Gene Effects on Kernel Moisture and Sugars of Near‐Isogenic Lines of Sweet Corn¹

Abstract

Numerous genes affect carbohydrate composition of the endosperm of corn (Zea mays L.). The objective of this study was to measure the effect of 10 gene combinations on level, rate of change, and interrelationships of kernel moisture and sugars during the first 4 weeks after pollination as influenced by the modifier complexes of seven adapted sweet corn inbreds. Four genes influencing endosperm carbohydrates, dull (du), sugary‐2 (su2), waxy (wx), and shrunken‐2 (sh2), and one double combination (du wx), each in association with the sugary‐1 alleles (Su1 and su1), were incorporated into adapted sweet corn inbreds to give seven near‐isogenic series. Determinations were made of moisture, reducing sugars, sucrose, and total sugars at four successive harvests. The sh2 gene, and to a lesser extent the du wx combination, show promise for improved kernel moisture and total sugars and for reduced rates of loss of these components as compared to sweet corn presently in use (su1) for processing. In view of the marked differences in the expression of these genes in the inbreds studied here it is desirable to incorporate them into a broad range of germplasm in a search for modifiers that will further improve and utilize their potential in hybrid combinations.

Endosperm Carbohydrate Composition and Kernel Characteristics of shrunken2‐intermediate (sh2‐i/sh2‐i Su1/Su1) and shrunken2‐intermediate–sugary1‐reference (sh2‐i/sh2‐i su1‐r/su1‐r) in Sweet Corn

“…For some kernel carbohydrates, such as WPS levels, the endosperm genotype has the dominant role in determining the amount of the individual carbohydrates, but for other carbohydrates, the genetic background can play nearly as great a role as endosperm genotype. The effect of genetic background on carbohydrate composition of endosperm mutants had been seen in other studies (Soberalske and Andrew, 1978; Wong et al, 1994). Besides the effects of endosperm genotype and genetic background, the environment has significant effects on the content of the carbohydrate components.…”

Shrunken2 Sweet Corn Yield and the Chemical Components of Quality

“…For example, of two hybrids with comparable sugar concentrations at 20 DAP, the average sugar loss per day was only 2.8% for 'Northern Extrasweet', but was 5.7% for 'Illini Gold'. Soberalske and Andrew (1978) have emphasized the importance of considering both the amount of sugar and its rate of change in varietal selection and breeding programs, since both factors influence sweet corn quality.…”

Variation in sweet corn kernel characteristics associated with stand establishment and eating quality

“…These rapid changes in the chemical composition of the kernel are of great interest for the sweet corn industry since the fresh quality of .the ears will therefore change rapidly during kernel maturation . Both the absolute amount and the rate of change with ear maturity for these characteristics should be considered in breeding programs designed to improve sweet corn eating quality (Soberalske & Andrew, 1978) .…”