Correlated inheritance in a cross between Dicklow X Sevier wheat

In the cross of Dicklow X Sevier wheats the characters studied were measured or counted. Spike density was studied by careful measurement of 10 rachis internodes on a leading spike from each plant. The coefficient of variability was obtained for each progeny and parent row and used as the basis of classifying the breeding behavior of the F2 plants. A 1:2:1 ratio was suggested, and when compared to a goodness of fit X2 = .8131 and P = .6852. Both parental types were recovered in the homozygous progenies. In the F3 Progenies 143 were homozygous for bronze, 205 heterozygous, and 112 progenies homozygous for white glumes. A one-factor difference was again suggested, and the goodness of fit compared to a 1:2:1 ratio is represented by X2 = 9.964 and P = .0071, which is a poor fit. The peculiar light bronze cast on some progenies and some weather stain caused difficulty in this classification. Dicklow is characterized by short awn tips, which were classified as awns 2, while the Sevier parent, fully-awned, is designated as having awns 4. The F3 progenies showed clear-cut segregation into three groups, viz., 111 progenies were homozygous for awns 2, 234 progenies heterozygous, and 115 homozygous for awns 4. A one-factor difference explains the results in this cross and when compared to a 1:2:1 ratio, P = .9803. Both parents were essentially alike for the number of culms, and the 459 Fa progenies studied showed about the same range and mean. The Dicklow parent showed a mean thickness of neck Of 2.6 mm, Sevier a mean of 2.4 mm, and the F3 progenies a mean of 2.65 mm. No segregation could thus be observed. The height of plant was studied with the dwarfs included and again with only the tall plants. When the dwarfs were included, unusually high variability occurred compared with the parental rows and with the study of only the tall plants of the progenies. Segregation of the homozygous dwarfs is clearly set apart in Table 9 as are also the homozygous tall plants. Correlation studies were made for all possible combinations of characters on which data were obtained. The only important positive correlation found was for spike density and awn length. This was merely suggestive, viz., r = .2322, when the entire population was considered; but when the 112 homozygous Progenies for awns 4 were studied, a correlation of + .7121 +/- .03141 was found.