Rate f fruit develpment, leaf grwth, and earliness determinate tmates m V. Pysa Agriculture Canada Research Statin, Harrw, Ontari, Canada N1R 1G0. Received 22 Oct. 1990, accepted 15 Apr. 1991. r persnal use nly. Pysa, V. 1991. Rate f fruit develpment, leaf grwth, and earliness in determinate tmates. Can. J. Plant Sci. 7l: 121 l-1218. The cmpnent subperids f reprductive develpment as well as rate f leaf grwth were determined fr three trusses in eight determinate tmat (Lycpersicn esculentum L. Mill) gentypes in an attempt t identify effective selectin criteria fr imprving earliness. Days frm transplanting t anthesis and first red fruit t the first truss crrelated well with days t plant maturity (r : 0.58 and r : 0.63 respectively; P<0.01). These crrelatins were strnger fr full seasn gentypes (r : 0.53 t r : 0.69) than fbr early maturing gentypes (r<0.41). Plant maturity was crrelated mderately better with these perids in the later trusses than in the first truss. Leaf grwth parameters were nt crrelated significantly with either earliness r fruit yield. Key wrds: Tmat, Lycpersicn esculentum, earliness Pysa, V. 1991. Taux de fructificatin, crissance fliaire et pr6ccit6 de gdntypes de tmates nn remntants. Can. J. Plant Sci. 71: l2ll-1218. Les sus-p6rides de d6velppement des rganes reprducteurs et la crissance fliaire nt 6t6 d6termindes pur tiis grappes de huiig6ntypes de tmate (Lycpersicn esculentum L. Mill) nn remntants dans une tentative visant ir d6terminer certains critbres efficaces de s6lectin capables d'am6lirer la pr6ccit6. Le nmbre dejurs du repiquage ir I'anthdse et ir la premidre tmate ruge de la premibre grappe snt bien crr616s au nmbre de jurs n6cessaires ir la maturatin des plants (r : 0,58 et r : 0,63 respectivement). Ces crr6latins snt plus frtes pur les g6ntypes tardifs (r : 0,53 d r - 0,69) que pur les gdntypes pr6cces (r<0,41). La maturit6 des plants est md6r6ment mieux crr6l6e ir ces p6rides chez les grappes plus tardives que chez la premibre grappe. Les paramdtres de la crissance fliaire ne mntrent aucune crr6latin significative avec la pr6ccitd ni le rendement. Mts cl6s: Tmate, Lycpersicn esculentum, pr6ccit6 arliness is f prime cncern t prcessing 1982, Lpez-Rivares and Cuarter 1985). and fresh market tmat (Lycpersic,re arliness in tmat is a cmplex character esculentum L. Mill) grwers in Ontari, as under plygenic cntrl with significant addithis is ne f the mst nrtherly, and there- tive, partial r cmplete dminance and freshrtestseasn, areasftmatprduc- epistatic gene effects (Crbeil and Butler tin in Nrth America. Althugh earliness 1965; Kubicki and Michalska 1978; Gibrel et fharvest is an imprtant ecnmic and hr- al. 1982; Lpez-Rivares and Cuarter 1985; ticultural trait in determinate, machine har- l,pez-rivares et al. 1986; Baneqee and Kall vestable tmates, mst published studies n 1989). Significant maternal effects have been earliness in tmat have examined the first reprted fr the perid frm seeding t flwertruss fruit develpment f indeterminate, ing (Cuarter and Cuber 1982; Lpez-Rivares fresh market tmates subject t several and Cuarter 1985). Several genetic and sequential harvests (Crbeil and Butler 1965; envirnmental factrs which influence meta- Michalska and Kubicki re78; Gibrer et ar nhtil:tn:xxflil;:'il#,:i*"i;ffi1: can. J. plant sci.7l: 12n-r218 (cr. reer) ;;;"ifi#;;;il;;t;.;';""*i;;;.";1";; 12tl
