7 E fe « { Geae yp fags wt daylal i cant ut dd Be 4 fe “tae Aa et af 51 test crosses of plants 6452-3, 653-3, and 6153-9 devibeated very much from 1 : 1 amd with plant 64.53-9, marked differences in ratio of these ov . two phenotypes were exvressed on ears produced from diffe-ent parts of this plant. Nevertheless, it was clear that some chromosomal comronent, MeL present in the a, “> carrying plants and not linked to this locus, was keikng segregated at meiosis and that the expression of PM unirorniy pale class of kernels and BP rpass showing deeply pigmented spots in a colorless backgrourdd was relsted to the presence or the absence of this component, - may, WL abo Since in the grandparent (5719A-1), in the two a, “,parent plants, and in 2 4 x e cabubut od aa all plants of cultures 64.52 and 6,53, variegation was expressed, it seemed 3 evident that the presence of this ccmponent in the chromosome complement -- Wwuedy ahotls wi ce typ days d- Cotelsrbodh cood =~ 9 sok rowel m was related bo, variegation and its absence the apocerance of the pale A . phenotype, As stated earlier, none of the kernels on the XRREXEKWEE Cars ° plants grown in the summ r of M-= derived from test crosses with the ay 1951 had been examined carefully up to this time, When it was vealiced that the ratio of kernel types appearing on the ears of vlants entered in jmdiecotod wer cebelup Ty covhnttucy table 3 xuxrexenkedt segregation of an indenendently located element in the A 7 ‘ . . i Kl Js fr chromosonme..complement—associated wish— r, the kernels on ears produced by test crosses of slants in the pa ent culture, 60L@g\, 6047 , 5e nue Qar. were then examined, More direct evidence of the prcsence of thts element A { 9 nul Be “Ty awe to was obteined, fer (it was found to be 1l'nked in some plants "ts Bpconsbtc a eee f N odo wt, marker, y, in chromosome 6 (Y¥, yellow shdrch in endosperm; y, recessive A . , oo — bOHT., allele, white starch in endosrcrm), ..The plants in tet culture, were * derived from kornels on am ear produced by the cross of plant homozygous q for aj, Sho and y ‘plant S719A-1, which was a m-1 sy fa, sh, Y/yy oneemed 1, She rE 1 2/4 sh, tac of te e 2) wer yellow OD) bebe. ys00- SomeVkernels inthe (variegated) Freese on this ear wexe sown in the Meee summer of 1951 under A of culture 601.7. Others that were v riegated dwy Aird ululi otenth (Q) soalton A 6B oe! Aa: Leek ay | wleOh teed Maia £3 ed Wesee sown under B and C of culture 60,7. In-addition, Variegated kernels er t Lee Mo . thet were ¥ were selected from the esr produced by selk+pollination of plant (A, table 2) 5719A-1/and ssown under B and C of culture 6046. All plants in evltures 6016 and 6047 received some type of ted by means of crosses to ~lants of I vader ef bottiyys ¢W plowolip known constitutiong ex by self-pollination, or beth, The k.rnel t*pes on homozygous for ears obtained by crosses of these plants to plants that we-e/ay y sh, and y en¢tered in column 1 are given in table }, All plants/in'this table were a_m-L Sho/ay Shoe Those in Part I were Y¥/y whereas those in Part II were y/Ve In Part I of table lh, a ratio of 1 pAhe to 1 variegated kernel | among those showing nigment eae one, amont—the-Resnots on errs produced from crosses conducted with plants 60l,6B-1 and 60 7A-3, 53 Linkage of the pale phenotype with Y and the variegated phenotype with y is clearly expressed by the test with plant 60).6B-1. In plant 60l,7A-3, these link: ge relations were reversed; the pale phenotvye was linked with y and the variegated phenot-pe with ¥. The ratio of kernel tynes obtained from tests of the other plants in Part I of table l, indicated that each controlling carried more than one of—tiebeindependent/element, inthe a, system, wn Lak od In plants 60)6B-3 and 60l.6C-2, Limkars—ef one of the¥a Srhcenemiae wa th ¥ eutdent but in plant 60),7A-1, no evidence of such tinkage & & gen rc ~~ The/olants in Part II of table were all y/y in constitution and var tip aorher vu Hone thus no linkage relationships/could be shown by then, Nevertheless, the evidence suggested the presence of more than one indenendently located controlling element in all plants except 60).7Ce3,. |The plants in culture onthe an 64.52 (table 3) originated from the y class of variegated kernels produced A by the cross of plant 60,7A-3 enééred in table . According to th nfe Onlin A Kiara p helmed a re % ow lus Lor, » this plant had only f'fndependent controlling element and it was located in the ¥ carrying chromosome, Theplants in onthe Lan culture 61153 originated from the wuriegated class of kernels produced trom A the test cross of plant 60l7C-l, table lL. The ratio of kernel tyves ary on -i+e—testorress ear suggested the presence in this vlant of two . { 4 Fetish PUA O of the -indenendemt controlling elements, each ab g different location in A ce god BPRS rT ih Ad fy ye fhe mye got WHA RE EL wr Wo UR Wicd the chromosome complement, Selection of+the-y-etess-—ef variegated kernels yak wae A, was made in order that the color of the anthocyanin pigment in the aleurone layer in kernels on ears of>lants derived from them would be ex ressed on a white rather than a deep-yellow background. As stated earlier, the only + purpose of tha$test had been to determine crossing over between a, and Sh. From the ratio of kernel types given in table lh, and from those obtained from self-pollination and from the test cross of plant 5719A-1,(4 and C of table 2, it would apvear that plant 5719A-1 had more than one td enercerb 1a otpie tL, leeetel controlling element , amdt—thet One of them, occuppied a position in A its y bearing chromosome 6, Gn awatww ade, . athe plants in cluture bu Sat table 3) arose from variegated kernels on veda, Loe Brag ul autilw¢ DeLee U- Tue, a “Phe whose Lerret-types— Saad, the ear of plant 60,7A-3_ “OH ~in-tabie-l, These MA gee ot 52 oud, plants would be expected to have only one im “A * Anu ere element, Tois apnezred to be true for all plants except plant 3, The t 4 ~ plants in culture 6453, table 3, arose from variegated kernels on the ear m od Wo toud wth Liou Eo es = SSI OILS produced by plant 604,7C~3, 5 “a Theplants in culture 614.53 would Yaeefore be expected to have either one or Qualle, ws uae DR 7 Ws Ag two of the—independentiy leeeted controlling element. As table 3 indi oS y Bxofxknex9x seven of the nine plants in this culture had one such element 55 ows) vio yi” we bet the remaining Z, plant 3 and plant 9, h:d more than one, such—elernent A A amd the ratio of kernel types on ears produced by different parts of plant 9 o| Ub suggested that the number of this element was not the same in all part , ef . tod melange thespian. It was suspected from this that rie anaes oe Wg a rma. elte rong element could undergo transposition in somatic cells and that this was A worn Gu bt - responsible for the observed i S ° 3. Initial evidence suggesting the prim-ry mode of operation of the independently located controlling clement in the azul system gs the SUppPeang7 ~wutaldr . , m1 : : . The mode of control of ay acbion induced by the independently located element of the system, whose discovery was outlined above, was not appreciated until the results of tests made in the summr of 1953 were Lay. eile analysed, From then, a reasonable interpretation covld be drawn ofits wit option mode—of—operation, With tris, in mind, all test cross ears that had been fothe jul Wwe 3 é. 3 peoduced in the summer of 1951 were then carefully examined. The x “ s mR ~~ evidence obtained from them ty with this interpretation, Wures pocra ther, 1% old pep ey had Bi clihy crt dmboys tab ou i - —ef prictse test | oftirts that short boa > and these were conductsd in the summer of 1954. Before these tests are 2% AID OD the mode of Ae: dau kom One Ade Hn Med ON RS yng a iy BP, tat of operation of the independently located contolling element will be outlined , A considered, the evidence 1 briefiy. 