CHANGES IN PHYTIC ACID, PHYTASE ACTIVITY AND INORGANIC PHOSPHORUS DURING MATURATION OF TRITICALE VARIETIES RESISTANT AND SUSCEPTIBLE TO PREHARVEST SPROUTING

Changes in phytase activity, phytic acid and inorganic phosphorus levels were examined in the grain of five triticale varieties during maturation. Only low phytase activity was found until the 16th dap (day after pollination), and then a rapid rise in activity was observed with the maximum at the 30-37th day, followed by a continuous decline until full maturity. The variety Malno, most susceptible to pre-harvest sprouting, showed higher phytase activity through maturation compared with other varieties. It seems that selection against susceptibility to pre-harvest sprouting should take this positive relationship into account. Phytic acid was detected as early as on the 9th dap. It was accumulated rapidly from about the 23th day onwards and its level increased until the end of vegetation period. On the other hand, the P-i level was the highest after 9 dap and then decreased along with the grain development and phytic acid accumulation. In mature grain the P-i level was 8-13-fold lower that on the 9th dap. The rapid rise in phytate content and decrease in phytase activity through the later period of triticale grain development may be involved in control of P-i concentration. The phytic acid and P-i level in the grain of triticales assayed during maturation, showed no direct relation to the pre-harvest sprouting resistance.