Effect of Production Environment on Seed Quality of Normal and High- Oleate Large Seeded Virginia-Type Peanut (Arachis hypogaea L.

Transcription

1 Effect of Production Environment on Seed Qulity of Norml nd High- Olete Lrge Seeded Virgini-Type Penut (Archis hypoge L.) M. Sun, J.F. Spers, T.G. Isleib, D.L. Jordn, B. Penny, D. Johnson, nd S. Copelnd* ABSTRACT Six Virgini-type penut (Archis hypoge L.) cultivrs nd their pired bckcross-derived high-olete lines were grown during 2003 nd 2004 in North Crolin to compre stndrd germintion (SG), cool germintion (CG), nd electricl conductivity (EC) of seed. Oleic cid level hd no influence on SG but did lter CG nd EC compred to the corresponding norml olete cultivrs. Averged cross bckground genotypes, high-olete lines hd lower seed vigor thn their pired lines with norml oleic content. The high-olete lines of three of the six pirs hd lower CG nd higher EC. Plnting nd hrvest dte ffected ll the seed qulity trits mesured. Stndrd germintion of both norml nd high-olete lines ws reduced in 2004 when hrvest ws delyed, but ws not ffected in In 2003, CG of the high-olete lines ws lower thn tht of norml lines in three of the four production environments; EC ws higher in the high-olete lines in ll plnting dte nd hrvest dte combintions. In 2004, there ws no difference between the CG of norml nd high-olete lines, but EC ws higher in the high-olete lines for three of the four environments. In the greenhouse, the Virginitype cultivrs NC-V 11 nd Gregory, long with their pired bckcross-derived high-olete lines were compred t 22/18 C, 26/22 C nd 30/26 C dy/night temperture regimes. Seed oleic to linoleic cid (O/L) rtio of norml penut grown in 30/26 C, 26/22 C, nd 22/18 C, mesured 1.9, 1.5, nd 1.3, respectively. The O/L rtio for their high-olete pirs decresed from 24.7 when grown in 30/26 C to 15.9 in 26/22 C nd to 13.7 in 22/18 C. Temperture did not ffect the ftty cid composition of xis totl lipid or phospholipid frctions. The high-olete trit ws expressed in the xis lipids. The verge O/L rtio of xes from norml penut ws 1.1 while tht of high-olete lines ws 4.6. Likewise, xis phospholipids for norml nd high-olete lines were 1.0 nd 5.9. A lower production environment temperture decresed the O/L rtio of seed oil of high-oleic penut lines, nd the higholete trit expressed in penut seed storge *Former Grdute Reserch Assistnt, Professor, Professor, Professor, Reserch Technicin, Reserch Technicin, nd Reserch Technicin, Deprtment of Crop Science, Box 7620, North Crolin Stte University, Rleigh, NC Corresponding uthor s e-mil: dvid_jordn@ncsu.edu. lipids is lso expressed in xismembrnelipids to lesser degree. Key Words: high oleic penut, plnt stress. Penut (Archis hypoge L.) is rich source of edible oils, protein, nd minerls such s phosphorus, clcium, mgnesium, potssium, nd vitmins (Svge nd Keenn, 1994). In the U.S., penut is n importnt csh crop nd is lrgely used for penut butter nd sncks while it is used primrily s n oil source in most other penut production res of the world. Seed oxidtive stbility is closely ssocited with oil nd ftty cid composition nd is n importnt qulity ttribute regrdless of whether it is used s food or oil. The two predominnt ftty cids in penut seed oil re oleic cid (18:1) nd linoleic cid (18:2) which together comprise bout 80% of the totl ftty cid composition (Ahmed nd Young, 1982). Typiclly, penut oleic cid to linoleic cid rtio, commonly referred to s O/L rtio, is bout 1.5 to 2.0 (pproximtely 50% oleic cid to 30% linoleic cid). Oleic cid, the 18-crbon monounsturted ftty cid nd precursor to linoleic cid, is less rective with oxygen nd s result, more stble thn linoleic cid. Therefore, penut seeds with high oleic cid content nd high O/L rtio hve improved stbility ginst lipid oxidtion tht led to dverse flvors (Mugendi et l., 1998; O Keefe et l., 1993) nd nerly twice the shelf-life s those with norml O/L rtio (Brddock et l., 1995; Brnch et l., 1990; Jmes nd Young, 1983). Virgini-type penut cultivrs nturlly produce oil with slightly lower linoleic percentge nd therefore hve greter oil stbility thn other mrket types (Norden et l., 1982). High-olete penut trit in runner breeding line, F 435, ws found to hve 80% oleic cid nd 2% linoleic cid (Norden et l., 1987). The reltionship between the two ftty cids is inversely relted so tht O/L rtio ccurtely reflects the reltive contents of these two ftty cids in penut (Knuft et l., 1993). Developing Virgini-type cultivrs with higher levels of oleic cid nd depressed levels of linoleic Penut Science (2014) 41:

