Journal of Integrative Agriculture 2017, 16(0): Available online at ScienceDirect

Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 Avill onlin t www.sinirt.om SinDirt RESEARCH ARTICLE Grin yil n wtr us iiny o supr ri unr soil wtr iit n ltrnt wtting n rying irrigtion ZHOU Qun 1, JU Chng-xin 1, WANG Zhi-qin 1, ZHANG Ho 1, LIU Li-jun 1, YANG Jin-hng 1, ZHANG Jin-hu 2 1 Jingsu Ky Lortory o Crop Gntis n Physiology/Co-Innovtion Cntr or Morn Proution Thnology o Grin Crops, Yngzhou Univrsity, Yngzhou 225009, P.R.Chin 2 Shool o Li Sins n Stt Ky Lortory o Agroiothnology, Th Chins Univrsity o Hong Kong, Hong Kong, P.R.Chin Astrt This stuy invstigt i supr ri oul ttr op with soil wtr iit n i it oul hv ttr yil prormn n wtr us iiny (WUE) unr ltrnt wtting n rying (AWD) irrigtion thn hk ri. Two supr ri ultivrs n two lit hk ri ultivrs wr grown in pots with thr soil moistur lvls, wll wtr (WW), mort wtr iit (MWD) n svr wtr iit (SWD). Two ultivrs, h or supr ri n hk ri, wr grown in il with thr irrigtion rgims, ltrnt wtting n mort rying (AWMD), ltrnt wtting n svr rying (AWSD) n onvntionl irrigtion (CI). Compr with tht unr WW, grin yil ws signiintly rs unr MWD n SWD trtmnts, with lss rution or supr ri thn or hk ri. Supr ri h highr prntg o proutiv tillrs, pr root istriution, highr root oxition tivity, n grtr ovgroun iomss proution t mi n lt growth stgs thn hk ri, spilly unr WMD n WSD. Compr with CI, AWMD inrs, whrs AWSD rs, grin yil, with mor inrs or lss rs or supr ri thn or hk ri. Both MWD n SWD trtmnts n ithr AWMD or AWSD rgims signiintly inrs WUE ompr with WW trtmnts or CI rgims, with mor inrs or supr ri thn or hk ri. Th rsults suggst tht supr ri hs strongr ility to op with soil wtr iit n hols grtr promising to inrs oth grin yil n WUE y option o mort AWD irrigtion. Kywors: supr ri, soil wtr iit, ltrnt wtting n rying (AWD), grin yil, wtr us iiny 1. Introution Riv 22 August, 2016 Apt 2 Novmr, 2016 ZHOU Qun, Moil: +86-15371341560, E-mil: 1146560437@ qq.om; Corrsponn YANG Jin-hng, Tl/Fx: +86-514- 87979317, E-mil: jyng@yzu.u.n 2017, CAAS. All rights rsrv. Pulish y Elsvir Lt. oi: 10.1016/S2095-3119(16)61506-X Ri is th stpl oo or mor thn 65% o th Chins popl, with th irst in totl mount o nnul proution n th son lrgst in nnul plnting r in th worl (Png t l. 2009; GRSP 2013; M n Yun 2015). Ri yil in this ountry hs rmtilly inrs uring th lst 60 yrs, u minly to gnti improvmnt, progrss in rop mngmnt n inrs in hmil rtilizr pplition (Png t l. 2009; Yng n Zhng 2010; M n

*** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 3 Yun 2015; Wu t l. 2016). Th rpi popultion growth n onomi vlopmnt, howvr, hv n posing growing prssur or inrs in oo proution, spilly in ri proution (Zhng 2007; M n Yun 2015). To urthr inrs th yil potntil, Chin hs sussully r supr ri or supr hyri ri ultivrs in th lst 20 yrs y us o intrsuspii htrosis n improvmnt plnt typ sign (Chng t l. 2007; Png t l. 2008, 2009; M n Yun 2015). Toy, out 150 supr ri ultivrs hv n rls with th nnul plnting r o mor thn 10 million h (Dng 2016, prsonl ommunition). Compr with non-supr ri ultivrs or hk ultivrs, supr ri ultivrs n inrs grin yil y 15 20% in th il xprimnts n y pproximtly 10% in th lrg-r proution (Zhng t l. 2009; Yng n Zhng 2010; M n Yun 2015; Hung t l. 2016). Mny gronomi n physiologil trits ontriut to highr grin yil in supr ri, suh s lrgr sink siz s rsult o mor numr o spiklts pr pnil (Ktsur t l. 2007; Png t l. 2009; Yng n Zhng 2010), grtr sour tivity whih is hrtriz with highr l r inx (LAI), lrgr l r urtion (LAD), highr photosynthti rt, n slowr l snsn (Zhi t l. 2002; Ktsur t l. 2007; Zhng t l. 2009; Hung t l. 2016), lrgr root iomss (Zhng t l. 2009, 2013), strongr loging rsistn spilly t high N rt (Zhng J t l. ; Zhng W J t l. ), n highr N us iiny t low N pplition (Ju t l. 2015; Wu t l. 2016), in rltiv to lit hk ultivrs. Howvr, littl is known whthr supr ri hs ttr yil prormn n highr wtr us iiny (WUE) thn hk ri unr ithr wtr iit or wtr-sving irrigtion. Wtr iit or rought is th mjor ioti strss tor limiting rop proutivity worlwi (Sini n Wstgt 2000; Shrp t l. 2004; Ll t l. 2012). Ri s py il rop is prtiulrly susptil to soil wtr iit (Inthpn n Fuki 1988; Cusly t l. 2002; To t l. 2006), n out 50% o th worl ri proution is t mor or lss y wtr iit (Bltr t l. 2004; Ll t l. 2012). It is liv tht ring n slting rought rsistnt ultivr n option o propr wtr mngmnt r th tiv pprohs to mitigt th t o wtr iit on ri yil, n tht unrstning plnt trits tht r ssoit with high grin yil n strong rought rsistn is vry importnt in ring progrm to vlop th ultivr with high WUE n in mking strtgy or wtr mngmnt (Bltr t l. 2004; Yng t l. 2007; Ll t l. 2012; Hl t l. 2016). Thror, it mrits invstigting how supr ri prorms with rgr to th gronomy n physiology unr wtr iit. Th ojtivs o this stuy wr to (i) mk ompssion twn supr ri n hk ri in yil prormn n WUE unr soil wtr iit, (ii) unrstn th mhnism in whih supr ri ops with soil wtr iit, n (iii) invstigt i supr ri oul hiv th ul gol o inrsing grin yil n WUE unr ltrnt wtting n rying (AWD) irrigtion, whih is rgr s novl wtr-sving irrigtion thniqu (Blr t l. 2004, 2005; Zhng t l. 2009; Yo t l. 2012; Liu t l. 2013). Som gronomi n physiologil trits tht r losly ssoit with ri growth, prntg o proutiv tillrs, l r urtion (LAD), l photosynthti rt, ry mttr umultion, rop growth rt (CGR), nonstruturl rohyrt (NSC) in th stm t hing n its rmoiliztion uring grin illing, root iomss n root oxition tivity (ROA) (Yoshi 1972; Fgri 2007; Yng t l. 2012), wr trmin. Suh stuy woul giv insight into unrstning how supr ri ops with soil wtr iit, n provi usul inormtion to ri ring n wtr mngmnt to hiv high grin yil n high WUE. 2. Mtrils n mthos 2.1. Pot xprimnt Plnt mtrils n growth onitions To ontrol soil moistur urtly, pot xprimnt ws onut t rsrh rm o Yngzhou Univrsity, Jingsu Provin, Chin (32.30 N, 119.25 E, 21 m ltitu) uring th ri growing sson (My Otor) o 2013. Th two supr ri ultivrs quliia y th Ministry o Agriultur o Chin, IIYou 084 (, n ini hyri) n Wuyunjing 24 (, jponi inr), wr us. Th two non-supr ri ultivrs, Shnyou 63 (, n ini hyri) n Huno 5 (, jponi inr), wr tkn s hk ultivrs. All th ultivrs r us in lol proution us thir high-yiling potntil n/or ttr qulity n pst rsistn ompr with othr ultivrs. Th our vritis hv similr growth prio rng rom 148 152 ys rom sowing to grin mturity, n thir ss wr otin rom Yngzhou S Co. (Yngzhou, Jingsu, Chin). Th slings wr ris in th s with sowing t on 15 16 My. 25--ol slings wr trnsplnt to porlin pots with thr hills pr pot n two slings pr hill. Eh porlin pot (30-m in hight n 25-m in imtr, 14.72-L in volum) ws ill with 18 kg sny lom soil (Typi luvqunts, Entisols (U.S. txonomy)) tht ontin 24.2 g kg 1 orgni mttr, 102 mg kg 1 lkli hyrolysl N, 33.5 mg kg 1 Olsn-P, n 67.5 mg kg 1 xhngl K. On th y o trnsplnting (9 10 Jun), 1 g N s ur, 0.3 g P s singl suprphospht n 0.5 g K s KCl wr mix into th soil in h pot. Nitrogn s ur ws lso ppli t th stgs o mi-tillring, pnil initition n spiklt irntition, with th N rt o 0.5, 0.6 n 0.4 g pot 1, rsptivly. Th pot ws kpt t 1 2

