Visual Quantification of Wheat Development 1

Changes in the morphology of winter and spring wheat ( Triticum aestivum L. em. Thell.) were quantified in a manner to provide a continuous numerical expression of plant development during the formative growth period. The notation system makes use of the regular appearance of leaves at the growing point. Each new leaf represents a unit of development. After the flag leaf has emerged the remaining visible morphological development is divided into four additional units. The growth units are subdivided into decimal fractions beginning with the appearance of each leaf or subsequent unit and ending with the appearance of the next. The daily status or stage of plant development is designated as the total number of units plus the fractional portion of the next unit. The rate of development is determined by subtraction of the previous stage of development from the current stage. Statistical analyses were made to determine the validity of the system with respect to uniformity of designated development units. The system of observation provides a convenient and sensitive method for objectively documenting the status of development throughout the season, or for evaluating the growth response to various treatments or environmental conditions.