Agronomic approaches in yield and quality stability of high oleic sunflowers (Helianthus annuus L.)

Transcription

1 Agronomic pproches in yield nd qulity stbility of high oleic sunflowers (Helinthus nnuus L.) to obtin the Ph. D. degree in the Fculty of Agriculturl Sciences, Georg-August-University Göttingen, Germny presented by Burcin Dilci born in Ankr, Turkey Göttingen, November 2008

2 D 7 1. Nme of referee: Prof. Dr. Jörg M. Greef 2. Nme of co-referee: Prof. Dr. Elke Pwelzik Dte of disserttion:

3 Nothing shocks me I m scientist.

4 hen the sunflower fell in love with the sun, ll the other plnts died lughing. The sun never budges from his throne in the sky, they ll sid together. He is mighty nd unpprochble. Why should he spre glnce for you? Give up this folly. The sunflower didn t sy word, just fixed her loving eyes on the sun nd gzed with longing. For long time the sun didn t notice nything, but finlly one dy he felt this gze upon him. At first he thought it ws pssing fncy, but in time he relized he hd been mistken. The sunflower ws so stubborn tht wherever he moved his throne she tirelessly turned her fce in tht direction. So it went until one fternoon, fed up with this constnt pursuit, the sun turned his yellow wrth on the sunflower nd scorched her. While the blck smoke ws still curling upwrds, people cme thronging to the scene. Wonderful! one of them sid, Now we ll be ble to nibble this love. The gze of the sunflower is turned on the sun ll dy, but in Turkish the nme is yçiçegi, or "moonflower." Is this becuse its love for the sun is fed by moonlight through the hours of the night? Source: Elif Sfk, Mhrem

5 LIST OF ABBREVIATIONS BBCH: Biologische Bundesnstlt,Bundessortenmt nd CHemicl industry BTH: Benzo (1,2,3) thidizole-7-crbothioic cid S-methyl-ester CULTAN: Controlled Uptke Long Term Ammonium Nutrition HO: High Oleic IR: Induced Resistnce N: Nitrogen PGPR: Plnt Growth-Promoting Rhizobcteri ppm: prts per million SAR: Systemtic Acquired Resistnce TSW: Thousnd Seed Weight UAN: Ure Ammonium Nitrte UAN-N: Ure Ammonium Nitrte with Nitrifiction inhibitor UAS: Ure Ammonium Sulfte I

6 TABLE OF CONTENT 1 INTRODUCTION 1.1 Sunflowers (Helinthus nnuus L.) High oleic (HO) sunflowers (Helinthus nnuus L.) Expnding HO sunflower production re in Germny - leding studies Cultivtion of HO sunflowers under climtic conditions of centrl Europe 4 Criticl points t sowing nd erly growing stges Importnce of vriety selection Fungl diseses nd their control Control of Sclerotini nd Botrytis diseses 1.5 Alterntive griculturl pproches in HO sunflower cultivtion 8 Induced resistnce nd Acibenzolr-S-methyl (BTH) Injection of mmonium bsed liquid fertilizer Mikro-Vitl 1.6 Objectives 11 2 MATERIAL AND METHODS 2.1 FIELD EXPERIMENTS Experimentl sites Wether Dt Plnt Mteril Applictions 17

7 Fungicide ppliction The plnt ctivtor BION Ammonium bsed liquid fertiliztion Mikro-Vitl pplictions Field evlution nd dt collection Chemicl nlysis Sttisticl nlysis GREENHOUSE EXPERIMENTS 25 3 RESULTS 3.1. LOCATION AND VARIETY EFFECT Chnges in chene yield Chnges in oil content nd composition Chnges in fungl infection rte Interctions nd correltions between the experimentl fctors AGRICULTURAL APPLICATIONS Effect of fungicide tretment Effect of BTH seed tretment Effect of Bion lef spry ppliction Effect of mmonium bsed liquid fertiliztion Effect of mmonium bsed liquid fertiliztion method in combintion with Bion ppliction Effect of Mikro-Vitl SUGAR CONTENT AND SUGAR COMPOSITION OF THE PLANT PARTS Totl sugr content Fructose Glucose Sucrose Other wter soluble crbohydrtes 82 III

8 4 DISCUSSION 4.1 Achene nd oil yield of HO sunflowers Influence of environment nd loction Influence of genotype Fungl diseses nd their influence Fungicide ppliction Alterntive griculturl pproches The plnt ctivtor BTH (BION ) Ammonium bsed liquid fertiliztion Combintion of BION nd Ammonium Fertiliztion Mikro-Vitl Sugrs content of sunflower plnt prts Role of sugrs in fungl infections Dynmics of sugrs in the plnt CONCLUSION SUMMARY ZUSAMMENFASSUNG REFERENCES APPENDIX 129 ACKNOWLEDGMENT 149 CURRICULUM VITAE 151

9 1 INTRODUCTION 1.1 Sunflowers (Helinthus nnuus L.) Sunflower (Helinthus nnuus L.) is, together with soyben, rpeseed nd penut, one of the most importnt nnul crops in the world grown for edible oil. Helinthus is genus in the tribe Helinthee of the Composite fmily. Helinthus nnuus L. is ntive of North Americ. Its introduction to Europe ws mde through Spin. Although this crop ws originted in subtropicl nd temperte zones, through selective breeding, it hs been mde highly dptble, especilly to dry nd wrm temperte regions. 1.2 High oleic (HO) sunflowers (Helinthus nnuus L.) Regulr sunflower oil is chrcterized by its high content of the essentil linoleic cid (C18:2). Through conventionl breeding techniques, high oleic sunflower type hs been developed. The high oleic sunflower oil is in ppernce very similr to regulr sunflower oil. The seed's oil content is round 50 percent, which is similr to the conventionl sunflower. However, the ftty cid profile of the high oleic sunflower oil differs quite drmticlly from conventionl sunflower oil. The HO sunflower oil contins over 80 % oleic cid (C18:1), wheres the regulr sunflower oils oleic cid content is round 20 % (Figure 1.1). In comprison to the other oleic cid sources, the high oleic sunflower oil contins the highest mount of the monounsturted ft levels (Tble 1.1). Typiclly, HO sunflower oil contins 82 percent oleic cid, 9 percent linoleic cid, nd 9 percent

