Cowpea (Vignaunguiculata) and bacterial inoculation: A plausible components of an integrated management strategy for the root parasitic weed Striga hermonthica on sorghum

Ad ances in En i onmen al Biology, 10(7) July 2016, Pages: 1-11 AENSI Jou nals Ad ances in En i onmen al Biology ISSN-1995-0756 EISSN-1998-1066 Jou nal home page: h p://www.aensiweb.com/AEB/ Copy igh © 2016 by au ho s and Copy igh , Ame ican-Eu asian Ne wo k o Scien i ic In o ma ion (AENSI Publica ion). Cowpea (Vigna unguicula a) and bac e ial inocula ion: A plausible componen s o an in eg a ed managemen s a egy o he oo pa asi ic weed S iga he mon hica on so ghum 1Es a A Mahmoud, 2Aisha A. M. Rezig, 3Mohammed M. Hassan, 3Randa H. Elslahi, 3Magdoline M. Ahmed, 3Rani E. Abike , 4RashidaM.A. Abusin, 3Migdam E. Abdel Gani, 3Abdel Gaba E.T. Babike 1Sudan Academy o Sciences (SAS). 2Sudan Uni e si y o Science and Technology, College o Ag icul u al S udies, Sudan. 3En i onmen and Na u al Resou ces and Dese i ica ion Resea ch Ins i u e, Na ional Cen e o Resea ch, Kha oum, Sudan. 4Bah i Uni e si y, College o Ag icul u e, Pes s and Plan Heal h, Kha oum, Sudan. Add ess Fo Co espondence: Mohammed M. Hassan, En i onmen and Na u al Resou ces and Dese i ica ion Resea ch Ins i u e, Na ional Cen e o Resea ch, Kha oum, Sudan. This wo k is licensed unde he C ea i e Commons A ibu ion In e na ional License (CC BY). h p://c ea i ecommons.o g/licenses/by/4.0/ Recei ed 22 May 2016; Accep ed 18 July 2016; A ailable online 8 Augus 2016 ABSTRACT Two se s o g eenhouse expe imen s we e conduc ed o in es iga e he e ec s o i) so ghum in e c opping wi h cowpea geno ypes and seeds le el o S iga on S iga incidence on so ghum Wad Ahmed, ii) in e c opping o cowpea, bac e ial s ains and ino ganic phospho us on S iga he mon hica pa asi ism and so ghum g ow h. T ea men s we e a anged in a andomized comple e block design wi h ou eplica ions. In he i s g eenhouse expe imen , i espec i e o in e c opping, S iga eme gence p og essi ely inc eased wi h seed bank size. In e c opping, signi ican ly, educed S iga eme gence and d y weigh . Base on he o e all means o S iga eme gence, in e c opping o B301 and T100K-901-6 cowpea geno ypes wi h so ghum educed S iga eme gence by 95- 45% and 96-52% a 1 – 16mg/po o S iga seed bank, espec i ely as compa ed o con ol. A consis en p og essi e decline in so ghum heigh , lea a ea and d y weigh was e iden in sole so ghum c op wi h inc easing S iga seed bank size. , In e c opped so ghum, in a iably, imp o ed so ghum g ow h han sole so ghum. In he second expe imen , in e c opping wi h cowpea, inocula ed wi h Rhizobium leguminosa um alone o in combina ion wi h phospho us, delayed and ep essed S iga eme gence, signi ican ly in compa ison o sole so ghumwi h a educ ion anging be ween 98 and 92%, espec i ely. Howe e , signi ican inc emen s o lea a ea we e only a ained when so ghum in e c opped wi h Rhizobium inocula ed cowpea, alone o in combina ion wi h phospho us a 92 kg ha-1 by 56 and 50%, espec i ely. In e c opping wi h cowpea inocula ed wi h Rhizobium alone o in combina ion wi h phospho us a 46 kg ha-1inc eased so ghum d y weigh signi ican ly as compa ed wi h he co esponding con ol. In conclusion, cowpea geno ypes inocula ed wi h he bac e ial combina ion, in a iably achie ed he highes educ ions in S iga eme gence as well as he highes inc ease in he measu ed so ghum g ow h a ibu es. KEYWORDS: cowpea, so ghum, bac e ial s ains, phospho us, incidence, S iga seeds size INTRODUCTION In e c opping is a po en ial bene icial sys em o c op p oduc ion. I o e s a be e u iliza ion o na u al and labo esou ces, p o ides sa e gua ds agains ailu e o single c op, gi es g ea e yield and e u n pe uni a ea, and minimizes he sp ead o pes s and diseases [1].Phospho us is one o se e al elemen s which a ec ni ogen 2 Es a A Mahmoud e al, 2016 Ad ances in En i onmen al Biology, 10(7) July 2016, Pages: 1-11 ixa ion, and along wi h ni ogen, i is a p incipal yield-limi ing nu ien in ag icul u al p oduc ion [2]. The applica ion o phospho us could hus, enhance maximum exploi a ion o he ad an ages o biological ni ogen ixa ion (BNF) mechanism by legumes. Hence, he use o g ain legumes in smallholde c opping sys ems is being widely p omo ed and has ecei ed subs an ial a en ion ac oss A ica as an al e na i e s a egy o enhance soil e ili y and imp o e g ain yields [3]. High illi e acy among a me s, lack o awa eness o he S iga li e cycle and he una oidable low c op p oduc i i y a ising om he damage he pa asi e in lic s while sub e anean, makes a me s eluc an o accep and/o adop pos -eme gence con ol measu es [4]. Deple ion o he soil seed bank o S iga by suicidal ge mina ion, which in ol es ge mina ion o he seeds in absence o o away om he hos