12t2 CANADIAN JOURNAL O PLANT SCINC r persnal use nly. vegetative and reprductive traits which are clsely assciated with earliness in tmat wuld facilitate selectin fr earliness in a breeding prgram. As the assciatin between earliness and ther traits may be sensitive t envirnmental factrs. it is useful t examine these assciatins in the prductin area targeted by the breeding prgram. The perid frm seeding r transplanting t fruit maturity can be subdivided int several different subperids depending n the crp f interest. r tmat it is cmmnly separated int the perids: (1) seeding t beginning f flwering; (2) flwering t fruit set; (3) fruit set t beginning f ripening; and, (4) beginning f ripening t end f ripening (Crbeil and Butler 1965; Gibrel et al. 1982; Lpez- Rivares et al. 1986). Of these, the perid frm flwering t first fruit set was fund by Wittwer et al. (1948) t be mst clsely related t earliness under cl Michigan cnditins. Other researchers (Michalska and Kubicki 1978; Lpez-Rivares et al. 1986) identified the perid frm seeding t the beginning f flwering as being the mst determinant f crp earliness. These studies als fund very little variatin fr the perid frm the beginning f ripening t the end f ripening fr the fruit n the lst r 3rd truss. During the perid f flwer develpment, the truss is primarily supplied with phtsynthates frm the tw leaves just belw the truss, but nt by the leafjust abve it; during the fruit develpment, the truss is supplied by the tw subtended leaves and, t a lesser extent, by the leafjust abve it (Shishid and Hri 197'7; H and Hewitt 1986; Shishid et al. 1988). In the sympdial branching pattern f tmat, the leaf, which is situated just abve the inflrescence, develped befre the inflrescence. This leaf can act as a relatively strng cmpeting sink fr phtsynthates during early inflrescence develpment (Shishid et al. 1988) befre cntributing as a net exprter f phtsynthates t the develping fruit. This acrpetal leaf thus has a cmplex relatinship with the develping truss. It is nt clear whether the increased dry matter accumulatin ptential assciated with faster leaf grwth rates (Kaplan and Kller 1977) wuld cmpensate fr the stress f the leaf's cmpetitin with the develping inflrescence fr phtsynthates. Therefre, the relatinship between the develping inflrescence and its acrpetal leaf might differ amng trusses. Mrever, as the rts are prvided with phtsynthates primarily frm the nine basal leaves, which als exprt assimilates t the first inflrescence, they prvide strng cmpetitin fr the first inflrescence, but nt later inflrescences (Russell and Mrris 1983; H and Hewitt 1986). This study was cnducted t determine the relatinship between length f the varius develpmental stages and plant maturity in determinate tmates in Ontari. The study als examined the relatinship between rate f fruit develpment and leaf develpment rate and size. inally, the crrelatins between these variables and fruit yield were determined. MATRIALS AND MTHODS ight inbred determinate tmat gentypes, selected t represent a range fbr earliness, fiuit size, and fruit yield (Sub Arctic arly, Oregn 11, Heinz 2653, Ohi 7814, Ktenai, Heinz 722, Ohi 8245, and Ohi 8243), were selfed fr tvr generatins t insure unifrmity. These lines were grwn in a cmpletely randmized blck design with three replicatins f I 2 plants per plt in 1986 and 1988 at Harrw and Wdslee. Ontari. Seeds were swn the 2nd week f April in a peat medium in 200-plug trays and the plug plants were transplanted t the field in the last week f May each year. Sil misture cnditins and temperature were favrable fr vigrus plant grwth at the time ftransplanting each year at each lcatin. Nrmal weed, insect, and disease cntrl measures were practiced. llwing transplanting t the field, five plants in each plt were flagged t permit repeat measurements t be made n them. r each plant, the number f days frm transplanting t first visible flral bud (I), anthesis f first flwer (AN), first green fruit )5 mm (G), first red fruit (R), and maturity f all fruit n a truss (MAT) were determined fr the first, third and fifth trusses. In these lines mre than 80% ffruit n the plant was red at frfth truss MAT, s plant maturity was attained. When all five flagged plants in a plt reached plant maturity, all ripe fruit was harvested and weighed t determine plt yield. The length (LL) and width (LW) f the terminal leaflet fthe leafjust abve each fthese