10 2 INTRODUCTION sturted ftty cids. In humn nutrition, the ftty cid composition cn be n importnt benefit to consider. In non-food pplictions, it is more necessity to extinguish the unwnted ftty cids. Regulr Sunflower Oil % 60 % 15-20% HO Sunflower Oil % 5-9% 9% Monounsturted ftty cids Polyunsturted ftty cids Sturted ftty cids Figure 1.1: Comprison between ftty cid composition of regulr nd HO sunflower oils. For mny pplictions, high oleic sunflowers provide n excellent rw mteril directly from the field. Primrily, no further cost intensive processes for the HO sunflower oil, like distilltion, crystlliztion or hydrogention, re necessry. At the moment, mostly used oleic cid source for the industry re beef tllow nd plm oleine. Besides higher levels of oleic cid, HO sunflower provides remrkble dvntges, such s neutrl smell, miniml coloring, lower melting point, or higher purity, over the trditionl oleic cid sources (Käb, 2001). Tble 1.1: Ftty cid composition of different oleic cid sources. *FA= Ftty Acid Oleic cid source Oleic Acid C18:1 Linoleic Acid C18:2 Linolenic Acid C18:3 Steric Acid C18:0 Plmitic Acid C16:0 HO-Sunflower Oil HO-Rpeseed Oil HO-Soyben Oil HO-Sfflower Oil Olive Oil Rpeseed Oil Plm Oil Tllow (Ft) Tllow-Oleine (FA*) Plm Oleine (FA*) Source: Käb, 2001, Gülzower Fchgespräche, Bnd 19 Others

11 INTRODUCTION 3 The high oleic sunflower plnt needs similr growing conditions s conventionl sunflowers. Nevertheless, there re some minor differences in cultivtion of this type. The high oleic sunflower plnts need two weeks longer vegettion period. The seed yield potentil of high oleic type is in generl slightly lower thn the regulr type. Lte ripening vrieties give higher seed yield, but therefore re under higher risk of getting infected by the lte fungl diseses. 1.3 Expnding HO sunflower production re in Germny - leding studies The lrgest production re for high oleic sunflower ppers in USA with 100,000 h HO sunflower cultivtion nnully, followed by Frnce (30,000-50,000 h/yer) nd is primrily for the food industry. In Germny, sunflower oil with high oleic cid content used minly in oleo-chemicl industry. Production re showed n incresing trend in up to 7-8 thousnd h in Germny. However it is still less importnt oil plnt in comprison to rpe seed nd linseed production. The min reson for this low interest in HO sunflower production from the frmers point of view is the yield instbility which is mostly relted to the griculturl constrints nd lck of know-how. Crop Science Institute of Federl Agriculturl Reserch Centre (FAL) in Brunschweig coordinted two previous projects with the object to secure yield nd increse HO sunflower production in Germny. The first model project ws promoted by Federl Ministry of Food, Agriculture nd Consumer Protection (BMELV) in order to encourge HO sunflower production under the title Expnding HO sunflower production in Germny in The im of the project ws to expnd the production re nd to develop new mrkets for the high oleic sunflower oil by trgeting good prices for the high qulity oil which shll ttrct the sunflower producers (Schlüter, 2001). In deed, the production re ws significntly incresed in 1998 nd 1999 in correltion with the higher prices. However, price decrese in high oleic sunflower oil in 2000 cused drmtic reduction in production re. The model project lso showed tht production risk cused by inconstnt yields is lso n importnt reson for the lck of interest from producer s point of view. Project coordintor Dr. Schlüter points t 3 importnt spects in HO sunflower production to be improved. A fst qulity mesurement method, well dopted vrieties, nd stbile yield through griculturl mesures.

12 4 INTRODUCTION The second project on HO sunflowers coordinted by the Crop Science Institute ws prtilly promoted by UFOP in under the title Yield security in HO sunflowers through griculturl mesures. The min objective of this project ws to stbilize the grin yield which is minly ffected by the insect nd fungl disese ttcks s well s the lte ripening behviour of HO sunflowers. On the field, driving through pths were estblished to be ble to pply the fungicide t the lte vegettion period. 1.4 Cultivtion of HO sunflowers under climtic conditions of centrl Europe Environmentl effects Sunflower is C3 plnt nd dpts best to the temperte. It requires dequte light, hs tolernce to both cold nd high tempertures tht contributes to sunflower s dpttion in different environments (Robinson, 1978). However, in generl, sunflowers grow best in dry nd wrm regions where sum of temperture reches C in the cultivtion period (Hugger, 1989). Its chrcteristics mke the sunflowers suitble to the southern Europe climtic conditions. Sunflower s dpttion decreses northwrds strting from centrl Europe, which includes northern Germny. Sunflower is clssified s very sensitive crop to environmentl influences (Diepenbrock, 1995). Environmentl fctors ffect the yield nd qulity trits of sunflower seeds (Ahmd, 2001). Yield prmeters such s number of full chenes nd the chene weight (Rwson et l., 1984) s well s the oil yield (Dompert nd Beringer, 1976) rect negtively to high temperture (bove 30 C). Temperture is lso the min environmentl fctor ffecting oil qulity (Tremolieres et l., 1982). It is lso reported in HO sunflowers tht environmentl fctors, especilly the soil chrcteristics, re the determining fctors in grin yield (Vetter, 1996). HO type sunflowers hve comprble yield potentil to the commercil type sunflowers (Müller-Sämnn et l., 2003). However, minly climtic fctors hinder its production in cooler temperte climte zones including Germny. In contrst to the min sunflower production regions in subtropicl or Mediterrnen zones, min constrint in Germny, regrding climtic fctors, is the cold nd wet wether conditions during germintion nd lte mturing. Therefore its cultivtion in Germny is considered to

13 INTRODUCTION 5 be problemtic (Grf et l., 1999) nd stbilizing seed yield nd qulity re the min objectives to the griculturl prctices. Furthermore, high tempertures re necessry for high oil nd oleic cid yield (Reinbrecht, 2003). Criticl points t sowing nd erly plnt development stges Actul HO sunflower vrieties germinte stisfctory only bove 10ºC soil temperture, lthough studies showed tht there re inbred lines tht germinte lredy t 8ºC (Rühl, 2003). Cultivrs germinting t low tempertures with rpid seedling development ply n importnt role in stble yield chievement in HO sunflower production. Erly germinted young plnts (t 6-8 leve stge) rect very sensitive to frost (Mielke, 2002) nd therefore the yield ccumultion stys risk. Wet nd cold wether conditions lso t the end of vegettion period in utumn increse the risk of diseses cused by fungl pthogens. The fct tht HO sunflower vrieties ripen in verge 14 dys lter thn the regulr ones underlines the importnce of erly sowing time. Importnce of vriety selection Choice of correct HO sunflower hybrids is n extremely importnt fctor for securing high yields. Following properties re to be considered in vriety selection for oil-type sunflower production in Germny; high grin yield potentil, high oil percentge, high oleic nd low steric cid content, disese resistnce, erly mturtion (Hugger, 1989; Müller-Sämnn et l., 2003). Commercilly, there re two types of HO sunflower vrieties vilble in Germny representing different oleic cid levels of the oil seed. The seed oil of 80+ HO sunflower vrieties contins over 80 percent oleic cid, wheres the 90+ vrieties chieve over 90 percent oleic cid (UFOP, 2003). Fungl diseses nd their control The most importnt fungl diseses of sunflowers in Germny re Sclerotini sclerotiorum (Lib.) de Bry, often clled the white mold fungus, nd Botrytis cinere (Schlüter nd Rühl, 1999). Sclerotini disese is spred over ll climte zones (Msirevic nd Guly, 1992; Porter nd Clrke, 1992; Keder, 1997; Leite et l.,

