with other est mngement prties, the tehnology will ply n importnt role in hieving higher surose yields s result of improved weed ontrol nd redued sugr eet injury. The improved yields in ddition to lower input osts will id in inresing net eonomi returns to produers who dopt the tehnology s long s the dditionl seed ost is not prohiitive. The lower ost of glyphoste ompred with onventionl sugr eet heriides, long with its extended window of pplition nd wider spetrum of weed ontrol represents redution in risk to produers. The differenes in yield, nd onsequently net return nd rek-even vlues etween glyphoste-resistnt ultivrs serve s ution to sugr eet produers ontemplting hnge to glyphoste-resistnt sugr eet. Beuse ultivr is glyphoste resistnt does not neessrily men greter profits. Choosing high yielding ultivr dpted to lol growing onditions should still e top priority. LITERATURE CITED Burgener, P. A. 2. Eonomis of sugreet prodution. In R. G. Wilson, ed. Sugreet Prodution Guide. University of Nersk Coopertive Extension. Linoln, NE: University of Nersk. Pp. 9 96. Burgener, P. A., D. M. Feuz, nd R. G. Wilson. 2. Eonomis of trnsgeni sugreet prodution. Western Agriulturl Eonomis Assoition Annul Meetings, June 29 July, 2. Vnouver, Cnd: Western Agriulturl Eonomis Assoition. 2 p. Dwson, J. H. 974. Full-seson weed ontrol in sugreets. Weed Si. 22: 33 33. Dexter, A. G., J. L. Lueke, nd L. J. Smith. 9. Influene of Cultivtion on Yield of Roundup Redy nd Lierty Link Sugreets. Sugreet Reserh nd Extension Reports, North Dkot Stte University: We pge: http://www.sre.org/reserh/weed/weed/p.htm. Aessed: June 26, 23. Eshel, J., R. L. Zimdhl, nd E. E. Shweizer. 97. Uptke nd trnslotion of ethofumeste [heriide] in sugr-eet plnts. Pesti. Si. 9:3 34. Ginessi, L. P., C. S. Silvers, S. Snkul, nd J. E. Crpenter. 22. Plnt Biotehnology: Current nd Potentil Impt for Improving Pest Mngement in U.S. Agriulture: An Anlysis of 4 Cse Studies. Wshington, DC: Ntionl Center for Food & Agriulturl Poliy. Guz, C. J., C. V. Rnsom, nd C. Mllory-Smith. 22. Weed ontrol in glyphoste-resistnt sugreet (Bet vulgris L.). J. Sugr Beet Res. 39: 9 23. Hmlin, W. G. nd D. C. Groskurth. 22. 22 Nersk Agriulturl Sttistis. Linoln, NE: Nersk Agriulturl Sttistis Servie. 44 p. Johnson, W. G., P. R. Brdley, S. E. Hrt, M. L. Buesinger, nd R. E. Mssey. 2. Effiy nd eonomis of weed mngement in glyphoste-resistnt orn (Ze mys). Weed Tehnol. 4:7 6. My, M. J. 23. Eonomi onsequenes for UK frmers of growing GM heriide tolernt sugr eet. Ann. Appl. Biol. 42:4 4. MAuliffe, D. nd A. P. Appley. 9. Effet of pre-irrigtion period on the tivity of ethofumeste pplied to dry soil. Weed Si. 29:72 77. MAuliffe, D. nd A. P. Appley. 94. Ativity loss of ethofumeste in dry soil y hemil degrdtion nd dsorption. Weed Si. 32:46 47. Miller, S. D. nd A. O. Mesh. 2. Weed ontrol nd sugreet response with miro-rtes of postemergene heriides. Pro. Western So. Weed Si. 3:73. Nolte, S. A. nd B. G. Young. 22. Effiy nd eonomi return on investment for onventionl nd heriide-resistnt orn (Ze mys). Weed Tehnol. 6:37 37. Nolte, S. A. nd B. G. Young. 22. Effiy nd eonomi return on investment for onventionl nd heriide-resistnt soyen (Glyine mx). Weed Tehnol. 6:3 39. Reddy, K. N. nd K. Whiting. 2. Weed ontrol nd eonomi omprisons of glyphoste-resistnt, sulfonylure-tolernt, nd onventionl soyen (Glyine mx) systems. Weed Tehnol. 4:24 2. Rie, C. A., A. Mesh, nd S. D. Miller. 2. Eonomi evlution of weed mngement systems in sugreets. Pro. Am. So. Sugr Beet Teh. 3: 64. [SAS] Sttistil Anlysis Systems. 2. The SAS System for Windows. Version e. Cry, NC: Sttistil Anlysis Systems Institute. (online version.) Shneider, K., R. Shfer-Pregl, D. C. Borhrdt, nd F. Slmini. 22. Mpping QTLs for surose ontent, yield nd qulity in sugr eet popultion fingerprinted y EST-relted mrkers. Theor. Appl. Genet. 4: 7 3. [USDA] United Sttes Deprtment of Agriulture. 9. Novrtis Seeds nd Monsnto Co.; vilility of determintion of nonregulted sttus for sugr eet genetilly engineered for glyphoste heriide tolerne. Fed. Reg. 64:77 7. University of Nersk. 22. 22 Guide for Weed Mngement in Nersk. University of Nersk Coopertive Extension EC-3-D. 33 p. Wilson, R. G. 9. Miro rtes of desmediphm plus phenmediphm for weed ontrol in sugreet. Pro. North Cent. Weed Si. So. 4:. Wilson, R. G., C. D. Yonts, nd J. A. Smith. 22. Influene of glyphoste nd glufosinte on weed ontrol nd sugreet (Bet vulgris) yield in heriide tolernt sugreet. Weed Tehnol. 6:66 73. 396 Volume, Issue 2 (April June) 24