4 *** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 m wtr lvl uring th irst 10 ys tr trnsplnting or ttr rovry o slings. Soil wtr iit trtmnts Th xprimnt ws 4 3 (our ultivrs n thr lvls o soil moistur) toril sign with 12 trtmnts. Eh trtmnt h 50 pots s rplits. From 11 ys tr trnsplnting to mturity, thr lvls o soil wtr moistur, wll-wtr (WW), mort wtr iit (MWD) n svr wtr iit (SWD), wr impos y ontrolling wtr pplition. Th WW trtmnt ws kpt t 1 2 m wtr pth (soil wtr potntil=0 kp), n th MWD ws mintin soil wtr potntil t ( 15±5) kp, n th SWD ws mintin soil wtr potntil t ( 30±5) kp in th pot y mnully pplying tp wtr. Soil wtr potntils in oth MWD n SWD trtmnts wr monitor in th 15 20 m soil pth in th pot. A tnsion mtr (Institut o Soil Sins, Chins Amy o Sins, Nnjing, Chin) onsisting o snsor o 5 m lngth ws instll in h pot to monitor. Tnsion mtr rings wr ror vry 4-h rom 0600 to 1 800 h. Whn th rings ropp to th sign vlus, 0.4 n 0.2 L o tp wtr ws mnully to h pot or MWD n SWD trtmnts, rsptivly. Th pots wr pl in il n shltr rom rin y rmovl polythyln shltr uring rin. Smpling n msurmnts L wtr potntils o th upmost ully-xpn lvs on stms wr msur t lr miy (1 130 h) t th stgs o jointing, hing n mi grin illing (20 22 ys tr hing). Thr prssur hmrs (Mol 3000, Soil Moistur Equipmnt Corp., Snt Brr, CA, USA) wr us or l wtr potntil msurmnt, with six lvs or h trtmnt. Plnts in 10 pots or h trtmnt wr tgg or osrvtion o tillr numr. Th osrvtion ws m t jointing stg, hing tim n mturity. Th prntg o proutiv tillrs ws in s th numr o pnils vlop rom tillrs n min stms t mturity s prntg o th numr o tillrs n min stms t th jointing stg. Th photosynthti rt o th upmost ully-xpn lvs ws msur t th stgs o jointing, hing, rly grin illing (10 12 ys tr hing), mi grin illing n lt grin illing (35 37 ys tr hing). Thr gs xhng nlyzrs (Li-Cor 6400 portl photosynthsis msurmnt systm, Li-Cor, Linoin, NE, USA) wr us to msur l photosynthti rt. Th msurmnt ws m uring 0900 1 100 h whn photosynthti tiv rition ov th nopy ws 1 300 1 500 µmol m 2 s 1, n six lvs wr msur or h trtmnt. At th ormntion growth stgs, plnts o our pots rom h trtmnt wr smpl or th msurmnt o ovgroun iomss n root oxition tivity (ROA). All plnt smpls wr sprt into grn l ls, stms (ulms+shths) n pnils (t hing tim n mturity). Dry mttr o h omponnt ws trmin tr rying t 70 C to onstnt wight n wigh. Th ROA ws trmin y msuring oxition o lph-nphthylmin (α-na) oring to th mtho o Zhng t l. (2009), n ws xprss s μg α-na pr grm DW pr hour (μg α-na g 1 DW h 1 ). Th smpl plnts t hing n mturity tim wr lso us to trmin l r n th mount o non-struturl rohyrt (NSC) in th stm (ulm+shth). Root ry wight ws msur t hing tim. Totl l r o th plnts inluing min stms, proutiv n unproutiv tillrs n th l r o proutiv tillrs n min stms wr msur with n r mtr (LI-3050C, Li-Cor, Linoin, NE, USA). Th NSC in th stm ws trmin oring to th mtho o Yoshi t l. (1976). For msuring root ry wight, soil in th pot (24 m rom soil sur to ottom) ws ut into two prts, with 12 m pth or h prt. Th roots in h prt o soil wr rully rins with hyropnumti lutrition vi (Gillison s Vrity Fritions, Bnzoni, MI, USA). Root ry wight ws trmin tr rying in n ovn t 70 C to onstnt wight n wigh. Plnts wr hn-hrvst on 12 14 Otor in 2013 n 13 15 Otor in. Grin yil ws trmin rom 10 pots in h trtmnt n just to 14% moistur. Aovgroun iomss n yil omponnts, i.., th numr o pnils m 2, numr o spiklts pr pnil, prntg o ill grins, n 1 000-grin wight, wr trmin rom plnts o iv pots in h trtmnt. Th prntg o ill grins ws in s th ill grins (spii grvity 1.06 g m 3 ) s prntg o totl numr o spiklts. Crop growth rt (CGR), l r urtion (LAD), NSC rmoiliztion, hrvst inx, n WUE wr lult using th ollowing ormuls: CGR (g m 2 1 )=(W 2 W 1 )/(t 2 t 1 ) Whr, W 1 n W 2 r th irst n son msurmnt o shoot iomss (g pot 1 ), rsptivly, n t 1 n t 2 prsnt th irst n son tim (), rsptivly, o th msurmnt. LAD (m 2 m 2 )= 1 2 (L 1 +L 2 ) (t 2 t 1 ) Whr, L 1 n L 2 r th irst n son msurmnt o l r (m 2 m 2 ), rsptivly, n t 1 n t 2 prsnt th irst n son tim (), rsptivly, o th msurmnt. NSC rmoiliztion (%)=(NSC in th stm t nthsis NSC in th stm t mturity)/nsc in th stm t nthsis 100 Hrvst inx=totl grin wight (ry wight)/totl ovgroun iomss (ry wight) WUE=Grin yil pr pot (g)/th mount o irrigtion wtr pr pot (L)

*** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 5 2.2. Fil xprimnt Plnt mtrils n ultivtion To vriy yil prormn unr soil wtr iit in th pot xprimnt n to invstigt i supr ri oul hv ttr WUE thn hk ri unr AWD irrigtion, il xprimnt ws onut t th sm sit s th pot xprimnt in n 2015. Soil typ n nutrint ontnt in th soil wr th sm s thos o th soil us in pot xprimnt, with 0.188 g g 1 il pity n 1.33 g m 3 ulk nsity. A supr ri ultivr n hk ri ultivr wr us. Th sown t o ss or oth ultivrs ws th sm s tht in pot xprimnt. Slings wr trnsplnt on 10 11 Jun t hill sping o 0.25 m 0.16 m with two slings pr hill. In oth yrs, N (60 kg h 1 s ur), P (30 kg h 1 s singl suprphospht) n K (40 kg h 1 s KCl) wr ppli n inorport just or trnsplnting. Nitrogn s ur ws lso ppli t th stgs o mi-tillring (30 kg h 1 ), pnil initition (45 kg h 1 ) n spiklt irntition (45 kg h 1 ). Th totl N pplition ws 180 kg h 1 whih is within th rommn rng. Ws, insts n isss wr ontroll s rquir to voi yil loss. Irrigtion trtmnt Th xprimnt ws 3 2 (thr irrigtion rgims n two ri ultivrs) toril sign with six trtmnts. Eh o th trtmnts h thr plots s rptitions in omplt rnomiz lok sign. Plot imnsion ws 5.5 m 4.8 m n plots wr sprt y n lly o 1 m wi with plsti ilm insrt into th soil to pth o 0.50 m to orm rrir. Th thr irrigtion rgims wr ltrnt wtting n mort rying (AWMD) ltrnt wtting n svr rying (AWSD), n onvntionl irrigtion (CI), n wr ppli rom 10 ys tr trnsplnting to mturity. In th AWMD rgim, ils wr not irrigt until th soil wtr potntil rh 15 kp (soil moistur ontnt 0.169 g g 1 ) t 15 20 m pth. Whil in th AWSD rgim, wtr ws withhl until soil wtr potntil rh 30 kp (soil moistur ontnt 0.150 g g 1 ) t 15 20 m pth. Expt ring t th mi-sson, th CI rgim ws mintin plots ontinuous loo with 2 3 m wtr pth until 1 wk or hrvst s r rommn rming prtis. Soil wtr potntil ws monitor t 15 20 m soil pth with tnsionmtr onsisting o snsor o 5 m lngth. Four tnsionmtrs wr instll in h plot o AWMD n AWSD rgims, n rings wr ror t 1 200 h 1. Whn soil wtr potntil rh th thrshol, loo with 2.0 2.5 m wtr pth ws ppli to th plots. Th mount o irrigtion wtr ws monitor with low mtr (LXSG-50 Flow mtr, Shnghi Wtr Mtr Mnuturing Ftory, Shnghi, Chin) instll in th irrigtion piplins. A rin shltr onsisting o stl-rm ovr with plsti sht ws us in h lok to minimiz th t o rinll pripittion on th trtmnts, n ws mov o tr th rin. Finl hrvsting Plnts wr hn-hrvst on 15 16 Otor. Th msurmnt o grin yil n yil omponnts ws ollow th prour s sri y Yoshi t l. (1976). Grin yil ws trmin rom hrvst r o 6 m 2 in h plot n just to 14% moistur ontnt. Aovgroun iomss n yil omponnts wr trmin rom plnts o 1 m 2 (xluing th orr ons) smpl rnomly rom h plot. WUE ws lult using th ollowing ormul: WUE=Grin yil (kg m 2 )/Th mount o irrigtion wtr (m 3 m 2 ) 2.3. Sttistil nlysis Anlysis o vrin ws prorm using SAS/STAT sttistil nlysis pkg (vr. 9.2, SAS Institut, Cry, NC, USA). Dt rom h smpling t wr nlyz sprtly. Mns wr tst y lst signiint irn t P<0.05 (LSD 0.05 ). 3. Rsults 3.1. L wtr potntil n l photosynthti rt Miy l wtr potntil vri with th lvls o soil wtr iit, ultivrs n growth stgs (Fig. 1-A F). At ll msurmnt stgs or ll ultivrs, l wtr potntil ws signiintly rs with th inrs in wtr iit, with th lowst unr SWD, intrmit unr MWD, n th highst unr WW, n show no signiint irn mong th our ultivrs unr WW. Unr ithr MWD or SWD, lthough l wtr potntil xhiit no signiint irn twn supr ri ( n ) n hk ri ( n ) t jointing (Fig. 1-A n B), it ws signiintly highr or supr ri thn or hk ri t hing n mi grin illing stgs (Fig. 1-C F), initing tht supr ri n kp highr wtr ontnt in plnts thn hk ri uring th mi n lt growth prios. In grmnt with l wtr potntil, l photosynthti rt rs with th inrs in wtr iit, n show no signiint irn mong th our ultivrs unr th sm soil moistur trtmnt t th jointing stg (Tl 1). Howvr, ithr (supr ri-1) or (supr ri-2) xhiit highr photosynthti rt thn or thn unr th sm soil moistur trtmnt, spilly unr MWD n SWD, t th stgs o hing, rly grin illing, mi grin illing, n lt grin illing (Tl 1), suggsting tht supr ri hs highr photosynthti ility thn hk ri t mi n lt growth stgs, spilly unr soil wtr iit.