14 6 INTRODUCTION 2000; Huguet nd Heilnd, 2000) nd cn infect ny prt of the plnt t ny growth stge regrdless of the wether conditions (Guly et l., 1997). Sclerotini fungus hs wide rnge of species including rpe seed, tobcco, soyben, severl vegetble nd leguminous species s well s of herbs (Hugger, 1989; Kndel, 2006). Predominntly three diseses, Sclerotini wilt, middle stlk rot nd hed rot, re recognized in the field (Nelson, 2000). Sclerotini wilt is cused by soilborne fungl bodies, so clled scleroti, tht infect primrily the plnt roots nd penetrtes directly into the stem. This type of infection occurs only t high scleroti intensity in the soil nd primrily is result of not dequte crop rottion (Hugger, 1989). Sclerotini hed rot nd mid-stem infections re cused by irborne scospores of fungus produced by crpogenic germintion of scleroti under sturted soil moisture conditions (Rshid, 2004). Stlk rot usully ppers in the middle or upper portion of the stlk while hed rot often strts s spots on the receptcle (Kndel, 2000). Both infections cn result complete deth of the plnt. Sclerotini hed nd stlk rot occur minly in cold nd wet regions (Hoffmnn nd Schmutterer, 1999) nd re the most common infection type in centrl Europe (Schuster, 1993; Schöber-Butin et l., 1999). Sunflowers re most susceptible to Sclerotini hed rot from full flowering until beginning of ripening (Duncn et l., 2003). It cuses reductions in yield components (Guly et l., 1989) nd oil content s well s composition (Lzr et l., 1986, Chhl et l, 1988). Botrytis cinere, lso clled gry mould, is fungus disese which infects wide rnge of nnul nd perennil plnts. It cuses infections on severl prts of the plnt such s flower prts, leves, buds, shoots, seedlings nd fruits (Schuster, 2007; Hugger, 1989). Botrytis cn ttck the plnt t ny growth stge; however it preferbly infects sunflowers through the conidi (infectious spores) t the end of flowering nd ripening which cuses the highest yield losses (Hugger, 1989; LfL, 2006) s well s reduction in oil qulity (CETIOM, 1989). Wet or humid wether is highly fvourble for the spred of the disese nd therefore ppers mostly in humid utumn (Dierurer, 2000). Botrytis disese occurs more intensively in humid res of Northern Germny, but its dmge on plnts is less thn of Sclerotini diseses (Hoffmnn nd Schmutterer, 1999; Schöber-Butin et l., 1999).

15 INTRODUCTION 7 Control of Sclerotini nd Botrytis diseses Conventionl mesures ginst Sclerotini diseses include chemicl control, disese resistnce by breeding, nd culturl control (Brdin nd Hung, 2000) such s suitble crop rottion nd selection of dequte production loction (Mielke, 2002). A 3-6 yer of cultivtion puse cn significntly reduce the scleroti intensity in the soil (Termorshuizen, 2002; Mielke, 2002). By choosing erly mturing cultivrs nd/or erly sowing dte, erly ripening of the sunflower heds in cold nd wet utumn in temperte climtes cn be enhnced nd thus hed nd stem rot of sclerotini cn be reduced (Clrke et l., 1992; Sltter, 1992). The level of resistnce to Sclerotini (Feng, 2006) nd Botrytis in ctul sunflower hybrids is indequte. Some resistnce to Sclerotini wilt ws observed mong vrious inbred lines (Hung, 1980) nd hybrids (Hung, 1980; Rshid nd Dedio, 1992). Also some inbred lines with high level of resistnce to Sclerotini hed rot could be identified in high oleic sunflowers (Rönicke et l., 2005). Yet the level of resistnce to Sclerotini in current sunflower hybrids is indequte (Feng et l, 2007). To dte no complete sclerotini resistnce is known in cultivted sunflower, lthough quntittive rections ginst S. sclerotiorum hve been described (Tourvieille de Lbrouhe et l. 1996, Degener et l. 1998, 1999, Hhn 2002). The chemicl control of Botrytis by Dichloflunide or Thiophntmethyl+Mneb, if spryed t beginning of flowering, is successful only to some extend (Zimmer nd Hoes, 1978). Selecting erly mturing cultivrs nd/or erly sowing might help preventing Botrytis ttck (LfL, 2000). Suitble crop rottion nd selection of suitble production loction is suggested s control method lso ginst Bortytis (Hoffmnn nd Schmutterer, 1999). There is no fungicide registered for control of fungl diseses on sunflower in Germny. Folicur is brod spectrum fungicide with specil strength ginst Sclerotini but shll lso effect on Botrytis (Byer, 2004). Commonly it is recommended in oil seed rpe cultivtion. It is reported by the producer tht besides disese control, it shows lso useful growth regultory effects in rpe by its use in utumn.

16 8 INTRODUCTION 1.5 Alterntive griculturl pproches in HO sunflower cultivtion Sunflowers cultivtion in Germny is ssocited with number of constrints ffecting its yield nd oil qulity. Unsuitble wether conditions hve influence on yield nd qulity fctors directly or indirectly through hevy fungl susceptibility. Since yield nd qulity reduction due to fungl disese dmge tkes the first plce in production constrints, it is importnt to screen potentil disese control mesures. Lck of registered fungicides ginst fungl diseses in sunflower mkes the disese control even more problemtic. Currently, biocontrol gents inducing systemtic cquired resistnce (SAR) in order to provide wide rnge of control mechnism ginst diseses re min object of reserch worldwide. Alterntively, bcteril mixture s soil tretment is being tested with the im of chieving helthy nd high yielding stnds in Europe. Furthermore, N fertiliztion method bsed on the injection of n mmonium bsed solution is lso being discussed by reserchers with the im of optiml plnt nutrition from cultivtion nd economicl point of view s well s chieving helthy stnds. Systemtic cquired resistnce (SAR) by Acibenzolr-S-methyl (BTH) The biologicl phenomenon induced resistnce (IR) hs been introduced s n lterntive or complementry crop helth mngement pproch for conventionl protection methods. The IR is in its brodest sense the control of wide rnge of microorgnisms like fungl pthogens or pests by ctivtion of geneticlly progrmmed plnt defence mechnisms (Kogel nd Lngen, 2005). In most plnts, low levels of pthogen inoculum nturlly trigger resistnce response much like the humn body s immune system mobilizes to fight disese (Syngent, 2001). This resistnce my be expressed loclly t the site of inocultion (locl resistnce) or it cn lso be triggered throughout the whole plnt which is clled systemtic cquired resistnce bbrevited s SAR (Sticher et l, 1997). SAR cn be induced in plnts by synthetic chemicl gents (Mlmy et l., 1990; Zeller et l., 2002). Severl biocontrol gents hve been shown to induce resistnce in the plnt (Bysl, 2001). A chemicl with the property of inducing resistnce systemticlly is the benzo (1,2,3) thidizole-7-crbothioic cid S-methyl Ester (cibenzolr-s-methyl) which is lso often clled BTH commercilized under the trde mrk Bion (Kessmnn et l., 1996).