POYSA TOMATODVLOPMNT 1213 r persnal use nly. three trusses were measured daily frm when the leallet was abut 10 mm lng until full expansin. rm these data, the length f flwer develpment (LD) was determined as the perid tim I t G; fiuit develpment (RD) was determined as the perid frm G t R; and truss develpment (TD) was determined as the perid fim l t MAT. The reprductive develpment perid (RDP) was determined as the perid frm first truss I t fifth truss MAT. Leaflet length expansin (LL) rates were determined as [(final leaflet length) - (riginal leallet length)l/(duratin f leaflet expansin). The duratin f leaflet expansin was determined by subtracting the first date f measuring leaflet size frm the date when final leaflet size was btained after discarding clearly nnlinear data at the beginning and end f leaflet expansin. Leaf'let width expansin (LW) rates were similarly determined. In the first year leaf area, terminal leaflet area, length and width were measured n l0 fully expanded leaves at the tp f the canpy frm nnflagged plants in each plt t determine if leaf area culd be adequately predicted by a mre readily measured variable. The significance fthe effects fyears, lcatins, gentypes and their interactins was determined by analysis f variance. Cmparisns between gentypes were made using Duncan's multiple range test. Simple crrelatin cefllcients were calculated between plant maturity r plt fruit yield and the reprductive and vegetative traits. These are presented pled acrss gentypes and years. Where imprtant differences between gentypes ccur which are masked by pling, they are presented separately. RSULTS AND DISCUSSION The weather patterns each year were substantially different, resulting in highly significant year effects fr mst variables. Accrdingly the data were analyzed and presented fr each year separately. Within years there was n significant effect f lcatin fr mst traits, s data were pled acrss lcatins. Reprductive Develpment There were significant gentypic differences in earliness and the number f days fr each f the develpmental stages fr each truss measured each year (Table la and 1b). The relative ranking f the gentypes was similar bth years fr mst develpmental stages. arly Sub- Arctic and Oregn 11 were cnsistently the earliest genrypes, while 'Ohi 8243' and 'Ohi 8245' were the latest. There was a range f apprximately 7-9 d frm the earliest t the latest gentypes fr I fr each truss fr each year. This range went up t 10-14 d fr AN and 15-23 d fr MAT. The ranges fr G and R were intermediate between AN and MAT (data nt shwn). The verall reprductive develpment perid (RDP) had nly a 9-d range in 1986 but a 16-d range in 1988. The duratin f the flwer develpment perid tld). frm flwer initiatin t green fruit develpment, ranged frm 17 t 24 d in 1986 depending n genq/pe, but was relatively cnsistent acrss trusses (Table 2a). In 1988 this perid was substantially lnger fr ttre first truss and the range fr it was greater fr all three trusses (Table 2b). The duratin f the fruit Table la. Days frrn transplanting t flwer initiatin (I), anthesis (AN), and fiuit maturity (MAT) fr first, third and fifth trusses and verall reprductive develpment perid (RDP) fr eight tmat gentypes, 1986. ach value is a mean f 15 nlants at each f tw lcatins Truss #1 Truss #3 Truss #5 Gentype I AN MAT I AN MAT AN MAT RDP arly Sub-Arctic Oregn 1l Heinz 2653 Ohi 7814 Ktenai Heinz 122 Ohi 82215 Ohi 8243 7d r4f 8cd 17 ef 9cd l9de lobc 2fbc I2b 22cd l2b 27a l2b 26ab 30a l5a 64e 68d 73t: '7 5b 10d 8la 8la 8la lld 27e ' le l8cd 30d 7ld ll d 3lcd 81.bt l9bc 33bc 830 20b 34b 80c 2lb 34b 86a 20h 34b 88a 24a 31a 88a 20d 33d 78J 71c 22hcd 35cd 82e 14b 2 cd 34d 86cd '77a 24b 37bt 89bc "78a 27a 38h 84de 72bc 24b 31bc 91ctb 79a 21b 3lbr: 9lab l9 27a 40a 93a 79a a-lvalues in a clumn fllwed by thc same letter are nt significantly different at P:0.05, using Duncan's multiple range test.