6 *** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 WW MWD SWD 0.0 A 0.3 0.6 0.9 1.2 B 1.5 1.8 Jointing 2013 Jointing L wtr potntil (ΜP) 0.0 C 0.3 0.6 0.9 1.2 1.5 1.8 Hing D 2013 Hing 0.0 E 0.3 0.6 0.9 1.2 1.5 1.8 F Mi grin illing 2013 Mi grin illing Cultivr Cultivr Fig. 1 L wtr potntil o ri unr vrious soil wtr iit trtmnts in 2013 (A C) n (D F). WW, MWD n SWD rprsnt wll wtr, mort wtr iit n svr wtr iit, rsptivly, uring th growing sson. n r hk ri ultivrs, n n r supr ri ultivrs. Msurmnts wr m on th upmost ully-xpn lvs t miy (1 130 h) t th stgs o jointing (A n D), hing (B n E) n mi grin illing (C n F). Vrtil rs rprsnt ±stnr rror o th mn (n=6) whr ths x th siz o th symol. Dirnt lttrs unr th olumn init sttistil signiin t th P=0.05 lvl within th sm msurmnt t. Th sm s low. 3.2. Tillrs, l r inx (LAI), ovgroun iomss n CGR Th mximum numr o tillrs t jointing, totl LAI n LAI o proutiv tillrs n min stms t hing, n LAI t mturity rs with th inrs in soil wtr iit (Tl 2). Expt MWD unr whih supr ri show smllr mximum tillr numr thn hk ri, th mximum tillr numr t jointing show no signiint irn twn supr ri-1 n CK-1 or twn supr ri-2 n CK-2 t th sm soil moistur trtmnt (Tl 2). Howvr, ithr supr ri-1 or supr ri-2 h grtr prntg o proutiv tillrs thn CK-1 or thn CK-2 t th sm soil moistur, spilly unr MWD n SWD trtmnts. Similr osrvtions wr m on totl LAI n LAI o proutiv tillrs n min stms t hing n LAI t mturity (Tl 2). As rsult, oth supr ri ultivrs h lrgr LAD rom hing to mturity thn th two hk ri ultivrs unr ll soil moistur trtmnts, spilly unr MWD n SWD, though th irn in LAD unr WW ws not signiint twn n (supr ri-2) (Fig. 2). Similr to th mximum tillr numr t jointing, ovgroun iomss n CGR rom trnsplnting to jointing show no signiint irn twn supr ri-1 n CK-1 or twn supr ri-2 n CK-2 unr th sm soil moistur trtmnt (Tl 3). Aovgroun iomsss t hing n mturity n CGR rom jointing to hing or rom hing to mturity, howvr, wr grtr or supr ri-1 thn or CK-1 or or supr ri-2 thn or CK-2 t th sm soil moistur trtmnt. Ths irns twn supr ri n hk ri wr mor ovious unr MWD n SWD, implying gin tht supr ri hs highr ility o mttr proution thn hk ri uring th mi n lt

*** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 7 Tl 1 L photosynthti rt (µmol CO 2 m 2 s 1 ) o ri unr vrious soil wtr iit trtmnts Yr/Cultivr Trtmnt 1) Jointing Hing Erly grin illing Mi grin illing Lt grin illing 2013 (supr ri-1) (supr ri-2) (supr ri-1) (supr ri-2) WW 22.8 23.8 21.5 15.6 10.5 MWD 17.5 16.7 15.3 10.7 g 7.2 SWD 12.8 11.8 10.7 7.5 h 5.4 WW 23.2 23.5 22.2 17.5 12.6 MWD 18.6 19.3 18.6 14.3 9.5 SWD 13.8 14.6 13.8 10.6 g 7.3 WW 23.5 23.8 22.1 18.6 12.8 MWD 18.4 17.4 16.4 14.3 9.6 SWD 12.5 13.6 12.5 10.5 g 7.5 WW 24.1 24.6 23.2 19.8 13.7 MWD 19.4 20.5 19.4 16.5 11.8 SWD 14.2 16.7 15.3 12.4 9.7 WW 24.5 21.5 20.6 17.2 12.4 MWD 19.6 15.8 14.7 12.5 8.6 SWD 14.5 11.6 11.3 9.5 6.2 g WW 24.7 22.4 21.5 18.4 13.2 MWD 20.2 18.5 17.4 15.6 10.9 SWD 15.8 15.3 14.5 11.9 8.3 WW 22.6 24.3 23.3 20.1 14.7 MWD 18.7 18.5 16.9 15.5 11.6 SWD 13.6 14.8 13.2 11.8 8.4 WW 23.2 25.2 24.2 21.2 16.3 MWD 20.2 21.7 20.3 18.4 13.5 SWD 15.7 17.9 16.5 14.5 10.4 1) WW, MWD n SWD rprsnt wll wtr, mort wtr iit n svr wtr iit, rsptivly, uring th growing sson. Dirnt lttrs init sttistil signiin t th P=0.05 lvl within th sm olumn n th sm yr. Th sm s low. Tl 2 Prntg o proutiv tillrs n l r inx (LAI) o ri unr vrious soil wtr iit trtmnts Yr/Cultivr 2013 (supr ri-1) (supr ri-2) (supr ri-1) (supr ri-2) Trtmnt Mximum no. o tillrs Prnts o proutiv pr pot t jointing tillrs (%) 2) Totl LAI t hing tim Proutiv tillrs+min stms LAI t mturity WW 46.1 67.2 h 7.59 6.40 1.87 MWD 37.2 75.3 6.49 5.75 1.16 g SWD 31.1 77.2 4.58 4.13 i 0.93 h WW 43.4 69.1 g 7.61 6.48 2.25 MWD 34.0 82.4 6.53 6.18 1.75 SWD 29.8 83.8 5.03 4.85 g 1.36 WW 48.2 68.4 gh 7.12 6.08 2.05 MWD 39.3 73.8 5.84 5.22 1.55 SWD 29.6 74.2 4.12 g 3.77 j 1.21 g WW 47.0 70.2 7.25 6.28 2.26 MWD 36.8 81.6 6.03 5.78 1.92 SWD 29.4 88.5 4.54 4.39 h 1.58 WW 48.9 65.4 g 7.63 6.31 1.92 MWD 39.3 73.8 6.54 5.64 1.24 g SWD 32.3 74.4 4.87 g 4.28 i 0.98 h WW 45.4 68.3 7.72 6.45 2.31 MWD 36.0 80.5 6.68 6.18 1.81 SWD 30.8 81.3 5.35 5.03 g 1.42 WW 50.1 67.9 7.21 6.04 2.13 MWD 41.3 72.7 5.98 5.21 1.64 SWD 31.2 73.8 4.33 h 3.88 j 1.27 g WW 49.4 68.8 7.36 6.23 2.29 MWD 39.9 77.6 6.35 5.93 1.95 SWD 30.9 87.4 4.86 g 4.62 h 1.60 1) Prntg o proutiv tillrs (%)=Proutiv tillrs (pnils)/th mximum numr o tillrs t jointing 100