oo s, is a po en ial con ol op ion and has been s ongly ad oca ed by se e al au ho s [5, 6]. Hence he e is a need o look o simple echniques as componen s o an in eg a ed S iga con ol package which is adap able o he A ican si ua ion. Legume o a ion ope a es h ough wo majo mechanisms, suicidal ge mina ion o S iga he mon hica seeds in he soil and imp o emen o soil e ili y. Sibha u [7] obse ed ha S iga in es a ion dec eased wi h inc easing o ganic ma e o he soil and ha o ganic ma e con en seemed o be he mos impo an ac o which p ese ed he soil e ili y. Since soil mic obial biomass lou ishes be e in a medium ich in o ganic ma e , o ganic o ino ganic soil amendmen s may inc ease soil supp essi eness o S iga he mon hica and also imp o e soil condi ions o inc ease yield o subsequen ce eal. In his wo k, wo g eenhouse expe imen s we e conduc ed o s udy he e ec s o in e c opping o selec ed cowpea geno ypes and S iga seed le el on S iga pa asi ism and so ghum g ow h as well as he supp essi e e ec s o cowpea inocula ed wi h hizobia, BMP, ino ganic phospho us each alone o in combina ion on S iga pa asi ism and so ghum g ow h. MATERIALS AND METHODS Seeds: So ghum cul i a Wad Ahmed was ob ained om he Ag icul u al Resea ch Co po a ion, Sudan. Tow cowpea geno ypes B301 and T100K-901-6we e ob ained om he In e na ional Ins i u e o T opical Ag icul u e (IITA) Ibadan Nige ia. S iga he mon hica, seeds we e collec ed om so ghum in es ed ields. Mic obial Bio- e ilize s: The bac e ial s ains (Rhizobium leguminosa um and Bacillus mega he ium a . phospha icum (BMP)) (selec ed on basis o hei abili y o supp ess S. he mon hica ge mina ion.) we e ob ained om En i onmen and Na u al Resou ces and Dese i ica ion Resea ch Ins i u e (ENRDRI), Na ional Cen e o Resea ch (NCR), Kha oum, Sudan. Au ocla e s e ilized ( o 20 min a 15 ba s and 121 ⁰C o 20 min) yeas ex ac manni ol and mea pep one b o h media we e inocula ed by Rhizobium leguminosa um (TAL 1399 and Bacillus mega he ium a . phospha icum (BMP), espec i ely. Gene al: Two se s o g een- house expe imen s we e conduc ed a he College o Ag icul u al S udies (CAS), Sudan Uni e si y o Science and Technology, In bo h expe imen s, unless o he wise men ioned, po s (36 cm i.d. and 32 cm in heigh ), pe o a ed a he bo om, we e illed wi h 7 kg sand mix (2:1) p epa ed by mixing soil collec ed om CAS a m wi h i e sand. S. he mon hica seeds we e mixed wi h he op 10 cm o soil in each po . So ghum Wad Ahmed seeds (5/po ) we e plan ed. Cowpea geno ypes B301 and T100K-901-6seeds (7/po ) we e plan ed as a companion c op. So ghum and cowpea seedlings we e hinned o 2 and 3, espec i ely, 7 days a e eme gence. Sole so ghum, S iga in es ed and S iga ee so ghum in e c opped wi h cowpea we e included as con ols o compa ison. All po s we e i iga ed a 2–3 days in e als h oughou he g owing pe iod. Weeds o he han S. he mon hica we e emo ed by hand. Eme gen S iga plan s we e coun ed weekly s a ing h ee weeks a e c op eme gence. S iga coun and so ghum heigh we e de e mined 30, 60 and 90 days a e sowing (DAS). Lea a ea was es ima ed by mul iplying he leng h o he second lea om op by hal o maximum wid h o he lea a 30, 60 and 90 DAS. A ha es , so ghum and S iga shoo s, each, we e cu a g ound le el, ai -d ied and weighed. Fi s expe imen , e ec s o in e c opping and le el o S iga seeds on S iga incidence and so ghum g ow h: Soil was inocula ed wi h di e en le els o S iga seeds (0, 1, 2, 4, 8, 16 and 32mg/po ). So ghum seeds (5/po ) we e plan ed a Ca. 2 cm. soil dep h. Cowpea B301 and T100K-901-6 seeds (7/po ) we e plan ed as a companion c op. So ghum and cowpea geno ypes we e hinned as desc ibed abo e. S iga eme gence, so ghum heigh s, lea a ea, so ghum and S iga d y weigh s we e measu ed as desc ibed abo e. 3 Es a A Mahmoud e al, 2016 Ad ances in En i onmen al Biology, 10(7) July 2016, Pages: 1-11 Second expe imen , e ec s o in e c opping, bac e ial s ains and ino ganic e ilize on S iga incidence and so ghum g ow h: In he g een house expe imen in e c opping was in eg a ed wi h inocula ion o Rhizobium leguminosa um TAL1399, phospho us solubilizing bac e ium (Bcillus mega he ium a phospha icum)as well as ino ganic phospho us. Soil in es ed wi h S. he mon hica seeds, placed in plas ic po s, was sown wi hso ghum c . Wad Ahmed and cowpea T100K-901-6 as desc ibed abo e. Cowpea seeds we e ei he inocula ed wi h Rhizobium leguminosa um and B. mega he ium each alone o in combina ions wi h ino ganic e ilize . Aliquo s (15 ml each)o each o he espec i e bac e ial suspensions ( (10-4 dilu ion) we e injec ed, wi hin he oo zone, a each po . I iga ions we e ca ied ou e e y 2 days. Phospho us was applied a wo doses 46 kg ha-1 and92 kg ha-1, immedia ely a e sowing. The expe imen was conduc ed in