Rick, C. M.
Albifolium, af (2-367, v\5), was discovered as an unfruitfull plant in a field of the variety XL. Progeny of this plant segregated for a new virescent trait, which has subsequently bred true. It appears likely that the partial male sterility of the original plant led to outcrossing, thus accounting for the mixed progeny. This mutant shows greatest resemblance to wv, but differs in important details. It emerges with white cotyledons, which slowly turn to a slightly greenish color basally. True leaves emerge darker and thereafter develop a nearly normal color, except for flecks of paler green that persist in the lower leaves but do not appear in mature leaves. Though terribly slow and weak at the start, af gains momentum and, by the time it flowers, growth in satisfactory, though subnormal. Crosses and selfs have been made without difficulty. It is weaker than wv and lacks the fine whits speckling of the latter. Segregations usually show a deficiency of af as the following summary indicates: 174+:34af; 80+:19af; 233+:12af; 439+:55af; 121+:16af. In some combinations the proportion drops even lower, and still others have never yielded af segregants. It is not certain what might account for this variable segregation, but differential germination and survival of af seedlings could be involved. For reasons of its extreme weakness and variable segregation, af is not an ideal mutant. It might have temporary usefullness for its linkage with the following mutant.
Wiry-4, w\4 (2-237) was encountered in a field of var. Pearson by Mr. M. P. Zobel. It corresponds in most respects with previously described wiry mutants, being distinguished from normal at all stages including the cotyledons, which are variously notched, narrowed, and curved. Leaves become progressively more modified until the uppermost consist of nothing but naked midveins. Flowers are greatly distorted, the gynoecium being most affected by proliferation and separation of carpels. All fruits set by selfing and crossing have proved parthenocarpic. In sporadic fashion its stamens yield pollen, which has factioned successfully in many crosses. Inheritance is normal in many families, the overall segregation being 4,428+:1,628w. Allele tests with other wiry mutants have not been made, and the possibility that it might be allelic must not be overlooked.
The following data from three repulsion F2 families reveal linkage between af and w\4.
Combination + + +w\4 af + af w\4 Chi-square
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af - w\4 59 21 19 0 4.86
183 50 12 0 2.04
414 153 109 4 27.86
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The combined data from these families give a crossover value of 19.5 units.
Another "floating" linkage group is therefore added to the tomato picture.