56 Due to unforseen conditions,the total planting during the summer of 1953 had to be restricted. Space was available for only a fraction of the number of plants usually grown in the summer season. For this reason, Te] AQ . : : study of ay was limited, prevVerence being given to other projects then under investigation, The—reason-tie+ Enes decision Wes—made ese! to limit study of amt was dictated by the fact that up to this time, procticetel many of the testcvross ears mandumke ebteined-f ducrtert=tn the \ \ summer of 1951 had not yet been exmmined and bhatle was peatise known of the rhe] Cavgeul behavior of ay ° It was decided, then, to 34 its study to an qiuyer. oul examination of the positiong of the independently located element in the A system in the progeny obtained from plant 60l.7C-2 o#(Cable lh), and to of ke nels the paamts derived from the pale class/in the progeny of plant 60)6C-l . this latter plant had been derived from a variegated kernel on the self R\ of plant 60) f0-4 pollinated ear of plant 5719A-1 (table 2). Dhe constitution/was A . - m= a,™ 1 Sho/a, bh, Y/y, pr/pr/. the ear from which the pale kernels were otis lank . Ow Urs PA ee ued selected had been produced by self-pollinationg{ea&# Tte-gave-rtse to 1106 Cunroy | hows’ hue usew uniformly 3-8 So 35/pale colored kernels of which kernels 33 were Y and 2 were y and to 371 kernels that had deeply-pigmented spots in a colorless background and 267 of these weve Y and 10l, were y. Twenty hat Woe Y CULL hg Karr mR APMED pale kernels were selectsd from this ear and paants grown from them under A A me. A ‘ A pleut drtud taro pace Dicrup | | A should carry a derivitate of ay e It was desired to examine the behawter ncnateae boda un Lod bourne 2 - Up abs tl ah culture number 6628, the decision to select Pate kernels Breem=hice—car . A was because the plant was homozygous for ay and thus eeeh chromosomes 3 } m=] ef-esrh—of these derivative, inxxthaxmrmgenyxiaxixvadxtranxkexkxexnssxat Therefore the plants derived from the pale kernels were tested for this ad, gy nul Ue Eo td at , Tay ap + a, al iv) by crosses with plants homogygous for @7 9, 845 and ee de vale Bla N ’ AP = ng Zar Wod the pale PaoweBiy, Plant 60),7C0=2, teble}, had the constitution at Sho4a, Sho, pr/pr, re An ear of this plant a planbh and Y/y. #k/had been crossed by mme/that was homozygous for Bas sho, y and hadePpmin one chromosome 5 and pr in its homologue. “he types of kernels appearing on the resulting ear, given in table lh, suggested that tarwd airy lant 60l,7C-2 h-d one of-the independently located element j p 7 p y ted e j ofthe a, the Uy 0 system in gmexeixkks Y bearing chromcsone and, in addition, two others locateé A elesewhere in the chromosome complement, Ten kernels in the variegated, Y, Pr class and ten other in the variegat-d, yyPr class were selected and be2F Nearly sown in the simmer of 1953 under culture number s 66294 and B, /&l1l the A ears produced by the plants derived “rom these kernels were used in crosses Lauplor.eeh with plants that were hoxzozygous for ay» sh, and y. Two stocks were weed. for this but their constitution with resnect to the Pr alleles was not then known. Tests conducted with them indicated that one stdock was Pr/Pr and 7 of the tester stocks the other pr/pr. the need for knowning the const’ tuticr/wit:. respect to Wd Pr ulin, _ rh aN pgae” ' will be evident shortly, &@ few ears of plants in culture 6629 were A either self-pollinated or sib crossed. The phenot»pes of kernels on the ears of plants in culture 6629A, produced by the test cross, ere entered in table 5, Again, it will be between the kernels carrying We noted taret these is very close linkage gf the Sixyxmkenakxmexwkkhxmkgment markexxthyxand Sh., marker and those exhibiting