a RCBD wi h ou eplica ions. Da a o so ghum lea chlo ophyll con en we e aken a 30, 45, 60 and 75 DAS by using a SPAD-502 Chlo ophyll Me e (Minol a). Lea a ea was measu ed a 30, 45, 60 and 90 DAS. S iga eme gence, so ghum heigh , lea a ea and shoo d y weigh o so ghum and S iga we e measu ed as desc ibed abo e. Resul s: G eenhouse expe imen s: Fi s expe imen , e ec s o in e c opping and le el o S iga seeds on S iga incidence and so ghum g ow h E ec s on S iga eme gence: S iga eme gence, on so ghum, i espec i e o in e c opping, inc eased wi h ime and seed bank size. A 30 DAS, a e age S iga eme gence on sole so ghum a he lowes seed bank size was 3 plan s/po (Table1). Inc easing S iga seed bank o 8 o 16 mg/po u he inc eased he pa asi e eme gence, albei no signi ican ly. A he highes seed bank size (32mg/po ),S iga eme gence inc eased signi ican ly (Table 1).So ghum in e c opped wi h cowpea B301 a he lowes seed bank size (0.3 plan / po ) displayed he lowes eme gence (Table 1). Inc easing S iga seed bank size o 8 o mo e /po inc eased S iga eme gence signi ican ly in compa ison o he lowes seed bank size. While, no any S iga eme gence was obse ed in so ghum in e c opped wi h cowpea T100K901 a he lowes seed bank size. Howe e , a p og essi e, albei non- signi ican inc ease in eme gence was obse ed up o a seed bank o 8 -16mg/po . Inc easing S iga seed bank size o 32mg pe po , u he inc eased S iga eme gence by mo e han 4- old (Table 1). A 60 DAS, S iga eme gence, i espec i e o seed bank size, showed conside able inc ease in compa ison o ha eco ded a 30 DAS (Table 1). A 90 DAS, S iga eme gence showed a simila end. The a e age S iga eme gence a he lowes and highes seed bank we e 13.3 and 25 plan s /po , espec i ely (Table 1). So ghum in e c opped wi h cowpea B301 and T100K-901-6, inc easing S iga seed bank size o 16 and 32mg pe po u he inc eased S iga eme gence by mo e han 2- o-4- old, espec i ely (Table 1). In he o e all mean, S iga eme gence on so ghum in e c opped wi h cowpea B301 and T100K-901-6 geno ypes educed S iga eme gence by 95- 45% and 96-52% a 1- 16mg/po , espec i ely as compa ed o he espec i e con ol. D y weigh : S iga d y weigh , i espec i e o in e c opping, p og essi ely inc eased wi h inc easing seed bank size (Table 2). On sole so ghum, S iga d y weigh p og essi ely inc eased wi h seed bank size. Inc easing S iga seed bank o 2 mg pe po inc eased S iga d y weigh by 74.9%. A S iga seed bank size o 4, 8, 16 and 32 mg pe po he inc ease in S iga d y weigh was 133.7, 216, 257, and 275.7%, espec i ely in compa ison o he lowes seed bank size (Table 2).S iga d y weigh on so ghum in e c opped wi h cowpea B301, albei p og essi ely inc eased wi h seed bank (Table 4.9). Inc easing seeds bank size o 16 and 32 mg/po esul ed in signi ican inc ease in d y weigh . S iga on so ghum in e c opped wi h cowpea T10K-901-6 displayed 19 g a he lowes S iga seed bank size. A Fu he inc ease in seed bank o 8, 16 and 32 mg inc eased S iga d y weigh by 52.6, 75.3 and 84%, espec i ely. Ac oss he seed bank size, sole so ghum sus ained he highes S iga d y weigh ollowed by so ghum in e c opped wi h cowpea B301 and T100K-901-6 (Table 2). E ec s on so ghum heigh : So ghum heigh , i espec i e o in e c opping, displayed a p og essi e dec ease wi h S iga seed bank size and inc eased wi h ime (Table3). In gene al, so ghum in e c opped wi h cowpea, i espec i e o he la e geno ype o S iga seed bank size, displayed be e g ow h han sole so ghum. S iga ee so ghum, when in e c opped wi h cowpea, i espec i e o geno ype o da e o obse a ion, displayed an inc ease in heigh o 27.7-64.5% in compa ison o he co esponding sole so ghum ea men . In sole so ghum a 30 DAS, S iga seed bank a 1-8mg/po in lic ed insigni ican (5.1-20.9%) dec ease in heigh (Table 3). Inc easing S iga seed bank size o 16 and 32 mg pe po educed so ghum heigh by 27.2and39.9%, espec i ely (Table 3). S iga seed bank 1 o 2 mg pe po educed so ghum heigh , albei no signi ican ly. Inc easing S iga seed bank size o 4 mg pe po o mo e esul ed in signi ican educ ions in so ghum heigh . While, so ghum in e c opped wi h cowpea 4 Es a A Mahmoud e al, 2016 Ad ances in En i onmen al Biology, 10(7) July 2016, Pages: 1-11 T100K-901-6 did no show a signi ican educ ion in heigh a he lowes le el. The highes educ ion (36.5%) was obse ed a he highes S iga seed bank (Table 3). A 60 DAS, educ ion in so ghum heigh ollowed mo e o less simila ends. A 90 DAS, S iga seed bank size a 2 and 4 mg pe po educed so ghum heigh by 2 and 17.1%, espec i ely. Inc easing S iga seed bank size o 8 mg pe po o mo e, educed (24.5-36.7%) so ghum heigh signi ican ly. In cowpea B301 and T100K-901-6, a seed bank o 4 mg /po o mo e esul ed in signi ican educ ions. The highes educ ion (31.7 and 