8 *** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 growth prio, n this ility is mor prominnt unr soil wtr iit. 3.3. Root iomss n ROA At th sm soil moistur n ompr with CK-1 or CK-2, supr ri-1 or supr ri-2 h highr totl root ry wight t hing, though th irn in rtio o root to shoot ws not signiint mong th our ultivrs (Tl 4). Whn totl root wight ws ivi into two prts o 0 12 m soil lyr n 12 24 m soil lyr, root wight in 0 12 m soil lyr unr WW show no signiint irn twn supr ri-2 () n CK-2 (), ut xhiit signiint irn twn supr ri-1 () n CK-1 (). Root wight in 0 12 m soil lyr ws signiintly highr or supr ri-1 thn or CK-1 or or supr ri-2 thn or CK-2 unr ithr MWD or SWD. Both supr ri ultivrs h highr root ry wight in 12 24 m soil lyr thn th two L r urtion (m 2 m 2 ) 300 250 200 150 100 50 0 A 2013 Cultivr WW MWD SWD B g Cultivr g Fig. 2 L r urtion rom hing to mturity o ri unr vrious soil wtr iit trtmnts in 2013 (A) n (B). Vrtil rs rprsnt±stnr rror o th mn (n=4) whr ths x th siz o th symol. Th sm s in Figs. 4 n 5. Tl 3 Aovgroun iomss n rop growth rt o ri unr vrious soil wtr iit trtmnts Yr/Cultivr 2013 (supr ri-1) (supr ri-2) (supr ri-1) (supr ri-2) Trtmnt Biomss (g pot 1 ) Crop growth rt (g 1 pot 1 ) Jointing Hing Mturity Trnsplnting to Jointing to Hing to jointing hing mturity WW 57.6 135.7 213.7 1.42 2.37 1.62 MWD 45.4 107.0 162.9 1.12 1.81 1.19 SWD 26.8 64.2 g 95.0 h 0.65 1.07 g 0.67 h WW 60.4 159.3 254.9 1.49 3.00 1.99 MWD 47.9 138.1 217.5 1.18 2.65 1.69 SWD 27.6 104.1 159.6 0.67 2.18 1.21 WW 56.5 131.8 208.8 1.36 2.28 1.57 MWD 44.8 99.9 153.2 1.07 1.62 1.11 SWD 26.5 53.5 h 79.7 i 0.63 0.77 h 0.56 i WW 59.3 143.0 226.6 1.43 2.54 1.71 MWD 46.7 121.7 189.6 1.12 2.21 1.41 SWD 28.2 86.1 132.9 g 0.67 1.66 1.00 g WW 55.8 132.6 210.5 1.34 2.40 1.66 MWD 46.2 103.1 158.2 1.11 1.73 1.20 SWD 30.7 61.7 g 92.0 g 0.73 0.91 0.67 h WW 59.8 157.3 253.7 1.44 3.05 2.05 MWD 47.5 136.3 216.3 1.14 2.69 1.74 SWD 32.5 99.4 153.7 0.77 1.97 1.21 WW 54.6 128.8 206.1 1.28 2.32 1.61 MWD 42.9 96.2 148.7 1.00 1.62 1.12 SWD 24.8 52.3 h 78.5 h 0.57 0.81 0.57 i WW 56.9 141.0 225.3 1.34 2.63 1.76 MWD 45.2 121.3 190.4 1.06 2.30 1.47 SWD 26.5 84.7 131.8 0.61 1.71 1.02 g

*** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 9 hk ri ultivrs unr WW, MWD or WSD. Morovr, th proportion o root wight in 12 24 m soil lyr to totl root wight ws inrs with th inrs in soil wtr iit, n supr ri h highr proportion thn hk ri unr th sm soil moistur trtmnt (Tl 4), initing pr root istriution in soil or supr ri thn or hk ri. Consistnt with l photosynthti rt (rr to Tl 1), ROA ws rs with th inrs in wtr iit, n show no signiint irn mong th our ultivrs unr th sm soil moistur trtmnt t th jointing stg (Tl 5). At th stgs o hing, rly grin illing, mi grin illing, n lt grin illing, ithr supr ri-1 or supr ri-2 h highr ROA thn CK-1 or CK-2 t th sm soil moistur trtmnt, spilly unr MWD n SWD n t th lt grin illing stg, initing gin tht supr ri posssss highr root tivity thn hk ri t mi n lt growth stgs, spilly unr soil wtr iit trtmnts. Rgrssion nlysis show tht ROA ws vry signiintly orrlt with th l photosynthti rt (r=0.90 ** to 0.93 ** ) (Fig. 3), suggsting root-shoot intrtion. 3.4. Grin yil n WUE Unr th sm soil moistur, grin yil ws highr or supr ri thn or hk ri (Tl 6). It ws signiintly rs with inrs in soil wtr iit. Howvr, th rution in grin yil unr oth MWD n SWD ws lss or supr ri thn or hk ri ompr with th grin yil unr rsptiv WW trtmnts. For xmpl, vrg grin yil ws ru y 21.6 n 54.9% or hk ri n y 10.7 n 34.3% or supr ri, rsptivly, unr MWD n SWD, suggsting tht supr ri posssss strongr rought or wtr iit rsistn thn hk ri with rgr to grin yil. Supr ri otin highr grin yil ws minly u to mor spiklts pr pnil unr WW, n to mor spiklts pr pnil n highr prntg o ill grins unr MWD, n to mor pnils pr pot, mor spiklts pr pnil, highr prntg o ill grins, n hvir grin wight unr SWD whn ompr with hk ri (Tl 6). Th rmoiliztion prntg o NSC rom stms (ulm+shth) to grins uring mturity ws not signiint twn supr ri-1 n CK-1 or twn supr ri-2 n CK-2 t th sm soil moistur trtmnt (Fig. 4-A n B). Similr to NSC rmoiliztion, hrvst inx show no signiint irn mong th our ultivrs whn soil moistur ws th sm (Fig. 4-C n D), implying tht highr grin yil or supr ri is minly ttriut to mor iomss proution thn hk ri. Unr th sm soil moistur trtmnt n whn om- Tl 4 Root iomss o ri t hing tim unr vrious soil wtr iit trtmnts Totl root ry Rtio o root to Root wight in 0 12 Root wight in 12 24 Yr/Cultivr Trtmnt wight shoot m soil (g pot (g pot 1 ) 1 ) m soil (g pot 1 ) 2013 (supr ri-1) (supr ri-2) (supr ri-1) (supr ri-2) Prntg o root wight in 12 24 m to totl root wight WW 18.72 0.138 11.85 6.87 36.71 MWD 16.81 0.157 10.02 6.79 40.38 SWD 11.11 0.173 6.35 h 4.76 g 42.86 WW 22.15 0.139 12.87 9.28 41.89 MWD 21.83 0.158 11.36 10.47 47.95 SWD 17.90 0.172 9.03 8.87 49.55 WW 18.31 0.139 12.25 6.06 33.11 g MWD 15.58 0.156 9.86 5.72 36.70 SWD 9.31 g 0.174 5.59 i 3.72 h 39.99 WW 20.02 0.140 12.45 7.57 37.80 MWD 19.11 0.157 11.03 8.08 42.29 SWD 14.73 0.171 8.07 g 6.66 45.22 WW 18.44 0.139 11.63 6.81 36.92 g MWD 15.99 0.155 9.75 6.24 39.02 SWD 10.55 h 0.171 6.15 g 4.40 g 41.72 WW 21.71 0.138 13.52 8.19 37.71 g MWD 20.98 0.154 12.52 8.46 40.33 SWD 16.80 0.169 9.19 7.61 45.31 WW 17.65 0.137 11.96 5.69 32.23 i MWD 14.81 g 0.154 9.57 5.24 35.40 h SWD 8.95 i 0.171 5.34 h 3.61 h 40.34 WW 19.46 0.138 12.06 7.40 38.03 MWD 18.67 0.154 10.74 7.93 42.49 SWD 14.32 g 0.169 7.89 6.43 44.91

