Leaching of Metabolites during Imbibition of Sweet Corn Seed of Different Endosperm Genotypes1
- E. V. Wann2
Sweet corn (Zea mays L.) hybrids with high-sugar genotypes shrunken-2 (sh2) and the triple recessive combination of genes amylose extender (ae), dull (du), and waxy (wx) have had limited acceptance for commercial production due to an inherent problem of low seed quality. The seed are lighter in weight and more shrunken than normal, or the sugary (su) genotype, and they frequently give erratic stands and low seedling vigor. This study was conducted to determine leaching of metabolites during imbibition of the high-sugar seed and whether excessive leaching was associated with genotypes and their inherent low seed quality. Commercial seed of hybrids ‘Iochief’ (su), ‘Florida Staysweet’ (sh2), and ‘Pennfresh ADX’ (ae du wx) were chosen to represent three sweet corn genotypes in this study. Leaching of metabolites during imbibition was determined by measuring electrical conductivity of the leachates and the amount of soluble protein in the leachate at various time intervals after imbibition. Conductivity of leachates was higher for seed of the high-sugar genotypes than for su. At 24- and 48-h imbibition, leachate conductivity for ae du wx seed was higher than the other two genotypes. Leaching of soluble protein during imbibition was also higher for seed of the high-sugar genotypes than from seed of su. There were no significant differences in the amounts of soluble protein initially present in seed of the various genotypes when expressed as milligrams per gram of seed. When expressed as milligrams per seed, however, the high-sugar genotypes had much less soluble protein than su due to their low seed weight. Protein leaching during imbibition appeared to be related to broken pericarps and high membrane permeability in the seed of sh2 and ae du wx endosperm genotypes. These studies suggest that seed pericarps and membranes in the high-sugar genotypes may be more susceptible to damage during harvest and drying than su and that special care may be required for producing high quality seed of the high-sugar genotypes.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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