45%) was obse ed a he highes le els, espec i ely (Table 3). Lea a ea: So ghum lea a ea, i espec i e o in e c opping o ime, dec eased wi h inc easing S iga seed bank size (Table 4).A 30 DAS, sole so ghum, in a iably, showed a p og essi e decline in lea a ea wi h S iga seed bank size in compa ison o he S iga ee con ol (Table 4). The educ ions in lea a ea a S iga seed bank o 8, 16 and 32mg/po we e 47.8, 54.9, and 66.4%, espec i ely. So ghum in e c opped wi h cowpea geno ypes did no show signi ican educ ion in lea a ea, i espec i e o he pa asi e seed bank size. A 60 DAS, he lea a ea o sole so ghum showed a p og essi e inc ease in compa ison o he eco ds made a 30 DAS, i espec i e o S iga seed bank size (Table 4).A 90 DAS, lea a ea showed mo e o less he same end, a p og essi e decline wi h S iga seed bank size. In e c opping wi h cowpea B301 and T100K-901-6, i espec i e o S iga in es a ion inc eased so ghum lea a ea in compa ison o sole so ghum (Table 4). A consis en p og essi e decline in lea a ea was in a iably a ec ed wi h inc easing S iga seed bank size. Howe e , he o e all e ec ac oss S iga seed bank le els was a p og essi e decline wi h inc easing seed bank size wi h signi ican educ ions a ained a he highes S iga in es a ion le els (16 and 32 mg/po ). So ghum in e c opped wi h cowpea T100K-901-6, i espec i e o ime, showed a consis en decline in lea a ea wi h S iga seed bank size (Table 4). D y weigh : So ghum d y weigh i espec i e o in e c opping dec eased wi h inc easing S iga seed bank size (Table 5). S iga seed bank size a 1and 2 mg/ po educed so ghum d y weigh by 7.7 and 22.5%, espec i ely. Inc easing S iga seed bank size o 4, 8, 16 and 32 mg/ po educed so ghum d y weigh by 31.9, 39.3, 54.8 and 60.7 %, espec i ely in compa ison o he espec i e S iga ee con ol. In e c opped so ghum in a iably showed signi ican ly highe d y weigh han he sole c op (Table 5). Howe e , i showed mo e o less he same ends in educ ion wi h S iga seed bank as sole so ghum in compa ison o he espec i e S iga ee con ol (Table 5). S iga ee so ghum in e c opped wi h cowpea B301 and T100K-901-6 displayed a d y weigh o 134.8 and 150g, espec i ely (Table 5). S iga a he lowes seed bank educed so ghum d y weigh by 2 and 4 %, he obse ed educ ion was no signi ican . Inc easing S iga seed bank o 8, 16 and 32 mg/ po dec eased so ghum d y weigh by 60.7- 70.3 %, and 57.7-67.3%, espec i ely and he obse ed educ ions we e signi ican . Second expe imen , e ec s o in e c opping, bac e ial s ains and ino ganic phospho us on S iga incidence and so ghum g ow h: E ec s on S iga: Resul e ealed ha mos o ea men s dec eased S iga eme gence conside ably in compa ison o he con ol (Table 6). Fu he mo e, S iga eme gence p og essi ely inc eased wi h ime. A 30 DAS, S iga eme gence was e y low as only 0.33 S iga plan s eme ged on he un ea ed con ol. Howe e , no any S iga eme gence was obse ed on so ghum in e c opped wi h cowpea T100K-901-6 geno ype alone o in combina ion wi h Rhizobium, BMP and phospho us a he highes dose. A 60 DAS, S iga eme gence inc eased, subs an ially, and was highes on he un e ilized un-inocula ed con ol (7 S iga plan s/ po ). In e c opping wi h cowpea inocula ed wi h each o Rhizobium alone o o BMP each alone o in combina ion wi h phospho us a 92 kg ha-1 educed S iga eme gence in he ange o 93-100%, espec i ely. A 75 DAS, S iga eme gence on sole so ghum showed simila end as in 60 DAS. Cowpea in e c opping ea ed wi h Rhizobium plus phospho us a he highes dose comple ely inhibi ed S iga eme gence. A 90 DAS, in e c opping wi h cowpea, p e iously inocula ed wi h Rhizobium alone o in combina ion wi h phospho us a 92 kg ha-1 educed S iga eme gence by 92 and 96%, espec i ely as compa ed wi h he co esponding con ol. The S iga eme gence da e was delayed by 75 days in cowpea p e iously ea ed wi h Rhizobium plus phospho us a 92 kg ha-1, compa ed o he con ol. E ec s on so ghum heigh (cm.): So ghum heigh , i espec i e o ea men , displayed p og essi e inc ease wi h ime and dec eased wi h S iga in es a ion (Table. 