Southeast Asianwaxymaize (Zea mays L.), a resource for amylopectin starch quality types?

Abstract Amylose-free (waxy) maize has been a vegetable (cooked ears) and staple food in Southeast Asia for centuries, resulting in hundreds of landraces (LRs) across the region. The recessivewaxyallele induces soft grains with preferred cooking and flavour properties. We hypothesized that eating preferences resulted in the additional selection for different starch properties, reflected in altered starch granule morphology or amylopectin structure. A total of 41 LRs were available as starting material that had been used by different ethnic groups in Vietnam and Thailand. Unluckily, some LR were not purewaxy, but we successfully regained the original purewaxystatus for most. Twenty LR were chosen for analysis of starch traits according to their purity. Four differentwaxymutations were identified, including two unknown alleles. This is a strong proof for parallel independent selection ofwaxymaize in the region. Starch granule morphology and size were similar among all LRs. Gelatinization properties differed only betweenwaxyand wild-type LR, and allwaxyLR were comparable to a commercialwaxyhybrid. The fine structure ofwaxyamylopectin had fewer short chains compared with that in wild-type. So far, the differences observed in starch properties are likely associated exclusively with thewaxytrait. Despite the strong selection for amylose-free starch, there was no evidence for additional region wide selection for other special starch properties in our collection. In conclusion, all analyses did not encourage further targeted research on allelic variation of other starch metabolism genes for future use in the food and feed industry.