Antixenotic and Allelochemical Resistance Traits of Watermelon Against Bactrocera cucurbitae in a Hot Arid Region of India

Transcription

1 Antixenotic nd Allelochemicl Resistnce Trits of Wtermelon Aginst Bctrocer cucurbite in Hot Arid Region of Indi Authors: Shrvn M. Hldhr, B. R. Choudhry, R. Bhrgv, nd S. R. Meen Source: Florid Entomologist, 98(3) : Published By: Florid Entomologicl Society URL: BioOne Complete (complete.bioone.org) is full-text dtbse of 200 subscribed nd open-ccess titles in the biologicl, ecologicl, nd environmentl sciences published by nonprofit societies, ssocitions, museums, institutions, nd presses. Your use of this PDF, the BioOne Complete website, nd ll posted nd ssocited content indictes your cceptnce of BioOne s Terms of Use, vilble t Usge of BioOne Complete content is strictly limited to personl, eductionl, nd non-commercil use. Commercil inquiries or rights nd permissions requests should be directed to the individul publisher s copyright holder. BioOne sees sustinble scholrly publishing s n inherently collbortive enterprise connecting uthors, nonprofit publishers, cdemic institutions, reserch librries, nd reserch funders in the common gol of mximizing ccess to criticl reserch.

2 Antixenotic nd llelochemicl resistnce trits of wtermelon ginst Bctrocer cucurbite in hot rid region of Indi Shrvn M. Hldhr*, B. R. Choudhry, R. Bhrgv, nd S. R. Meen Abstrct Host plnt resistnce is n importnt component of integrted pest mngement of the melon fly, Bctrocer cucurbite (Coquillett) (Dipter: Tephritide). We studied vrious ntixenotic nd llelochemicl trits in the fruit for 15 vrieties/genotypes of wtermelon Citrellus lntus (Thunb.) Mtsumr & Nki (Cucurbitles: Cucurbitcee) in reltion to resistnce ginst B. cucurbite under field conditions in hot rid region of Indi. Results showed significnt differences in tested vrieties/genotypes in levels of fruit infesttion nd lrvl density per fruit. The vrieties/genotypes Ashi Ymto (12.73%), AHW/BR-16 (15.10%), nd Thr Mnk (18.27%) were found to be resistnt; Durgpur Ll (23.03%), Sugr Bby (26.67%), AHW/BR-12 (29.73%), Ark Mnik (34.15%), Chrleston Gry (38.70%), AHW-65 (35.80%), nd AHW-19 (48.97%) were found to be modertely resistnt; nd IC (53.18%), AHW/BR-60 (55.52%), BSM-1 (59.10%), AHW/BR-137 (60.58%), nd AHW/BR-9 (67.37%) were found to be susceptible to fruit fly infesttion. Significnt positive correltion (r = 0.99; P < 0.01) ws observed between percentge fruit infesttion nd lrvl density per fruit. Percentge fruit infesttion nd lrvl density per fruit were significntly nd positively correlted with fruit length (r = 0.57 nd 0.55, respectively) nd with dys to first fruit hrvest (r = 0.75 nd 0.76, respectively), but negtively correlted with length of ovry pubescence (r = 0.91 nd 0.91, respectively), rind hrdness (r = 0.86 nd 0.87, respectively), nd rind thickness (r = 0.77 nd 0.75, respectively). Mximum vrition in fruit infesttion nd lrvl density were explined by length of ovry pubescence (82.5 nd 83.6%, respectively) followed by fruit length (4.3 nd 3.0%, respectively) nd rind thickness (3.2 nd 2.0%, respectively). Free mino cid content ws lowest in the resistnt Ashi Ymto nd highest in the susceptible BSM-1, wheres the contents of phenols, tnnins, totl lkloids, nd flvonoids were highest in resistnt nd lowest in susceptible vrieties/genotypes. Flvonoid nd totl lkloid contents explined 88.4 nd 92.0%, respectively, of the totl vrition in fruit fly infesttion nd in lrvl density per fruit. Key Words: flvonoid; lkloid; phenol; tnnin; Ashi Ymto ; BSM-1 Resumen L resistenci de ls plnts hospeders es un componente importnte pr el mnejo integrdo de plgs de l mosc del melón, Bctrocer cucurbite (Coquillett) (Dipter: Tephritide). Estudimos vrios crcterístics ntixenotics y de leloquímicos en el fruto de 15 vrieddes/genotipos de sndí Citrellus lntus (Thunb.) Mtsumr y Nki (Cucurbitles: Cucurbitcee) en relción l resistenci contr B. cucurbite en condiciones de cmpo en un región árid y cliente de l Indi. Los resultdos mostrron diferencis significtivs en ls vrieddes/genotipos probdos en los niveles de infestción de l frut y de l densidd de lrvs por fruto. Ls vrieddes/genotipos Ashi Ymto (12,73%), AHW/BR-16 (15,10%) y Thr Mnk (18,27%) resultron ser resistentes; Durgpur Ll (23,03%), Sugr Bby (26,67%), AHW/BR-12 (29,73%), Ark Mnik (34,15%), Chrleston Gry (38,70%), AHW-65 (35,80%) y AHW-19 (48,97%) resultron ser moderdmente resistente; y se encontrron IC (53,18%), AHW/ BR-60 (55,52%), BSM-1 (59,10%), AHW/BR-137 (60,58%) y AHW/ BR- 9 (67,37%) susceptibles l infestción de mosc de l frut. Se observó un correlción positiv significtiv (r = 0,99; P < 0,01) entre el porcentje de infestción de frut y l densidd de lrvs por fruto. Se correlcionron