10 *** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 Tl 5 Root oxition tivity (µg -NA g 1 DW h 1 ) o ri unr vrious soil wtr iit trtmnts Yr/Cultivr Trtmnt Jointing Hing Erly grin illing Mi grin illing Lt grin illing 2013 WW 642 685 632 475 216 MWD 567 576 518 326 149 SWD 475 483 422 233 112 (supr ri-1) (supr ri-2) (supr ri-1) (supr ri-2) WW 653 691 646 499 253 MWD 584 624 584 398 207 SWD 489 548 511 315 163 WW 635 667 615 469 255 MWD 554 575 536 352 167 SWD 469 485 441 254 124 WW 672 682 638 488 270 MWD 572 631 575 384 226 SWD 481 542 498 303 181 WW 657 645 619 507 240 MWD 578 567 526 346 158 SWD 492 476 437 258 123 g WW 686 665 626 532 262 MWD 597 592 573 429 212 SWD 502 496 488 335 184 WW 654 651 624 498 267 MWD 573 545 531 376 191 SWD 486 469 452 277 145 g WW 685 672 657 525 291 MWD 584 603 589 420 245 SWD 516 525 512 325 197 L photosynthti rt (µmol CO 2 m 2 s 1 ) 30 25 20 15 10 5 A B 2013 r=0.93 ** r=0.90 ** 0 0 100 200 300 400 500 600 700 800 Root oxition tivity (µg α-να g 1 DW h 1 ) 0 100 200 300 400 500 600 700 800 Root oxition tivity (µg α-να g 1 DW h 1 ) Fig. 3 Corrltion o root oxition tivity with l photosynthti rt o ri in 2013 (A) n (B). Dt us or th lultion r rom Tls 1 n 5. ** init orrltion signiin t th P=0.01 lvl (n=60). pr with CK-1 or CK-2, supr ri-1 () or supr ri-2 () us mor wtr (Fig. 5-A n B). On vrg, th mount o irrigtion wtr pr pot or supr ri ws 154, 112 n 86 L, rsptivly, unr WW, MWD n SWD, whih ws 6, 14 n 19%, rsptivly, mor thn tht o hk ri. Howvr, supr ri-1 or supr ri-2 show highr WUE thn CK-1 or CK-2 whn soil moistur ws th sm (Fig. 5-C n D). Th vrg WUE (g L 1 ) o supr ri ws 0.87, 1.07 n 1.02, rsptivly, unr WW, MWD n SWD, n ws 7, 13 n 39%, rsptivly, highr thn hk ri. 3.5. Yil prormn n WUE unr AWD irrigtion in th py il As shown in Tl 7, grin yil o supr ri ws signiintly highr thn tht o hk ri in th sm irrigtion rgim. AWMD inrs, whrs AWSD

*** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 11 Tl 6 Grin yil n yil omponnts o ri unr vrious soil wtr iit trtmnts Yr/Cultivr Trtmnt Grin yil (g pot 1 ) Pnils pot 1 Spiklts pnil 1 Fill grins (%) 10 00-grin wight (g) 2013 WW 120 31 162 89.4 27.5 MWD 97 28 154 85.3 27.2 SWD 59 h 24 131 g 75.5 g 26.1 (supr ri-1) (supr ri-2) (supr ri-1) (supr ri-2) WW 142 30 207 86.6 27.7 MWD 128 28 205 84.8 27.4 SWD 98 25 192 77.8 26.8 WW 118 33 138 93.7 28.5 MWD 91 29 128 g 89.2 28.2 SWD 49 i 22 104 h 81.5 27.3 WW 127 33 162 90.5 27.3 MWD 112 30 159 88.7 27.1 SWD 81 g 26 143 84.6 26.5 WW 118 32 161 88.5 27.3 MWD 94 29 152 83.6 26.9 SWD 57 h 24 130 g 73.8 g 25.8 WW 141 31 205 85.3 27.3 MWD 127 29 202 83.9 27.1 SWD 94 25 190 76.7 26.4 WW 116 34 136 92.6 28.2 MWD 88 30 125 h 87.5 27.8 SWD 48 i 23 102 i 79.6 27.1 WW 126 34 159 90.2 27.1 MWD 112 31 157 88.4 26.8 SWD 80 g 27 142 84.2 26.2 Anlysis o vrin Yr (Y) NS NS NS NS NS Cultivr (C) 21 ** 4.2 * 16 ** 14 ** 5.3 * Wtr iit (W) 89 ** 54 ** 37 ** 26 ** 18 ** Y C NS NS NS NS NS Y W NS NS NS NS NS C W 6.8 ** NS 8.6 ** 7.1 * NS * n **, F vlus signiint t th P=0.05 n P=0.01 lvls, rsptivly. NS mns non-signiint t th P=0.05 lvl. Th sm s low. rs, grin yil. Whn ompr with rsptiv CI rgims. Th inrs ws mor n th rs ws lss or supr ri thn or hk ri (Tl 7). Tking grin yil in CI rgims s 100%, grin yil ws 107 n 82%, rsptivly, in AWMD n AWSD rgims or supr ri, n only 102 n 73%, rsptivly, in AWMD n AWSD rgims or hk ri, initing ttr yil prormn in supr ri thn hk ri unr AWD-s wtr-sving irrigtion. Compr with CI, ithr AWMD or AWSD signiintly rs th mount o irrigtion wtr or oth ultivrs, with mor rution in AWSD rgims thn in AWMD rgims (Fig. 6-A n B). At th sm irrigtion rgim, th mount o irrigtion wtr ws mor or supr ri thn or hk ri, ut it show no signiint irn twn th two ultivrs. Both AWMD n AWSD signiintly inrs WUE ompr with CI (Fig. 6-C n D). Thr ws no signiint irn in WUE twn AWMD n AWSD. In th sm irrigtion rgim, supr ri xhiit highr WUE thn hk ri. On vrg, th WUE o supr ri ws 1.18, 1.68 n 1.71 kg m 3, rsptivly, in CI, AWMD n AWSD rgims, n ws 5, 9 n 13%, rsptivly, highr thn tht o hk ri, suggsting tht supr ri uss wtr mor iintly thn hk ri, spilly unr wtr-sving irrigtion. 4. Disussion Thr r mny rports showing tht supr ri hs strong ility o iomss proution n grtr yil potntil thn hk ri (Chng t l. 2007; Png t l. 2008, 2009; Yng n Zhng 2010; M n Yun 2015; Hung t l. 2016). Prior to this stuy, howvr, littl inormtion is vill sriing yil prormn o supr ri unr soil wtr iit, n littl is known i supr ri oul us wtr mor iintly thn hk ri, spilly unr wtr iit or unr AWD-s wtr-sving irrigtion. Th

12 *** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 NSC rmoiliztion (%) 80 70 60 50 40 30 20 10 0 0.60 A 2013 C 2013 WW MWD SWD B D Hrvst inx 0.55 0.50 0.45 0.40 0.00 Cultivr Cultivr Fig. 4 Non-struturl rohyrt (NSC) rmoiliztion (A n B) n hrvst inx (C n D) o ri unr vrious soil wtr iit trtmnts in 2013 (A n C) n (B n D). Wtr us iiny (g L 1 ) Irrigtion wtr (L pot 1 ) 210 180 150 120 90 60 30 0 1.2 1.0 0.8 0.6 0.4 0.2 0.0 A 2013 C 2013 g Cultivr WW MWD SWD B g g D g Cultivr Fig. 5 Amount o irrigtion wtr (A n B) n wtr us iiny (C n D) o ri unr vrious soil wtr iit trtmnts in th pot xprimnt in 2013 (A n C) n (B n D). rsults hrin monstrt tht supr ri h smllr yil rution unr soil wtr iit (Tl 6), n inrs grin yil mor in AWMD rgims or rs grin yil lss in AWSD rgims thn hk ri (Tl 7). Although supr ri us mor irrigtion wtr, it show highr WUE, spilly unr soil wtr iit or in AWD rgims (Figs. 5 n 6). Ths rsults suggst tht, ompr with hk ri, supr ri posssss not only grtr yil potntil unr WW or CI onitions, ut lso strongr rought rsistn, ttr yil prormn n highr WUE unr soil wtr iit or AWD-s wtr-sving irrigtion. Th mhnism in whih supr ri shows ttr yil

*** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 13 Tl 7 Grin yil n yil omponnts o ri in vrious irrigtion rgims Yr/ultivr Irrigtion rgim 1) Grin yil (t h 1 ) Pnils m 2 Spiklts pnil 1 Fill grins (%) 1 000-grin wight (g) CI 9.35 275 135 92.5 28.3 (CK) AWMD 9.56 266 141 93.2 28.6 AWSD 6.73 243 122 84.6 27.5 (supr ri) 2015 (CK) (supr ri) CI 9.88 274 147 91.2 27.2 AWMD 10.59 269 158 93.8 27.8 AWSD 8.03 252 139 86.8 26.7 CI 9.57 273 138 94.3 28.5 AWMD 9.83 269 144 95.2 28.7 AWSD 7.02 252 125 86.8 27.6 CI 10.18 270 151 93.4 27.4 AWMD 10.87 268 160 95.6 28.1 AWSD 8.35 253 142 88.4 26.8 Anlysis o vrin Yr (Y) NS NS NS NS NS Cultivr (C) 12 ** NS 17 ** NS 4.6 * Irrigtion rgim (I) 89 ** 25 ** 63 ** 21 ** 12 ** Y C NS NS NS NS NS Y I NS NS NS NS NS C I 5.7 * NS 6.8 * 3.5 * 4.9 * 1) CI, AWMD n AWSD rprsnt onvntionl irrigtion, ltrnt wtting n mort rying irrigtion, n ltrnt wtting n svr rying irrigtion, rsptivly, uring th growing sson. Wtr us iiny (kg m 3 ) Irrigtion wtr (m 3 m 2 ) 1.0 0.8 0.6 0.4 0.2 0.0 2.0 1.6 1.2 0.8 0.4 0.0 WW MWD SWD A B 2015 C Cultivr D 2015 Cultivr Fig. 6 Amount o irrigtion wtr (A n B) n wtr us iiny (C n D) o ri unr vrious irrigtion rgims in th il xprimnt in (A n C) n 2015 (B n D). CI, AWMD n AWSD rprsnt onvntionl irrigtion, ltrnt wtting n mort rying irrigtion, n ltrnt wtting n svr rying irrigtion, rsptivly, uring th growing sson. is hk ri ultivr, n is supr ri ultivr. Vrtil rs rprsnt ±stnr rror o th mn (n=3) whr ths x th siz o th symol. prormn n highr WUE thn hk ri unr ithr soil wtr iit or wtr-sving irrigtion is not ully unrstoo. Bs on our osrvtions in this stuy, svrl possil xplntions oul m. Firstly, supr ri h lrgr root iomss, pr root istriution n highr ROA thn hk ri, spilly unr soil wtr iit (Tls 4

14 *** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 n 5). It is liv tht lrg root iomss is rquir to support lrg ovgroun iomss proution (Grntt t l. 2009; Yng t l. 2012; Ju t l. 2015; Chu t l. 2016). Whil p root istriution oul mximiz soil moistur ptur, n onsquntly, mintin high plnt wtr sttus unr rought onitions (Grntt t l. 2009; Luo 2010; Luo t l. 2011; Chu t l. ; Ju t l. 2015). ROA hs n rgr s n importnt inx o root physiologil tivity (Rmsmy t l. 1997; Smjim t l. 2004; Zhng t l. 2008; Yng t l. 2012; Ju t l. 2015, Chu t l. 2016). A highr ROA is nssry to mintin root iomss, root n shoot growth, n nutrint n wtr uptk (Wng t l. 2006; Zhng t l. 2008; Ju t l. 2015; Chu t l. 2016). A lrgr root iomss, pr root istriution, n highr ROA or supr ri woul ontriut to highr l wtr potntil, grtr photosynthti rt n lrgr ovgroun iomss thn hk ri, spilly unr soil wtr iit t mi n lt growth stgs (Fig. 1, Tls 1 n 3). In turn, tiv shoots my nsur suiint supply o rohyrts to roots n mintin tiv root untions (Oski t l. 1997; Yng t l. 2004; Zhng t l. 2009; Ju t l. 2015). A synrgisti root-shoot intrtion ws lso vin with th signiint orrltion twn ROA n l photosynthti rt in this stuy (Fig. 3). All ths oul ontriut to ttr yil prormn n highr WUE or supr ri unr wtr iit or wtr sving irrigtion. Sonly, supr ri show highr mttr proution uring th mi n lt growth prios. W osrv tht, unr th sm soil moistur trtmnt, ovgroun ry wight t jointing n CGR rom trnsplnting to jointing wr not signiintly irnt twn supr ri n hk ri (Tl 3). Howvr, th iomss wight t hing tim n mturity, CGR orm jointing to hing n rom hing to mturity, n LAD rom hing to mturity wr signiint grtr thn hk ri, spilly unr soil wtr iit trtmnts (Tl 3 n Fig. 2). Th rsults init strongr ility o ovgroun iomss proution or supr ri t mi n lt growth stgs. It is propos tht high mttr proution ility t th mi growth stg (rom jointing to hing) n prou lrg sink siz y promoting spiklt irntition, ruing spiklt gnrtion, n inrsing prolirtion o nosprm lls t th rly s vlopmnt stg (Hori t l. 2005; Fgri 2007; Fu t l. 2011; Zhng t l. 2013). As grin illing is th inl stg n ry mtr proution uring this prio trmins ill-grin prntg n grin wight, n oringly, trmins th totl yil (Yoshi 1972; Yng n Zhng 2006; Fgri 2007; Li t l. 2012), highr ry mtr proution ility uring th lt growth stg (rom hing to mturity) n nhn grin illing vi inrss in sink strngth n sour tivity (Yng n Zhng 2006, 2010; Li t l. 2012; Zhng t l. 2013; Wng t l. 2016). Thror w spult tht strongr ility o ry mttr proution uring th mi n lt growth prio is n importnt mhnism unrlying ttr yil prormn n highr WUE or supr ri thn hk ri unr soil wtr iit n AWD-s wtr-sving irrigtion. Thirly, supr ri xhiit lss runnt vgttiv growth thn hk ri. Th prsnt rsults show tht th prntg o proutiv tillrs n th proportion o LAI o proutiv tillrs plus min stms to totl LAI (LAI o proutiv tillrs, unproutiv tillrs n min stms) t hing tim wr signiintly grtr in supr ri thn in hk ri, spilly unr soil wtr iit (Tl 2), implying ru runnt vgttiv growth n improv nopy qulity in supr ri. Th ru runnt vgttiv growth n improv nopy qulity oul ru th wtr us in proution o unproutiv tillrs n trnspirtion rom runnt l r (Yng n Zhng 2010), n inrs rition us iiny (Fgri 2007; Yng t l. 2016), ling to highr yil n highr WUE or supr ri. It shoul notworthy tht thr wr no signiint irns twn supr ri n hk ri in hrvst inx n NSC rmoiliztion rom stms to grins uring grin illing t th sm soil moistur trtmnt (Fig. 4), implying tht highr grin yil or supr ri is minly ttriut to its mor iomss proution. As th grin yil is th prout o hrvst inx n totl ovgroun iomss, hrvst inx is rgr s mtr proution iiny n is losly ssoit with grin yil n WUE in rls (Ehi n Wins 1993; Yng n Zhng 2010). It is propos tht nhning hrvst inx is vitl pproh to hiving th ul gol o inrsing grin proution n sving wtr (Flthr n Jmison 2009; Yng n Zhng 2010; Yng 2015). Thror urthr rsrh is n to nhn hrvst inx in supr ri though ring n rop mngmnt. It is lso n to us mor supr ri n lit hk ri ultivrs in th utur to urthr unrstn th mhnism in whih supr ri ultivrs ttr op with soil wtr iit. 5. Conlusion Compr with hk ri, supr ri posssss not only grtr yil potntil unr WW or CI onitions, ut lso ttr yil prormn n highr WUE unr soil wtr iit or unr AWD-s wtr-sving irrigtion. Th ttr yil prormn n highr WUE or supr ri r minly ttriut to its lrgr root iomss, pr root istriution, highr ROA, strongr ility o ovgroun iomss proution t mi n lt growth stgs, ru runnt vgttiv growth, n improv nopy qulity. Th ining tht supr ri hs strongr ility to op