pigments Keormereh— tans , fhe position of the ear on tar plant is. vindioated. It @1il behoted that on A cult eof od the esrs of plants A-2, A-5, and A-8, and on the first car of the main apt stalk ofplant A-7, therewas a ratio of tna kernel to ip variegated kerneh re Ped antnocysnin vigment 4emong the gmkwx bearing classes, and that the pale phenotyre was linked with ¥ whereas the variegated phenotyre was linked with y. To facilitate ready appreciation of toais, the p:enotypes of the pigment bearing classes of kernels sdacre ‘The wabhelof.kernel types &ntered_3 on these ears are entered in table 6. / @n the remaining ears a€Ttable 5, a more re dy aporeciation of ratios and for EQRXRRLSREEXOLXLLLMRLAALINE this, kHxxE exhibited other es ., mkaxxes in the Y and y class yom these ratios that more . % % vy -eared in the aleurone O49 urdu Col layer of the kernel, xexmnkk thet weaning when A, is present, the intensity of anthocyanin pigment in “yey rLavush 74 COWpaudY In contrast :/those that were homozygous for pr was much ess then—ther - A WHrd Det wht Qup plato olip 1ewtls, distinguishing woickh—+s—preduesd with Ay. These @evld be no confusion in iitenkitying ou Kiran QUA pornup tHe pale, pr, eiess from tre A, spr etess, With this in mind, attention o Gv DAL witt—-se-given-to the note entered at the base of mebir table 5 and table 8, , O- Here is given the number of kernels tht expressed the full A, phenotype Dak owes, - aikxmfxwatkhx in the pr class. Those of this tyne in the Pr class could not hy. @ hot lf cinbauail, sas . Wuol (AM i . : : . cue, be distinguished Rrbmxkhepe—readity and therefore they are included in the pale classes in these tables, The fresuency of appearance of kernels with an A. phenotype is so low that inelusionf of a few of them in the pale 62 Hout? Yep po didtetymno dew fuga Who dut eto ae classes does not inva Lidate naan Significance ef the-given—setios in Whe tabres, (4n this regard, it may be mentioned here that in subsequent study ~ m= . of a," 1 it was often necessary to use another state of ay 1 that pives Apes rise to k rnels exhibiting a,pale phenotype in both the purple (Pr) and red (pr) classes) that ke-rondsiy cisti-erisied from tie purpte—and—ne d \ classes produced by Ay, ) : A In examining the kernels on the ears derived from cross of plants 6629B-2 and 6629B-6, which were y/y, by plant 6629A-l,, which was Y/¥y some pcg ee Une ound w oddllien te thy Aen D.— Riches pia that had severed areas exhibiting tl pale phenotype. A the pigment in In the Pr class,/these arenas wase quits intense. In the pr class, in contrast, the pigment intensity in theym aneas was how, Tghfact, with exhbitied respect to “pigment inkeanuikiax, the pale areas/mexm similar «mxknoxex intensities ef-pigwemt as those expressed by the pale kernels in the Pr and on ears pr classes of=kbesmets/entered in tables 5 and 8, In plant 6629A-l1, one A wpb independently located controlling element was present and carried in its b Ovo Cowse fuduse << y-bearing chromcsome, By means of crossing over, some of the * carrying A gametes produced by this nlant shoutd have this element, and ij the crosses with plants in B629B, some kernels on the resulting ear should p ’ g thos bowel Adwuidle yuseut Wat he+e—ontiene- 3 xv I corraee in the Y bearing chromosome, 63 Among the Y class of variegated kernels on this che several kermmmrs were \itaed & apilyur ov aade found that exhibited white sterch immediately benigh 9 pale area, and the A On those Caavs correspondence in their borders was exact, A The ‘e seemed little doubt that a Gna ipsa pate cutgaa are whi ear servant seg was associated with loss of the segment a ~bearing 6 of the ¥,chromosome/that removed both Y and the independently located sup eoustel bf Coteebuctid thee controlling element, In other words, the pale areas appearing tn the >>, ee \ + aia - . n, variegated kernels distxmmk orbse