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The breeding behavior of the F, classes in the F, generation by. percentages in comparison with the calculated was as shown in Table 10.

TABLE 10.-Comparison of the breeding behavior of the two classes with that calculated

A fairly close fit to the expected 1:2:1 ratio was obtained for the F, families involved. There resulted, however, an excess of class 3 plants in the F, generation.

On the basis of the F, distribution, assuming that 22.9 per cent of the Bozeman F, families would have proved homozygous for class 3 if tested, it appears that 4.51 per cent should be added to the 18.34 per cent, as originally classified. Correcting the Bozeman F, data on the F, results, the figures obtained agree closely with the original Moccasin data. (Table 11.)

TABLE 11.-Comparison of the corrected Bozeman and original Moccasin data

These deviations are less than three times their probable errors and show a fit which is not significantly different from the one factor or 3:1 ratio. It seems reasonably certain, therefore, that there is a primary factor for the degree of awn development of Marquis (class 3) which is recessive to a factor determining less awn development. On the hypothesis that a second factor is responsible for the differences between the awnless and apically awnletted classes, it will be necessary to find 6.25 per cent of recessives of F, strains at the other extreme breeding true.

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TABLE 12.-Percentage totals of F2 results obtained by combining classes 2 and 3 in comparison with class i

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The F2 plants as classified fell into groups with percentage values as shown in Table 12.

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In the F, generation the Bozeman material bred into percentage distributions in comparison with the calculated as shown in Table 13.

TABLE 13.-Comparison of the breeding behavior of the two classes with that calculated

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A close fit was obtained for the percentage distribution of F, plants. There was, however, an excess of F, families breeding true for the combined 2 and 3 classes and a deficiency in the second group breeding in a 1:3 ratio. Correcting the Bozeman F, data on the F, results, the figures shown in Table 14 are obtained for the total F2.

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TABLE 14.-Comparison of the corrected Bozeman and original Moccasin data

The deviations are less than three times their probable errors and show a fit which is not significantly different from a 2-factor or 1:15 ratio.

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The classification of F, material resulted in a shortage of plants in class 3, while there was an excess of plants of this class in F. It is apparent that environment affects the awnedness of plants differently in different seasons and that the results of classification did not exactly coincide in either year with the genetic constitution of the hybrid plants. In general, however, the results indicate the presence of two pairs of factors.

TABLE 15.-Correction of the Bozeman F2 awnedness data for the three classes on the basis of the F3 results

The expected ratio for the three awnedness classes on the above hypothesis is 1:11: 4. It will be recalled that the distribution of the original Moccasin F2 data was close to this ratio, but that of the Bozeman data was nearer a 1:12:3 ratio. Correcting the Bozeman F, data for the three classes on the Bozeman F, results, the figures shown in Table 15 are obtained.

A close fit to the expected ratio for the corrected Bozeman data is thus obtained.

A genetic interpretation of these results can best be made by assuming that a primary factor pair (A, a) is responsible for the distinction between the awnlessness or short awn development of classes 1 and 2 (dominant) as opposed to the longer awn development of class 3 (recessive). Complete dominance is not indicated, as it is postulated that it requires the homozygous "dominant" (AA) combined with the recessive bb of a secondary pair of factors to give complete elimination of awns (class 1).

The formula for Hard Federation (1) would be AAbb, Marquis (3) aaBB, and the F, AaBb. In the F, generation the following formulas may represent the breeding behavior of the three classes in F:

The awnletted allelomorph in the primary pair (Aa) of factors is represented as recessive in accord with its primary effect. On the other hand, it is the awnlessness factor of the second pair (Bb) that is represented as recessive in accordance with the one effect ascribed to it in this cross.

Of 145 F, families of class 2, one-eleventh, or 13 families, would be expected to breed true. It is shown in Table 8 that 17 families were of that sort. The segregation of the remaining class 2 groups can be determined accurately only by correcting F, data on the basis of F, results, which has not yet been done.

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From the F, data, however, which prove classes 1 and 3 are true breeding and that the expected portion of class 2 also breeds true, it appears probable that the 1:11: 4 ratio is the essential explanation of inheritance of awnedness in the three awnedness classes in this cross. The corrected numbers corresponding to this 1:11:4 ratio from the Bozeman data of 1,050 F, plants are 63, 729, and 258

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plants, respectively. The expected numbers are 66, 722, and 262. The deviations are 3, 7, 4, and the value of P, 0.896 indicates a very close fit.

GLUME COLOR

Glume colors of wheat are most commonly classed as white and brown. Biffen (2) was first to report brown glume color dominant over white in the single 3:1 ratio. No other ratio is known to have been found in crosses between varieties of common wheats. The present study includes data on the segregation of F, plants for color of glumes at Bozeman and Moccasin in 1923. The results obtained are shown in Table 16.

TABLE 16.-Segregation in the Fa generation into brown and white glume classes of 1,050 plants of Marquis-Hard Federation wheats and reciprocal crosses grown at Bozeman and Moccasin, Mont., in 1923

There is no evidence of maternal influence in the reciprocal crosses, although there are small consistent differences in the percentages at the two points. The percentages of brown-glumed plants are slightly greater when Hard Federation is used as the female parent and the percentages of white-glumed plants slightly greater with Marquis as the female parent. In all cases, however, the differences are not sufficiently large to be significant.

The deviations in numbers from the simple 3:1 ratio are not significantly different in any family or in the several totals. In general, the F2 data show a remarkably close fit. The study was continued on the F, generation at Bozeman, and the data obtained are given in Table 17.

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TABLE 17.-Breeding behavior in the F3 generation of white and brown glume classes and 12,197 plants of Marquis-Hard Federation wheat crosses grown at Bozeman, Mont., in 1924

These data show that the white-glumed plants all bred true and that the brown-glumed plants either bred true or segregated in a 3:1 ratio in proportions which approximate the ratio of 2:1.

KERNEL COLOR

The inheritance of red kernel color was first reported by Biffen (2) to be dominant over white in F, and to segregate in a 3:1 ratio in F. Nilsson-Ehle (13) first reported crosses which in F2 gave 15:1 and 63:1 ratios of red-kerneled to white-kerneled plants, proving the presence of two and three genetic factors. Similar ratios have been found since by other workers.

In the present study red proved dominant as usual in the F, generation. The data on segregation of F2 plants from 12 F, families including reciprocal crosses are given in Table 18. .

The data in Table 18 show little or no difference between reciprocal crosses. Of the 12 families 10 show a close fit to a 2-factor or 15:1 ratio and the remaining two families, 2A1 and 2A3, to a 1-factor or 3:1 ratio. The deviation in numbers, for each family and for the totals, are all less than three times their probable errors. The fact that two different ratios were obtained indicates that either Marquis does not have homozygous dominant factors for kernel color or shows that the Hard Federation male-parent plants differed in their genotype. Family 2A2 which segregated in a 15:1 ratio was produced from an F, kernel produced on the same spike

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