significtivmente y positivmente el porcentje de infestción de fruts y l densidd de lrvs por fruto con l longitud del fruto (r = 0,57 y 0,55, respectivmente) con el número de dís hst l primer cosech de l frut (r = 0,75 y 0,76, respectivmente), pero fueron negtivmente correlciondos con l durción de l pubesenci de ovrio (r = 0,91 y 0,91, respectivmente), l durez de cortez (r = 0,86 y 0,87, respectivmente), y el grueso de l cortez (r = 0,77 y 0,75, respectivmente). Se explic l vrición máxim de l infestción de fruts y l densidd lrvl por l longitud de pubescenci del ovrio (82,5 y 83,6%, respectivmente) seguido de l longitud del fruto (4,3 y 3,0%, respectivmente) y el grueso de l cortez (3,2 y 2,0%, respectivmente). El contenido de minoácidos libres fue más bjo en el resistente Ashi Ymto y más lto en el susceptible BSM-1, mientrs que el contenido de fenoles, tninos, lcloides totles y flvonoides fue más lto en ls vrieddes/genotipos resistentes y menor en ls vrieddes susceptibles. El contenido de lcloides y flvonoides totles explicron el 88,4 y 92,0%, respectivmente de l vrición totl de l infestción por l mosc de l frut y de l densidd de lrvs por frut. Plbrs Clve: flvonoides; lcloide; fenol; tninos; Ashi Ymto ; BSM-1 Wtermelon (Citrullus lntus [Thunb.] Mtsumr & Nki; Cucurbitles: Cucurbitcee) is populr dessert crop throughout the tropics nd the Mediterrnen regions of the world (Tindll 1983). Becuse of its ntioxidnt properties, the fruit is being rted equl to pple, bnn, or ornge. Fruits contin diverse crotenoids tht re responsible for the different flesh colors. Different crotenoid ptterns Centrl Institute for Arid Horticulture, ICAR, Bikner, Indi *Corresponding uthor; E-mil: hldhr80@gmil.com 2015 Florid Entomologist Volume 98, No

3 Florid Entomologist Volume 98, No. 3 hve been ssocited with distinct cultivrs nd cultivted environments (Zho et l. 2013). Fruits lso vry in size, shpe, nd rind pttern (Choudhry et l. 2012); re rich in lycopene nd hve totl ntioxidnt cpcity similr to tomto (Djuric & Powell 2001; Perkins-Vezie et l. 2001); nd re rich source of β-crotene, vitmins (B, C, nd E), minerls (K, Mg, C, nd Fe), mino cid (citrulline), nd phenols (Perkins-Vezie & Dvis 2007). Plnts generlly re exposed to vriety of biotic nd biotic fctors tht my lter their genotypic nd/or phenotypic properties resulting in expression of different mechnisms of resistnce to pest ttck (Gogi et l. 2010). Such mechnisms of plnt resistnce hve been used effectively ginst insect pests in mny field nd horticulturl crops (Dhillon et l. 2005; Gogi et l. 2010). Mechnisms of resistnce in plnts re either constitutive or induced (Trw & Dwson 2002) nd re grouped into 3 min ctegories: ntixenosis, ntibiosis, nd tolernce (Pinter 1951). Plnts responsible for ntibiosis resistnce my cuse reduced insect survivl, prolonged development time, decresed size, nd reduced fitness of new-genertion dults (Srfrz et l. 2006, 2007; Gogi et l. 2010). Antixenosis refers to the potentil plnt chrcteristics/trits, either llelochemicl or morphologicl, tht imprt or lter insect behvior towrds the host (Moslem et l. 2011; Wr et l. 2012; Hldhr et l. 2013). Insect pests re mjor constrint for incresing the production nd productivity of the wtermelon crop. The melon fly, Bctrocer cucurbite (Coquillett) (Dipter: Tephritide), is serious pest of wtermelon in Indi, nd its outbreks cuse substntil crop losses to the growers. The melon fly hs been observed on 81 host plnts, with wtermelon being highly-preferred host, nd hs been mjor limiting fctor in obtining good-qulity fruits nd high yield (Nth & Bhushn 2006). The extent of losses vries between 30 nd 100%, depending on the cucurbit species nd the seson. As the mggots dmge the fruits internlly, it is difficult to control this pest with insecticides. Hence, development of wtermelon vrieties/genotypes resistnt to the melon fly is n importnt component of integrted pest mngement (Pnd & Khush 1995), but it hs been limited in Indi owing to indequte informtion on the sources of plnt trits ssocited with resistnce to pest infesttions. The present study ws designed to identify vrious morphologicl (ntixenotic) nd biochemicl (llelochemicl) fruit trits of wtermelon vrieties/genotypes ssocited with resistnce ginst the melon fly in terms of fruit infesttion nd lrvl density under field conditions. Mterils nd Methods PRELIMINARY SCREENING OF WATERMELON VARIETIES/ GENOTYPES (SUMMER 2012) Twenty-seven vrieties/genotypes of wtermelon (RSS-1, AHW/ BR-18, AHW/BR-8, AHW/BR-21, AHW/BR-20, AHW/YF-4, AHW/BR-19, AHW/BR-96, AHW/YF-5, AHW/YF-7, AHW/BR-10, Durgpur Kesr, AHW/BR-137, Durgpur Ll, AHW/BR-9, Sugr Bby, AHW-65, AHW- 19, IC , BSM-1, AHW/BR-16, Chrleston Grey, Ashi Ymto, Ark Mnik, AHW/BR-60, AHW/BR-12, nd Thr Mnk) were sown t