2 EFFECT OF ENVIRONMENT ON HIGH-OLEATE PEANUT 91 cid is one of severl importnt gols in public penut breeding progrms in the US. High-olete penut lines were developed through bckcrosses using the high-olete line F 435 s the source of the trit nd lrge-seeded Virgini cultivrs such s NC-V 11 (Wynne et l., 1991) nd Gregory (Isleib et l., 1999) s the recurrent prents. High-olete lines were selected fter two to four bckcrosses to the commercil cultivr. The progrm hs resulted in severl dvnced high-olete penut lines with 80 to 85% oleic cid content in their seed oil (Isleib, personl communiction, 2012). A uniform stnd of helthy, vigorous seedlings is essentil if growers re to chieve the yield nd qulity needed for profitble penut production. Spers et l. (2002) reported tht penut seed qulity cn be seprted into five relted components: germintion, vigor, genetic purity, crop purity nd helth. Germintion nd vigor hve the gretest impct on seedling emergence nd survivl. Germintion tests re stndrdized throughout the United Sttes. Vigor tests, however, re common only for mjor commodities nd high vlue crops. Seed qulity nd vigor re gretly influenced by environmentl fctors tht occur during seed growth, development, nd mturtion (Copelnd nd McDonld, 2001; TeKrony et l., 1984). High temperture during development hs been shown to reduce soyben seed germintion nd vigor (Egli et l., 2005; Keigley nd Mullen. 1986; Spers et l., 1997). Spers et l. (1997) reported tht soyben seeds grown in 27/22 C dy/night temperture hd higher germintion nd ccelerted ging germintion nd lower EC thn those grown t 38/33 C high temperture stress environment. Temperture lso influences vegettive nd reproductive growth rtes (Leong nd Ong, 1983). High temperture reduces the numbers of pegs nd pods (Ketring, 1984) nd the reductions in pod nd seed dry weight were reportedly due to reductions in totl dry mtter nd hrvest index (Crufurd et l., 2002). In ddition to influencing seed plnting qulity, production environment cn lso ffect penut seed chemicl composition. Dwivedi et l. (1993) reported significnt genotype, environment nd genotype-by-environment interction effects on oil content, individul ftty cid content, nd derived oil qulity in penut. Chnge in seed chemicl composition hs been identified s one of the fctors tht cn influence seed germintion nd vigor (Copelnd nd McDonld, 2001). While much of the penut industry s concern hs been bout penut dietry oil qulity, seed technologists know tht lipids re n importnt source of energy for germintion. Consequently, ltering penut seed ftty cid or totl lipid composition could influence germintion rte, seed nd seedling vigor, nd seedling survivl, especilly if seeds re plnted in stressful soil conditions. Altertions of seed lipid ftty cid composition brought by trditionl or moleculr techniques could lso chnge membrne lipid composition nd therefore ffect membrne function nd permebility. Membrne integrity is linked to seed qulity, seedling energy, nd tolernce to environmentl stress during germintion nd emergence. However, there is little informtion vilble in the literture on the effect of ltering penut seed lipid on seed membrne function, germintion, or vigor of penut. With the incresing number of high-olete penut cultivrs, there is need to nlyze qulity of high-olete penut seed produced in vrious environments. The objectives of this study were to 1) determine the influence of high oleic cid on penut seed germintion nd vigor; 2) evlute plnting dte nd hrvest dte ffect on norml nd high-olete penut seed germintion nd vigor; nd 3) investigte the effect of temperture on seed oil qulity of high-olete nd norml Virgini-type penut cultivrs. Mterils nd Methods Influence of Plnting nd Digging Dte on Seed Qulity in the Field High-oleic penut lines NC 7 HO, NC 9 HO, NC 10C HO, NC-V 11 HO, NC 12C HO, nd Gregory HO were developed by bckcrossing the high-olete trit from F 435 into six lrge-seeded Virgini-type cultivrs: NC 7 (Wynne et l., 1979), NC 9 (Wynne et l., 1986), NC 10C (Wynne et l., 1991), NC-V 11 (Wynne et l., 1991), NC 12C (Isleib et l., 1997), nd Gregory (Isleib et l., 1999) (Tble 1). These six lrge-seeded Virgini-type cultivrs hve 50 to 55% oleic cid content in the seed oil. High-oleic lines were selected fter two, three, or four bckcrosses to the cultivr nd their seed oils contin 80 to 85% oleic cid. Experiments were conducted t the Penut Belt Reserch Sttion ner Lewiston-Woodville, North Crolin during 2003 nd 2004 (36.07N, W). The tretment design included two plnting dtes, erly My nd erly June, nd two hrvest dtes erly October nd lte October. A split-plot experimentl design ws used with 2 by 2 fctoril combintions of plnting nd hrvest dte serving s whole plot tretments. The fctoril combintion for two penut oleic cid levels nd

3 92 PEANUT SCIENCE Tble 1. Pedigrees of high-olete lines developed by bck-crossing the Florid high-oleic genes into lrge-seeded Virgini-type cultivrs. Line Bckground genotype Prentge Pedigree b NC 7 HO NC 7 NC 7*5 / F-435 BC4F : F04 NC 9 HO NC 9 NC 9*5 / F-435 BC4F : F04 NC 10C HO NC 10C NC 10C*4 / F-435 BC3F : F05 NC-V 11 HO NC-V 11 NC-V 11*4/ F-435 BC3F : F05 NC 12C HO NC 12C NC 12C*3 // NC 9*2 / F-435 BC2F : F04 Gregory HO Gregory Gregory*3 // NC 9*2 / F-435 BC2F : F04 Abbrevitions: NO, norml cultivr; HO, high-olete cultivr. b Pedigrees indicte the BC n F 1 nd BC n F 2 plnts selected nd the current genertion of the test mteril. six cultivrs were subplot. Ech subplot consisted of two rows, ech on rised bed spced on 91-cm centers nd 10 m in length. Experimentl test plots were estblished ccording to the tretment design of the experiment nd stndrd production prctices pproprite for the region were followed. Soil ws Goldsboro sndy lom (fine-lomy, kolinitic, thermic typic Kndiudults) with 1.8% orgnic mtter content nd ph 6.1. At hrvest, plnts were dug with commercil digger/inverter nd pods were removed by mchine 3 to 4 dys fter digging, plced in mesh bgs, nd dried over non-heted