guamimmbationrinkrke’ tral (or inactivatio SP) ppireomsd) AM Mud iI. inal OB rune g Yre clbywiT colle m 2ipruntenr ») tp Be ter) of the independently located controlling element ¢ Conhouddd por Coudintine Deru pron elie 4 DLE TEL On Gok tive Lave. No attempt was made to cross plants of culture 6629 to those of culture 6628,wh¢ich were homozygous for a derivative of a and for pr, and y, “Similar types of cross had been made in the summer of 1951 even though the ears derived from them had not been examined, However, on one car of a plant of culture 6628, which had been used in a cross with a plant homozygous for ay > sho, y, and pr, a single variegated kernel was present. ap Muu tye Urn 24 Pitroel It was a comtamittant in that Mea Pr and Y instead of pr andy. & \y Wwe Obviously Was deowived from functioning of a stray pobin grain produced ~~ WLUW © 6.4 by a plant in culture 66294, These plants were growing in the next row 4 and were immediately adjacent to those in culture 6628, Since this Ry iy Aust 2d 21 obanh: pas kernel showed spots of deep pigment ina colorless, background a8—werlae- a lap —Lewpsete-ereses, it seemed evident that the independently located element A Oh, in the at system had a duel function. In its absence, am functioned in the production of anthocyanin pigment, although in a manner onthe oth, aval not totaiby comparable to Ay. In the presence of this element, all “A evidence of this feemrtten was suppressed, In its absence, the—made Lehaued ano- atabte abbilee Rr , offunctioning—of ay m= wes—constans, no change in-tuts-ecceurreg, In Lopoal,} Aeburt its presence, on the other hand, return to “fee A_-tyoe of femettesal oe - ~ 1 wen mutated Awa Dy bay PV UdG Da bdo-cel wy pro ley-y expmestien erese in some cellg, and the time during development then this chang: in mode of action occurred #re-cett, and the number of cells in wud The melts Q duno? wardur mip tee Cpl cur coud wllrog 4000 Get wy ata 4) which this took place was geneticelly controlled.” Acrefvl examination of ears produced during the summer of 1951 was then immediately undertaken) snot sncighet amen a mechanism associated with control of gene action at a.™1 had been gained to allow meaningful interpretations to be drawn Ve. trowel ons, Wols Wao We Wan fod wt been Fue - from them, which—had not been-true-up-te-bhis--time, fhese examinations substantiated the interpretation of the mode of opsration of the indevendentl, element and therefore this element was given the designation A Suppressor-mutator and symbolized as Spm. Before considering the evidence obtained from these examinations, a resume will be given of the results so far obtained, the interpretations drawn from them, and the problems they posed, 65 Studies outlined in this and the previous section were conducted with the progeny of oneplant, that of plant 5719A-1,. In this plant, + the expression of ts By lesswe, carried in one of its chromosomes 3, mo 1 section ' Ty be febcu? sa plot 5098 As stated in pzrk 3 of this report, ewes considered te-h=ve,an altered “ 4 was very different from that given by the parent plant having a state of ay “hy In plants having this state and also Spm, small streaks with ak deep-anthocyanin pigmentation appear in a non-pigmented background although occasionally, a large area exhibiting this vhenotvpe may appear. In the kernel, small zpmkexh@éingxieepxpiznentakionx deeply pigmented spots anrear in a non-pigmented beckground (photo, ) altnough, here also, ancasionally, a large area of this type apvesrs, The degetaiced “JOML pnenot peg wWwerxe exhibited b the kernel that gave rise to plant 5719A-1, by phe plant itself and-tt-eaise anveared in the majority of variegated \ . i Lent 714 B-? plants and kernels in the progeny of JA that. were carried through three As reel bCOa generations, tlowever, on some test cross cars produced by some of the progeny plants, a few kernels