the experimentl frm of ICAR-Centrl Institute for Arid Horticulture (CIAH), Bikner (28 06'N, 73 21'E), Indi. The crop ws sown in summer 2012 with 3 replictes (blocks) for ech vriety/genotype in rndomized block design. The re of ech bed ws 5 2 m, nd the plnt-to-plnt distnce ws mintined t 50 cm with drip irrigtion system. All the recommended gronomic prctices (e.g., weeding, fertilizing, hoeing) were performed eqully in ech experimentl bed ccording to locl prctices. Three pickings were done during the entire growing seson of wtermelon. Five fruits were selected rndomly from ech picking from ech experimentl bed (repliction) of ech vriety/genotype nd were brought to the lbortory for exmintion using stereomicroscope for fruit infesttion. The infested fruits were sorted nd the percentge fruit infesttion ws clculted. Five fruits from ll infested fruits from ech picking of ech vriety/genotype were then selected rndomly for further exmintion, nd the lrve were counted in ech infested fruit. The vrieties/genotypes were ctegorized by following the rting system given by Nth (1966) for fruit infesttion s: immune (no dmge), highly resistnt (1 10%), resistnt (11 20%), modertely resistnt (21 50%), susceptible (51 75%), nd highly susceptible (76 100%). FINAL SCREENING OF THE SELECTED WATERMELON VARIETIES/ GENOTYPES (RAINY SEASON 2013 & SUMMER 2014) Fifteen selected vrieties/genotypes from the preliminry screening of wtermelon (AHW/BR-137, Durgpur Ll, AHW/BR-9, Sugr Bby, AHW-65, AHW-19, IC , BSM-1, AHW/BR-16, Chrleston Grey, Ashi Ymto, Ark Mnik, AHW/BR-60, AHW/BR-12, nd Thr Mnk) were sown t the experimentl frm of ICAR-CIAH, Bikner, Indi, in Jul 2013 nd Feb 2014 using rndomized block design, with 3 blocks for ech vriety/genotype nd ech block representing repliction. The re of ech bed ws 5 2 m, nd the plnt-to-plnt distnce ws mintined t 50 cm with drip irrigtion system. The picking nd exmintion of fruits were performed s described for the preliminry screening. ANTIXENOTIC FRUIT TRAITS OF THE WATERMELON VARIETIES/ GENOTYPES Ten mrketble fresh fruits of ech of the 15 vrieties/genotypes were used to record dt on the biophysicl trits (length of pubescence, rind hrdness, rind thickness, dy to first hrvest, fruit length, nd fruit dimeter). Length of ovry pubescence, rind thickness, fruit dimeter, nd fruit length were mesured t 5 different positions of ech fruit using Digitl Vernier Cliper (MITU-TOYO, 300 mm, 0.01 mm reding cpcity). The dys of first hrvesting of fruits were recorded visully in the field. The hrdness of fruit rind ws ssessed t hrvesting using fruit pressure tester (Model FT 327, 0 13 kg/cm 2 ). ALLELOCHEMICAL FRUIT TRAITS OF THE WATERMELON VARIET- IES/GENOTYPES Two fresh fruits of ech vriety/genotype from ech repliction were selected, cut into smll pieces, nd dried. For estimtion of metbolites, the procedure s published for ech metbolite ws followed to determine contents of phenols (Mlik & Singh 1980), tnnins (Schnderl 1970), scorbic cid (Sdsivm & Blsubrminn 1987), free mino cids (Lee & Tkhshi 1966), nd flvonoids (Ebrhimzdeh et l. 2008; Nbvi et l. 2008). STATISTICAL ANALYSES Trnsformtions (ngulr nd squre-root trnsformed vlues) were used to obtin normlity in the dt distribution before nlysis (Steel et l. 1997), but untrnsformed mens re lso presented in ll tbles. The dt on percentge fruit infesttion, lrvl density per fruit, nd biochemicl fruit trits were nlyzed through 1-wy ANOVA using SPSS 16 softwre (O Connor 2000). The mens of significnt prmeters, mong tested vrieties/genotypes, were compred using Tukey s Honest Significnt Difference (HSD) test for pired comprisons t probbility level of 5%. Correltions between biophysicl

4 Hldhr et l.: Resistnce trits in wtermelon vrieties nd genotypes ginst Bctrocer cucurbite 829 nd biochemicl fruit trits nd fruit fly prmeters (percentge fruit infesttion nd lrvl density per fruit) were determined by correltion nlysis nd bckwrd stepwise multiple regression nlysis t the 95% significnce level. Results PRELIMINARY SCREENING OF WATERMELON VARIETIES/ GENOTYPES In the preliminry screening ginst the melon fly, significnt differences were found in percentge fruit infesttion nd lrvl density per fruit mong the 27 tested vrieties/genotypes. The lrvl density per fruit hd significnt positive correltion with percentge fruit infesttion (r = 0.99; P < 0.01). The vrieties/genotypes Ashi Ymto, Thr Mnk, nd AHW/BR-16 were resistnt; AHW/BR-12, Ark Mnik, Chrleston Grey, AHW-65, AHW-19, Sugr Bby, Durgpur Ll, AHW/ BR-19, AHW/BR-96, AHW/YF-5, AHW/YF-7, nd RSS-1 were modertely resistnt; nd AHW/BR-18, AHW/BR-8, AHW/BR-21, AHW/BR-20, AHW/YF-4, AHW/BR-10, Durgpur Kesr, AHW/BR-137, AHW/BR-9, IC , BSM-1, nd AHW/BR-60 were susceptible (Tble 1). The lrvl density rnged from 9.97 