forced ir to pproximtely 8% seed moisture content. Sound mture seeds were collected from ech plot, plced in plstic bgs, nd stored t 12 C until evlution. Seed qulity evlution included stndrd germintion (SG), cool germintion (CG), nd electricl conductivity (EC) (ISTA, 1995). Prior to SG evlution, seeds were treted with commercil seed tretment consisting of 45% cptn, 15% PCNB, nd 10% crboxin (Vitvx PC, Gustfson LLC, Plno, TX). Stndrd germintion tests were conducted by plcing four 25-seed subsmples in rolled towels t lternting 30/20 C (dy/night) with 16 h t 20 C. The stndrd germintion test procedure followed Assocition of Officil Seed Anlysts Rules for Testing Seeds (AOSA, 2002; McDonld, 1994). Seedlings were evluted t 8 dys fter plnting nd germintion ws ssessed s the percentge of seeds producing norml seedling with rdicl t lest 3.5 cm long. Seeds were rndomly smpled from the sme seed lot used for SG nd pretreted with the commercil blend of cptn, PCNB, nd crboxin. Cool germintion tests were conducted on four 25- seed subsmples plced in rolled towels t 18 C (6 0.5 C). The test ws conducted in the drk. Seedlings were evluted t 9 dys fter plnting nd only those seedlings with rdicls 2.5 cm or longer were considered to hve germinted. Seed vigor ws lso evluted by electricl conductivity of seed sok wter. Seeds were djusted to bout 7.5% moisture content in chmber (Model 3020 Wter Jcketed Incubtor, VWR Scientific, Inc., Suwnee, GA) t 20 C nd ner 95% RH prior to mesuring seed lekge. Fifty seed were weighed nd plced in 250 ml deionized wter t 25 C. Continers (Fisher Scientific Pyrex Erlenmeyer Flsk, Fisher Scientific, Suwnee, GA) were covered with foil nd held t 25 C (60.5 C) for 24 h (60.5 h). Following incubtion, the continers were gently swirled nd the conductivity of the seed sok wter ws mesured using Cole Plmer Conductivity meter model (Cole-Plmer Instrument Compny, Niles, IL). Conductivity is reported s mohms cm 21 g 21 of seed. Two rndomized subsmples from ech field plot s two replictions nd completely rndomized design (CRD) were used in this experiment. Prior to sttisticl nlysis, SG nd CG percentges were trnsformed using the ngulr (rcsin of squre root) trnsformtion nd EC vlues were trnsformed using nturl log. Anlysis of vrince ws conducted using the generl liner models procedure (PROC GLM) of SAS (SAS Institute, Inc., Cry, NC). Yers nd replictions were considered rndom effects while plnting nd hrvest dtes, oleic cid level, nd cultivr were considered fixed effects. Tretment mens were seprted by t-test using significnce level P Influence of Temperture Regime on Seed Qulity in the Greenhouse Studies were estblished during 2003 nd 2004 in greenhouses locted t the Southestern Plnt Environment Lbortory t North Crolin Stte University min cmpus. (35.77N, W) Four penut cultivrs, NC-V 11 (Wynne et l., 1991), high-olete NC-V 11 (NC-V 11 HO), Gregory (Isleib et l., 1999), nd high-olete Gregory (Gregory HO) were used in this experiment. A split plot experimentl design ws used, with greenhouse s the whole plot (three levels) nd cultivr s subplot (four levels). All greenhouses were mintined t 80% reltive humidity nd nturl photoperiod plus 3 h night interruption (11pm to 2 m). The three temperture levels in this study were 22/18 C, 26/22 C, nd 30/26 C dy/night with

4 EFFECT OF ENVIRONMENT ON HIGH-OLEATE PEANUT 93 Tble 2. Men squre from pooled nlysis of vrince of stndrd germintion, cool germintion, nd electricl conductivity. Source df Stndrd germintion Cool germintion Electricl conductivity % m mhos cm 21 g 21 Yer ** ** Plnting dte in yer ** ** ** Hrvest dte in yer ** ** ** Plnt 3 hrvest in yer ** Oleic cid level ** * Genotype Oleic 3 genotype Error CV (%) Abbrevitions: * nd ** denote men squres tht re significnt t p, 0.05 nd p, 0.01, respectively. 12 hours of high nd low tempertures. Single plnts were grown in 45-cm dimeter pots filled with three prts snd (stem sterilized) nd one prt pet. Plnts were wtered twice dily with complete nutrient solution (Downs nd Thoms, 1991). In ech greenhouse, rndomized complete block designs were used with seven blocks in 2003 nd five blocks in The four cultivrs were rndomly rrnged within ech block. Hull scrpe nd penut mturity profile method were used to determine mturity nd implement hrvest (Willims nd Drexler, 1981). Following hrvest, pods were dried with unheted forced ir, shelled by hnd, nd the seeds stored t 10 C until nlyzed for oil qulity. Ten sound mture kernels nd 15 embryos of ech of the four lines produced under three environments in 2003 nd 2004 were nlyzed for ftty cid profile using the technique of Zeile et l. (1993). Kernel mss ws not determined. Smples were extrcted for 12 h in 1 ml of solvent (chloroform: hexne: methnol, 8:5:2 volume) in 16 by 100 mm stoppered test tubes (Fisherbrnd Disposble Culture Tubes, Fisher Scientific, Suwnee, GA). Ftty cid methyl esters of the lipid extrcts were prepred using sodium methoxide. The smples were nlyzed by gs chromtogrphy using n HP 5890 Series II GC (Agilent Technologies, Inc., 2850 Centerville Rd., Wilmington, DE) equipped with n AT-Silr 30 m by 0.53 mm column (sme source). Operting conditions were 1 ml injection volume, 20:1 split rtio, nd He crrier gs flow of 6 ml min 21. Tempertures were 250 C, 200 