Brnrd nd Booyse (2018). Seed Science nd Technology, 46, 1, 53-63. https://doi.org/10.15258/sst.2018.46.1.05 The effect of seed tretments on the yield nd yield components of vrious levels of sprouted whet Annelie Brnrd 1 nd Mrdé Booyse 2 1 ARC-Smll Grin, Privte Bg X29, Bethlehem, 9700, South Afric (E-mil: brnrd@rc.gric.z) 2 ARC-Biometry, Privte Bg X5013, Stellenbosch, 7599, South Afric (Submitted June 2017; Accepted August 2017; Published online December 2017) Abstrct The effect of seed tretments ws determined on vrious levels of sprouted whet seeds intended for plnting in the summer rinfll region of South Afric. Five groups of whet seeds, vrying in sprouting levels, were treted with combintion of either imidcloprid nd crboxim + thirm, or imidcloprid nd triticonzole. Trils were plnted with these seeds directly fter tretment, s well s fter storge periods of 12 nd 24 months. Seed tretments did not hve n effect on sound seeds, but fter 24 months of storge, germintion nd emergence were significntly lower in the sprouted seeds nd resulted in lower yields. Seeds treted with imidcloprid nd triticonzole hd higher yields thn seeds treted with imidcloprid nd crboxim + thirm. Seeds without ny tretment resulted in lower yields compred with seeds tht hd been treted. However, seeds tht hve been sprouted, should not be treted, s direct exposure of embryos to the chemicls of the seed tretment, my hrm the embryos resulting in poor emergence nd seedling stnd. Keywords: seed tretment, sprouting, storge, whet Introduction Whet crops worldwide re constntly dmged by numerous diseses which cuse quntittive nd especilly qulittive yield losses. Seed, soil nd ir borne diseses cn cuse significnt yield reductions if not mnged properly (Krupinsky et l., 2002). Wether conditions, seed qulity, culturl prctices nd levels of disese inoculum ffect the level of disese pressure in ny given yer. Seed tretments re vilble to control most soil nd seed borne fungi (Beres et l., 2016; Turkington et l., 2016). These tretments protect germinting seeds nd young seedlings from pthogens. The positive effect of seed tretments on whet hs been documented widely (Pike et l., 1993; Gilbert nd Tekuz, 1995; Ashrf nd Foold, 2005). A number of fungicide seed tretment products re vilble for control of erly seson seed nd seedling problems (Beres et l., 2016; Turkington et l., 2016). 2017 Brnrd et l. This is n open ccess rticle distributed in ccordnce with the Cretive Commons Attribution Non Commercil (CC BY-NC 4.0) license, which permits others to distribute, remix, dpt, build upon this work non-commercilly, nd license their derivtive works on different terms, provided the originl work is properly cited nd the use is non-commercil. See: https://cretivecommons.org/licenses/by-nc/4.0 53
ANNELIE BARNARD AND MARDÉ BOOYSE Prehrvest sprouting in whet is described s the premture germintion of the kernels while still ttched to the mother plnt (Kulwl, 2012) nd it results from rinfll nd prolonged moist conditions just prior to or during hrvest (Brnrd nd Smith, 2009). It is n importnt considertion for frmers since prehrvest sprouting leds to biologicl chnges tht lower grin yield, hectolitre mss nd flour qulity, nd ultimtely leds to huge economic losses (Brnrd nd Purchse, 1998). Although lot of informtion is vilble on the effect of fungicides nd insecticides on whet (Singh et l., 2016), little hs been reported on the effect of these tretments on the germintion, emergence nd yield potentil of sprouted whet seed. During yers when considerble prehrvest sprouting occurs s result of wet wether conditions nd whet is downgrded due to poor qulity, mny frmers see this s n opportunity to retin their seeds for plnting in the next seson (Brnrd nd Clitz, 2011). When sprouting occurs, the pericrp ters so tht the embryo is exposed to dmge. Reserch hs shown tht severely sprouted seeds hve significnt negtive effect on the emergence nd yield of crop (Brnrd nd Clitz, 2011). The im of this study ws therefore to determine the effect of different combintions of seed tretments (n insecticide nd two fungicides) pplied to vrious levels of sprouted seeds on different yield prmeters of whet. Mterils nd methods Elnds is winter whet cultivr tht hs been plnted extensively under drylnd conditions in the summer rinfll re of South Afric nd hs been the qulity stndrd for mny yers. Seeds from this cultivr were obtined from ARC-Smll Grin nd were germinted for 48 hours under optiml conditions in the lbortory nd then ir-dried to 12% moisture content. These germinted kernels were mixed with sound seeds from the originl seed lot to obtin four groups ccording to the severity of sprouting: 25, 50, 75 nd 100% sprouted. A fifth group contined only sound seeds (0% sprouted). Ech of the groups were treted with two different seed tretments: imidcloprid (350 g.i. l -1 ) with crboxim + thirm (200 g.i. l -1 ) (seed tretment 2) nd imidcloprid (350 g.i. l -1 ) with triticonzole (200 g.i. l -1 ) (seed tretment 3), herefter referred to s ST2 nd ST3, respectively. The tretments were pplied t the recommended dosges of 2.0 ml imidcloprid kg -1 seeds, 3.0 ml crboxim + thirm kg -1 seeds nd 3.0 ml triticonzole kg -1 seeds. Untreted seeds of ech sprouting severity group ws used s control (ST1). A subsmple of the seeds ws stored t 22 C nd used for plnting trils fter 12 nd 24 months. Before plnting, germintion tests were conducted ccording to ISTA (2012). Trils were plnted for three consecutive yers in Bethlehem, South Afric (28 09'55.12''S, 28 18'32.97''E) using seeds vrying in sprouting level nd given different seed tretments. In the second nd third yers, fresh seeds, tht hd not been stored, were lso plnted s control. These trils were used s reference trils nd the results thereof re not discussed in this pper. The trils were fertilised t the stndrd rte of 30 kg N h -1, 20 kg P h -1 nd 10 kg K h -1. The seeds were plnted in five 5 m-long rows per plot t n inter-row spcing of 54
EFFECT OF SEED TREATMENT ON SPROUTED WHEAT 0.5 m nd n effective plnting rte of 45 to 52 seeds m 2 (pproximtely 15 kg h -1 ), which is the recommended plnting rte of the cultivr for the region. Emergence ws determined 42 dys fter plnting. Yield components (i.e. plnts per m -2, ers per plnt, number of kernels per er nd thousnd kernel mss) were determined t mturity for ech of the tretments nd sprouting levels. The tril ws hrvested when the kernels reched hrvest ripeness (moisture < 13%) fter which yield ws determined in ton h -1. The experimentl design ws completely rndomised design with four replictes. The tretment design ws split-split plot with sprouting levels s min plot fctor, seed tretments s subplot fctor nd storge periods s the sub-subplot fctor. The dt were subjected to n ANOVA using the restricted (or residul or reduced) mximum likelihood (REML) procedure of Genstt softwre version 18 (VSN Interntionl Ltd., Hemel Hempsted, UK). The residuls of the vribles were normlly distributed (Shpiro nd Wilk, 1965). Levene s test ws used to verify homogeneity of yer vrinces (Levene, 1960). The tretment mens of the vribles were compred by Student s t-lest significnt difference (LSD) t the 5% significnce level. Furthermore, principl component nlysis (PCA), with the correltion mtrix to stndrdise the dt, ws performed to exmine the reltionships mong nd between the vribles nd observtions (Rencher, 2002; Leil nd Al-Khteeb, 2005) using XLStt softwre version 2015.1.03 (Addinsoft, Pris, Frnce). Results