to lrve per fruit nd ws significntly lower in resistnt vrieties/genotypes thn in susceptible ones. It ws highest in genotype AHW/BR-9 (19.10 lrve/fruit) followed by Tble 1. Lrvl density nd percentge fruit infesttion by the melon fly on different vrieties/genotypes of wtermelon during preliminry screening trils (summer seson). Genotype Lrvl density per fruit Fruit infesttion (%),b Resistnce ctegory c Thr Mnk b (24.85) bc R Ashi Ymto (20.59) R AHW/BR b (22.54)b R Ark Mnik de (35.51) fgh MR AHW/BR cde (32.49) ef MR Chrleston Grey de (38.05) hi MR AHW ef (44.39) kl MR AHW de (36.46) ghi MR Sugr Bby cd (31.10) de MR Durgpur Ll bc (28.28) cd MR AHW/YF de (34.00) efg MR AHW/YF cd (31.23) de MR AHW/BR d (40.13) ij MR AHW/BR efg (39.74) ij MR RSS ef (41.88) jk MR Durgpur Kesr ij (51.68) opq S AHW/BR hij (52.72) pq S AHW/BR j (54.91) q S AHW/BR hij (50.37) np S AHW/BR ghi (48.18) mno S BSM hij (49.70) mnop S IC fgh (46.53) lm S AHW/BR hij (52.22) pq S AHW/BR hi (50.19) mnop S AHW/BR ij (49.74) mnop S AHW/BR ij (53.02) pq S AHW/YF hij (47.99) lmn S Vlues in prentheses re ngulr trnsformed. b Vlues followed by different letters re significntly different (Tukey s Honest Significnt Difference test). c R, resistnt; MR, modertely resistnt; S, susceptible; nd HS, highly susceptible. AHW/BR-8 (18.33 lrve/fruit). The minimum lrvl density ws found in Ashi Ymto (9.97 lrve/fruit) followed by AHW/BR-16 (10.60 lrve/fruit). The percentge fruit infesttion ws highest in AHW/BR-9 (66.90%) nd lowest in Ashi Ymto (12.60%) followed by AHW/BR- 16 (14.73%). The fruit infesttion rnged from to 66.90% nd ws significntly lower in resistnt nd higher in susceptible vrieties/ genotypes (Tble 1). FINAL EVALUATION OF WATERMELON VARIETIES/GENOTYPES The 15 vrieties/genotypes selected for finl evlution of melon fly resistnce were tested during the riny seson 2013 nd summer seson The vrieties/genotypes Ashi Ymto, Thr Mnk, nd AHW/BR-16 were resistnt; AHW/BR-12, Ark Mnik, Chrleston Grey, AHW-65, AHW-19, Sugr Bby, nd Durgpur Ll were modertely resistnt; nd AHW/BR-137, AHW/BR-9, IC , BSM-1, nd AHW/ BR-60 were susceptible in both sesons (Tble 2). The lrvl density per fruit incresed with n increse in percentge fruit infesttion, nd there ws significnt positive correltion (r = 0.99; P < 0.01) between percentge fruit infesttion nd lrvl density per fruit (Tble 3). The lrvl density rnged from to nd to lrve per fruit in the riny seson 2013 nd the summer seson 2014, respectively. Pooled dt showed tht lrvl density per fruit in both sesons ( lrve/fruit) ws significntly lower in resistnt nd higher in susceptible vrieties/genotypes. Pooled dt showed tht fruit infesttion in both sesons ( %) ws significntly lowest in resistnt nd highest in susceptible vrieties/genotypes. In pooled dt, the percentge fruit infesttion ws highest in AHW/BR-9 (67.37%) nd lowest in Ashi Ymto (12.73%) followed by AHW/BR-16 (15.10%) (Tble 2). ANTIXENOTIC FRUIT TRAITS OF THE WATERMELON VARIETIES/ GENOTYPES Length of ovry pubescence, rind hrdness, nd rind thickness rnged from 3.82 to 6.20 mm, 8.37 to kg/cm 2, nd 0.80 to 1.58 cm, respectively. However, dys to first fruit hrvest ( d), fruit length ( cm), nd fruit dimeter ( cm) were different mong vrieties/genotypes of wtermelon (Tble 4). Length of ovry pubescence, rind hrdness, nd rind thickness hd significnt negtive correltions, wheres dys to first fruit hrvest, fruit length, nd fruit dimeter hd significnt positive correltions with percentge fruit infesttion nd lrvl density per fruit (Tble 3). Stepwise regression nlysis indicted tht length of ovry pubescence, rind hrdness, rind thickness, fruit length, dys to first hrvest, nd fruit dimeter explined 94% of the totl vrition in melon fly infesttion. The mximum vrition in fruit infesttion ws explined by length of ovry pubescence (82.5%) followed by fruit length (4.3%) nd rind thickness (3.2%), wheres the remining biophysicl fruit trits explined < 3.0% vrition in the fruit infesttion (Tble 5). Length of ovry pubescence, rind hrdness, rind thickness, fruit length, dys to first fruit hrvest, nd fruit dimeter explined 93.3% of the totl vrition in the lrvl density per fruit. The mximum vrition in the lrvl density per fruit ws explined by length of ovry pubescence (83.6%) followed by fruit length (3.0%) nd dys to first fruit hrvest (2.6%), wheres other trits explined < 2% vrition in lrvl density (Tble 5). ALLELOCHEMICAL FRUIT TRAITS OF THE WATERMELON VARIETIES/ GENOTYPES The free mino cid content in fruits of different vrieties/genotypes rnged from 2.00 to 8.47 mg/g (on dry weight bsis) with vlues significntly lower in resistnt nd higher in susceptible vrieties/geno-