C, nd 275 C for the injector, oven nd flme ioniztion detector (FID), respectively. Chromtogrms were nlyzed using HP Chem- Sttion softwre (Agilent Technologies, Snt Clr, CA). For sttisticl nlysis, dt were subjected to nlysis of vrince over two yers nd three tempertures bsed on mixed liner model with temperture nd cultivr s fixed effects of vrince nd yer, repliction (yer) s rndom effects were used. Anlyses were conducted using the generl liner models procedure (PROC GLM) with rndom sttement of SAS (SAS Institute, Inc., Cry, NC). Tretment mens were seprted by t- test using significnce level of P Results nd Discussion Influence of Plnting nd Digging Dte on Seed Qulity in the Field There ws no correltion between SG nd CG or between SG nd EC. However, CG nd EC were negtively correlted (r , p, 0.01, dt not shown). Although they mesure different spects of seed vigor, the two vigor tests pper to be in greement when evluting the seed lot vigor potentil for the seed used in our study. It is interesting tht the two outlying points re NC 10C nd NC 10C HO. Why this cultivr pir does not fit into the pttern of the other five cultivr pirs is not known. Further tests might revel ny genetic influence on subsequent seed qulity. The interction of oleic cid level by cultivr ws not significnt for ny of the mesured trits (Tble 2). Likewise, penut seed oleic cid level hd no effect on SG, but did influence CG nd EC. All 12 lines, regrdless of production environment or oleic cid level, hd stndrd germintion percentges bove 88% (djusted men) nd there were no differences for SG between the pired norml nd high-olete lines (Tble 3). These dt suggest tht SG is not ffected by the elevted oleic cid content found in the high-olete lines. When verged cross production environments, penut seed CG ws lower thn SG for ech cultivr used in this study (Tble 3). The differences between SG nd CG were lrger for high-olete lines thn those corresponding norml lines. The high-olete lines hd djusted mens

5 94 PEANUT SCIENCE Tble 3. Adjusted mens of stndrd germintion, cool germintion, nd electricl conductivity of six norml nd high-oleic penut lines. Olete level Genotype Stndrd germintion Cool germintion Electricl conductivity % m mhos cm 21 g 21 Norml NC High NC 7 HO Norml NC High NC 9 HO Norml NC 10C ** 2.22 High NC 10C HO Norml NC-V * High NC-V 11 HO Norml NC 12C * High NC 12C HO Norml Gregory * High Gregory HO Abbrevitions: * nd ** denote significnt differences between the norml- nd high-olete vrints within bckground genotype by t-test t the 0.05 nd 0.01 p-levels, respectively. Sttisticl difference is bsed on ngulr trnsformtion of stndrd germintion nd cool germintion nd nturl log trnsformtion of electricl conductivity. rnging from 66.4 to 76.0% while the norml lines hd vlues rnging from 76.2 to 82.3%. Three higholete lines, NC 10C HO, NC-V 11 HO, nd NC 12C HO hd lower CG (66.9, 66.4, nd 67.4%) thn their pired NC 10C, NC-V 11, nd NC 12C prents (82.3, 77.8, nd 76.2%). Oleic cid level lso influenced penut seed EC (Tble 3). Three high-olete lines NC V11 HO, NC 12C HO nd Gregory HO hd higher EC (2.98, 2.93, nd 2.61 mmhos cm 21 g 21 ) thn their three pired norml lines (2.23, 2.32, nd 2.10 mmhos cm 21 g 21 ). The stndrd germintion test is designed to provide the mximum germintion percentge for the seed lot tested (AOSA, 2002; McDonld, 1994). If seeds re plnted in fields with ner idel conditions, SG will provide good estimte of seedling estblishment. However, soil environments re rrely idel nd the SG test my not ccurtely reflect potentil seedling emergence nd survivl (Guerke, 2005; Spers et l., 2002). Seed vigor tests were developed to help prctitioners evlute seed lot field emergence potentil. For this reserch, seed vigor of four of the six pired high-olete, norml lines (NC 10C, NC-V 11, NC 12C nd Gregory) ws reduced when the high-olete trit ws incorported into the cultivr. Plnting nd hrvest dte influenced SG, CG nd EC but the genotype by oleic interction ws not significnt (Tble 2). Becuse of the wide temperture nd rinfll pttern vritions seen in 2003 nd 2004, dt re presented s eight environments (two yers by two plnting dtes by two hrvest dtes) for men comprisons. In 2003, there ws no difference in penut SG for plnting dte or for hrvest dte (Tble 4). Germintion ws bove 90% in ll production environments. In 2004, however, germintion of both norml nd high-olete penut seed hrvested on October 26 ws significntly lower thn those hrvested 20 dys erlier. In ddition, penut seed plnted in June nd hrvested on Oct26 hd lower SG thn those plnted in My nd hrvested on October 26. In the 2003 production environments, CG for norml cultivrs ws significntly higher thn tht of the high-olete lines, with the exception of CG for penuts plnted on My 8 nd hrvested on October 7 (Tble 4). Delying hrvest of penut plnted in My resulted in lrge increse on CG for the norml cultivrs (67.7 to 81.4%) but only slight increse in CG for the high-olete lines (62.5 to 63.9%). When penuts were plnted in June, delying hrvest dte resulted in lrge increse in CG for the high-olete lines (67.0 to 79.7%) but only slight increse for the norml cultivrs (85.3 to 87.8%). The highest CG vlue for the high-olete lines (79.7%) occurred when penuts were plnted in June nd hrvested on October 21. Electricl conductivity ws lower in norml cultivrs compred to the pired high-olete line in 2003 for ll plnting nd hrvest dtes (Tble 4). Electricl conductivity vlues of My nd June plnted norml nd high-olete penuts decresed when the hrvest dte ws delyed. One would predict tht the penut seed with the most time to develop (plnted in My nd hrvested October 21) would hve the highest vigor potentil. The lowest EC, 1.42 nd 1.62 mmhos cm 21 g 21 for norml nd high-olete lines, respectively, ws found in these penuts. However, highest CG ws found in penuts, both norml nd high-olete, plnted in June nd hrvested on October 21. Electricl conductivity nd CG tests mesure different

