Identification of Maize Inbreds with High Levels of Maltose in Endosperm of Germinating Seeds

Abstract

Maltose appears in germinating seeds due to enzymatic hydrolysis of starch, but is absent or scant during development, except for endosperm of the sugary-1 (su-1) maize inbred IL677a and some related inbreds (Carey et al., 1984; Shaw and Dickinson, 1984). Mature dry seeds of these inbreds still contain some maltose (2% to 4%). IL677a is also the source of sugary enhancer (se), which increases endosperm sucrose (Ferguson et al., 1978). We attempted to learn whether the unknown biochemical change causing maltose accumulation in developing endosperm also operates during germination. Entries included the starchy (Su) inbred B73, IL451b and ‘Seneca Scout’ (both su-1), and the su1se inbreds IL677a and IL731a, which accumulate maltose during development (Shaw and Dickinson, 1984). Endosperms were dissected from seeds germinated in the dark under sterile conditions at 30C and moistened with 0.1 mM CaCl2, with 10 to 15 endosperms per sample, except for five to eight at 6 days due to limited seed supplies. Dissected tissue was kept on ice until ethanol extraction, and maltose was determined by gas chromatography (Shaw and Dickinson, 1984). Results of analyses sometimes varied; thus, data are presented as means over duplicates. Maltose was consistently higher in IL677a than in the other inbreds (Fig. 1) and increased rapidly early in germination when the others had none or only trace amounts, reaching the highest level (27 mg/endosperm) on the 4th day. An analysis of variance indicated the difference between IL677a and the other inbreds was highly significant