t2l4 CANADIAN JOURNAL O PLANT SCINC Table 1b. Days fim transplanting t flwer initiatin (I), anthesis (AN), and fruit maturity (MAT) fbr first, third and fifth trusses and verall reprductive develpment perid (RDP) fr eight tmat gentypes, 1988. ach value is a mean f 15 nlants at each f tw lcatins r persnal use nly. Truss #1 Truss #3 Truss #5 Gentype I AN MAT I AN MAT 1 AN MAT RDP arly Sub-Arctic Oregn I I Hcinz 2653 Ohi 7814 Ktenai Heinz 122 Ohi 8245 Ohi 8243 8d l3e 8d l,3e loc 20c 15a 26a 9cd lld I2b 22b 14a l4a 24ab 21ab 10d 2td 69d 18e 88a 23c 88a 25b 80c 23c 84b 25b 87a 2'7a 88a 24b 28e 74c 24f 68d 34cd 90a 31ab 9la 32d 81b 36bc 90a 39a 90a 34cd 90a 21d 36c 22e 30d 28cd 38b 3la 43a 29bc 38b 28cd 39h 30ab 42a 28cd 10b 83d 15d 78e 70e 96ab 86a 99a 84a 88c 90c 98a 84a 94b a-lvalues in a clumn fllwcd by the same letter are nt significantly different at P:0.05, using Duncan's multidle ranse test. Table 2a. Duratin, in days, fflwer develpment (LD), fruit develpment (RD), and truss develpment (TD) fr hrst, third, and fifth truss in eight tmat gentypes, 1986. ach value is a mean f 15 plants at each f tw lcatins Truss #1 Truss #3 Truss #5 Gentypc LD RD TD LD RD TD LD RD TD 30d 580 arlv Sub-Arctrc Oregn I I Heinz 2653 Ohi 7814 Ktenai Hetnz'722 Ohi 8245 Ohi 8243 lle 19de 2lbc 23ab 20t'd 24a 23ab 23ab 30r/ 32d 36c 37 bc 3td 39ab 40a 38ubc 56d 60c 64b 65b 58cd 69a 68a 66b t9d 2lt: 24a lzd( ltc 22b 23ab 22bc 29d i4c 37abc 38ab 35bc 39a 39 3'7 abc 55d 60c 64b 64b 60r: 66b 68a 64b 24a I ldt) z-10 21bc l9c 22ab 21bc l,9bt: 80bc 18cd 80bc 34t: 60ab 38ab 65a 39ab 65a 37bc 57b 67a 42a 4la 6'7 a 40ctb 66a a-cvalues in a clumn fllwed by the same letter are nt significantly different at P:0.05, using Duncan's multidle ranse test. Table 2b. Duratin, in days, f flwer develpment (LD), fruit develpment (RD), and truss develpment (TD) fbr first, third, and fifth truss in eight tmat gentypes, 1988. ach value is a mean f 15 plants at each f tw lcatins Truss #l Truss #3 Truss #5 Gentype LD RD TD LD RD TD LD RD TD arly Sub-Arctic Oregn l1 Heinz 2653 Ohi 7814 Ktenai Heinz 722 Ohi 8245 Ohi 8243 22bc 20c 33a 28ab 26bc 26bc l)d( 21ab 29t' 3lbc 40a 36ab 36ab 36ab 38a 38a 62c 6lc 18 73b 7lb 12b 73b '74b 17c 14d 20br: 26a 1,7 c 23b 20bt' 2tb 30c 29c 38a 35ab 31bc 35ab 31a 37a 53c 50c 67a 65a 57b 65a 63a 66a 20c 13d 28a 25ab 11 cd 19c 21bc 21a 28b 31ab 33ab 35ab 33ab 40a 38ab 32ab a-dvalues in a clumn fllwed by the same letter are nt significantly different at P:0.05, using Duncan's multrple range test. develpment perid (RD), which ranged frm 28 t 42 d, differed amng gentypes, but within gentypes it was similar bth years and fr all three trusses. The duratin f the develpment f the first r all fruit was 56c 56c 68a 68a 59bc 61b 67a 66a cnsistent within gentypes acrss trusses and years, but differed substantially between gentypes. xamined acrss gentypes and years, the duratin f the perids t flwer initiatin,
r persnal use nly. anthesis, red fruit, and truss maturity fr the first and third trusses as well as flwer initiatin and anthesis fr the fifth truss all had similar crrelatins with plant maturity, ranging frm r : 0.55 t r :0.16, depending n truss (Table 3). Similarly, Gibrel et al. (1982) reprted a crrelatin f r : 0.'76 between time t first flwering and time t first ripe fruit. When examined by gentypes, the crrelatin between time t flrst truss anthesis r red fruit and plant maturity was weak (r<0.41) fr the early gentypes Sub Arctic arly, Oregn 11 and H2653 but better (r : 0.53 t r : 0.69) fr the later gentypes, Ohi 8243, Ohi 8245, andh122. This culd reduce the usefulness f these selectin criteria fr develping ultra-early lines. Plant maturity was mderately