6 EFFECT OF ENVIRONMENT ON HIGH-OLEATE PEANUT 95 Tble 4. Difference of seed qulity between norml nd high-olete seed produced in vried plnting nd hrvest dtes, estimted by djusted mens of stndrd germintion, cool germintion, nd electricl conductivity. Olete level Plnting Hrvest Stndrd germintion Cool germintion Electricl conductivity % m mhos cm 21 g Norml My 8 Oct ** High My 8 Oct Norml My 8 Oct ** 1.42 ** High My 8 Oct Norml June 3 Oct ** High June 3 Oct Norml June 3 Oct * 1.71 ** High June 3 Oct Norml My 12 Oct ** High My 12 Oct Norml My 12 Oct High My 12 Oct Norml June 7 Oct ** High June 7 Oct Norml June 7 Oct ** High June 7 Oct Abbrevitions: * nd ** denote significnt differences between the norml- nd high-olete vrints verged cross bckground genotypes by t-test t the 0.05 nd 0.01 p-levels, respectively. Sttisticl difference is bsed on ngulr trnsformtion of stndrd germintion nd cool germintion nd nturl log trnsformtion of electricl conductivity. mechnisms ssocited with seed vigor. It is possible tht the components of seed vigor rech mximum potentil t different times in penut seed development or tht they vry in their response to production environment. In 2004, there were no differences between the CG of norml nd high-olete lines for ny plnting dte/hrvest dte combintion (Tble 4). Electricl conductivity of the norml cultivrs ws significntly lower thn tht of the high-olete lines with the exception of the My plnting, October 26 hrvest. For both plnting dtes, CG ws reduced when hrvest dte ws delyed nd the lowest CG (54.8 nd 52.4% for norml nd high-olete, respectively) nd highest EC (3.40 nd 3.87 mmhos cm 21 g 21 ) occurred when penuts were plnted in June nd hrvested on October 21. Highest CG vlues (92.0% for both norml nd high-oleic) nd lowest EC (2.23 nd 2.45 mmhos cm 21 g 21 ) occurred when penuts were plnted in My nd hrvested on October 6. Seed lot qulity of most species is influenced by production environment. The two plnting nd hrvesting dtes for 2003 nd 2004 in this experiment represented diverse production environments (dt not shown). Cold nd wet wether occurred between the first nd second hrvest dtes in 2004, which resulted lower SG, CG nd higher EC for seeds hrvested on October 26 compred to those hrvested on October 6, regrdless of plnting dte. In contrst, 2003 wether conditions between the first nd second hrvests were cool with only trce mounts of rinfll. Stndrd germintion of penuts hrvested on October 21 did not differ from seed hrvested on October 7, regrdless of plnting dte. Seed vigor of penuts for both plnting dtes, s mesured by CG nd EC ctully, incresed when hrvest dte ws delyed. However, CG nd EC tests for the two yers reveled tht cross genotype, high-olete lines hd lower vigor thn norml penut lines in ech plnting dte nd hrvest dte environment. Penut growers plnting high-oleic cultivrs should increse the seeding density thn over norml penut cultivrs. Influence of Temperture Regime on Seed Qulity in the Greenhouse As expected, penut growing under the cooler temperture regime required more dys to rech optimum mturity bsed on pod mesocrp color thn wrmer regimes. When pooled over runs of the experiment, pproximtely 175, 160, nd 130 d from emergence to optimum hrvest mturity were noted for the 22/18 C, 26/22 C, nd 30/26 C temperture regimes, respectively (dt not shown in tbles). There ws no significnt temperture or temperture by cultivr interction effect on whole seed levels of plmitic cid (16:0) (Tble 5). When

7 96 PEANUT SCIENCE Tble 5. Men squres from nlysis of vrince of ftty cid nd oleic/linoleic rtios for four penut cultivrs grown in three temperture environments. Ftty cid Source df Plmitic (16:0) Steric (18:0) Oleic (18:1) Linoleic (18:2) Oleic/linoleic (O/L) Whole seed ftty cids Temperture ** ** ** Cultivr ** ** ** ** Temperture 3 Cultivr * * Error CV (%) Axis ftty cids Temperture * Cultivr ** ** ** ** Temperture 3 Cultivr Error CV (%) Axis phospholipid ftty cids Temperture * Cultivr ** 1.08 ** ** ** ** Temperture 3 Cultivr Error CV (%) Abbrevitions: * nd ** denote men squres tht re significnt t p, 0.05 nd p, 0.01, respectively. verged cross the three tempertures, plmitic cid levels of NC-V 11, NC-V 11 HO, Gregory, nd Gregory HO, were 9.7, 5.5, 8.5, nd 5.5%, respectively. Cultivr effect for plmitic cid ws significnt. The high-olete lines hd lower 16:0 content thn their pired norml lines in ll environments (Tble 6). There ws significnt temperture effect on steric cid (18:0) content (p, 0.01), but no cultivr or temperture by cultivr interction (Tble 5). Steric cid content incresed