The effect of seed tretment on germintion (%) under controlled conditions The untreted fresh seeds (ST1) germinted significntly (P 0.05) better thn those treted with either imidcloprid nd crboxim + thirm (ST2) or imidcloprid nd triticonzole (ST3) with n verge of 95.6%, lthough the germintion ws still high in treted seeds (> 80%) (tble 1). However, when seed ws stored for 12 or 24 months, the effect of seed tretments, nmely decline in germintion, becme even more obvious (tble 1). The untreted seeds hd significnt higher germintion percentge thn the treted seeds fter both storge periods. The effect of seed tretment on seed emergence (%) t plnting In the first nd second yer of the study, when fresh seeds were used or seeds were stored for 12 months, seed tretments did not hve significnt effect on the emergence (%) of plnted seeds (tble 2). ANOVA on the emergence (%) showed tht fter 24 months of storge, seed tretments hd significnt effect (P 0.05) on seed emergence (tble 2). Seeds treted with imidcloprid nd crboxim + thirm (ST2) nd imidcloprid nd triticonzole (ST3) hd significntly lower emergence (13.1 nd 17.1%, respectively) thn the 26.2% of the untreted seeds (ST1). The effect of seed tretment on plnt density The number of plnts m -2 ws significntly ffected by sprouting level (P < 0.001) nd seed tretment (P = 0.002), while the interction between sprouting levels nd seed tretments ws not significnt (P = 0.178). The proportion of the vrince from the 55
ANNELIE BARNARD AND MARDÉ BOOYSE Tble 1. Germintion (%) fter 72 hou rs under controlled conditions (22 C) of whet seeds with different levels of prehrvest sprouting nd treted with different seed tretments. Storge period Seed tretment Prehrvest sprouting level (%) Fresh seeds 0 25 50 75 100 Men ST1 99 97 95 92 95 95.6 ST2 93 92 84 84 86 87.8 ST3 89 87 85 84 91 87.2 12 months ST1 96 88 50 27 7 53.6 ST2 82 66 55 27 9 47.8 ST3 75 55 33 22 11 39.2 ST1 90 65 26 17 3 40.2 24 months ST2 64 46 13 9 0 26.4 ST3 44 30 13 6 0 18.6 ST1 = no tretment; ST2 = imidcloprid nd crboxim + thirm; ST3 = imidcloprid nd triticonzole. LSD (0.05) Sprouting level = 3.53 LSD (0.05) Seed tretment = 2.18 LSD (0.05) Storge period = 2.81 LSD (0.05) Sprouting level Seed tretment = 5.13 LSD (0.05) Sprouting level Storge period = 6.06 LSD (0.05) Seed tretment Storge period = 4.49 LSD (0.05) Sprouting level Seed tretment Storge period = 10.16 Tble 2. Emergence (%) under field conditions of whet seeds with different levels of prehrvest sprouting nd treted with different seed tretments Storge period Seed tretment Prehrvest sprouting level (%) Fresh seed 0 25 50 75 100 Men ST1 80 70 59 47 38 58.8 ST2 79 79 53 47 35 58.4 ST3 83 72 72 73 44 68.8 12 months ST1 71 60 33 10 0 34.8 ST2 57 52 30 23 2 32.9 ST3 61 55 44 18 0 35.5 ST1 48 46 20 17 0 26.2 24 months ST2 26 15 18 6 0 13.1 ST3 37 30 8 8 2 17.1 ST1 = no tretment; ST2 = imidcloprid nd crboxim + thirm; ST3 = imidcloprid nd triticonzole. LSD (0.05) Sprouting level = 4.86 LSD (0.05) Seed tretment = 4.48 LSD (0.05) Storge period = 5.15 LSD (0.05) Sprouting level Seed tretment = 9.26 LSD (0.05) Sprouting level Storge period = 10.39 LSD (0.05) Seed tretment Storge period = 8.46 LSD (0.05) Sprouting level Seed tretment Storge period = 18.60 56