17 INTRODUCTION 9 Bion, is selective, systemic compound used for the disese control in mny crops by ctivting the plnt s nturl resistnce mechnisms. It induces host plnt resistnce nd hs no direct ctivity ginst trget pthogens. Resistnce inducing gent Bion is product of the compny Syngent. Induced resistnce derived by BTH ws reported ginst severl fungl diseses (Kessmnn et l., 1994; Ruess et l., 1995; Oostendorp et l., 1996; Bysl, 2001) in different plnts (Benhmou, 1998; Hung, 2000; Soylu, 2003), but only some in sunflowers (Buschmnn, 2002; Fn, 2003; Prts et l., 2002). Zeller (1999) reported high decrese in fire blight disese rte by the plnt ctivtor Bion in per fruit. In sunflowers, BTH provides good protection ginst Plsmopr helinti (Tosi, 1999) nd ginst Orobnche cumn (Suerborn, 2001). BTH ws lso effective controlling Sclerotini disese in soyben (Dnn, 1998). Injection of mmonium bsed liquid fertilizer In conventionl brodcst fertiliztion, minerl nitrogen is pplied to the soil surfce primrily in form of nitrte in number of splits. The brodcst nitrte fertiliztion ssocites with some ecologicl nd economicl disdvntges. Fertiliztion hs to be repeted during the vegettion period depending on the N demnd of the plnt which leds to physicl dmge of the plnt leves s well s the soil. Nitrogen pplied s NH3 is rther instble in the complete soil profile. N losses occur esily through leching, denitrifiction, nd votliztion ccompnied with environmentl nd tmospheric pollution, s well s economicl losses (Sommer, 1992, 2001; Kücke, 2001). An lterntive fertiliztion method ws developed by Prof.Dr. K. Sommer in order to overcome the disdvntges of conventionl fertiliztion method. In contrst to the brodcst ppliction of N fertilizers, in this lterntive method mmonium bsed fertilizer solution is plced by injection loclly to the root zone. Subsurfce plcement of the liquid fertilizer method is clled CULTAN (Controlled Uptke Long Term Ammonium Nutrition) in Germny. The nitrogen nutrition source for the plnts by this method is minly mmonium insted of nitrte s common ppliction form. Ammonium is reported to be the better nitrogen form for crops, if pplied correctly

18 10 INTRODUCTION (Sommer nd Mertz, 1974). Principlly, mmonium bsed solution is injected in liquid form 4-10 cm deep, depending on the crop, into the soil nd forms high concentrted spot. The plnt roots crete dense root-net round this mmonium hotspot (Kücke, 2006). Only prt of the plnt roots re directly in contct with the spots t the surfce of the mmonium deposits due to its phytotoxicity, nd cn tke up the nitrogen throughout the vegettion period s needed (Sommer, 2001). Thus, the totl required nitrogen for the crop cn be pplied in one tretment which will lso prevent losses through leching nd nitrifiction (Sommer, 1992). This plnt nutrition method shll lso led to more yielding nd vitl plnts in ddition to its ecologicl benefit by minly hindering nitrte leching nd reducing plnt nutrition costs. In response to liquid fertilizer injection, cerels shows in generl similr or high grin yield in comprison to the conventionl brodcst fertiliztion (Sommer nd Fischer, 1993; Weimr, 2001). Yield increses with this lterntive fertiliztion method were reported for potto (Weimr, 2001; Schumcher, 2001), s well s for winter whet nd winter brley (Kücke, 2001). Blnke nd Bcher (1999) indicted reduction in ny pthogen infection potentil due to the increse in light reflectnce in cbbge. Mikro-Vitl Recently, new bcteril fertilizer, clled Mikro-Vitl, hs been developed by Hungrin reserchers. The Mikro-Vitl is liquid product consisting nitrogen nd phophorus mobilizer bcteri. This bcteril mixture contins 50% Pseudomons, 25% Azotobcter nd 25% Azospirillum strins. These microorgnisms in prt trnsfer N from the ir into the soil in form tht is usble by plnts; n verge of 60 kg N per hectres depending on the type of the soil nd the vegetl residue of peduncle nd mobilize the phosphorus bsorbed between the crystl-lttices of the soil (180 mg P/kg soil depending on the type of the soil) nd they mke it vilble for the plnt (BIO-NAT Kft, 2005). In prllel, other bcteri stocks decompose the orgnic surpluses in the soil nd increse the quntity of the soil s orgnic colloids, the bility of providing nourishment, the cpcity of wter, the volume of interstice, the iriness, nd decrese the solidness of the soil. It is reported by the producer tht it dditionlly provides disinfection effect with n increse of the fertilizer

19 INTRODUCTION 11 concentrtion. It ws lso proven by the producer tht it disinfects the scleroti of Sclerotini sclerotiorum in the soil nd decreses the infection level of Fusrium ssp. There is still on-going reserch on Mikro-Vitl in Europe, but only limited informtion nd reserch results re vilble until now. Nevertheless, the product is commercilly vilble on the mrket since 1997 nd widely used by frmers in Hungry. 1.6 Objectives Unstble yield nd oil qulity s well s fungl disese susceptibility under centrl Europen climtic conditions re the min constrints for the HO sunflower production. Correct griculturl pproch selection plys the most importnt role in order to stbilize the yield nd qulity. An integrted project finnced by the Agency of Renewble Resources (FNR) ws initited in 2003 to identify plnt production mesures to extend the production re of HO sunflowers in Germny. In this respect, it is essentil to screen lterntive griculturl pproches tht ensure stble kernel nd oil yield, desired oil composition, nd secure helthy plnt development in the predominntly wet utumn, since HO sunflowers mture lte under centrl Europen climtic conditions. Reserch objectives of this project re s following; ) Determine how different loctions representing different climtic conditions for sunflower production ffect HO sunflower yield nd qulity, b) Screen the potentil of different HO sunflower vrieties representing different mturity clsses t two loctions in Germny, c) Exmine lterntive gronomic pproches in order to chieve stble yield nd oil qulity s well s to reduce fungl disese severity. The following lterntive pplictions will be focused on: In order to screen ny possible effect of fungicides on HO sunflowers, representtive fungicide, Folicur is tested As n lterntive disese control method, the resistnce inducing gent, BTH, commercilly known s Bion, is exmined under field nd greenhouse conditions to figure out its effect on HO sunflowers,

