Detection of photoperiod responsive and non-responsive flowering time QTL in barley

A QTL analysis was performed to determine the inheritance of flowering time in barley, using a set of recombinant inbred lines developed from a winter-type × spring-type cross. Two photoperiod responsive loci, Ppd-H1 and Ppd-H2, were detected on chromosome arms 2HS and 1HL respectively. Segregation for eam8 (mapping to the terminus of chromosome arm 1HL) and Eam5 (close to Sgh2 on chromosome arm 5HL) was also observed. These latter two genes functioned under 12 h to 24 h photoperiods. In addition, eps2S and eps7S, known to lie on chromosome arms 2HS and 7HS respectively, were detected. A new QTL for flowering time, qDHE.ak-1HS, was mapped 23 cM from the terminus of chromosome 1HS, and appears to be expressed under extremely short day lengths.