slightly but significntly with incresing growth temperture (Tble 6). Averge steric cid levels cross the four cultivrs for three temperture regimes, 22/ 18 C, 26/22 C, nd 30/26 C were 2.1, 2.3, nd 2.6%, respectively. Interction of temperture by cultivr ws significnt for whole seed oleic cid nd linoleic cid levels (Tble 5). Therefore, temperture effect ws sliced by cultivr (Tble 7). The oleic cid level of ll four cultivrs incresed when the temperture incresed from 22/18 C to 30/26 C for both cultivrs. For their corresponding high-olete lines however, increses were not significnt (Tble 8). Linoleic cid levels of the four cultivrs were reduced when the temperture incresed from 22/ 18 to 30/26 C. The reduction ws significnt for NC-V 11, Gregory, nd Gregory HO but not for NC-V 11 HO (Tbles 6 nd 7). The low growth temperture resulting in decresed oleic content nd incresed linoleic levels were lso observed in soyben [Glycine mx (L.) Merr.] (Wilson, 2004), rpeseed (Brssic mpus L.) oil (Mrie et l., 1999), nd sunflower (Helinthus nnus L.) (Hrris et l., 1978). The increse in linoleic content for seeds grown in low temperture my be due to incresed ctivity of desturse enzymes involved in the conversion of oleic to linoleic cid (Hrris et l., 1978). Erlier studies indicted tht the increse in desturse ctivity t lower growth temperture could be ssocited with the incresed vilbility of O 2 in the tissue s result of its greter solubility t low temperture (Hrries nd Jmes, 1969). Temperture effects on oleic/linoleic rtio vried depending on cultivr (Tble 6). The O/L rtio for ll cultivrs incresed with the incresed growth temperture, however, only the increses for the high-olete lines, NC-V 11 HO nd Gregory HO were significnt. The verge O/L rtio of these two norml cultivrs grown in 22/18 C, 26/22 C, nd 30/ 26 C, mesured 1.3, 1.5, nd 1.9, respectively. The O/L rtio for their high-olete pirs incresed from 13.8 when grown in 22/18 C to 16.2 when grown in 26/22 C nd 25.4 when grown in 30/26 C (Tbles 5 7). Min effect of temperture nd the interction of temperture by cultivr were not significnt for xis lipid ftty cid composition or O/L rtio, except for the temperture effect on plmitic cid.

8 EFFECT OF ENVIRONMENT ON HIGH-OLEATE PEANUT 97 - Tble 6. Adjusted mens of whole seed ftty cids of four penut cultivrs grown in three temperture environments. Ftty cid Temperture Plmitic (16:0) Steric (18:0) Oleic (18:1) Linoleic (18:2) Oleic/linoleic (O/L) dy/night NO HO NO HO NO HO NO HO NO HO C % NC-V 11 22/ / / Men Gregory 22/ / / Men Abbrevitions: NO, norml cultivr; HO, high-olete cultivr. When verged cross the three temperture regimes for NC-V 11, NC-V 11 HO, Gregory, nd Gregory HO, plmitic levels were 18.8, 12.7, 17.4, nd 12.0%, respectively. The verge levels of plmitic cid cross the four cultivrs were 13.9, 15.3, 16.6% in three temperture regimes, 22/18, 26/ 22, nd 30/26 C. Thus, seed produced in the low growth temperture hd significntly lower mounts of plmitic cid in their xis (Tbles 5 nd 8). The high-olete trit expressed in the oils of the whole seed (primrily storge oils) ws lso found in the totl lipid frction of embryonic xis. The verge oleic cid content for whole seed of NC-V 11 nd Gregory ws 47.5 nd 51.5% (Tble 6) nd for their xis, these vlues were 31.0 nd 32.1% (Tble 8). Similrly, whole seed vlues of oleic for NC-V 11 HO nd Gregory HO were 80.3 nd 80.2%, while xis vlues were 62.1 nd 62.5%. Likewise, the lower linoleic cid levels in the higholete whole seed lipids were lso expressed in the xis totl lipid frction. The respective chnges in xis oleic nd linoleic cid content re reflected in the O/L rtio. While the whole seed O/L rtio of the high-olete cultivrs ws much greter thn tht of the xis, these dt show tht xis O/L rtio is much higher for the high-olete lines thn for their pired norml lines. The effects of temperture on xis phospholipid ftty cids were similr to the effects on xis totl lipid composition. There were no significnt interctions between temperture nd cultivr on ny xis phospholipid ftty cid components, nor on O/L rtio. Except for steric cid, temperture hd no significnt effect on xis phospholipids ftty composition or O/L rtio (Tbles 5 nd 9). Like the xis totl lipid frction, NC-V 11 HO nd Gregory HO xis phospholipids hd much higher levels of oleic cid (63.6 nd 63.2%) compred to their norml pired cultivrs (30.5 nd 32.4%). The comprble reduction in linoleic cid content ws lso seen nd reflected in the O/L rtio. Phospholipids re primrily locted in membrnes, nd membrne function nd fluidity re gretly influenced by ftty cid composition. Membrnes with high levels of unsturted ftty cids (18:2) re more fluid nd more functionl (Somerville, 1992). This reserch shows tht the high-olete trit is expressed, not only in the storge lipids of the cotyledons nd xis, but lso the membrnes of the xis. The embryonic xis is the seed component where seedling growth begins. Tble 7. Probbility ssocited with their F-sttistic for temperture by cultivr interction effect for oleic cid, linoleic cid, nd rtio of oleic cid to linoleic cid in whole seed of ech cultivr. P. F Cultivr df Oleic cid Linoleic cid Oleic/linoleic (O/L) NC-V 11 NO Gregory NO NC-V 11 HO Gregory HO Abbrevitions: NO, norml cultivr; HO, high-olete cultivr.

