2. Fine mottling of rrR seeds. In 1937 an ear of Connecticut 720 y Su A C r when pollinated by C697 (a C R) gave seeds that were all mottled. There were 94 regular or coarse mottled kernels, 86 with very fine mottling, color often limited to a few patches of from one to a few cells each, and 6 colorless. (These probably were fine mottling where no color was visible, or were contaminations. They are being tested).
In 1938 seeds of the two classes were planted in separate rows and selfed or again crossed by 697 A-tester. Two ears of the fine mottled stock selfed produced only whites, solid, and fine mottling. One ear crossed by 697 gave 180 white, 92 solid color, and 82 fine mottled kernels. Three ears from the coarse mottled stock when crossed by 697 gave 534 white, 250 solid color, 132 coarse mottling and 94 fine mottled kernels. This is not a great deviation from a 4 : 2 : 1 : 1 ratio expected if the fine mottled factor shows independent inheritance with Mt.
Does anyone have any convincing evidence that Mt is not an allele of the R r gene? Kempton's (GENETICS 4: 261-274) data can be interpreted on an allelic basis as well as assuming 12.5% C O. He secured 29.4% mottled seeds when selfed, whereas 33 1/3% of the colored seeds should have been mottled. He incorrectly states he expected 25% whereas 33 1/3% was the correct proportion of the colored kernels. Selfed ears are rather unsatisfactory for determination of this point. We plan to test this by backcrossing if it has not been done.