Genetic resources for breeding of spring barley for organic farming

Abstract

Plant height and powdery mildew (PM) resistance of spring barley varieties were investigated at the Lithuanian Institute of Agriculture during 2004- 2005. The spring barley genotypes tested were Lithuania-registered cultivars, cultivars from genetic resources collection and new cultivars used for initial breeding. The old cultivars were sufficiently tall but very susceptible to PM (resistance score 6-9) in both years. The cultivars released more than a decade ago were shorter, more than half of them were too short in 2004 and only 2 of the 24 cultivars were tall enough (71-80 cm) in 2005. Only one cultivar was resistant of the tall genotypes in 2004. The new resistant cultivarswere tall enough (11 genotypes of 22) in 2004, but these cultivars were too short in 2005. The resistance to PM highly correlated between years (r=0.92, significant at P=0.01), the other traits did not correlate so highly. The Mlo gene was the most frequent (32% of cultivars). Only Mlo and 1-B- 53 genes conferred complete resistance to PM.