Puant Coors In MAIzE 73 
difference between these two percentages of crossing-over, 9.6 + 3.9, is 
considerable, it is probably not statistically significant, P equaling 0.09. 
Still further evidence in favor of the assumption that weak purple is 
differentiated from dilute purple by the factor pair BY b, just as weak 
sun red is differentiated from dilute sun red, is afforded by data from six 
of the progenies recorded in group 2 of table 34. These data, it will be 
recalled, were obtained from F;’s of weak purple x dilute sun red back- 
crossed to dilute sun red. The F, weak purples were heterozygous for 
liguleless leaf as well as for plant color, A A BY b Pl pl Lg lg, and the dilute 
sun reds with which they were backcrossed were liguleless, A b plly. The 
1724 plants were distributed as follows: 
Weak Weak Dilute Dilute 
Color types: purple sun red purple sun red Total 
Ib IIb Illa IVa 
iNormailtleaves. 0. ..4 6%... . 296 315 119 164 894 
Liguleless leaves........... 108 125 280) tol’, 830 
Evidently the linkage relations of liguleless with weak purple and dilute 
purple are similar to those already known for liguleless with weak sun red 
and dilute sun red (page 67). Of the 921 weak sun reds, A BY pl, and 
dilute sun reds, A 6 pl, 632 belong to the non-crossover and 289 to the 
crossover class, a percentage of crossing-over of 31.4 + 1.0. Similarly, 
of the 803 weak purples and dilute purples, the non-crossovers are to 
the crossovers as 576:227, a percentage of crossing-over of 28.3 + 1.1. 
The difference between these two percentages of crossing-over, 3.1 + 1.5, 
is such as might occur by chance once in six trials, P equaling 0.16. 
By way of summary, it may be noted that, from appropriate intercrosses 
of the several color types and from determinations of the linkage relations 
of these types with liguleless leaf and with yellow endosperm, weak purple 
and weak sun red have been shown to have the genotypes A BY” Pl and 
A B” pl, respectively. This establishes the existence of the triple alle- 
lomorphs, B, B”, b. There is some evidence in favor of the occurrence 
of a fourth member of this series, b’. 
ch 
CROSSES INVOLVING THE MULTIPLE ALLELOMORPHS R’, R’, R”, 1", 7%, 7° 
In an earlier section of this account (page 29) dealing with crosses involv- 
ing only Aa, Bb, and Pl pl, three types of green plants were reported, 