7).In gene al, he majo i y o he ea men s esul ed in heigh s compa able o he co esponding con ol (S iga in es ed sole so ghum). Sole so ghum displayed be e g ow h han so ghum in e c opped wi h cowpea, in p esence o absence o S iga. A 30 DAS, cowpea inocula ed wi h Rhizobium alone o in combina ion wi h phospho us, BMP plus phospho us esul ed in a signi ican inc ease in plan heigh compa able o he co esponding con ol. Among o he ea men s, so ghum in e c opped wi h cowpea, 5 Es a A Mahmoud e al, 2016 Ad ances in En i onmen al Biology, 10(7) July 2016, Pages: 1-11 p e iously inocula ed wi h he combina ion o BMP plus Rhizobium plus phospho us a 46 kg ha-1 o 92 kg ha-1, displayed he highes g ow h. A 60 DAS, so ghum in e c opped wi h cowpea inocula ed wi h he combina ions o Rhizobium plus BMP plus phospho us a 92 kg ha-1,Rhizobium plus BMP plus phospho us a 46 kg ha-1, sus ained he highes g ow h as compa ed o he co esponding con ol. A 90 DAS, S iga educed so ghum heigh signi ican ly as compa ed wi h he co esponding con ol. Among all ea men s, Rhizobium alone o in combina ion wi h phospho us plus BMP we e he mos s imula o y e ec on so ghum g ow h. So ghum heigh was nega i ely co ela ed wi h S iga eme gence. Chlo ophyll con en : A 30 DAS, he e we e signi ican di e ences be ween he ea men means wi h ega d o so ghum chlo ophyll con en (Table 8). Among ea men s, so ghum in e c opped wi h cowpea T100K-901-6, p e iously inocula ed wi h BMP plus phospho us a he highes dose displayed he highes chlo ophyll con en . A 60 and 90 DAS, SPAD alue declined wi h ime as well as S iga in es a ion. Lea a ea: Lea a ea, i espec i e o in e c opping o ime, dec eased wi h S iga in es a ion (Table 9).So ghum ee S iga plan in he con ol po had he highes lea a ea. A 30 DAS, sole so ghum, in a iable, showed a p og essi e decline in lea a ea wi h S iga albei no signi ican ly, in compa ison o he S iga ee con ol. In e c opping wi h cowpea inocula ed wi h Rhizobium plus phospho us a 92 kg ha-1inc eased so ghum lea a ea by 70% in compa ison o sole so ghum. A 60 DAS, lea a ea o sole so ghum showed a p og essi e inc ease in compa ison o he eco ds made a 30 DAS. In e c opping wi h cowpea inocula ed wi h he combina ion o Rhizobium and BMP plus phospho us a 92 kg ha-1 inc eased so ghum lea a ea by 9%, in compa ison o sole so ghum. A 90 DAS, lea a ea showed mo e o less he same end, a p og essi e decline wi h S iga in es a ion. Howe e , signi ican inc emen s we e only a ained a so ghum in e c opped wi h cowpea inocula ed wi h Rhizobium alone o in combina ion wi h BMP plus phospho us a 92 kg ha-1by 56 and 50%, espec i ely. D y weigh : The e we e signi ican di e ences among he ea men means wi h ega ds o o al so ghum biomass (Tables 10). So ghum d y weigh i espec i e o in e c opping dec eased wi h S iga in es a ion (Tables 10). S iga ee so ghum and in es ed c op showed oo d y weigh o 68 and 36/po , espec i ely (Table 10). In e c opped so ghum in a iable showed highe d y weigh han he sole c op. All ea men inc eased oo d y weigh signi ican ly as compa ed o he con ol. Cowpea inocula ed wi h Rhizobium inc ease so ghum oo d y weigh signi ican ly as compa ed o sole so ghum con ol. Almos all ea men s inc eased shoo d y weigh as compa ed o he con ol. Among o he ea men s so ghum in e c opped wi h cowpea inocula ed wi h BMP alone o in combina ion wi h Rhizobium plus phospho us a 46 kg ha-1 sus ained he highes shoo d y weigh . Discussion: Soil e ili y deple ion is he majo limi ing ac o in c op p oduc ion in A id and semi-a id lands [8]. Con inuous mono-c opping o ce eal c ops wi hou allowing has wo sened he si ua ion. S iga he mon hica, a pa asi ic weed, has long been belie ed o be co ela ed wi h he declining soil e ili y s a us. Legumes hold g ea po en ial as sou ces o high p o ein ood and eed [9]. They also enhance N up ake and plan capaci y o wi hs and d ough [10]. No mally, o op imal legume-Rhizobium symbiosis o occu , a su icien amoun o phospho us is equi ed, while ce eals need conside ably la ge amoun s o bo h N and P o op imal g ow h [11]. I is no ewo hy ha a plan species may p oduce se e al s igolac ones which di e signi ican ly in hei ge mina ion inducing ac i i y (GIA) and ha he main s igolac one om so ghum and cowpea we e epo ed o be so golac one and alec ol, espec i ely [12]. Cowpea is no pa asi ized by S. he mon hica, howe e , i is a hos o he closely ela ed species S.gesne iodies. In he p esen wo k a holis ic app oach was adop ed wi h he objec i es o p o iding in o ma ion on in e c opping in g eenhouse expe imen s whe e in e c opping was in eg a ed wi h inocula ion o R. leguminosa um and B. mega he ium a phospha icum, a phospho us solubilizing bac e ium and ino ganic phospho us. In he i s g eenhouse expe imen , i espec i e o in e c opping, S iga eme gence p og essi ely inc eased wi h seed bank size (Table 1). Howe e , in e c opping wi h cowpea, i espec i e o ime and seed bank size delayed and ep essed S iga eme gence, signi ican ly in compa ison o sole so ghum whe e he educ ions a ied be ween 50 and 100% and 1and 30 % a he lowes and highes seed bank size, espec i ely. The educ ion in he pa asi e eme gence could be as poin ed ou by Pa ke and Riches [ 5], in simila si ua ions, due o induc ion o ge mina ion by he ad ancing cowpea oo s away om hose o so ghum and/o compe i ion be ween cowpea oo s and hose o so ghum o he ju enile S iga ge milings. Ni ogen ixed by he legumes has also been poin ed as a eason o S iga con ol. Incidence o S iga is known o nega i ely co ela e wi h soil e ili y, pa icula ly ni ogen a ailabili y [13]. S iga d y weigh , in a iably, inc eased a a as e a e on sole so ghum han in e c opped plan s (Table 5). A he lowe 6 Es a A Mahmoud e al, 2016 Ad ances in En i onmen al Biology, 10(7) July 2016, Pages: 1-11 seed bank size, S iga d y weigh om unde so ghum in e c opped wi h cowpea T100K-906-1 educed by 22.8%. A S iga seed bank size o 4 - 32 mg/po in e c opping wi h cowpea B301 and T100K-906-1 educed S iga d y weigh by 39.5- 49.2.