5 Florid Entomologist Volume 98, No. 3 Tble 2. Lrvl density of nd percentge fruit infesttion by the melon fly on different vrieties/genotypes of wtermelon during finl evlution trils. Genotype Lrvl density per fruit Fruit infesttion (%) Riny seson Summer seson Pooled Riny seson Summer seson Pooled Resistnce ctegory Thr Mnk b b b (25.41) bc (24.97) b (25.23) bc R Ashi Ymto (20.83) (20.55) (20.73) R AHW/BR b (23.04) b (22.63) (22.84) b R AHW/BR de de c (33.70) ef (32.32) cde (33.02) ef MR Ark Mnik ef def cd (36.03) fg (35.33) def (35.68) fg MR Chrleston Grey f ef cd (38.77) g (38.13) f (38.45) g MR AHW fg fg de (44.58) h (44.20) g (44.39) h MR AHW ef def cd (37.43) fg (36.03) ef (36.74) g MR Sugr Bby cd cd b (31.25) de (30.90) cd (31.07) de MR Durgpur Ll bc bc b (28.48) cd (28.48) bc (28.48) cd MR AHW/BR j j h (55.31) k (55.11) i (55.14) k S BSM hi ij g (50.97) ij (49.49) h (50.22) ij S IC gh gh ef (46.93) hi (46.68) gh (46.81) hi S AHW/BR hi ghi fg (48.35) hij (47.95) gh (48.15) hij S AHW/BR i hi g (51.65) j (50.55) h (51.09) j S Vlues in prentheses re ngulr trnsformed. b Vlues followed by different letters re significntly different (Tukey s Honest Significnt Difference test). c R, resistnt; MR, modertely resistnt; S, susceptible; nd HS, highly susceptible. Tble 3. Correltion coefficient (r) between percentge fruit infesttion nd lrvl density per fruit with vrious ntixenotic fruit trits of wtermelon vrieties/ genotypes. Percentge infesttion Lrvl density Length of ovry pubescence (mm) Rind hrdness (kg/cm 2 ) Rind thickness Dys to first fruit hrvest Fruit length Lrvl density 0.991** Length of ovry pubescence 0.908** 0.914** Rind hrdness 0.856** 0.872** 0.880** Rind thickness 0.770** 0.746** 0.728** 0.591* Dys to first hrvest 0.746** 0.763** 0.669** 0.763** NS Fruit length 0.568* 0.545* NS NS NS NS Fruit dimeter NS NS NS NS NS NS 0.581* **, significnt t P = 0.01 (2-tiled); *, significnt t P = 0.05 (2-tiled); NS, not significnt. Tble 4. Antixenotic fruit trits of different vrieties/genotypes of wtermelon. Genotype Length of ovry pubescence (mm) Rind hrdness (kg/cm 2 ) Rind thickness Dys to first fruit hrvest Fruit length Fruit dimeter Thr Mnk 5.44 gh fg 1.17 cd (8.45) c cd AHW/BR g ef 1.13 bcd (8.60) bcd AHW/BR cde 9.20 b (9.04) e d e Ark Mnik 5.21 fg 9.97 bcde 1.58 e (8.98) de c h Ashi Ymto 6.20 i g 1.57 e (8.47) b c gh Chrleston Grey 5.09 efg def 1.04 bc (8.66) bcde d bc AHW/BR h h 1.46 e (8.48) bc c b BSM bc 9.40 bc 1.07 bc (8.70) bcde g h IC cd 9.87 bcde (8.83) bcde b bc AHW def bcde 1.16cd (8.73) bcde f fg AHW def 9.67 bcd 1.49 e (8.85) bcde c e Sugr Bby 5.03 efg def 1.20 cd (8.73) bcde c d AHW/BR (8.87) cde ef cd Durgpur Ll 4.88 def cdef 1.33 de (8.54) bc b cd AHW/BR b 9.77 bcde 0.90 b (8.98) de de ef Vlues in column followed by different letters re significntly different (Turkey s Honest Significnt Difference test). Vlues in prentheses re squre-root trnsformed.

6 Hldhr et l.: Resistnce trits in wtermelon vrieties nd genotypes ginst Bctrocer cucurbite 831 Tble 5. Bckwrd stepwise regression models showing the effect of different ntixenotic fruit trits of wtermelon on percentge fruit infesttion nd number of lrve per fruit. Model R 2 Role of individul trits (%) Percentge fruit infesttion Y = X X X X X X Y = X X X X X Y = X X X X Y = X X X Y = X X Y = X Lrvl density per fruit Y = X X X X X X Y = X X X X X Y = X X X X Y = X X X Y = X X Y = X X 1, length of ovry pubescence; X 2, rind hrdness; X 3, rind thickness; X 4, dys to first fruit hrvest; X 5, fruit length; X 6, fruit dimeter; nd R 2, coefficient of determintion. types. Flvonoid, tnnin, totl lkloid, phenol, nd scorbic cid contents rnged from to mg/100 g, to 60.83mg/100 g, 0.43 to 1.55%, to mg/g, nd to mg/10 g, respectively, with vlues significntly higher in resistnt nd lower in susceptible vrieties/genotypes (Tble 6). The free mino cid content of fruit hd significnt positive correltion wheres flvonoid, tnnin, totl lkloid, phenol, nd scorbic cid contents hd significnt negtive correltion with percentge fruit infesttion nd lrvl density per fruit (Tble 7). Bckwrd stepwise regression nlysis indicted tht flvonoid nd totl lkloid contents explined 88.4% of the totl vrition in fruit fly infesttion (Tble 8). The mximum vrition in fruit infesttion ws explined by flvonoid content (69.7%) followed by totl lkloid (18.7%), phenol (3.3%), scorbic cid (1.4%), tnnin (1.0%), nd free mino cid contents (0.3%). The flvonoid nd totl lkloid contents explined 92.0% of the totl vrition in lrvl density per fruit. The mximum vrition in lrvl density per fruit ws explined by flvonoid content (71.1%) followed by totl lkloid (20.9%), phenol (2.0%), nd scorbic cid contents (1.0%), wheres the rest of the biochemicl fruit trits explined < 1% vrition in lrvl density (Tble 8). Discussion Host plnt selection by insects is expressed either by the occurrence