10 Abstract SPAD-502 (Minolta Ltd, Osaka Japan), a 11 hand-held chlorophyll meter is widely used in the 12 synchronization of N supply with actual crop demand, 13 however it is also known, that genotype and environ-14 ment may effect SPAD value. Consequently, the aim of 15 this study was to evaluate the genetic and environ-16 mental variation in SPAD value and to determine the 17 relationship between SPAD value at heading (GS 59) 18 and grain yield. Field experiments were conducted in 19 three consecutive cropping seasons between 2012 and 20 2015 in Hungary and forty winter wheat varieties were 21 tested at two nitrogen levels. Strong significant positive 22 correlation was found between grain yield and SPAD 23 values, but it was highly influenced by cultivars. The 24 proportion of the phenotypical variance explained by 25 the cultivars was different in each growing season and 26 was ranged from 12.50 to 59.04 %.