20 12 INTRODUCTION A bcteril mixture, Mikro-Vitl, s soil tretment is tested in order to screen its effectiveness s plnt nutrition nd soil disinfection method ginst soil-borne fungl infections Injection of mmonium bsed liquid fertilizer insted of conventionl brodcst fertiliztion, is tested for its efficcy s plnt nutrition method nd/or for its bility to promote more vitl stnds. d) Explin the development of the fungl pthogens by screening sugr content of the plnt prts during the lte vegettion period, since fungl pthogens use sugr s the min nutrition source in the plnt.

21 2 MATERIAL AND METHODS 2.1 FIELD EXPERIMENTS A preliminry field experiment ws conducted with three replictions in 2002 on the experimentl fields of the Federl Agriculturl Reserch Centre (FAL) t Brunschweig. The im of the preliminry experiment ws to figure out, whether or not selected griculturl pproches in this study hve potentil in stbilizing yield nd oil qulity of HO sunflowers. The preliminry experiments consisted of two experimentl fields tht were locted 100 m prt from ech other. Soil properties of both fields were very similr. On the Field-1 Gleg officinlis L. (Leguminose) ws grown in 2000 followed by mize in Rye, lupine nd grss ws grown on the Field-2 in 2000 nd mize in The min field experiments were estblished t two loctions, t Brunschweig (north Germny) nd t Eckrtsweier (south Germny). The different vrints were set up in 3 (2003) or 4 ( ) replictions. All experiments were conducted in rndomized block design with 2.5 m x 8.0 m plots. Number of replictions s well s sowing nd hrvest dtes is given in Tble 2.1. All plots except of the liquid fertilizer experiments were supplied by 60 kg N/h t Brunschweig nd 80 kg N/h t Eckrtsweier. In order to void losses through bird ttck, the plots were covered with polyester mshes t the onset of fruit development (Figure 2.1).

22 14 MATERIAL AND METHODS Tble 2.1: Sowing nd hrvest dtes in the field experiments. Experimentl Sowing Hrvest Field experiments Yer site *Rep. dte dte Preliminry experiments 2002 Brunschweig 3 08.My 1-20 Oct Min experiments *Rep: Replictions 2003 Brunschweig Eckrtsweier 2004 Brunschweig Eckrtsweier 2005 Brunschweig Eckrtsweier April 29 April April 29 April 4 25 April 11 My 8-19 Sept 09 Sept 8-19 Sept 09 Sept 4-13 Sept 27 Sept Figure 2.1: HO sunflower fields covered with nets t fruit development stge ginst bird ttck Experimentl sites The experimentl fields of the FAL t Brunschweig (52 17` N ltitude, 10 26`E longitude, 80 m ltitude) represent, from climtic point of view, mrginl site for sunflower cultivtion with sndy lom soil. Additionl field trils were conducted t loction in Southern Germny, t Eckrtsweier (48 7` N ltitude, 7 50` E longitude, 140 m ltitude) on silty lom soil. The field experiments t Eckrtsweier were estblished nd mnged by the Stte Plnt Breeding Institute of University of Hohenheim in Stuttgrt.

23 MATERIAL AND METHODS Wether Dt Brunschweig: Climtic dt of the experimentl site Brunschweig were obtined from the Agronomicl Reserch Centre Sttion of the Germn Ntionl Meteorologicl Service within FAL. Uncommon hevy rinfll ws recorded in 2002 while it ws extrordinry wrm nd dry in 2003 (Figure 2.2). The highest monthly rinfll in 2002 ws recorded in July (225 mm) which corresponds the mid-vegettion period for HO sunflowers in Europe. The highest vlue for totl monthly rinfll in 2003 ws chieved in September with 94 mm. In comprison to the first two yers, 2004 nd 2005 were moderte yers with most rin t the end of the vegettion period nd reltively higher ir temperture. The highest totl monthly rinfll for 2004 nd 2005 ws 116 nd 80 mm, respectively, in both cses in July / Brunschweig Rinfll Temperture Totl rinfll [mm] Temperture [ C] 0 My June July August September October 0 Figure 2.2: Monthly totl rinfll nd verge ir temperture t Brunschweig during vegettion period in Eckrtsweier: Generlly, 2003 ws moderte yer t the beginning (My-July) nd drier t the lte vegettion period (August-September) t Eckrtsweier (Figure 2.3). Totl monthly rinfll for this period ws 63.4, 44.5, 92.7, 31.4 nd 36.1 for My, June, July, August nd September 2003, respectively showed in comprison to 2003 slightly higher rinfll with 287 mm in totl. However, the highest precipittion ws recorded lter in the vegettion period in August ws the wettest yer with 320 mm in totl during the whole vegettion period.

24 16 MATERIAL AND METHODS Brunschweig (mm) Brunschweig ( C) Eckrtsweier (mm) Eckrtsweier ( C) Rinfll [mm] Temperture [ C] Rinfll [mm] Temperture [ C] Rinfll [mm] Temperture [ C] My June July August September 0 Figure 2.3: Monthly totl rinfll nd verge ir temperture t Brunschweig nd Eckrtsweier during vegettion period in

25 MATERIAL AND METHODS Plnt Mteril Three HO-sunflower vrieties, Aursol (Monsnto), Olsvil (Pioneer) nd PR64H61 (Pioneer), representing different ripening clsses, were used for the study. All vrieties selected for this study hve round 90 % oleic cid. Olsvil is lte ripening vriety with the highest oleic cid content. It presents high nd stble yield, long plnt height, high oil content, nd good tolernce ginst diseses. PR64H41 belongs to the mid-ripening clss with high oil yield, short plnt height nd lso good tolernce ginst diseses. The vriety PR64H61 from Pioneer ws used in the preliminry experiment insted of PR64H41. Aursol, the only vriety from Monsnto, is lso mid-erly type with moderte plnt height. It ws reported by the seed producer Deklb tht Aursol shows very good resistnce ginst fungl ttcks especilly ginst hed sclerotini nd botrytis Applictions The resistnce inducing product Bion, mmonium bsed liquid fertizer injection nd bcteril mixture Mikro-Vitl were tested on three HO-sunflower vrieties. All pplictions were compred to untreted nd conventionlly fertilized (60kg N/h) control plots. A fungicide ppliction with Folicur from Byer ws lso tested in ll experimentl yers. Ech ppliction included different concentrtions of the tretment medium s well s different ppliction times, which re explined in detil in corresponding sub-chpters. Appliction times re presented s BBCH codes, which re shown in Figure 2.4. Hrvest: Mid-October Sowing: End of April / Figure 2.4: Phenologicl growth stges of sunflower nd corresponding BBCH identifiction keys (Source: BBA, 2001).