better crrelated with these perids in the later trusses than in the first truss. Days t red fruit fr the fifth truss was highly crrelated with plant maturity while fifth truss maturity cincided with plant maturity. The duratin f flwer develpment (LD) and fruit develpment (RD), were prly crrelated with plant maturity fr all three trusses. The truss develpment perid (TD) fr the first and third trusses was mderately well crrelated with plant maturity, while fr the fifth truss this perid was highly crrelated with plant maturity. The duratin f the ttal reprductive perid (RDP) was highly crrelated with plant maturity (r : 0.90). Table 3. Crrelatin cefficients between plant maturity and the develpment stages days frm transplanting t flwer initiatin (I), anthesis (AN), red fruit appearance (R), truss maturity (MAT), flwer develpment (LD), fiuit develpment (RD), and truss develpment (TD) fr three trusses pled acrss eight tmat gentypes and 2 yr. N:480. Crrelatin cefficients greater than 0.12 are sisnificantlv different frm 0 at P<0.01 I AN R MAT LD RD TD Truss #l Truss #3 Truss #5 0.55 0.58 0.65 0.68 0.34 0.33 0.52 0.67 0.69 0.68 0.16 0.33 0.27 0.56 POYSA TOMATODVLOPMNT 1215 0.62 0.73 0.90 1.00 0.42 0.30 0.86 These results fail t supprt the findings f Wittwer et al. (1948) that in cl, nrtherly areas, the perid frm flwering t fruit set plays a majr rle in determining crp earliness. Amng these gentypes LD was prly crrelated with crp maturity. These results are cnsistent with thse f Lpez- Rivares and Cuarter (1985), Lpez-Rivares et al. (1986) and Michalska and Kubicki (1978) in that the perid frm transplanting t flwering was a majr determinant f plant maturity, althugh the results als indicate that the ttal reprductive perid, frm first flral initiatin t fifth truss maturity was better crrelated with plant maturity. Althugh RD was relatively cnstant frm truss t truss and frm year t year within gentypes, its lw crrelatin with plant maturity indicates that selecting fr gentypes with reduced fruit r truss develpment perids wuld nt be an efficient means f selecting fr earlier gentypes. Rather. selecting fr a shrter RDP by selecting fr greater cncentratin f set culd cntribute t selecting fr imprved earliness. rm these results we wuld cncur with Kubicki and Michalska (1918) that evaluatin f time t first truss flwering r first red fruit wuld be adequate predictrs f crp earliness. This wuld permit identificatin f early gentypes in a segregating ppulatin in time t use them as parents in a field crssing blck. While the duratin f fifth truss develpment perid and ttal reprductive perid were better crrelated with plant maturity, these traits are mre difficult t evaluate and cincide with plant maturity in time f evaluatin. There is little advantage t be gained by evaluating later develping trusses. Vegetative Develpment The crrelatin between tmat leaf area, terminal leaflet area, terminal leaflet length and terminal leaflet width was investigated fr 10 fully expanded leaves frm nnflagged plants per plt in 1986. Terminal leaflet length was highly crrelated (P<0.01) with terminal leaflet area (r:0.90, n:480); and with ttal leaf area (r:0.76, n:480). Including terminal leaflet width with leaflet lensth
