Abstract
The life history of a hybrid corn, Tomorokoshi Ko No. 7,can be divided into eight reasonable periods in relation to some important transitional stages in the physiological and morphological development of the plant. These periods are as follows ; (I) Pre-emergence. (II) Early vegetative growth from emergence to knee high in a plant height. (III) Mid vegetative growth from knee high to differentiation of the spikelet of tassel. (IV) The begining of rapid vegetative growth and tassel development. (V) The rapid vegetative growth and ear development. (VI) Grain formation from fertilization to milky stage. (VII) Rapid starch accumulation in grains. (VIII) Maturation and drying of grains.
