Auteur: Halling M.A.
Jaar van uitgifte: 2015
Classifying earliness, or adaptation to a certain climate, is very important in varieties of maize (Zea mays L.). The most common classification system is the Food and Agriculture Organization (FAO) maturity class. This study systematically explored the response of maize varieties with different earliness in the maize-growing area in Sweden and examined possible alternatives to the FAO system for classifying earliness in maize varieties in Sweden. Based on differences in maturation rate according to the FAO index, four maize varieties were selected from variety trials in Sweden 2009-2011. At four sites (56°02- 59°71N), the development of these varieties was determined on four occasions, when the standard variety Avenir was at silking, milk, dough and dent. Aboveground dry matter (DM) yield, DM content and starch content were measured on the latter three occasions and at final harvest of Avenir. Ontario Corn Heat Units (CHU) were calculated for all sites. DM and starch content in the varieties Avenir and Jasmic showed a significant high linear correlation with CHU (R2=0.79 and 0.75, respectively). It was concluded that an index based on the correlation between DM or starch concentration and CHU could be an alternative to the FAO maturity class system for ranking earliness in maize varieties in the Nordic countries.