Rick, C. M.
The original plant of ds was encountered as a sterile plant, suspected to be male-sterile, in a field of Earlypak. Its dwarfness was also noted, but adjacent plants in the field were also stunted by obviously adverse growing conditions. In the field ds plants are very much stunted, reaching only a small fraction of the size of normal plants. Internodes are reduced in length and leaves are very much smaller than normal, exposing flower clusters, making them more conspicous than normal. The reduction in growth is less marked in the greenhouse. Anthers are paler than normal and contain little or no pollen. A few fruits are usually set spontaneously and they may contain seeds developed from self-fertilization. Pollen of sufficient viability is usually produced to permit artificial selfing or crossing. It has not been possible to distinguish ds in the seedling stage.
The line has bred true for dwarf sterile phenotype in several cultures derived from self-pollination. The F1 ds x normal has normal phenotype, and the total F2 segregation observed to date is 286*: 49ds -- a significant deficiency of recessives. A single BC farmily has been grown, yielding 6+:llds. The following repulsion data reveal a significant dissociation, hence linkage, with a. This mutant has been transmitted to Dr. Burdick for his analysis of group V.
Contingency
Tester + + + t ds + + t chi square co.
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a 160 82 48 1 20.4 14.0 +- 3.9
c 190 52 36 13 0.34
d 185 56 34 14 0.48
l\1 179 63 36 12 0.001