9 98 PEANUT SCIENCE - Tble 8. Adjusted mens of xis ftty cids of four penut cultivrs grown in three temperture environments. Ftty cid Temperture Plmitic (16:0) Steric (18:0) Oleic (18:1) Linoleic (18:2) Oleic/linoleic (O/L) dy/night NO HO NO HO NO HO NO HO NO HO C % NC-V 11 22/ / / Men Gregory 22/ / / Men Abbrevitions: NO, norml cultivr; HO, high-olete cultivr. Therefore, it is possible tht chnging xis membrne ftty cid composition nd function will impct seedling growth rte nd the bility of the seedling to tolerte less thn optimum growth tempertures. Low seed supply in this study prevented ccurte evlution of seed qulity. NC-V 11 nd NC-V 11 HO seed from the 2004 study were nlyzed for electricl conductivity of seed sok wter (dt not shown). These dt indicte tht the high-olete line hd higher conductivity (lower seed vigor) thn the norml cultivr t ll production temperture regimes nd tht conductivity incresed five-fold for seeds grown in the 22/18 C environment compred to those grown in 30/26 C. Sun et l. (2005) noted tht four out of six high-olete penut lines were lower in vigor thn their pired norml cultivr in field experiments conducted in 2003 nd Conclusions This reserch indictes tht low growth temperture ffected whole seed ftty cid composition, but hd little or no effect on xis totl or phospholipid ftty cids. Seed grown in low tempertures hd decresed whole seed oleic nd incresed linoleic content, resulting in decrese in the O/L rtio for seeds grown in cooler tempertures. For this reserch, dt supports tht there ws significnt temperture by cultivr interctions for the O/L rtio. The whole seed O/L rtio of high-olete cultivrs decresed significntly with decresing growth temperture, but the corresponding decrese in the norml cultivrs ws not significnt. The high olete trit seen in the storge lipids of the whole seed ws lso expressed in the embryonic xis. Dt indicted significnt - Tble 9. Adjusted mens of xis phospholipid ftty cids of four penut cultivrs grown in three temperture environments. Ftty cid Temperture Plmitic (16:0) Steric (18:0) Oleic (18:1) Linoleic (18:2) Oleic/linoleic (O/L) dy/night NO HO NO HO NO HO NO HO NO HO C % NC-V 11 22/ / / Men Gregory 22/ / / Men Abbrevitions: NO, norml cultivr; HO, high-olete cultivr.

10 EFFECT OF ENVIRONMENT ON HIGH-OLEATE PEANUT 99 increse in the O/L rtio of NC-V 11 HO nd Gregory HO xis totl lipids nd xis phospholipid when compred to their norml pired cultivrs. Further studies re needed to determine if the chnge in xis phospholipids O/L rtio seen in the high-olete lines is responsible for ny chnge in membrne function nd penut seed vigor. Acknowledgements This reserch ws supported finncilly by the North Crolin Penut Growers Assocition. Literture Cited Ahmed, E.M. nd C.T. Young Composition, qulity, nd flvor of penuts, pp In H.E. Pttee nd C.T. Young (eds.), Penut Science nd Technology. Am. Penut Res. Educ. Soc., Inc., Yokum, TX. [AOSA] Assocition of Officil Seed Anlysts Seed vigor testing hndbook. No. 32. Assoc. Officil Seed Anlysts, Ls Cruces, NM. Brddock, J.C., C.A. Sims, nd S.F. O Keefe Flvor nd oxidtive stbility of high- nd norml-oleic cid penuts. J. Food Sci., 60: Brnch, W.D., T. Tkym, nd M.S. Chinnn Ftty cid vrition mong U.S. runner-type penut cultivrs. J. Am. Oil Chem. Soc. 67: Copelnd, L.O. nd M.B. McDonld Seed vigor nd vigor testing, pp In: Principle of seed science nd technology. 4th edition. Kluwer Acdemic. Crufurd, P.Q., P.V. Vr Prsd, nd R.J. Simmerfield Dry mtter production nd rte of chnge of hrvest index t high temperture in penut. Crop Sci. 42: Downs, R.J. nd J.F. Thoms Phytotron procedurl mnul for controlled-environment reserch t the Southestern Plnt Environment lbotory. Technicl Bulletin, 224 (revised). North Crolin Stte University, Rleigh. Dwivedi, S.L., S.N. Nigm, R. Jmbunthn, K.L. Shrwt, G.V.S. Ngbhushnm, nd K. Rghunth Effect of genotypes nd environments on oil content nd oil qulity prmeters nd their ssocition in penut (Archis hypoge L.). Penut Sci. 20: Egli, D.B., D.M. TeKrony, J.J. Heitholt, nd J. Rupe Air temperture during seed filling nd soyben seed germintion nd vigor. Crop Sci. 45: Guerke, W.R Evluting penut seed vigor. Seed Technol. 