2. Endosperm characteristics with Su₁ Su₂ and Du

For the past several seasons we have attempted to isolate and recognize the tvelve true breeding genotypes involving the three loci Su su^am su, Su₂ su₂, and Du du. It is believed that all twelve stocks have now been isolated although final tests have not been ccmpleted. It appears to us at present that three testers will distinguish between the stocks. The following reactions are expected:

Genotype to be identified	Selfed appearance	su2	Appearance on Female Tester Stock
			su^am du	su du
Su Su2 Du	Dent	Dent	Dent Translucent	Dent
Su Su2 du	Dent	Dent	Slightly wrinkled	Dent
Su Su2 Du	Dull surface	Dull surface	Dent	Dent
Su su2 du	Translucent Slightly wrinkled	Dull surface	Translucent Slightly wrinkled	Dent
su^am Su2 Du	Dent	Dent	Dent	Semi opaque Slightly wrinkled
su^am Su2 du	Translucent Wrinkled	Dent	Translucent Wrinkled	Translucent Wrinkled
su^am su2 Du	Translucent Wrinkled	Dull surface	Dent	Translucent Slightly wrinkled
su^am su2 du	Translucent Wrinkled	Dull surface	Translucent Wrinkled	Translucent Wrinkled
su Su2 Du	Strongly wrinkled	Dent	Dent	Strongly wrinkled
su Su2 du	Strongly wrinkled	Dent	Translucent Wrinkled	Strongly wrinkled
su su2 Du	Strongly wrinkled	Dull surface	Dent to Slightly wrinkled	Strongly wrinkled
su su2 du	Strongly wrinkled	Slightly wrinkled	Translucent wrinkled	Strongly wrinkled

During the past season, the 64 possible endosperm genotypes involving Su su, Su₂ su₂ and Du du were produced and are in the process of being analyzed for amylose content, water soluble polysaccharides, and starch content. A program of combining the wx and wx^a alleles with certain of the tvelve genotypes has been undertaken with the hope of elucidating more fully, the sequence of gene action in determining amylose content in the endosperm.

Herbert H. Kramer

Gerald Dunn

Roy L. Whistler