EFFECT OF SEED TREATMENT ON SPROUTED WHEAT ANOVA indicted tht the effect of sprouting levels ws high (57%) compred with the effect of seed tretment (9.8%). Similr to the emergence dt, seed tretments did not hve significnt effect (P > 0.05) on the plnt density (number of plnts m -2 ) when fresh seeds were plnted, or fter storge period of 12 months (tble 3). However, fter 24 months of storge, the number of plnts m -2 tht survived ws significntly (P 0.05) reduced in the plnts grown from treted seeds. This becme even more evident with n increse in sprouting level where fewer plnts survived s sprouting level incresed. Seeds treted with imidcloprid nd triticonzole (ST2) hd significntly fewer plnts m -2 (5.2) thn ST1 nd ST3 (11.0 nd 9.8, respectively). With 100% sprouting, very few plnts were counted over the four replictions nd were therefore not included in the nlyses of ers per plnt, kernels per er nd thousnd kernel mss (TKM). The effect of seed tretment on the number of ers per plnt The number of ers per plnt vried significntly within the vrious sprouting levels, irrespective of storge period nd seed tretment (tble 4). Plnts grown from sound seeds hd n verge of 6.4 ers per plnt, wheres the few plnts grown from 100% sprouted seeds, hd men of 11.5 ers per plnt. Seed tretment did not hve significnt (P > 0.05) effect on the number of ers per plnt when fresh seed ws plnted or fter 12 months storge. After 24 months storge however, plnts grown from seeds tht hve been treted (ST2 or ST3) developed significntly (P 0.05) more ers per plnt thn those grown from untreted seeds (tble 4). This correltes well with the results of the number of plnts m -2 (r = -0.792, P = 0.05) where significntly fewer plnts developed from treted seeds (tble 3). Tble 3. Plnt density (number of plnts m -2 ) under field conditions of whet seeds with different levels of prehrvest sprouting nd treted with different seed tretments. Storge period Seed tretment Prehrvest sprouting levels (%) Fresh seed 0 25 50 75 100 Men ST1 49 43 37 29 23 36.4 ST2 49 49 33 29 22 36.2 ST3 52 44 44 46 27 42.7 12 months ST1 30 25 14 4 0 14.6 ST2 24 22 13 10 1 13.8 ST3 34 23 19 8 0 16.6 ST1 20 20 9 7 0 11.0 24 months ST2 11 7 6 3 0 5.2 ST3 18 19 6 6 1 9.8 ST1 = no tretment; ST2 = imidcloprid nd crboxim + thirm; ST3 = imidcloprid nd triticonzole. LSD (0.05) Sprouting level = 2.49 LSD (0.05) Seed tretment = 2.39 LSD (0.05) Storge period = 2.62 LSD (0.05) Sprouting level Seed tretment = 4.89 LSD (0.05) Sprouting level Storge period = 5.29 LSD (0.05) Seed tretment Storge period = 4.36 LSD (0.05) Sprouting level Seed tretment Storge period = 9.54 57
ANNELIE BARNARD AND MARDÉ BOOYSE ANOVA of the number of ers per plnt over levels of sprouting, seed tretments nd storge period to test for men differences, indicted highly significnt interction (P < 0.001) between sprouting levels nd storge period. Significnt effects (P < 0.001) for individul sprouting levels nd storge period were lso observed, which is evident in the vrition between mens in tble 4. However, the interction between sprouting level nd seed tretment ws not significnt (P > 0.05). Tble 4. Number of ers per plnt developed from whet seeds with different levels of prehrvest sprouting nd treted with different seed tretments. Storge period Seed tretment Prehrvest sprouting levels (%) Fresh seed 0 25 50 75 100 Men ST1 6.6 6.7 7.6 9.1 11.6 8.3 ST2 6.8 6.4 8.7 9.0 12.6 8.7 ST3 5.8 6.6 6.5 5.7 10.5 7.0 12 months ST1 5.2 7.9 8.2 18.7 * 10.0 ST2 8.4 10.3 13.8 22.5 8.0 12.6 ST3 6.1 8.1 9.9 17.3 * 10.3 ST1 11.1 11.9 15.3 24.3 * 15.7 24 months ST2 16.9 26.5 36.5 37.5 * 29.3 ST3 8.1 11.1 31.6 25.9 41.5 23.6 ST1 = no tretment; ST2 = imidcloprid nd crboxim + thirm; ST3 = imidcloprid nd triticonzole. LSD (0.05) Sprouting level = 2.65 LSD (0.05) Seed tretment = 2.58 LSD (0.05) Storge period = 2.48 LSD (0.05) Sprouting level Seed tretment = 5.26 LSD (0.05) Sprouting level Storge period = 5.12 LSD (0.05) Seed tretment Storge period = 4.29 * No plnts developed nd therefore no ers could be determined. LSD (0.05) Sprouting level Seed tretment Storge period = 9.34 The effect of seed tretment on other yield components The number of kernels per er