% and 59.5 – 61.7%, espec i ely. The educ ion in S iga d y weigh is consis en wi h he educ ions in eme gence ins iga ed by in e c opping wi h cowpea. The high anspi a ion a e enhances ans e o hos xylem sap in o he pa asi e. In e c opping shades he soil and lowe s he empe a u e. Fu he mo e educed anspi a ion and pho osyn hesis o he pa asi e esul ing om shading by he in e c op, as epo ed in simila si ua ions [4, 5], could accoun , a leas in pa , o a conside able p opo ion o he loss in d y weigh . So ghum heigh , i espec i e o in e c opping, displayed a p og essi e dec ease wi h S iga seed bank size (Table 3). Howe e , he in e c opped so ghum wi h cowpea geno ypes appea ed o display be e g ow h han sole so ghum. Lea a ea, i espec i e o in e c opping, dec eased wi h S iga seed bank size (Table. 4). Lea a ea was in a iably highe o in e c opped so ghum. As indica ed by he magni ude o he educ ion in lea a ea wi h ime i would appea ha limi ed eco e y in lea a ea occu ed wi h ime. So ghum in e c opped wi h cowpea geno ype T100K-901-6 displayed less educ ion in lea a ea han he one in e c opped wi h cowpea B301 and sole so ghum c op. So ghum d y weigh , i espec i e o in e c opping, p og essi ely declined wi h S iga seed bank. Howe e , d y weigh o in e c opped so ghum, i espec i e o S iga seed bank size, was in a iably highe han ha o sole so ghum. The d y weigh o in e c opped S iga ee so ghum was abou 2- old ha o he espec i e S iga ee sole so ghum. Such a di e ence could be a ibu ed, a leas in pa , o di e ences in he geno ypes used. In he p esen s udy cowpea geno ypes wi h p os a e and sp eading habi we e employed. Fu he mo e, cowpea is a legume and a ni ogen ixe . T ans e o ni ogen and possibly phospho us om legumes o neighbo ing non-leguminous plan s om decaying cowpea oo s and nodules has been epo ed by [12, 14]. Gbehounou and Adango [14] poin ed ou ha in e c opping wi h cowpea leads o highe yield, and ha his may be ela ed o he bene i s o ni ogen ixa ion unde cowpea c opping, as well as a educ ion in leaching o soil nu ien s by cowpea co e . In he second expe imen , ea men s comp ising so ghum in e c opped wi h cowpea T100k-901-6, inocula ed wi h B. mega he ium, R. leguminosa um, phospho us o hei combina ions sus ained and main ained signi ican ly less S iga eme gence han sole so ghum (Table6). A ea ly season, educ ions in S iga eme gence on so ghum in e c opped wi h cowpea T100k-901-6 inocula ed wi h B. mega he ium, R. leguminosa um and hei combina ion we e 43,89 and 69%, espec i ely, in compa ison o ha on sole so ghum. Howe e , he educ ion was inc eased in p esence o phospho us alone o in combina ion o bac e ial s ains (54 -100%). I is no ewo hy, albei di e ences be ween he indi idual ea men s we e o en no signi ican , ha inocula ing cowpea wi h he bac e ial combina ions and phospho us we e he mos e ec i e in supp essing he pa asi e eme gence. Howe e , in e c opping wi h cowpea, inocula ed wi h R. leguminosa um alone o in combina ion wi h phospho us, i espec i e o ime, delayed and ep essed S iga eme gence, signi ican ly in compa ison o sole so ghum whe e he educ ion a ied be ween 98 and 92%, espec i ely. The educ ion in he pa asi e eme gence could be as poin ed ou by Pa ke and Riches [5], in simila si ua ion, due o induc ion o ge mina ion by he ad ancing cowpea away om hose o so ghum and/o compe i ion be ween cowpea oo s and hose o so ghum o he ju enile S iga ge milings. Fu he educed anspi a ion and pho osyn hesis o he pa asi e esul ing om he shading by he in e c opped plan s [5]. These indings ag ee wi h Musyoka [ 15]. S iga eme gence was delayed in cowpea ea ed wi h Rhizobium plus phospho us a 92 kg ha-1. In e c opping cowpea geno ypes may cause suicidal ge mina ion o some o S iga seeds whe eas he bac e ial inoculum would inhibi S iga ge mina ion and/o eme gence [ 16]. Supp ession o S iga eme gence, d y weigh and he inc ease in so ghum d y weigh and he associa ion o he maximum inc emen s wi h he combina ion o R. leguminosa um plus B. mega he ium and phospho us a e consis en wi h epo s by Musyoka[ 15] who obse ed o e 2-3- old inc ease in so ghum and g asses g ow h a ibu es on in e c opping o so ghum wi h cowpea inocula