Variation in Rate and Duration of Growth Among Spring Barley Cultivars1

Abstract

AbstractTen two‐rowed spring barley cultivars (Hordeum vulgare L.) were evaluated for growth parameters, i.e. crop growth rate, crop growth duration, grain filling rate, grain filling duration, vegetative growth rate, vegetative growth duration, single caryopsis filling rate, single caryopsis filling duration. Field studies were conducted on a sandy loam at Hohenschulen, Northern Germany with three levels of nitrogen fertilization and three sowing rates in 1986 to 1988. Cultivar effects were observed for all growth parameters except for crop growth rate and vegetative growth rate. But only crop growth duration n and grain filling duration showed positive correlations with grain yield. No growth rate parameter was related to yield. Biomass was correlated to crop growth duration and not to crop growth rate, while average caryopsis weight was strongly related to caryopsis filling rate and only moderately to caryopsis filling duration. Comparing grain filling rate and duration to individual caryopsis filling rate and duration, only grain filling rate and duration appeared to be relevant to grain yield. Since genetic variability for crop growth rate was lacking in the spring barley material tested, further improvement of yield would only result from increase in harvest index and/or longer crop growth duration.