27: Hrris, P. nd A.T. Jmes Effect of low temperture on ftty cid biosynthesis in seeds. Biochem. Biophys. Act 187: Hrris, H.C., J.R. McWillim, nd W.K. Mson Influence of temperture on oil content nd composition of sunflower seed. Aust. J. Agric. Res. 29: Isleib, T.G Registrtion of NC 12C penut. Crop Sci. 37:1976. Isleib, T.G., P.W. Rice, R.W. Mozingo, R.W. Mozingo, II, nd H.E. Pttee Registrtion of Gregory penut. Crop Sci. 39:1526. [ISTA] Interntionl Seed Testing Assocition H.A. vn de Venter (ed.). Seed Vigour Testing Seminr, Copenhgen. 7 June ISTA, Zurich. Jmes, S.L.H. nd C.T. Young Comprison of ftty cid content of imported penuts. J. Am. Oil Chem. Soc. 60: Keigley, P.J. nd R.E. Mullen Chnges in soyben seed qulity from high temperture during seed fill nd mturtion. Crop Sci. 26: Ketring, D.L Temperture effects on vegettive nd reproductive development of penut. Crop Sci. 24: Knuft, D.A., K.M. Moore, nd D.W. Gorbet Further studies the inheritnce of ftty cid composition in penut. Penut Sci. 20: Leong, S.E. nd C.K. Ong The influence of temperture nd soil wter deficit on the development nd morphology of groundnut (Archis hypoge L.). J. Exp. Bot. 34: Mrie, A., T. Blondel, nd M. Renrd Effect of temperture nd wter stress on ftty cid composition of rpeseed oil. Proc. 10th Interntionl Rpeseed Congress. Cnberr, Austrli. Mtthews, S. nd A.A. Powell Electricl conductivity test, pp In: D.A. Perry (ed.). Hndbook of Vigor Test Methods, 2nd ed. ISTA, Zurich, Switzerlnd. McDonld, M.B The history of seed vigor testing. J. Seed Tech. 17: Mugendi, J.B., C.A. Sims, D.W. Gorbet, nd S.F. O Keefe Flvor stbility of high-oleic penuts stored t low humidity. J. Am. Oil Chem. Soc. 75: Norden, A.J., D.W. Gorbet, D.A. Knuft, nd C.T. Young Vribility in oil qulity mong penut genotypes in the Florid breeding progrm. Penut Sci. 14:7-11. Norden, A.J., O.D. Smith, nd D.W. Gorbet Breeding of the cultivted penut, pp In: H.E. Pttee nd C.T. Young (eds.). Penut Science nd Technology. Am. Penut Res. Educ. Soc., Yokum, TX. O Keefe, S.F., V.A. Wiley, nd D.A. Knuft Comprison of oxidtive stbility of high- nd norml-oleic penut oils. J. Am. Oil Chem. Soc. 70: Svge, G.P. nd J.I. Keenn The composition nd nutritive vlue of groundnut kernels. pp In: J. Smrt (ed.). The Groundnut Crop: A Scientific Bsis for Improvement. Chpmn nd Hll, London. Somerville, C Direct tests of the role of membrne lipid composition in low-temperture-induced photo inhibition nd chilling sensitivity in plnts nd cynobcteri. pp In: Proc. Nt. Acd. Sci. USA. Spers, J.F., D.M. TeKrony, nd D.B. Egli Temperture during seed filling nd soyben seed germintion nd vigour. Seed Sci. Technol. 25: Spers, J.F., D.L. Jordn, nd J.E. Biley Penut seed production - guide for producers of Virgini-type penut seed. N.C. Coop. Ext. Serv. Bull. No Sun, M.H Effect of production environment on seed qulity of norml nd high-olete lrge seeded Virgini-type penut (Archis hypoge L.). In: Seed Qulity Issues Associted with High-Oleic Penut. NCSU. TeKrony, D.M., D.B. Egli, J. Blles, L. Tomes, nd R.E. Stuckey Effect of dte of hrvest mturity on soyben seed qulity nd Phomopsis sp. seed infection. Crop Sci. 24: Willims, E.J. nd J.S. Drexler A non-destructive method for determining penut pod mturity. Penut Sc. 8: Wilson, R.F Seed composition, pp In: Soybens: Improvement, Production, nd Uses. 3rd edition. H.R. Boerm nd J.E. Specht (eds.). Mdison, Wisconsin, USA. Wynne, J.C., M.K. Beute, J. Biley, nd R.W. Mozingo Registrtion of NC 10C penut. Crop Sci. 31:484. Wynne, J.C., T.A. Coffelt, R.W. Mozingo, nd W.F. Anderson Registrtion of NC-V 11 penut. Crop Sci. 31: Wynne, J.C., R.W. Mozingo, nd D.A. Emery Registrtion of NC 7 penut (Reg. No. 22). Crop Sci. 19:563. Wynne, J.C., R.W. Mozingo, nd D.A. Emery Registrtion of NC 9 penut. Crop Sci. 26:197. Zeile, W.L., D.A. Knuft, nd C.B. Kelly A rpid nondestructive technique for ftty cid determintion in individul penut seed. Penut Sci. 20:9-11.