Inhibition of α-Amylase Acting in Hexaploid Triticale Lines by Exogenous Abscisic Acid

Hexaploid triticale introgressive lines developed after recombination of A-genome with Am-genome of diploid wheat (Triticum monococcum) were analysed in respect of grains responsiveness to exogenous ABA treatment. This was assessed by in vivo bioassay as grain germination indices, and by α-amylase assay as quantity of synthesised α-amylase measured with the technique of radial diffusion in agarose gel. The results showed an important diminishing of seedling length caused by ABA (variable in different lines) as well as genotype dependant variability of α-amylase synthesis inhibition. The differences of ABA responsiveness were seen both in whole grains and in embryoless half-grains as a direct reaction of the aleurone layer. Variation of grain sensitivity to ABA treatment compared with two sprouting resistance indices showed a significant correlation with Falling Number values in grains, but not with a dormant grains germination in spikes. This is an evidence that in triticale precocious starch decompose in unripened and ungerminated grains is dependent on genotype ABA-responsiveness of the aleurone layer.