anneared that exhibited a marked deviation from this pattern, In them, the number of deeply-pigmented spots was very much reduced or none apnecred, No explanation for this had yot been found. Also, on a few ears produced by the test cross, a ke»nel exhibitin;the full A,-tyve pigmentation appeared, The nature of the J The) responsible for their anvearance had not yet been determined , Lonel t wes Apr pred ad Ue Coup aanon LU Mntaled aa ey at Sida Ri igi LE Glo Heh ust Qed) “to bull; i io 2 pderigru In the absence of Spm, the STLOA- 1 state of a gave rise to change ata é 1 plants that were uniformly pigmented but the intensity of this, and its Win wt We A drut oy Nao} tou Ri, distribution within the plant differed £ =e TT A pHeseat.“ The kernels were likewise pigmented Gn the absence of Spm 2 and this rigment was uniformly distributed over the aleurone layer of the kernel, It was intense when Pr was-present but tiem Jicht when the PrOcluead vy thy ahlene of Spun VW) k ment * WwePe homo 2 ‘sous for pre The phenots a anosared to be cauite To SA ueeuy wey Court aut wm eareerive eit alg 4 stable oe Span, WR OnQut, 5 a cht ey | ~ ws these-plants were either-seif-pellin-ted—er- lerossed by plants—in-—the tester stocks thst—were NOMOZTLOUS- LOMA, « From the ratio of pale to voriegated kernels on the ears ~roduced the by/test cross of »lant 5719A-1 (C, table 2), and from the ratio cf these (tables zt 8) kernel types on ears produced by test crosses of its progeny, it was concluded that plant 5719A-1 had at least three Spm elements in it and that one of them was located in its y bearings chrouosome,. However, the number of this element in the progeny derived from a test cross did not alwavs conform with that expected, and the test of vlant 6l,52-3, table 3, illustrates this. It was expected to have one Spm element but the ratio of 57 pale to variegated ke-nels deviated markedly from the expected one to one, AAP Noe. wth A foud par ry 0h aruges poauy, -- Also, simile» types of test conducted A stuitieb vec one an bod onetimes BZanexxrkxexkex praduced of these two classes Alu wk thy “dp ratiof/on—the nu sulting sans that did not Agree, With one amother, same plant or with. pollen This suggested that the Spm constitution in different parts of an alway Ws Dawe, individual plant weme not alike. It was sustected that these differences “A arose from somatically occurring transposition of Spm but no tests of this had yet been conducted, td pee it \ NS na IPO € 2 ofealion t SI fun. As emphasized above, tee interpretations of the Spamepee seston “A were drawn from evidence oba ined only from this one isolate of am, WOrtur Calin, Se venus celion pallirur ar Mrerlsek Others that produced quite different phenotees had been isolated, It A \ was therefore necessary 'to determine to what degree the behavior of each of them would conform with the interpretaticn that had evolved from study of oiusen Soup Drop Th poly butones a rests had been conducted with then during the summer of 1951 and when the ears produced by these tests were examined, it was r:alized Corumel, for 2) tmnelDoo 4 ove q oon kd Now, inn wiererdy tp Peep un smd that the interp: kal caer ak wuld apply th them, HP Mit Were, comstdened that each isolate of a origim lly selected because of the modified 0. Rov variegation ps oe re had exhibited, arose from some alteration that hed occurred to the original ay" and that each such alteration was r: sponsible for the tyne of variegation pattern exhibited in the presence of Spm and 68 also for the type of expression given in its absence, Some of the evidence for this may now be reviewed, Oudobt rod Lotetees oupportung Wy wut puody 9 te PU lg. Subpientséticn of —swe—node of ection of pm amimmi—bheo sdb duals a - el. During the surmer of 1951, plants were grown from selected kernels C537]) carrying plant, to those on ears produced by crosses of the original