ed wi h a comme cial Rhizobium s ain oge he wi h u he supplemen a ion o ino ganic phospho us. They a ibu ed he imp o emen o cowpea in e c opped so ghum and g asses in legume/g ass pas u es o inc eased a ailabili y o ni ogen h ough biological ni ogen ixa ion. Fu he mo e, S iga in es a ion and damaging e ec s a e also linked wi h low soil e ili y and ha ni ogen and phospho us play key oles in he pa asi ic synd ome [4]. The use o legumes oge he wi h inocula ion wi h Rhizobium as e ealed by Musyoka[15] and phospho us solubilizing bac e ia as shown in his s udy may p o ide he cheapes iable op ion o he esou ce- cons ain sub-Saha an A ican a me s o imp o e soil e ili y and consequen ly imp o e c op pe o mance and S iga managemen . These esul s demons a ed ha S iga bio-con ol based on bac e ial inoculum inco po a ion and he in e c opping sys em cons i u e each an e ec i e con ol me hod agains S. he mon hica and hei syne gis ic e ec is mo e e ec i e o educe he pa asi e in es a ion. Soil mic oo ganisms and in e c opping in e e ing wi h ea ly de elopmen al s ages we e hough o as possible al e na i es and/o iable supplemen s o o he con ol me hods [17]. 7 Es a A Mahmoud e al, 2016 Ad ances in En i onmen al Biology, 10(7) July 2016, Pages: 1-11 Conclusions: The echnical and economic easibili y o in eg a ing in e c opping wi h cowpea geno ypes B301 and T100K-901-6, inocula ed wi h R. leguminosa um TAL1399and he phospho us solubilizing bac e ium B. mega he ium a phospha icum wi h exis ing measu es o S iga managemen should be conside ed and e alua ed unde a me ’s ield condi ions adop ing an e icien pa icipa o y app oach. Fu he s udies a e needed o unde s and he impac o a me managemen p ac ices on S iga in es a ion and soil e ili y. Table 1: E ec s o so ghum in e c opping wi h cowpea and seed le el o S iga on S iga incidence (S iga eme gence) S iga seed le el (mg/po ) S iga eme gence (plan /po ) Time a e c op sowing (Days) 30 60 90 Mean a-Sole so ghum 1 3.0 (±1.1) c 7.0 (±1.6) d 13.3 (±1.9) d 7.8 d 2 6.5 (±0.6) bc 12.0 (±1.5) c 17.5 (±1.0) cd 12.0 c 4 7.5 (±0.6) b 13.5 (±0.6) bc 21.3 (±0.9) abc 14.1 bc 8 9.5 (±0.6) b 15.0 (±0.4) bc 20.0 (±1.1) bc 14.8 b 16 10.0 (±2.7) b 16.3 (±1.3) ab 23.0 (±1.6) ab 16.4 b 32 14.3 (±0.9) a 18.5 (±0.6) a 25.0 (±1.8) a 19.3 a Mean 8.5 c 13.7 b 20.0 a b-cowpea B301 Mean 1 0.3 (±0.3) d 0.5 (±0.3) d 0.5 (±0.3) d 0.4 e 2 0.8 (±0.5) cd 1.5 (±0.6) d 1.8 (±0.6) cd 1.3de 4 1.5 (±1.0) cd 2.3 (±0.9) cd 2.5 (±0.9) cd 2.1 d 8 3.3 (±0.5) c 4.5 (±1.6) c 5.5 (±1.3) c 4.4 c 16 6.8 (±0.9) b 8.8 (±0.9) b 11.8 (±1.5) b 9.1 b 32 13.0 (±1.5) a 16.8 (±1.0) a 24.8 (±2.5) a 18.2 a Mean 3.6 a 4.9 a 6.7 a ccowpeaT100K901-6 1 0.0 (±0.0) c 0.5 (±0.5) c 0.5 (±0.5) c 0.3 d 2 0.8 (±0.5) bc 1.3 (±0.8) c 1.0 (±0.4) c 1.0 d 4 1.8 (±0.8) bc 2.3 (±1.1) c 2.5 (±1.3) c 2.2 cd 8 3.3 (±1.8) bc 4.0 (±1.5) c 4.5 (±1.7) c 3.9 c 16 5.3 (±1.3) b 9.0 (±0.8) b 9.5 (±1.6) b 7.9 b 32 10.0 (±3.1) a 17.0 (±2.2) a 19.0 (±2.4) a 15.3 a Mean 3.0 a 4.9 a 5.3 a Table 2: E ec s o so ghum in e c opping wi h cowpea and seed le el o S iga on S iga d y weigh S iga seed le el (mg/po ) S iga d y weigh (g) Sole So ghum B301 T100K-901-6 Mean 1 24.3 (±2.4) d 30.5 (±2.3) c 19.0 (±2.3) c 24.6 d 2 42.5 (±6.2) cd 32.0 (±0.9) c 21.8 (±1.5) bc 32.1 cd 4 56.8 (±7.4) bc 34.5 (±5.0) bc 23.0 (±3.1) bc 38.1 bc 8 76.8 (±15.9) ab 40.8 (±4.2) abc 29.0 (±3.5) ab 48.8 ab 16 86.8 (±2.5) a 44.0 (±5.3) ab 33.3 (±4.7) a 54.7 a 32 91.3 (±2.4) a 46.3 (±3.1) a 35.0 (± ) a 57.5 a Mean 63.0 a 38.0 b 26.8 c 42.6 Table 3: E ec s o so ghum in e c opping wi h cowpea and seed le el o S iga on so ghum g ow h (so ghum heigh ) So ghum heigh (cm) Time a e sowing (Days) S iga seed le el (mg/po ) 30 60 90 Mean a- Sole so ghum 0 15.8 (±1.8) a 19.0 (±2.0) a 24.5 (±2.6) ab 19. a 1 15.0 (±2.2) ab 18.8 (±1.9) a 26.3 (±1.8) a 20 a 2 14.0 (±0.9) ab 18.8 (±1.5) a 24.0 (±1.6) abc 18.9 ab 4 15.5 (±1.0)a 18.3 (±1.3) a 20.3 (±1.3) bcd 18 ab 8 12.5 (±1.0) abc 16.5 (±0.6) ab 19.8 (±0.9) cde 16. abc 16 11.5 (±0.6) bc 15.8 (±0.5) ab 18.5 (±0.6) de 15. bc 32 9.5 (±1.0) c 13.3 (±0.9) b 15.5 (±0.6) e 12. c Mean 13.4 c 17.2 b 21.3 a 8 Es a A Mahmoud e al, 2016 Ad ances in En i onmen al Biology, 10(7) July 2016, Pages: 1-11 b-cowpeaB301 0 24.8 (±2.9) a 27.8 (±3.4) a 31.3( ±2.4) a 27.9 a 1 22.8 (±3.1) ab 24.3 (±3.0) ab 30.5 (±1.7) a 25.8 ab 2 18.8 (±1.1) abc 22.3 (±2.1) abc 26.5 (±2.5) ab 22.5 bc 4 20.5 (±1.3) bc 21.8 (±1.4) bc 24.5 (±1.8) bc 22.25 bc 8 18.3 (±0.9) bc 19.3 (±0.5) bc 22.3 (±1.1) bc 19.9 c 16 17.5 (±0.6) bc 19.0 (±0.7) bc 21.5 (±1.3) bc 19.3 c 32 15.3 (±0.9) c 17.5 (±0.6) c 20.0 (±0.7) c 17.6 c Mean 19.8 b 21.7 b 25.2 a c- T100K-901-6 0 26.0 (±1.5) a 30.3 (±1.3) a 34.5 (±1.7) a 30.3 a 1 24.3 (±3.1) ab 29.3 (±1.5) ab 30.5 (±1.6) ab 28.0 ab 2 21.0 (±1.5) bc 28.3 (±1.2) ab 29.0 (±0.7) ab 26.1 abc 4 20.0 (±1.1) bc 27.0 (±3.0) abc 27.5 (±3.3) b 24.8 bc 8 19.3 (±0.8) c 23.8(±2.7) bcd 25.0 (±2.6)bc 22.7 cd 16 18.0 (±1.1) c 21.5 (±2.6) cd 24.3 (±2.1) bc 21.3 cd 32 16.5 (±0.6) c 19.0(±1.7) d 19.0 (±2.4) c 18.2 d Mean 20.7 a 25.6 a 27.1 a Table 4: E ec s o so ghum in e c opping wi h cowpea and seed le el o S iga on so ghum lea a ea Lea a ea(cm2) S iga seed le el (mg/po )Day A e Sowing (DAS) 30 60 90 means a-Sole so ghum 0 45.0 (±6.1) a 53.3 (±5.3) a 73.6 (±6.7) a 57.3 a 1 38.1 (±5.9) ab 54.0 (±9.3) a 69.9 (±6.4) ab 54.0 ab 2 32.9 (±7.6) abc 46.0 (±11.0) ab 60.7(±10.8)ab 46.5 ab 4 28.1(±7.5) bcd 43.2 (±9.6) ab 58.1(±9.4) bc 43.1 abc 8 23.5 (±5.3) bcd 39.2 (±8.4) ab 55.8(±7.9) bc 39.5 abc 16 20.3 (±4.2) cd 37.4 (±6.7) ab 50.7 (±4.8) bc 36.1 bc 32 15.1 (±2.4) d 23.1 (±2.8) b 36.1 (±4.0) c 24.8 c Mean 29.0 c 42.3 b 57.8 a b-B301 0 141.8 (±30.3) a 170.4 (±27.1) a 176.8(±19.0)a 163.0 a 1 130.1 (±15.0) a 160.0 (±8.7) ab 173.5(±31.3)a 154.5 ab7 2 123.4 (±14.6) a 143.8(±12.5) bc 166.1(±16.7)a 144.4 abc 4 117.5 (±15.3) a 139.6(±7.3) abc 149.4(±25.1)a 135.5 abc 8 114.6 (±13.9) a 130.4(±10.4)abc 134.1(±21.0)a 126.4 abc 16 104.1 (±15.1) a 126.6(±12.4) bc 118.4(±17.8)a 116.3 bc 32 95.6 (±13.4) a 106.8 (±12.7) c 116.4(±18.6)a 106.0 c Mean 118.1b 139.6 a 147.8 a c-T100K-901-6 0 157.4 (±19.8) a 171.8 (±11.5) a 182.9 (±13.2) a 170.7 a 1 154.3 (±17.4) a 157.6 (±9.2) a 163.5 (±17.5) a 158.5 ab 2 142.0 (±14.0) a 150.7 (±9.9) a 155.6 (±16.8) a 149.4 ab 4 138.2 (±29.4) a 148.1 (±20.2) a 155.2 (±26.3) a 147.1 ab 8 124.2 (±18.4) a 144.6 (±16.1) a 144.9 (±21.9) a 137.9 ab 16 118.7 (±21.7) a 131.7 (±7.2) a 142.1 (±11.7) a 130.8b 32 104.2 (±23.4) a 128.3 (±31.1) a 138.3 (±24.0) a 123.6 b Mean 134.1b 147.5 ab 154.6 a Table 5: E ec s o so ghum in e c opping wi h cowpea and seed le el o S iga on so ghum d y weigh S iga seed le el(mg/po ) So ghum d y weigh (g) Sole so ghum B301 T100K-901-6 Mean 0 67.5 (±11.2) a 134.8 (±19.4) a 150.0 (±16.6) a 117.4 a 1 62.3 (±7.6) ab 131.8 (12.7) a 144.0 (±13.5) ab 112.7 a 2 52.3 (±4.9) abc 104.8 (±11.6) ab 116.3 (±12.2) bc 91.1 b 4 46.0 (±8.9) bcd 73.0 (±18.1) bc 84.3 (±13.0) cd 67.8 c 8 40.3 (±4.8) cd 53.0 (±8.3) c 63.5 (±8.8) de 52.3 cd 16 30.5 (±1.4) d 52.5 (±4.3) c 58.0 (±3.4) de 47.0 cd 32 26.5 (±3.5) d 40.0 (8.4) c 49.0 (±4.3) e 38.5 d 9 Es a A Mahmoud e al, 2016 Ad ances in En i onmen al Biology, 10(7) July 2016, Pages: 1-11 Mean 46.5 b 84.3 a 95.0 a Table 6: E ec s o so ghum in e c opping wi h cowpea, bac e ial s ains and ino ganic e ilize , on S iga eme gence Days a e sowing (DAS) S iga eme gence day a e sowing (DAS) T ea men s 30 60 90 I.C s(+) 0.0000 A 2.3333 A 6.3333 AB so ghum s(+) 0.3333 A 7.10 A 16.000 A I.C +P1 0.6667 A 2.0000 A 2.3333 B I.C +P2 0.0000 A 2.6667 A 4.6667 AB I.C+ izo 0.0000 A 0.6667 A 2.0000 B I.C + izo+P1 0.3333 A 3.6667 A 4.6667 AB I.C + izo+P2 0.0000 A 0.0000 A 1.0000 B I.C + BMP 0.6667 A 7.3333 A 10.000 AB I.C + BMP+P1 0.6667 A 5.3333 A 4.0000 B I.C + BMP+P2 0.0000 A 7.0000 A 8.6667 AB I.C +BMP+Rizo 0.0000 A 3.6667 A 4.0000 B I.C +BMP+Rizo+P1 0.6667 A 3.6667 A 3.0000 B I.C +BMP+Rizo+P2 0.0000 A 1.3333 A 6.0000 AB S anda d e o (±) 0.57 4. 42 5.56 I.C.: So ghum in e c opped wi h cowpea;P1 and P2: Phospho us a 46 kg ha-1 and 92 kg ha-1, espec i ely. izo: Rhizobium leguminosa um:BMP: B.mega he ium; +: in p esence o S iga; -: in absence o S iga Table 7: E ec s o so ghum in e c opping wi h cowpea, bac e ial s ains and ino ganic e ilize on so ghum heigh So ghum heigh (cm) day a e sowing (DAS) T ea men s 30 60 90 I.C s(-) 78.50 A 80.83 AB 76.00 ABCD so ghum s(-) 73.28 AB 86.36 A 92.94 A I.C s(+) 54.17 BC 62.08 E 71.17 ABCD so ghum s(+) 54.67 BC 73.5 ABCDE 69.78 ABCD I.C +P1 63.00 ABC 64.33 DE 52.50 BCD I.C +P2 54.75 BC 73.8 ABCDE 67.17 ABCD I.C+ izo 70.33 ABC 70.1 BCDE 78.00 ABC I.C + izo+P1 75.00 AB 69.75 BCDE 49.83 CD I.C + izo+P2 75.67 AB 78.00 ABC 75.17 ABCD I.C + BMP 62.67 ABC 66.75 CDE 60.79 BCD I.C + BMP+P1 50.50 C 60.88 E 57.02 BCD I.C + BMP+P2 71.33 ABC 70.91 BCDE 49.17 D I.C +BMP+Rizo 67.83 ABC 68.58 BCDE 64.33 ABCD I.C +BMP+Rizo+P1 76.83 A 76.25 ABCD 77.00 ABCD I.C +BMP+Rizo+P2 76.83 A 80.50 AB 80.67 AB S anda d e o (±) 10.51 6.44 14.07 I.C.: So ghum in e c opped wi h cowpea;P1 and P2: Phospho us a 46 kg ha-1 and 92 kg ha-1, espec i ely. izo: Rhizobium leguminosa um:BMP: B.mega he ium; +: in p esence o S iga; -: in absence o S iga Table 8: E ec s o so ghum in e c opping wi h cowpea, bac e ial s ains and ino ganic e ilize , on chlo ophyll con en on so ghum Chlo ophyll con en Day A e Sowing (DAS) T ea men s 30 60 90 I.C s(-) 36.600 AB 27.667 BC 21.36 ABC so ghum s(-) 39.167 A 37.933 A 29.367 A I.C s(+) 30.500 C 24.20 BCD 14.76 BCD so ghum s(+) 35.633 AB 30.067 AB 23.700 AB