of popultion of insects on the plnt in nture or by feeding, oviposition, or use of the plnt for complete offspring development (Rfiq et l. 2008). Plnt chrcteristics influence the herbivores directly by ffecting host plnt preference or survivl nd reproductive success (direct defense) nd indirectly through influencing the behvior of other species such s nturl enemies of the insect pests (indirect defense) (Dudrev et l. 2006; Hower & Jnder 2008; Arimur et l. 2009). Direct defenses re medited by plnt chrcteristics tht ffect the herbivore s biology such s mechnicl protection on the surfce of the plnts (e.g., hirs, trichomes, thorns, spines, nd thick leves) or production of toxic chemicls such s terpenoids, lkloids, nthocynins, phenols, nd quinones tht either kill or retrd the development of the herbivores (Hnley et l. 2007). Inheritnce of resistnce to the fruit fly ws studied in intervrietl crosses of wtermelon C. lntus nd 2 sources of resistnce (J 18-1 nd J 56-1) were used. The resistnce of wtermelon to the fruit fly ws controlled by Tble 6. Allelochemicl fruit trits of different vrieties/genotypes of wtermelon. Genotype Flvonoid content (mg/100 g) Tnnin content (mg/100 g) Totl lkloid content (%) Phenol content (mg/g) Ascorbic cid (mg/10 g) Free mino cids (mg/g) Thr Mnk (8.29) cd (7.04) d 1.55 i efg (9.00) g 4.74 cd AHW/BR (8.46) de (6.87) c 1.06 f efg (8.72) efg 4.59 cd AHW/BR (7.50) b (5.97) 0.74 b bcd (7.71) c 7.43 f Ark Mnik (7.72) bc (7.69) fg 0.89 cde def (8.38)de 5.19 d Ashi Ymto (10.09 )g (7.77) fg 1.35 h h (9.51) i 2.00 Chrleston Grey (7.78) bc (7.62) efg 0.82 bc bcde (8.55) ef 6.13 e AHW/BR (9.39) f (7.22) def 1.34 h gh (9.32) hi 2.83 b BSM (7.39) (5.89) bc (7.35) b 8.47 g IC (8.07) bcd (6.06) b 0.98 def cde (8.03) cd 6.00 e AHW (7.52) b (6.00) 0.84 bcd bcde (7.95) c 6.55 e AHW (7.63) b (6.56) bcd 1.09f g bcde (7.75) d 7.30 f Sugr Bby (9.32) f (7.24) def 1.02 ef gh (8.84) gh 4.31 c AHW/BR (7.17) (5.64) (6.90) 8.11 g Durgpur Ll (9.00) ef (7.85) g 1.21 gh fgh (8.79) fg 4.85 cd AHW/BR (7.36) (5.79) b (7.04) b 8.38 g Vlues in column followed by different letters re significntly different (Turkey s Honest Significnt Difference test). Vlues in prentheses re squre-root trnsformed.

7 Florid Entomologist Volume 98, No. 3 Tble 7. Correltion coefficient (r) between percentge fruit infesttion nd lrvl density per fruit with vrious llelochemicl fruit trits of wtermelon vrieties/ genotypes. Percentge infesttion Lrvl density PC FC TC AA FAA Lrvl density 0.991** PC 0.930** 0.933** FC 0.835** 0.843** 0.946** TC 0.847** 0.810** 0.794** 0.692** AA 0.953** 0.954** 0.955** 0.878** 0.821** FAA 0.911** 0.914** 0.955** 0.919** 0.824** 0.967** TAC 0.912** 0.934** 0.841** 0.730** 0.692** 0.874** 0.836** **, significnt t P = 0.01 (2-tiled); *, significnt t P = 0.05 (2-tiled); AA, scorbic cid (mg/10 g); FAA, free mino cids (mg/g); FC, flvonoid content (mg/100 g); PC, phenol content (mg/g); TAC, totl lkloid content (%);TC, tnnin content (mg/100 g). single dominnt gene. The symbol Fwr hs been proposed to denote the resistnt gene (Khndelwl & Nth 1978). In the present study, the vrieties/genotypes Ashi Ymto, Thr Mnk, nd AHW/BR-16 were resistnt nd AHW/BR-9, AHW/BR-137, BSM-1, IC , nd AHW/ BR-60 were susceptible vrieties/genotypes of wtermelon ginst the melon fly. The percentge fruit infesttion nd lrvl density were found to be significntly lower in resistnt nd higher in susceptible vrieties/genotypes of wtermelon. Numerous studies hve shown tht genotypes of the sme species could differ significntly in their resistnce to insect pests (Simmons & Levi 2002,b; Thies & Levi 2003; López et l. 2005; Kousik et l. 2007; Simmons et l. 2010; Moslem et l. 2011; Hldhr et l. 2013), nd tht this resistnce ws influenced by morphologicl nd biochemicl trits of plnts. Our findings re in line with those of Dhillon et l. (2005b) nd Gogi et l. (2010), who observed lower fruit infesttion nd lrvl densities on resistnt thn on susceptible genotypes of bitter gourd. The ntixenotic fruit trits were significntly different mong the tested wtermelon vrieties/genotypes. Fruit length, fruit dimeter, nd dys to first fruit hrvest hd significnt positive correltion wheres rind hrdness, rind thickness, nd length of ovry pubescence hd significnt negtive correltion with percentge fruit infesttion nd lrvl density. In previous studies, biophysicl fruit trits lso were found significntly different mong genotypes (Dhillon et l. 2005b; Gogi et l. 2010; Simmons et l. 2010). Pubescence consists of the lyer of hirs (trichomes) extending from the epidermis of the bove-ground plnt prts including stem, leves, nd fruits, nd occurring in severl forms such s stright, spirl, stellte, hooked, nd glndulr (Hnley et l. 2007). Similr to our results, Gogi