nd thousnd kernel mss were not ffected by sprouting level or seed tretment (results not shown). This dt re therefore not shown. The effect of seed tretment on whet yield Averge yields over ll sprouting levels tht were obtined when fresh seeds were plnted, were significntly (P 0.05) higher (2.79 ton h -1 ) (figure 1A) thn the yields obtined from seeds tht were stored for 24 months (1.67 ton h -1 ) (figure 1B). ANOVA showed no interction between sprouting level nd seed tretment (P = 0.837) nd no seed tretment min effect (P = 0.537). The results lso showed tht vrition in yield is driven by the sprouting levels within yer. In the control tril with fresh seeds (figure 1A), no significnt differences (P > 0.05) were observed in the verge yield between ny of the sprouting levels. Although the plnt density significntly (P 0.05) decresed with n increse in sprouting levels (tble 58
EFFECT OF SEED TREATMENT ON SPROUTED WHEAT 3), the number of ers per plnt significntly (P 0.05) incresed (tble 4) to the extent tht no significnt (P > 0.05) differences in yields were obtined. Kernels per er did not differ significntly, therefore indicting tht ny chnges in yield increse could be scribed to the incresed number of ers per plnt. The verge yield of this tril ws 2.79 ton h -1. The tril plnted with seeds stored for 24 months t 22 C hd n verge yield of 1.53 ton h -1 (figure 1B). This ws significntly lower thn the yield obtined when fresh seeds were plnted in the control tril (figure 1A). ANOVA of yield of plnts derived from seeds tht hve been stored for 24 months, indicted significnt differences (P < 0.001) in yield between sprouting levels nd seed tretments. Sprouting levels contributed 90% of the vrition in yields when seeds were stored before plnting. A significnt (P 0.05) decrese in yields could be observed with n increse in sprouting levels, especilly if sprouting levels were high (> 50%). The verge yields of the 0 nd 25% sprouting levels were significntly (P 0.05) higher with 2.16 nd 2.10 ton h -1, respectively in comprison with the 50% (1.87 ton h -1 ), 75% (1.45 ton h -1 ) nd the 100% (0.06 ton h -1 ) sprouting levels. (A) (B) Yield (ton h -1 ) Yield (ton h -1 ) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 b b b c c c c e ST1 ST2 ST3 Seed tretment ST1 ST2 ST3 Seed tretment Figure 1. The influence of seed tretments on the yield of whet when fresh seeds (A) or 24-months-stored seeds (B) with different levels of pre-hrvest sprouting (% vlues indicted to right of grphs) nd different seed tretments were plnted. ST1 = no tretment; ST2 = imidcloprid nd crboxim + thirm; ST3 = imidcloprid nd triticonzole. A: LSD (0.05) Sprouting level = 0.38; LSD (0.05) Seed tretment = 0.19; LSD (0.05) Sprouting level Seed tretment = 0.61 B: LSD (0.05) Sprouting level = 0.15; LSD (0.05) Seed tretment = 0.12; LSD (0.05) Sprouting level Seed tretment = 0.27 d e b b c e 0% 25% 50% 75% 100% 0% 25% 50% 75% 100% 59
ANNELIE BARNARD AND MARDÉ BOOYSE Seeds treted with imidcloprid nd triticonzole (ST3) nd stored for 24 months (figure 1B) hd significntly higher verge yield (1.67 ton h -1 ), over ll sprouting levels, thn untreted seeds (ST1) nd seeds treted with imidcloprid nd crboxim + thirm (ST2). ANOVA indicted tht lthough these differences were significnt (P < 0.001), only 2.3% of the vrition ws explined by seed tretment. Yield, germintion (%) (r = 0.477), emergence (%) (r = 0.520) nd number of plnts m -2 (r = 0.520) were significntly (P < 0.05) positively correlted, nd negtively correlted with TKM (r = -0.728), number of kernels per er (r = -0.642) nd ers per plnt (r = -0.724). A holistic picture of these correltions between the seven vribles nd the reltionship between seed tretments nd sprouting