(Department of Agronony)

Evidence has been obtained that su_x is effective in reacting with su to increase amylose content as well as increasing the percentage of total sugars as Horowitz reported in last year's News Letter. The triple recessive su du su_x should be of interest now to see whether amylose content is further increased. In addition it would be of interest to determine whether the combination du su_x will increase amylose without causing extreme wrinkling. We expect to study wx in combination with these factors. Isogenic lines are being established in a dent inbred to get a more precise measure of gene effects on sugars, water-soluble polysaccharides and starch formation of these various combinations as well as any new ones which seem to affect amylose content.

Table 1. Per cent of amylose in endosperm starch of eight lines
of corn and reciprocal crosses between them

	Homozygous	Recessives	Per cent amylose
Series	P1	P2	P1 selfed	P1 x P2	P2 x P1	P2 selfed
1	su wx	wx	0.0	0.0	0.0	0.0
2	wx	-	0.0	20.0	22.2	22.3
3	su wx	-	0.0	17.3	24.0	22.3
4	wx	su	0.0	20.9	24.9	26.6
5	su wx	su	0.0	21.3	24.6	26.6
6	-	su	22.3	24.3	24.1	26.6
7	-	su^amdu	22.3	25.8	27.1	44.2
8	su	su^amdu	26.6	25.4	27.5	44.2
9	-	su du	22.3	26.1	25.7	50.9
10	su	su du	26.6	28.2	30.4	50.9
11	su^amdu	su du	44.2	49.3	49.2	50.9
12	-	sux	22.3	24.2	26.9	35.9
13	su	sux	26.6	25.3	26.7	35.9
14	-	susux	22.3	23 9	26.4	49.5
15	su	susux	26.6	25.8	36.9	49.5
16	sux	susux	35.9	34.8	43.4	49.5

In our studies su₂ seemed to give about the same amylose values as did su_x and crosses between su_x and su₂ stocks were about the same. Some data involving selfs and crosses between dent, waxy, amylaceous sugary, Cameron's supersugary, sugary‑x, Horowitz' supersugary, sugary, and sugarywaxy are summarized in table 1.

Herbert H. Kramer and

Roy L. Whistler