26 18 MATERIAL AND METHODS Fungicide ppliction The folir fungicide tebuconzole (Folicur,.i. 430 g/l, Byer) ws pplied 1 L/h concentrtion with conventionl fungicide spryer t full flowering stge (BBCH 65) on conventionlly fertilized (60 kg N/h) plots Plnt ctivtor Bion Benzo (1,2,3) thidizole-7-crbothioic cid S-methyl-ester (BTH) formulted s Bion ws obtined from the compny Syngent, Bsel, Switzerlnd. It ws pplied s seed tretment s well s folir spry. Tretment of HO sunflower seeds were done by using beer s sticking gent. Bion s folir spry ppliction ws crried out with conventionl crop spryer. Five different developmentl stges were chosen for ppliction time; emergence (BBCH-Code 09), 6 leves unfolded (BBCH- Code 16), inflorescence emergence (BBCH-Code 51), full flowering (BBCH-Code 65), nd end of flowering (BBCH-Code 69). The plnts were spryed with wter suspension of Bion t following concentrtions: 10, 125 nd 250 ppm, prepred from wettble formultion contining 50% (w/w) ctive ingredient. Appliction scheme for the plnt ctivtor, which differed in the four experimentl yers, is listed in the Tble 2.2 in detil. Tble 2.2: Appliction scheme of the plnt ctivtor Bion in the field experiments. APPLICATION TIME METHOD YEAR DOSES DESCRIPTION CODE Bion Seed Tretment ppm 250ppm Bion Folir Appliction ppm 125ppm 250ppm ppm 125ppm 250ppm ppm 125ppm ppm 125ppm inflorescence emergence full flowering emergence 6 leves unfolded inflorescence emergence full flowering end of flowering emergence 6 leves unfolded full flowering emergence 6 leves unfolded full flowering BBCH-51 BBCH-65 BBCH-09 BBCH-16 BBCH-51 BBCH-65 BBCH-69 BBCH-09 BBCH-16 BBCH-65 BBCH-09 BBCH-16 BBCH-65

27 MATERIAL AND METHODS 19 Figure 2.5: Appliction of the plnt ctivtor s folir sprying on HO sunflower plots with crop spryer t full flowering stge (BBCH 65) Ammonium bsed liquid fertiliztion The lterntive fertiliztion method, injection of mmonium bsed liquid fertilizer, lso clled CULTAN Controlled Uptke Long Term Ammonium Nutrition ws investigted for 3 yers during this study. In the preliminry experiments, two vilble pproches were tested to pply the mmonium bsed liquid fertilizer to the soil. The first pproch ws surfce ppliction of the liquid fertilizer, in which the fertilizer solution is between the rows brought to the soil with specil pipes tht were pulled over the surfce of the field. The second method is bsed on injection of the mmonium solution into the soil with point injector crrying wheels (Figure 2.6). In the min field experiments from 2003 to 2004, n improved closed-bnd-injection of liquid fertiliztion ws used (Figure 2.5b). In this method, mmonium solution ws plced round 12 cm deep below the surfce on continuous line nd immeditely covered with soil. The detiled ppliction scheme for this liquid fertilizer ppliction nd its combintion with Bion is listed in Tble 2.3. Plnts were supplied with liquid fertilizer s three different concentrted solutions; ure mmonium nitrte (UAN), ure mmonium nitrte with nitrifiction inhibitor (UAN-N) nd ure mmonium sulfte (UAS). Different nitrogen concentrtions were selected for this study bsed on the

28 20 MATERIAL AND METHODS recommendtions in conventionl prctices. Regrding soil property t the experimentl site Brunschweig, 60 kg N/h fertilizer solution is recommended. In the preliminry experiments, which ws crried out only t Brunschweig, three N concentrtions were tested, recommended N mount (60 kg/h), 20% reduced N mount (48 kg/h), nd 20% incresed N mount (72 kg/h). In the min field experiments, 20% incresed N mount ws excluded from the ppliction scheme. In Eckrtsweier, recommended N/h is 80 kg. Regrding the recommendtion for this site, two N levels, 80 kg/h nd 64 kg/h, were tested in liquid fertilizer pplictions. () (b) Figure 2.6: Two different methods for injection of the liquid fertilizer () the point injection (b) closed-bnd injection. Tble 2.3: Appliction scheme of the liquid fertiliztion method in the field experiments. APPLICATION TIME METHOD YEAR SOLUTION N/HA DESCRIPTION CODE Surfce ppliction 2002 UAN 48 kg 60 kg 72 kg Point Injection 2002 UAN 48 kg 60 kg Closed-bnd-injection 2003 Closed-bnd-injection 2004 UAN UAN-N UAS UAN UAN-N UAS 72 kg 48 kg 60 kg emergence emergence 6 leves unfolded stem elongtion BBCH-09 BBCH-09 BBCH-16 BBCH kg 6 leves unfolded BBCH-16

29 MATERIAL AND METHODS 21 Additionlly to the liquid fertiliztion methods, its combintion with the plnt ctivtor Bion ws included to the experiments in UAN (48 kg N/h) ws mixed with Bion nd injected to the soil, offering the plnt ctivtor to be tken by the plnt roots. In the first yer of this combintion, the plnt ctivtor ws mixed to the liquid fertilizer solution in 4 different concentrtions: 250, 500, 1000, nd 2000 ppm t BBCH16 (Tble 2.4). In 2004, only the two lower N concentrtions were pplied since the higher concentrtions were economiclly not resonble. But therefore the mixed solution ws tested dditionlly t lte growth stge (BBCH-30: beginning of stem elongtion) Tble 2.4: Appliction scheme of liquid fertiliztion including Bion in the field experiments. APPLICATION TIME METHOD YEAR Bion DOSES DESCRIPTION CODE UAN + Bion (Closed-bnd-injection) ppm 500 ppm 1000 ppm 2000 ppm ppm 500 ppm 6 leves unfolded BBCH-16 6 leves unfolded stem elongtion BBCH-16 BBCH Mikro-Vitl pplictions The bcteril mixture Mikro-Vitl consists of three microorgnisms (Pseudomons, Azotobcter, Azospirillum), nd is vilble t the compny Bio-Nt Kft. in Hungry. According to the recommendtion by the compny, 1 liter Mikro-Vitl per hectre ws diluted into 400 liters wter before ppliction to the soil. Mikro-Vitl solution ws spryed over the prepred soil just before sowing, nd immeditely mixed 5-6 cm deep into the soil in 2003 to In ddition to the Mikro-Vitl ppliction, its combintion with the plnt ctivtor Bion ws tested in 2004 nd In these plots, the soil ws treted with Mikro-Vitl solution prior to seeding nd folir treted with 125 ppm Bion t 6 leves stge (BBCH 16).