et l. (2010) documented tht fruit length, fruit dimeter, number of longitudinl ribs per fruit, nd number of smll ridges per cm 2, which were significntly lowest in resistnt nd highest in susceptible genotypes, hd significnt positive correltion with percentge fruit infesttion nd lrvl density per fruit. In contrst to our results, rind hrdness, height of smll ridges, height of longitudinl ribs, nd pericrp thickness, which were significntly highest in resistnt nd lowest in susceptible genotypes, hd significnt negtive correltion with percentge fruit infesttion nd lrvl density per fruit (Gogi et l. 2010). These vritions in mesured biophysicl fruit trits my be ttributed to differences in the tested genotypes nd/or stge of the fruits selected for mesuring these trits, s reported in erlier studies (Dhillon et l. 2005b; Kumr et l. 2006; Gogi et l. 2010). Stepwise regression nlysis of our dt indicted tht mximum vrition in percentge fruit infesttion nd lrvl density per fruit were explined by length of ovry pubescence followed by fruit length. However, Gogi et l. (2010) showed tht the tested morphologicl trits explined 100% of the totl vrition in percentge fruit infesttion nd lrvl density per fruit. The mximum vrition, in percentge fruit infesttion nd lrvl density per fruit, in their study ws explined by rind hrdness followed by fruit dimeter nd number of longitudinl ribs. The llelochemicl compounds in fruit were significntly different mong the tested wtermelon vrieties/genotypes. The free mino cid content ws lowest in resistnt nd highest in susceptible vrieties/genotypes, wheres flvonoid, tnnin, phenol, lkloid, nd scorbic cid contents were highest in resistnt nd lowest in susceptible Tble 8. Bckwrd stepwise regression models showing effects of different llelochemicl fruit trits of wtermelon on percentge fruit infesttion nd number of lrve per fruit. Model R 2 Role of individul trits (%) Percentge fruit infesttion Y = X X X X X X Y = X X X X X Y = X X X X Y = X X X Y = X X Y = X Lrvl density per fruit Y = X X X X X X Y = X X X X X Y = X X X X Y = X X X Y = X X Y = X X 1, flvonoid content (mg/100 g); X 2, tnnin content (mg/100 g); X 3, totl lkloid content (%); X 4, phenol content (mg/g); X 5, scorbic cid (mg/10 g); X 6, free mino cids (mg/g); nd R 2, coefficient of determintion.

8 Hldhr et l.: Resistnce trits in wtermelon vrieties nd genotypes ginst Bctrocer cucurbite 833 vrieties/genotypes. Very little informtion is vilble on correltion of the biochemicl trits. Ismil et l. (2010) reported tht of ll tested cntloupe plnt prts, the lef extrcts showed the highest totl phenol content (26.4 mg/g extrct) nd totl flvonoid content (69.7 mg/g extrct). Others showed tht the ph ws lowest nd tnnin, flvnol, nd phenol contents were highest in fruit fly resistnt genotypes of bitter gourd (Gogi et l. 2010). Totl soluble solids nd ph of fruit hd significnt positive correltion wheres tnnin, phenol, lkloid, nd flvonoid contents hd significnt negtive correltion with percentge fruit infesttion nd lrvl density per fruit (Gogi et l. 2010). Biochemicl chrcters such s totl sugr nd crude protein were positively correlted wheres totl phenols were negtively correlted with fruit borer infesttion (Shrm & Singh 2010; Wr et l. 2012; Hldhr et l. 2013). Similr to our findings, it hs been demonstrted tht phenols, tnnins, nd flvonoids enhnced plnt defenses ginst insects (Gogi et l. 2010; Wr et l. 2012; Hldhr et l. 2013). Bckwrd stepwise regression nlysis of our dt indicted tht the mximum vrition in percentge fruit infesttion nd lrvl density per fruit were explined by flvonoid followed by totl lkloid contents. Flvonoids re cytotoxic nd interct with different enzymes through complextion. Flvonoids nd isoflvonoids protect the plnt ginst insect pests by influencing the behvior, growth, nd development of insects (Simmonds 2003). In ddition, flvonoids scvenge the free rdicls including rective oxygen species nd reduce their formtion by chelting metls (Treutter 2006). Tnnins re stringent (mouth puckering), bitter polyphenols nd ct s feeding deterrents to mny insect pests. They precipitte proteins non-specificlly (including the digestive enzymes of herbivores) by hydrogen bonding or covlent bonding of protein NH 2 groups. Phenolic heteropolymers ply centrl role in plnt defense ginst insects nd pthogens (Brkt et l. 2010). Phenols lso ply n importnt role in cyclic reduction of rective oxygen species such s superoxide nion nd hydroxide rdicls, H 2 O 2, nd singlet oxygen, which in turn ctivte cscde of rections leding to the ctivtion of defensive enzymes (Mffei et l. 2007). Gogi et l. (2010) indicted tht the mximum vrition in percentge fruit infesttion ws explined by tnnin nd flvnol contents wheres other biochemicl fruit trits