amt thet were homozygous for aj. Fifty-two -lants were derived from kernels , eel Wwe +ipl exhibiti-g the mttern of variegation paodused by this original state of -yoce ok 1 a 1 (photo, Ve seven were derived from kernels whose aleurone layer 1 * i ipuot Dra aT dy was uniformly pigmented ,but the intensity of this was iow, In addition, sw cath, aloug Be modified patte rng of Soe plants were grown from two kernels , Au variegation, One had very many small deepiy—picmented spots rn a colorless. background, The other apa apd r pate pig taton waa Cus olion WO. Colorton lavge;—decerty—pigmented axeas, In addition, kernels were selected from enuductcad ye am Cans: etree ears produced by crosses of some of the plants grown in the greenhouse A wd during the winter of 1950-51, Selections were made from, earg produced 63 the pReit Loug acmi . eut either by self-pollination or by a cross witn a plant homozygous for By, A 4 Qabrarda whe pe WAL OO REE cep and sduotaty % plants 5700A, 5718, 5719A-1, S719A-2, and 5720. Tre—vatio A 4 7 she Shp. vats Le ooh Pann Cue Doth to be rotm w by Adenleen ef | 195] of kernel _types—on cars produced. by -ptants- 5710,-57194~-1,--end-5SZ1L9GA-2 DAL OL olid Willow. Ta 4 Mp pLeuat Aniuenetdeen Tee wed Thou be are entered in table 2, Corn elo - 69 Plant S700A, derived from a very pale colored kernel, developed 3 Palin ww. intense anthocvanin pigment in stalk, leaf-she th, and glume gp.» 1 as used in a cross with a ylant homozygous for By sad On the resulting ear, half of the kernels were very pale colored and half we ve colorless, It hed - this plemt eeeeiod a derivative of a4 mi ginat hac been received from the A . f Lh nad 2. +s m= . aa . ; : + . original ay plant, in one of :$6a chrovuosomeg 3 and ay in the otner, Plants were grown from some of the pale k:rnels on this ear, From the self-pollinated ear of plant 5718, some of the veriegated p yan Dre palo 4 to wo mull Ai np wa Uolmlers boebcocull ( ul —) kernels were selectcd and plants grown from them, Plant 5720, described A : . 2 tas m1 . a 84 in section 3 , had a modified state of a in one Gt-bée chromoscoref 3 Yhuo Votes LL pale AL Tae paleg and ay in the other, Phe-modift+sd state prodv ised. both large and small areas in rlant and kernel that exhibited only low levels of nigment ond (Vutd -) cove one Wp abe poilonaTee don. aud ono intensity in them, 4N-riegated re ears produced by ON wou pent Dprner cert fH 1 Crosses ae were sown in this summer of 1951, tush On the self-pollinated ear of plant 5719A-1 and | of plant 5719A-2, (A, table 2), ha) v bod me 7 hus am on ears produced by, cross of trese lant to pprents homo ygous Tor ay AN UEC Al tel " (C, table 1), some kernels a cared that had areas of verious sizes “ bt TYP a Oy Tap Mars prawil, Amul lan lo thot apy ka wus, UWA thy f 4G atid Atul exhibiting “eoute wontons in a addition to the deeplr-pigmented spots Ur copay Cv — — + —) Vere ¢ which apncatred in all variegated kernels, The number of such kernels “A a fh 4 rps Alte? Wao Wels among the variegated class was low, The majority of them exhibited onlyty . 70 y it (Ulett - tie ofan : ( oh ba: AN Unbwrst DAL “eur hen {ws awd tue oti we decply- pigmented spots) bat were neerly alweyvs small in size. Theretere, Musa vob “2 ahs 09 narie carted Derm nels ct Ltisn elpul Oy olf yothru ulea du) M4 thy il Ae dual plants were grown from each Dey wKerrel . anol takin Yao by T:ble 9 is_cornstructed toshowl Hw ty es of kernels that were Couduefodd wh’ 5700R, S117, SARA, 27a Selected from ears produced by crosses efV plants pos AHA SIO, and the culture number given to the plants derived from each selection. A ulrp Discussion will commence with tests conducted with plants derived UAL 4 f otleve from selected kernels on the ear produced by theczoss of mlant 5719A~2 A onde euths 5 Om Corao pdawt be-ene that was homozygous for ay. Plant S719A-2 was aay in ( C, Veto) constitution, On the eor this cross produced, thers were 2l, uniformly A Aj tyne pale colored kernels, 250 kernels exhibiting dots of deep/color in a colorless beekground, and 259 totally colorless kernels. Among the variegated class of kernels, some showed, in addition tc the deenly- pigmented dots, arcas of light pigmentation, all of weich had the same dn wivk woud abgve ene of the grade of intensity. In a few kernels, kaese lightly pigmented sreas wae “A lavge, covering as much as an eighth of the area of the alu rone laver, abe pale There was, however, much variation in size of areas within a single kernel, Some of the kernels exhibiting these areas were selected anc. the plants grown from them given culture number 60814, The frecuency of apnesrance of different classes of kernels on the oy Wouita wm ville oxi oul atehasstnl ot tae self-pollinated ears, on ears produced by, crosses with plants homoryvgous A A - 71 2B, Gude 2 are given in table 10 ,(f for ass “ nh 7 THIEAD —nipht— The ratio of ksrnel types appcaring onvears produced by test crosses path A sino QUA wt OGrae ured vhost Jurem-teese appearing on ears vroduced by CAPO similar types of test conducted with the parent plant, 5719A-2 (A, B, C, nA rrumaliire ey table 2), There was a marked reduction in Prequenci-of app Maule, h variegated Cheseeef kernels and an equivalent incresse in tebs of the Colored Aovviudr. wa te Rowdy thet wee yungeel |. ee ead pale chess, In-the-pale class, Pigment intensity was greater when Fr A owever, the Pr-carrying kernels in the pale class could be distinguished readily from those that exhibited the full or near full Ay tyoe pigmentation, This is with Wo ost in contrast to the pale, Pr class apneargin produced bx state [736453 m1 or wzet fom pleut s719R-) ay wiere difficulties were encountered in making this distinction, as “A described in the previous section, . _ = ~ cae. On Faom hos ltt, por ented! Ont Onthe basis—ef the ratiog, sien in table 10, the smsmeeted constitutior wu ite port g ao ve doomed be Uhet ufuch opuutlo Ty these plant? wkth=ressect= | {Last 5 74h ) x af ¥ : ; r A NN § r ‘ ra 7 dpe aber tagt MOAN OF ep es oth UDP eta pag Be MU cepen: wy! bob. °\ leat Olfarud qe VOAY wh woah UOT fae p dee i 78 Oy Yous Uline qubbe 6O4OC : Ry that exhibited some pale areas in addition to te small spots, with—A. - tope—nignent—in—therr, Three plants weme derived from kernels of this Sd Th) 3 pOpuily m: 046 B, (tortor) two type Tests of, them indicated that in # of these three plants one Spm wey Waited park tho ow vate Gated pesto of U7 was present ,and in the third, two Spm elements wore present, asthe Wi Cau} tai, : _ an. we e A tho Uirce Dit plauity we bouec Mak 2 Span Leuaeetly Crane rs) data—in—tableth—tedieate, Again, it was noted that the variegated kernels * “Owed on ears entered in C of this table were characterized b:« the appearance of pale a in addition to the A, spots, whereas these pake areas were rarely exhibited among the variegated class of kern’els in B of this table, Variegated kernels derived from the self-pollinated ear of plant 5718 (A, table 2) were sown under culture number 6015, Although 16 kernels were sown, only vlants derived from them survived to maturity. Two of them were self-pollinated and crossed to plants homozygous for ays The tyne of kernels on the resulting ears are shown in A and B of table 15. The pattern of variegation produced by[tee 5718 state! of a is very Sharply expressed, There are small dots of the Aj, phenotype in a colorless background, as shown in photo 00. In the absence of Spm, this state gives rise to kernels that are only very faintly pigmented. | Difficulty Was encountered in detecting this pigment in some kernels on tne ears entered in - ek table 15 ,thet—sheuld be-eanpying this—steteof—a,———bub—neo_Som, Unless this pigment was undoubtedly present, the kernel was placed in the colorless