1216 CANADIAN JOURNAL O PLANT SCINC r persnal use nly. imprved the crrelatin with terminal leaflet area mderately (t r:0.94) but did nt imprve the crreiatin with ttal leaf area. Accrdingly, terminal leaflet length (LL) was used as a first apprximatin f ttal leaf area fr the leaf assciated with the trusses f interest. The best fitting equatin fr the regressin f leaf area n terminal leaflet length fr these fully expanded leaves was: Area:0.368LL+40.01. There were significant differences amng the gentypes fr leaflet length and width each year fr each truss (Table 4a and 4b). The later maturing gentypes Heinz 122, Ohi 8245, and Ohi 8243 generally had the largest leaves while the early gentypes arly Sub-Arctic and Oregn 11 had the smallest leaves. The early gentypes als had lwer expansin rates, especially fr the first truss. In bth years, the first truss leaves tended t be smallest while the third and fifth truss leaves were similar in length and width. The leaves were generally larger in 1986 than in 1988, with the average difference between years being greatest fr the first truss and least fr the fifth truss. The leaflet length differences between years were attributable t a slight average increase in the leaflet expansin rate (LL) in 1986, cmpared t 1988, and a lnger duratin f leaflet grwth in 1986. Similarly, bth the duratin f leaf grwth and the leaflet expansin rate tended t be greater fr the third and fifth trusses than fr the first truss bth years. Analyzed by truss, neither the rate r duratin f leaf develpment, nr the final leaf size were usefully crrelated with the rate f flwer, fruit, r truss develpment r crp maturity either year (r ranged frm -0.05 t 0.30, n:240). Palmares et al. (1986) als failed t find any crrelatin between earliness and several vegetative trials, including number f leaves between trusses. Neither leaf size nr rate f leaf develpment wuld be useful adjuncts in selecting fr imprved earliness. Crrelatins with Yield There was little cnsistency between years fr the crrelatins between develpmental stages J 4 -u - a- 3e X : J* ts i 3> ild - >b' } OC J-4 /-l J- il a a? >r> -> -3" >tr.a= a'? - -> B 'r > l--^ >tr> 2c5 J: rrr>^ '-1t> r ; *:" r >tr t3:-\ B B B d6icid;-i-;dd ISt\ icii'i-id c<-+flr,a d+.+*-sns <j- d+$s h rrm@@r x -:* ^ :: ONOr--O -NdN-NN- +6O6:d- -ddd'-ddn \S A -Q-C: 6n@-+ -rrd-ddd i\ai -OOOd*i aid.i6i6idd;-; nnrr N++nnhn :r Nd+ n@@rna -+@ - n- N-:d s-\-\-e.-ir ONN NOOT c;-j--j-;iici \: c tr -=-tst = nn S-- *.i ci.i -icdri + \ a -Q-Q (l 6idn 6h :O-+OQ n+drms +n n c) A*ri + d- =+ -._Nvv,z cnk -SS '::A+A\/+AA = e =
POYSA TOMATODVLOPMNT 1217 r persnal use nly. -l 6 '-.' ^:: U v;: B i'r' a> B5 ^ 5 J-. v-6 ^a B J >e >tr I, ^3 l-;^ >h -. J --i ^@ ii- :=trl>^ -tr> : >tr -*n l<--n-n-d =\t:: i.: nvl1qq-.?q -+N--NNN s \aa-c c:: nsrndd-+ dn<-$++ -* ^ -** n-+ Nnn- ++\O hr r 6 \ - " "\:I *+-N it " - nn *N rnd --d--nd \-:a: t:: Ns dndt-+ r-=r+ooo -s nn rr +\d-+n$r nrri r dn-ntn + r@*sr N+ --Ndd \ { q @$-+O*h $ht$nn $ ^-hs NnO =-a- 6 -d++ s^k -SA >Y^ - 9 ^ ^ ;= 8;:: fri-favt^^ b c = c tl e a c Table 5. Crrelatin cefficients between plt yield and the develpment stages days frm transplanting t flwer initiatin (I), anthesis (AN), red fruit appearance (R), truss maturity (MAT), flwer develpment (LD), fruit develpment (RD), and truss develpment (TD) fr three trusses pled acrss eight tmat gentypes and 2-yr. N:96. Crrelatin cefflcients greater than 0.26 are significantly different frm 0 at P<0.01 I AN R MAT LD RD TD Truss #1 Truss #3 Truss #5 0.36 0.49 0.41 0.38 0.07 0.36 0.76 0.23 0.41 0.53 0.49 0.29 0.31 0.48 0.13 0.28 0.45 0.49 0.12 0.36 0.46 and final plt yield. r each truss, hwever, days t red fruit and days t maturity were fa.irly well crrelated with final crp yield, with r values ranging frm 0.38 t 0.53, depending n truss (Table 5). The duratin f truss develpment fr the third and fifth trusses were als crrelated with final plt yields (r:0.48 and 0.46, respectively). The ttal reprductive perid (RDP) was nt well crrelated with final yield (r:0.32). N leaf trait was well crrelated with plt yield (r<0.32). Similarly, Palmares et al. (1986) fund n meaningful crrelatin