Numeric codes for developmental stages of oat apex in the growing conditions of Southern Finland

Authors

• Pirjo Peltonen-Sainio Department of Plant Production, Section of Crop Husbandry, Box 27, Viikki, FIN-00014 University of Helsinki, Finland
• Tiina Pekkala Department of Plant Production, Section of Crop Husbandry, Box 27, Viikki, FIN-00014 University of Helsinki, Finland

DOI: https://doi.org/10.23986/afsci.72655

Abstract

Scales that categorize the development of cereal apex have been introduced by several authors. Daylength markedly affects the rate of apex organogenesis and, hence, numeric codes for developmental stages of apices introduced for lower latitudes cannot be used in Finland without modifying them into a ratio scale. The present study introduces numeric codes that categorize the 22 developmental stages of oat (Avena saliva L.) apex in the growing conditions of Southern Finland. Field experiments, including 14 oat cultivars and six breeding lines that differ in the duration of the period from initiation of double ridges to pollination, were carried out at the Viikki Experimental Farm of the University of Helsinki (60°13’N) for two years. The numeric codes were established by relating them to cumulated degree days (CDD). This study showed that when estimating the developmental stages of oat apex by calculating CDD from sowing, the error of estimation was ±1 stage unit at the most.