levels is shown by the PCA in figure 2. The first two principl components hd eigenvlues lrger thn 1 nd ccounted for 88.10% of the vrition in the dt. All seven vribles loded hevily on PC1, confirmed by the squred cosine vlues which rnged from 0.41 (kernels per er) to 0.91 (emergence (%)), thus seprting the biplot into high sprouting levels on the left nd low sprouting levels on the right. A strong ssocition exists between lower sprouting levels seed tretment nd yield, germintion (%) nd emergence (%). Higher sprouting vlues re 5 Kernels / per er 4 Ers / per plnt Yield 3 PC2 (16.20%) 2 1 0 100xST3 TKM 75xST2 50xST2 75xST3 50xST3 75xST1 50xST1 25xST2 25xST3 Germintion Emergence Plnts m -2 0xST2 0xST1 25xST1 0xST3-1 -2 100xST1 100xST2-3 -5-4 -3-2 -1 0 1 2 3 4 5 PC1 (71.90%) Figure 2. Biplot of the principl component nlysis of whet seeds with different levels of prehrvest sprouting nd treted with different seed tretments fter 24 months of seed storge. ST1 = no tretment; ST2 = imidcloprid nd crboxim + thirm; ST3 = imidcloprid nd triticonzole. 60
EFFECT OF SEED TREATMENT ON SPROUTED WHEAT strongly ssocited with TKM, number of ers per plnt nd number of kernels per er. Seeds from ST1 nd ST2 t 100% sprouting level re further wy from the rest of the sprouting levels seed tretment, indicting tht they do not influence ny of the vribles (figure 2). Discussion Fresh seeds tht hve not been stored for ny period of time germinted significntly better thn those stored for either 12 or 24 months. This effect ws even more pprent when sprouting occurred. It ws reported previously (Foster et l., 1998; Brnrd nd Clitz, 2011) tht seedling vigour of sprouted seeds is negtively influenced by storge: modertely or severely sprouted seeds tht hd been stored for 12 to 27 months resulted in reduced germintion. This is in greement with results from this study tht showed tht seeds tht hd been stored for 12 nd 24 months, hd significntly lower germintion (%) thn fresh seeds. Results from this study further showed tht germintion (%) of fresh seeds ws not ffected by seed tretment, but fter 12 nd 24 months of storge, seed tretment significntly ffected germintion (%) negtively. Moś nd Wójtowicz (2005) reported tht the germintion bility of triticle ws negtively influenced by sprouting. They reported 30% difference in emergence between sprouted nd sound seeds. In ddition, they found tht n increse in sprouting dmge intensifies decrese in germintion bility. In the current study, similr results were observed with significnt differences in emergence between the control nd severely sprouted seeds (75% sprouting). These differences mount to 33% in fresh seeds. Emergence (%) decresed significntly with n increse in sprouting level. It hs previously been reported tht seed tretments hve negtive effect on seedling emergence of sprouted seeds (Brnrd nd Purchse, 1998; Moś nd Wójtowicz, 2005). In the current study, lthough emergence ws not ffected by seed tretment in the first nd second yers of the study, it hd significnt effect on emergence fter 24 months of storge with untreted seeds hving the highest emergence. The direct exposure of embryos to seed tretments could be responsible for this decrese in emergence. It is therefore risk for producers to plnt seeds tht hve been stored, especilly if the seeds hve been treted. The risk becomes even higher when germintion hs occurred. Plnt density ws significntly lower fter storge. The verge number of plnts m -2 tht developed from seeds tht hd been stored ws significntly lower thn when fresh seeds were plnted. Seed tretment hd smll but significnt effect on the number of plnts m -2. Seeds treted with imidcloprid nd crboxim + thirm (ST2) resulted in lower plnt density thn untreted