Late Maturity Α-amylase Research Articles

Expression of late maturity α-amylase in wheat containing gibberellic acid insensitivity genes

Two wheat cultivars, Spica and Lerma 52, which consistently produce high levels of α-amylase during the later stages of grain development (late maturity α-amylase), were crossed with a set of four near-isogenic lines carrying the tall (rht) allele or one of the dwarfing genes Rht1, Rht2 or Rht3 (GA-insensitive alleles). The F1 and F2 populations were developed and analysed for grain α-amylase and plant height. The Rht3 gene exhibited the strongest influence on plant height and strongly inhibited new α-amylase synthesis during the later part of grain ripening. By comparison, Rht1 and Rht2 had a less pronounced effect but still significantly reduced the expression of late maturity α-amylase. These observations suggest that gibberellic acid is involved either directly or indirectly in this phenomenon. The implications of the effect of dwarfing genes on expression of late maturity α-amylase are discussed in relation to cultivar improvement and to the identification and control of high α-amylase germplasm.

Inheritance of late maturity α-amylase in wheat

Two wheat cultivars that consistently show high levels of grain α-amylase at harvest ripeness, in the absence of preharvest sprouting, were crossed with a control, low α-amylase cultivar, and F1, F2 and BC1 populations were developed. Grain of these populations was analysed for α-amylase activity at harvest ripeness. Distribution and segregation patterns were consistent with control at a single locus with high α-amylase the recessive allele. This mode of inheritance would make it extremely difficult to differentiate homozygous low α-amylase lines from heterozygotes (low α-amylase phenotype but carriers of high α-amylase) and has important implications for wheat breeders. High α-amylase, termed late maturity α-amylase, was not linked with the awned inhibitor gene, B2, located on the long arm of chromsome 6B.