between fruit yield and number f leaves between trusses. Nne f the leaf traits evaluated wuld be useful selectin criteria fr selecting fr imprved earliness r yield. The present results recnfirm the widely reprted psitive crrelatin between maturity and yield (Khalf-Allah and Pierce 1963; Gibrel et al. 1982). Selectin fr imprved earliness by selecting fr earlier anthesis r fruit set culd result in indirect selectin fr reduced yields. These findings with eight widely diverse determinate gentypes, rncluding five cultivars cmmercially grwn in Ontari, supprt previus findings that time t flwering is a majr determinant f earliness in tmat. Mrever, they highlight the need t select fr reduced reprductive perid thrugh imprved cncentratin f fruit set in imprving crp earliness. These selectin
1218 CANADIAN JOURNAL O PLANT SCINC r persnal use nly. strategies might be mre effective in imprving maturity in the mid- t full-seasn gentypes than in the early-seasn material. Abad. M. and Mnteir. A. A. 1989. The use f auxins fr the prductin f greenhuse tmates in mild-winter cnditins: a review. Sci. Hrtic. 38: 16'7-192. Banerjee, M. K. and Kall. 1989. The inheritance f earliness and fruit weight in crsses between cultivated tmates and tw wild species f Lycpersicrz. Plant Breed. 102: 148 152. Crbeil, R. R. and Butler, L. 1965. A genetic analysis f time t maturity in a crss between species f the genus L1'-cpersicn. Can. J. Genet. Cytl. T: 341-348. Cuarter, J. and Cuber, J. I. 1982. Genetics f earliness in tmat. Genet. Agra. 36: 119-128. Gibrel, G., Be, A. A., Simpsn, W. R. and versn, D. O. 1982. valuatin f ' hybrid tmat cultivars fr earliness, fruit size, and yield using diallel analysis. J. Am. Sc. Hrtic. Sci. 107: l+-1-l+. H, L. C. and Hewitt, J. D. 1986. ruit develpment. Pages 201-239 in J. G. Athertn and J. Rudich, eds. The tmat crp: a scientific basis fr imprvement. Chapman and Hall Ltd., Lndn. U.K. Kaplan, S. and Kller, H. 1977. Leaf area and COr-exchange rate as determinants f the rate f vegetative grwth in sybean plant. Crp Sci. 17: 35-38. Khalf-Allah, M. and Pierce, L. 1963. A cmparisn f selectin methds fr imprving earliness, fruit size, and yield in the tmat. Prc. Am. Sc. Hrtic. Sci. 82: 414 419. Kubicki, B. and Michalska, A. M. 1978. Transgressin f the duratin f develpmental perids in hybrids f early frms f tmat, Lvcpersicn esculentum Mill. Genet. Pl. 19: 165-182. Lpez-Rivares, P. and Cuarter, J' 1985' Use f flwer beginning and end t study tmat earliness. Indian J. Genet. 45:92-96. Lpez, Rivares, P., Cuarter, J. and Cuber, J. J. 1986. Genetics f the earliness in flwering, fruit setting and fruit maturity in tmat. Genet. Agrar.40: 221-230. Michalska, A. M. and Kubicki, B. 1978. Crrelatins between earliness and ther characters in tmat (lycp ersicn e s culentum Mill.). Genet. Pl. 19: 309-320. Palmares, G., Balasch, S.r Nuez'. and Cuarter, J. 1986. Vegetative characters ln tmat. Acta Agrnm. Hung. 35:20'7-218. Russell, C. and Mrris, D. 1983. Pattern f assimilate distributin and surce-sink relatinship in the yung reprductive tmat plants (L1'cpersicn esculenturr Mill.). Ann. Bt. 52 357 363. Shishid, Y. and Hri, y. 1977. Studies n translcatin and distributin f phtsynthetic assimilates in tmat plants. II. Distributin pattern as affected by phylltaxis. Thku J. Agric. Res. 28: 82-95. Shishid, Y., Seyama, N. and Hri' Y. 1988. Studies n distributin patterns f 14C-assimilates in relatin t vascular pattern derived frm phylltaxis f tmat plants. J. Jpn. Sc. Hrtic. Sci. 57: 418-425. Wittwer, S., Stallwrth, H. and Hwell, M. 1948. The value fa "hrmne'' spray fr vercming delayed fruit set and increasing yields f utdr tmates. Prc. Am. Sc. Hrtic. Sci. 51: 37 1-380.