30 22 MATERIAL AND METHODS Tble 2.4: Appliction scheme of the liquid fertiliztion nd Bion combintion in the field experiments. APPLICATION TIME METHOD YEAR CONCENTRATION DESCRIPTION CODE Mikro-Vitl L/h t soil preprtion - Mikro-Vitl+ Bion L/h + 125ppm 6 leves unfolded BBCH Field evlution nd dt collection Evlution of the fungl infection by the pthogens Sclerotini nd Botrytis ws crried out 3-4 times in 2-3 weeks intervls strting from beginning of the flowering nd until the end of vegettion period just before hrvest. Number of plnts of three rows showing ny infection symptom ws recorded nd clculted s percent per plot. All smples were hrvested per hnd. Grin yield ws determined on totl hrvested heds, clculted s dt/h nd djusted for 9% seed moisture. Yield relted trits (Tble 2.5) were determined on 20 plnts stnding next to ech other in the middle row of the plots. Tble 2.5: Evluted prmeters in the evlution for the field experiments PARAMETER Fungl infection rte [%] Yield relted trits Grin yield [dt/h] Plnt height [cm] Hed dimeter [cm] Thousnd seed weight [g] (TSW) Oil qulity prmeters Oil content [%] Oleic cid [%] Linoleic cid [%] Steric cid [%] Sugr components Fructose [%] Glucose [%] Sucrose [%] Rest soluble crbohydrtes [%] DESCRIPTION % infected plnts in plot Clculted on plot yield (9% seed moisture) Averged on 20 plnts in middle row Averged on 20 plnts in middle row Evluted on representtive smples from totl hrvested seeds Evluted on representtive smples from totl hrvested seeds Averged on 10 selected plnts in plot

31 MATERIAL AND METHODS 23 For the oil content nd ftty cid nlysis, seeds from totl hrvest plots were mixed, nd representtive smples were tken. For sugr nlysis, dditionl plots were estblished. 10 plnts per plot were hrvested, segmented, nd nlyzed for sugr content nd components Chemicl nlysis Oil nlysis Smple preprtion: Hrvested seeds were mixed, ground with n herb mill nd stored cold. 300 mg per smple ws weighted into the centrifuge glss tubes for the nlyses. 3 ml petroleum benzene (boiling point C) ws dded to the tubes, closed with lid. The smples were extrcted for 20 min in n ultrsound bth nd then centrifuged (Sonorex Super Digitl 10P). 1 ml of the surfce liquid were pipetted nd trnsferred to rection tube. 20µl sodium methylte (diluted in 1.7 ml 2 mol/l methnol; CH 3 ON is s 5.4 mol/l commercilly vilble) ws dded to the tube for deesterifiction nd shken for 15 sec. After minimum of 15 min of incubtion time, wter free clcium chloride ws dded with the point of sptul nd shken. The surfce liquid ws trnsferred into the glss vils nd mde redy for gs chromtogrphy (GC) nlysis. Anlysis: The ftty cid spectrum ws determined using HP 5890 Series II plus gs chromtogrph fitted with n utomtic smpler (HP 7673) for split-type injection (280 C), flme ionistion detector (FID) t 270 C nd n isotherm oven (220 C). The GC ws equipped with 30 m AT-Silr cpillry column (Alltech, 0.25 mm I.D., 0.25 µm film thickness. No.: 13855). 40 ml/min nitrogen (N 2 ) ws used s crrier gs. Soluble sugr nlysis Smple preprtion: 5 plnts per plot of the vriety Aursol in 2002 were hnd hrvested within the border rows of the control plots. In 2003, 10 plnts per plot of ll three studied vrieties were lso hnd hrvested in dditionlly estblished plots. 3 smpling dtes in 2002 (118, 145 nd 159 dys fter sowing) nd 5 smpling dtes in 2003 (66, 79, 86, 109 dys fter sowing) were selected. Since there were both green nd ripe plnts 159 dys fter sowing in 2002, those were nlyzed seprtely. Plnts were cut into segments of length of 30 cm strting from the

32 24 MATERIAL AND METHODS bottom. Ech segment ws cut verticlly into hlf nd thn horizontlly into smll peces. The sunflower hed ws seprted to four prts s receptcle centre, inner nd outer disc nd the seeds (Figure 2.7). The three hed prts were lso cut in smll peces. The smples were pcked in plstic bgs nd immeditely stored t - 20 ºC. For the nlysis, smples were freeze-dried nd ground to fine powder. Inner disc Receptcle Outer disc Figure 2.7: Sunflower hed prts used for sugr nlysis. Anlysis: Fructose, glucose, sucrose, nd the rest wter soluble crbohydrtes were nlyzed g per smple ws weighted into 50 ml flsks. Distilled wter ws dded to bout 50 % volume, shken for n hour to dissolve free sugrs nd filled up to 50 ml level. The mixture ws filtered nd the filtrte ws poured into vil bottles. Sugr nlysis ws done by using n isocrtic High Performnce Liquid Chromtogrphy (HPLC) of Kontron Instruments with column Rezex RPM (300 x 7.8 mm, Phenomenex) nd RI-detection (ERMA ERC-7512) with distilled wter s solvent t flow rte of 0.6 ml/min t 60 ºC temperture Sttisticl nlysis All sttisticl nlyses were done by the Generl Liner Model (GLM) procedures of the Sttisticl Anlysis System (SAS) softwre version 8.1 (SAS Institute, 1999). All yield nd qulity prmeters s well s the fungl infection rte dt were nlyzed seprtely for yers nd sites, s the concentrtion nd the ppliction time of the tretments differed. Differences between tretments were detected by the lest significnt difference bsed on Tukey Krmer s Honestly Significnt Different (HSD) test t the P<0.05 probbility level.

