The alpha-amylase enzyme activity in the whole meals of six wheat genotypes that were grown in different altitude areas, over different planting dates in Zimbabwe in winter 1996, was measured to ascertain the genotypic differences and the effect of different cultural conditions on the expression of this phenomenon. The enzyme activity was tested using the conventional Perten Hagberg Falling Number method. High genotypic differences in the expression of alpha-amylase activity were observed. The cultivar Deka, which is a Veery x Musala cross, gave the lowest Falling Numbers. Scarlet, a red grained new release out of a CIMMYT cross, gave the highest and most stable Falling Numbers. The cultivar Scan and three other cultivars that are all Sengwa onto Veery type crosses, gave intermediate Falling Number values that lie within the ideal range of 250 seconds. A general decrease in Falling Numbers with increase in altitude was noted. Steeper decline in Falling Numbers occurred at altitudes above 1,200 m a.s.1., particularly in less stable genotypes like Deka. Earlier planting by about two weeks before the recommended time of early to mid-May, in Zimbabwe, decrease Falling Numbers by about 40 seconds. About 20 seconds in Falling Numbers were gained by allowing wheat to store for about a month after reaping. Low Falling number problems have been encountered in Zimbabwe due to the use of Veery types that are inherently unstable in the expression of alpha-amylase enzyme activity; and also due to pre-harvest sprouting caused by early rains. New varieties that are more stable with some showing high tolerance to sprouting in the field, have been released. The agronomic and baking features of these will be presented.

English

0007|AGRIS 0101|AL-Wheat Program

Jose Juan Caballero

CIMMYT Publications Collection