explined < 0.2% vrition. The mximum vrition in lrvl density per fruit ws explined by tnnin followed by flvnol contents wheres other biochemicl fruit trits explined < 0.1% vrition (Gogi et l. 2010). Hldhr et l. (2013) found in muskmelon tht the totl lkloid content nd ph explined 97.96% of the totl vrition in percentge fruit infesttion, nd lkloid nd totl sugr contents explined 92.83% of the totl vrition in lrvl density per fruit. Thus, we suggest tht reduction in fruit fly infesttions on resistnt vrieties/genotypes could be due to ntixenosis (biophysicl properties) nd ntibiosis (llelochemicls). Certin biophysicl trits (e.g., length of ovry pubescence, rind hrdness, nd rind thickness) nd biochemicl trits (e.g., flvonoids, tnnins, phenols, scorbic cid, nd totl lkloids) described in Fig. 1 nd Fig. 2 were linked to resistnce of wtermelon ginst B. cucurbite nd, therefore, cn be used s mrker trits in plnt breeding progrms to select resistnt vrieties/ genotypes. Acknowledgments The uthors re thnkful to S. K. Shrm, Director, ICAR-Centrl Institute for Arid Horticulture, Bikner, Indi, for providing fcilities nd dvice required for experimenttion, nd to R. Swminthn, Professor, Deprtment of Entomology, MPUAT, Udipur, Indi, for criticl discussion nd suggestions. Fig. 1. Associtions of mjor ntixenotic nd llelochemicl fruit trits of wtermelon with resistnce to the melon fly evluted by percentge fruit infesttion under different infesttion ctegories. Fig. 2. Associtions of mjor ntixenotic nd llelochemicl fruit trits of wtermelon with resistnce to the melon fly evluted by the number of lrve per fruit under different infesttion ctegories. References Cited Arimur GI, Mtsui K, Tkbyshi J Chemicl nd moleculr ecology of herbivore-induced plnt voltiles: proximte fctors nd their ultimte functions. Plnt nd Cell Physiology 50: Brkt A, Bgniewsk-Zdworn A, Frost CJ, Crlson JE Phylogeny nd expression profiling of CAD nd CAD-like genes in hybrid Populus (P. deltoides P. nigr): evidence from herbivore dmge for subfunctionliztion nd functionl divergence. BMC Plnt Biology 10: 100. Choudhry BR, Pndey S, Singh PK Morphologicl diversity nlysis mong wtermelon (Citrullus lntus) genotypes. Progressive Horticulture 44: Dhillon MK, Singh R, Nresh JS, Shrm HC The melon fruit fly, Bctrocer cucurbite: review of its biology nd mngement. Journl of Insect Science 5: 40. Dhillon MK, Singh R, Nresh JS, Shrm NK. 2005b. Influence of physico-chemicl trits of bitter gourd, Momordic chrnti L. on lrvl density nd resistnce to melon fruit fly, Bctrocer cucurbite (Coquillett). Journl of Applied Entomology 129: Djuric Z, Powell LC Antioxidnt cpcity of lycopene-contining foods. Interntionl Journl of Food Science nd Nutrition 52: Dudrev N, Negre F, Ngegowd DA, Orlov I Plnt voltiles: recent dvnces nd future perspectives. Criticl Reviews in Plnt Science 25:

9 Florid Entomologist Volume 98, No. 3 Ebrhimzdeh MA, Pourmord F, Bekhrdni AR Iron chelting ctivity, phenol nd flvonoid content of some medicinl plnts from Irn. Africn Journl of Biotechnology 7: Gogi MD, Ashfq M, Arif MJ, Srfrz RM, Nwb NN Investigting phenotypic structures nd llelochemicl compounds of the fruits of Momordic chrnti L. genotypes s sources of resistnce ginst Bctrocer cucurbite (Coquillett) (Dipter: Tephritide). Crop Protection 29: Hldhr SM, Bhrgv R, Choudhry BR, Pl G, Kumr S Allelochemicl resistnce trits of muskmelon (Cucumis melo) ginst the fruit fly (Bctrocer cucurbite) in hot rid region of Indi. Phytoprsitic 41: Hnley ME, Lmont BB, Firbnks MM, Rfferty CM Plnt structurl trits nd their role in nti-herbivore defence. Perspectives in Plnt Ecology, Evolution nd Systemtics 8: Hower GA, Jnder G Plnt immunity to insect herbivores. 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Shrm BN, Singh S Biophysicl nd biochemicl fctors of resistnce in okr ginst shoot nd fruit borer. Indin Journl of Entomology 72: Simmonds MSJ Flvonoid insect interctions: recent dvnces in our knowledge. Phytochemistry 64: Simmons AM, Levi A Sources of whitefly (Homopter: Aleyrodide) resistnce in Citrullus for the improvement of cultivted wtermelon. Hort- Science 37: Simmons AM, Levi A. 2002b. Evlution of wtermelon germplsm for resistnce to Bemisi, pp In Mynrd DN [ed.], Cucurbitce. Americn Society of Horticulturl Science, Alexndri, Virgini, USA. Simmons AM, Kousik CS, Levi A Combining reflective mulch nd host plnt resistnce for sweetpotto whitefly (Hemipter: Aleyrodide) mngement in wtermelon. Crop Protection 29: Steel RGD, Torrie JH, Dickey DA Anlysis of vrince II: multiwy clssifictions, pp In Steel RGD, Torrie JH, Dickey DA [eds.], Principles nd Procedures of Sttistics: A Biometricl Approch (3rd ed.). WCB/McGrw- Hill, Columbus, Ohio, USA. 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