Gene Effects on Water Soluble Polysaccharides and Starch of Near‐Isogenic Lines of Sweet Corn1

Abstract

Effects of 10 gene combinations in near‐isogenic backgrounds on endosperm water soluble polysaccharides (WSP) and starch in corn (Zea mays L.) are reported. The genes, dull (du), sugary‐2 (su2), and waxy (wx) and one double combination (du wx) were incorporated into seven lines of corn in association with the sugary alleles (Su and su) Additionally, for each line the shrunken‐2 (sh2) gene was incorporated with Su, and the su sh2 genotype (standard sweet corn) included for comparison. For the near‐isogenic lines or series studied here, genotypes su du, su su2, and su du wx had high levels of WSP, low levels of starch, and slow rates of starch increase as compared with standard sweet corn. There were marked differences among the near‐isogenic series within genotypes. For the su genotypes, range was greater among series than among genotypes for WSP, but greater among genotypes for starch. For su genotypes, all except su du had a wide range among series for WSP, while su wx and su Sh2 had the widest range among series for starch. Modifying genes of the seven series had greater differential effects on WSP and starch later as compared to early in kernel development. In view of the range of expression in a limited number of lines for the genes studied here, they should be incorporated into a broad range of germplasm in a search for other modifers which may further enhance their potential for improved sweet corn quality as compared to standard sweet corn.