seeds or seeds treted with imidcloprid nd triticonzole (ST3). This is similr to the findings of Chstin et l. (1994) who reported tht sprouted seeds treted with crboxin + thirm produced lower density stnds thn norml seeds. As expected, the number of ers per plnt incresed with decrese in plnting density, resulting in higher number of ers per plnt when the number of plnts m -2 ws low. It is cler tht these plnts, due to reduced competition, were ble to compenste significntly by producing more ers per plnt. The number of kernels per er did not vry between tretments. 61
ANNELIE BARNARD AND MARDÉ BOOYSE Yields obtined when fresh seeds were plnted, were not ffected by sprouting level. Similrly Foster et l. (1998) reported tht if whet seeds were sown in the yer of hrvest, sprouting dmge did not significntly ffect the yield. This ws confirmed by Moś nd Wójtowicz (2005) who found no significnt effect of sprouting dmge on yield. Sound seeds without ny tretment resulted in lower yields compred with seeds tht hve been treted with either imidclopridid nd crboxim + thirm or imidcloprid nd triticonzole. This is in greement with the findings of Turkington et l. (2016) who showed tht fungicide/insecticide tretments positively influenced stnd estblishment nd grin yield in winter whet. However, fter 24 months of storge, yields were significntly decresed t the higher sprouting levels (> 50%). This decrese in yield correlted with n increse in the severity of sprouting levels nd ws lso found by Brnrd nd Purchse (1998) nd Elis nd Copelnd (1991). Seed tretments hd significnt effect on the yield when seeds were stored. Seeds treted with imidcloprid nd triticonzole (ST3) hd higher yields thn ST1 nd ST2. High qulity seeds re essentil for estblishing productive stnds of whet (Bojovic, 2010). The improved emergence, yield nd other yield components when plnting untreted, sprouted seeds s opposed to treted, sprouted seeds will be lost, to some extent, by n increse in soil borne diseses nd insect dmge since untreted seed re completely unprotected. This hs dire consequences for the producer nd highlights the fct tht clen, certified, undmged seeds should be used from the strt. However, if crop is slightly sprouted, producer cn use these seeds for plnting, s whet plnts re ble to compenste significntly, resulting in cceptble yield levels. It is importnt, however, to tke note tht these seeds should not be treted, s direct exposure of embryos to the chemicls of the seed tretment my be hrmful. Sprouted kernels should lso not be stored, s seeds loses its vibility fter storge, resulting in poor emergence nd seedling stnd. Acknowledgements The uthors would like to thnk the Winter Cerel Trust nd the Agriculturl Reserch Council for finncil support nd Ms. Shuny Humn for technicl ssistnce. References Ashrf, M. nd Foold, M.R. (2005). Pre-Sowing Seed Tretment - A shotgun pproch to improve germintion, plnt growth nd crop yield under sline nd non sline conditions. Advnces in Agronomy, 88, 223-271. Brnrd, A. nd Clitz, F.J. (2011). The effect of poor qulity seed nd vrious levels of grding fctors on the germintion, emergence nd yield of whet. South Africn Journl of Plnt nd Soil, 28, 23-33. Brnrd, A. nd Purchse, J.L. (1998). The reltionship of prehrvest sprouted seed nd seed tretment to emergence nd yield of winter whet (Triticum estivum L.) in the Estern Free Stte. Seed Science nd Technology, 26, 711-718. Brnrd, A. nd Smith, M.F. (2009). The effect of rinfll nd temperture on the prehrvest sprouting tolernce of winter whet in the drylnd production res of the Free Stte Province. Field Crops Reserch, 112, 158-164. https://doi.org/10.1016/j.fcr.2009.02.011 62
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