*** t l. Journl o Intgrtiv Agriultur 2017, 16(0): 60345-7 15 with soil wtr iit suggst tht option o AWD-s wtr-sving irrigtion hols grt promising to hiv th ul gol o inrsing grin yil n sving wtr in supr ri. Aknowlgmnts This stuy ws sponsor y th Ntionl Nturl Sin Fountion o Chin (31461143015, 31271641, 31471438), th Ntionl Ky Thnology Support Progrm o Chin (AA10A605), th Priority Ami Progrm Dvlopmnt o Jingsu Highr Eution Institutions (PAPD), th Jingsu Crtion Progrm or Post-grution Stunts (KYZZ15_0364), n th Shnzhn Ovrss Tlnts Innovtion & Entrprnurship Funing Shm (Th Pok Shm, KYZZ15_0364). Rrns Blr P, Boumn B A M, Cngon R, Guon L, Quilng E J P, Li Y, Spirtz J H J, Tuong T P. 2004. Et o wtrsving irrigtion on ri yil n wtr us in typil lowln onitions in Asi. Agriulturl Wtr Mngmnt, 65, 193 210. Blr P, Spirtz J H J, Boumn B A M, Lu G, Tuong T P. 2005. Nitrogn onomy n wtr proutivity o lowln ri unr wtr-sving irrigtion. Fil Crops Rsrh, 93, 169 185. Cusly G S, Ito O, Aljr A A. 2002. Physiologil vlution o rsponss o ri (Oryz stiv L.) to wtr iit. Plnt Sin, 163, 815 827. Chng S H, Zhung J, Fn Y, Du J, Co L Y. 2007. Progrss in rsrh n vlopmnt on hyri ri: A supromstit in Chin. Annls o Botny, 100, 959 966. Chu G, Chn T T, Wng Z Q, Yng J C, Zhng J H.. Morphologil n physiologil trits o roots n thir rltionships with wtr proutivity in wtr-sving n rought-rsistnt ri. Fil Crops Rsrh, 162, 108 119. Chu G, Wng Z Q, Zhng H, Yng J C, Zhng J H. 2016. Agronomi n physiologil prormn o ri unr intgrtiv rop mngmnt. Agronomy Journl, 108, 117 128. Ehi B, Wins J G. 1993. Vrition in wtr-us iiny n its omponnts in wht: I. Wll-wtr pot xprimnt. Crop Sin, 33, 294 299. Fgri N K. 2007. Yil physiology o ri. Journl o Plnt Nutrition, 30, 843 879. Flthr A L, Jmison P D. 2009. Cuss o vrition in th rt o inrs o wht hrvst inx. Fil Crops Rsrh, 113, 268 273. Fu J, Hung Z H, Wng Z Q, Yng J C, Zhng J H. 2011. Prnthsis non-struturl rohyrt rsrv in th stm nhns th sink strngth o inrior spiklts uring grin illing o ri. Fil Crops Rsrh, 123, 170 182. Grntt T, Conn V, Kisr B N. 2009. Root s pprohs to improving nitrogn us iiny in plnts. Plnt, Cll n Environmnt, 32, 1272 1283. GRSP (Glol Ri Sin Prtnrship). 2013. Ri Almn, 4th. Intrntionl Ri Rsrh Institut, Los Bňos, Philippins. p. 283. Hl S M, Kto Y, Singh S. 2016. Climt ry ri: Augmnting rought tolrn with st mngmnt prtis. Fil Crops Rsrh, 190, 60 69. Hori T, Shiriw T, Homm K, Ktsur K, M Y, Yoshi H. 2005. Cn yils o lowln ri rsum th inrss tht show in th 1980s? Plnt Proution Sin, 8, 259 274. Hung M, Shn S L, Zhou X F, Chn J N, Co F B, Jing L G, Zou Y B. 2016. L photosynthti prormn rlt to highr rition us iiny n grin yil in hyri ri. Fil Crops Rsrh, 193, 87 93. Inthpn P, Fuki S. 1988. Growth n yil o ri ultivrs unr sprinklr irrigtion in south-strn Qunsln. 2. Comprison with miz n grin sorghum unr wt n ry onitions. Austrin Journl o Exprimntl Agriultur, 28, 243 248. Ju C X, Bursh R J, Wng Z Q, Zhng H, Liu L J, Yng J C, Zhng J H. 2015. Root n shoot trits or ri vritis with highr grin yil n highr nitrogn us iiny t lowr nitrogn rts pplition. Fil Crops Rsrh, 175, 47 59. Ktsur K, M S, Hori T, Shiriw T. 2007. Anlysis o yil ttriuts n rop physiologil trits o Lingyoupijiu, hyri ri rntly r in Chin. Fil Crops Rsrh, 103, 170 177. Ll R, Dlgo J A, Gullior J, Nilsn D, Ri C W, Vn Plt R S. 2012. Apting griultur to rought n xtrm vnts. Journl o Soil n Wtr Consrvtion, 67, 162A 167A. Li H, Liu L J, Wng Z Q, Yng J C, Zhng J H. 2012. Agronomi n physiologil prormn o high-yiling wht n ri in th lowr rhs o Yngtz Rivr o Chin. Fil Crops Rsrh, 133, 119 129. Liu L J, Chn T T, Wng Z Q, Zhng H, Yng J C, Zhng J H. 2013. Comintion o sit-spii nitrogn mngmnt n ltrnt wtting n rying irrigtion inrss grin yil n nitrogn n wtr us iiny in supr ri. Fil Crops Rsrh, 154, 226 235. Luo L. 2010. Bring or wtr-sving n rought-rsistn ri (WDR) in Chin. Journl o Exprimntl Botny, 61, 3509 3517. Luo L, Mi H, Yu X, Liu H, Fn F. 2011. Wtr-sving n rought-rsistn ri n its vlopmnt strtgy. Chins Sin Bulltin (Chins Vrsion), 56, 804 811. M G H, Yun L P. 2015. Hyri ri hivmnts, vlopmnt n prospt in Chin. Journl o Intgrtiv Agriultur, 14, 197 205. Oski M, Shinno T, Mtsumoto M, Zhng T, Tno T. 1997. A root-shoot intrtion hypothsis or high proutivity o il rops. Soil Sin n Plnt Nutrition, 37, 445 454.

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