Mutations at specific loci Stadler's method. L.J. Stadler studied frequencies of spontaneous mutations in maize for endosperm characters. The following steps were involved.
(i) A genetic stock dominant for several genes was grown as female parent and detasseled. Multipte recessive stock was sown on every 5th row to supply pollen.
(ii) Seed set on female plants was examined for endosperm characters e.g. shrunken. Most of the seeds showed dominant phenotype; the number of seeds showing recessive character represented mutations in female gametes.
Stadler also induced mutations artificially. For this purpose, he used irradiated pollen from dominant stock for pollinating recessive stock. Progeny showing recessive phenotype were classified as mutants, even though, atleast in some cases, these were later found to be due to deficiencies.