33 MATERIAL AND METHODS GREENHOUSE EXPERIMENTS Additionl to the field trils, n experiment ws estblished in 2003 in order to evlute the effect of Bion on Sclerotini sclerotiorum infection under greenhouse conditions. 125 ppm Bion ws tested s seed tretment nd folir ppliction t two growth stges (BBCH12 nd BBCH16). Ten pots with single plnt of the vrieties Aursol nd Olsvil were used per tretment. The greenhouse conditions were mintined t 14 h dylight, 20±3 ºC dy nd 13±1 ºC night tempertures. The plnts were irrigted s needed. The test of Bertrnd nd Tourvieille (1987) ws modified to determine the rection of sunflowers to rtificil infection by Sclerotini. At five different growth stges, with 2 weeks intervls, strting from the first lef pir stge, the third fully grown lef from the top ws infected with Sclerotini inoculum (Figure 2.8). The Sclerotini culture ws supplied by the Stte Plnt Breeding Institute Reserch Sttion in Eckrtsweier. One cm 2 ws cut from the culture nd plced t the extremity of the lef. The mycelium ws fixed with tpe to the lef. In order to keep the inoculum in humid tmosphere, spryed with bout 10 ml wter nd covered with trnsprent plstic bg. For dt recording, the plnts were observed periodiclly fter inocultion for lef lesions, disesed stems nd the number of infected or ded plnts. Figure 2.8: Artificil infection of the fully grown lef with Sclerotini inoculum.

34 26 MATERIAL AND METHODS

35 3 RESULTS 3.1. LOCATION AND VARIETY EFFECT The loctions of the min field experiments represent two different climtic conditions for sunflower production in Germny. The three selected high oleic sunflower vrieties represent three different ripening clsses. In the following subchpters, their influence on chene yield, oil content nd fungl infection rte re presented Chnges in chene yield The highest yield (34.4 dt/h t 9% seed moisture) throughout the men of ll vrieties ws chieved t Eckrtsweier in dry nd wrm yer 2003 (Tble 3.1). Achene yield ws higher t Eckrtsweier thn t Brunschweig in 2003 nd 2004, however it ws only significnt in In contrst to the first two yers, chene yield ws significntly lower t Eckrtsweier by nerly 20% in No significnt difference in chene yield between the vrieties ws observed in 2003, lthough the yield showed tendency to increse from lte to erly ripening vrieties. Lte ripening vriety Olsvil showed the lowest chene yields in ll study yers in comprison to the other the vrieties. Achene yield of Olsvil ws significntly lower in 2004 (24.0 dt/h) in comprison to the vriety PR64H41 (29.3 dt/h), nd in 2005 (24.6 dt/h) in comprison to Aursol (31.3 dt/h). The mid-erly vriety Aursol showed higher chene yield in comprison to the moderte ripening vriety PR64H41 nd lte ripening vriety Olsvil, in 2003 nd Achene yield of vriety Aursol decresed in the reltively cooler nd wet yer 2004.

36 28 RESULTS Tble 3.1: Men differences for chene yield (dt/h) in between the loctions () nd the vrieties (b) Fctor Achene yield (dt/h) () Loctions Brunschweig b 30.9 Eckrtsweier b (b) Vrieties Olsvil b 24.6b PR64H b Aursol b 31.3 For loctions nd vrieties, vlues in column with different letters re significntly different t P>0.05 Achene yield of ll three vrieties ws for ech experimentl site s verge of three study yers is presented in Tble 3.2. According to the differences in men vlues, Olsvil showed lower chene yield t both experimentl sites. Significnt difference in yield between Olsvil nd the other two vrieties ws observed only t Brunschweig. Olsvil showed with 24.3 dt/h the lowest chene yield in comprison to 30.9 dt/h in PR64H41 nd 30.3 dt/h in Aursol. Similr results were lso observed t Eckrtsweier. Olsvil showed the lowest but the difference ws negligible yield with 27.1 dt/h in comprison to 29.8 dt/h in PR64H41 nd 29.5 dt/h in Aursol. Tble 3.2: Men differences for chene yield (dt/h) between the two loctions cross ll vrieties Achene yield (dt/h) Brunschweig Eckrtsweier Olsvil 24.3b 27.1 PR64H Aursol Vlues in column with different letters re significntly different t P> Chnges in oil content nd composition The most importnt qulity prmeters in HO sunflower re the oil content of the seeds nd the ftty cid composition of the oil. Chnges in oil content in dependence on the compred loctions () nd HO sunflower vrieties (b) in the different study yers re presented in Tble 3.3. At the two experimentl sites, the oil content vried between 49.3 % (Brunschweig, 2003) nd 51.8 % (Eckrtsweier, 2005) throughout the experimentl yers. In 2003, oil content ws lower t Brunschweig thn t

37 RESULTS 29 Eckrtsweier. Nerly no difference in oil content t the different study loctions ws detected in Similr to the results in 2003, oil content t Brunschweig with 49.7 % ws lower thn t Eckrtsweier with 51.8 % in Significnt difference in oil content between two experimentl sites ws only observed in this lst study yer. Oil content significntly differed between the vrieties. In 2003, the vriety Aursol showed slightly higher oil content with 51.2 % in comprison to PR64H41 with 50.7 % nd Olsvil with 49.1 %. In contrst, Aursol showed significntly lower oil content in 2004 with 49.7 % in comprison to Olsvil with 51.5 %, wheres 50.2 % oil ws observed in PR64H41. Also in 2005, Aursol showed with 49.5 %, significntly lower oil content in comprison to the other two vrieties. Tble 3.3: Men differences for oil content (%) in between the loctions () nd the vrieties (b) Oil content (%) () Loctions Brunschweig b Eckrtsweier (b) Vrieties Olsvil b PR64H b 51.9 Aursol b 49.5b For loctions nd vrieties, vlues in column with different letters re significntly different t P> Chnges in fungl infection rte Fungl infection rte ws clculted s the percentge of infected plnts of the totl number of plnts irrespective of the fungl pthogen. Only 1.6 % fungl infection rte t Brunschweig nd 1.5 % t Eckrtsweier ws observed in 2003 (Tble 3.4). In contrst, much higher fungl infection rtes were observed in The verge fungl infection rte t Brunschweig with 87.3 % ws double s high s t Eckrtsweier (40.7 %). In opposite, fungl infections were significntly higher t Eckrtsweier thn t Brunschweig in Infection rte t Brunschweig ws 7.6 % in comprison to 57.9 % t Eckrtsweier. All vrieties showed nerly no fungl infection in 2003 (Tble 3.4b). In contrst, highest infection rtes in the min field experiments were observed in 2004 in ll