Genetic Characterization of Dormancy in Durum Wheat
Abstract
Two populations derived by crossing LDN x LDN Dic-3A (Population I) and LDN x LDN Dic-3B (Population II) were genetically characterized for the seed dormancy present on chromosome 3A and 3B of durum wheat. The genes for seed dormancy in these two populations were contributed by the wild parent T. dicoccoides. Although the populations showed transgressive segregants for both dormant as well as nondormant parent, the populations were similar to the dormant parent at Langdon and Prosper 2006 field locations for Population I and at Langdon 2007 and Autumn greenhouse season for Population II. Genotypic and phenotypic analysis over the combined populations showed an environmental effect on expression of the trait. Different QTL were identified for both field and greenhouse season for the population derived from the cross between LDN x LDN Dic-3A. Five QTL for seed dormancy were identified on chromosome 3A for the QTL analysis performed over combined field locations. One QTL ranging between marker interval Xcfa2193 and Xcfd2a was consistently present for the 30 day period of seed germination and was also found to be linked to red grain color trait. The QTL analysis performed on the population derived from the cross between LDN x LDN Dic-3B identified only one major QTL on the long arm of chromosome 3B between the marker interval Xbarc84 and Xwmc291. This QTL was consistently present for all the field and spring greenhouse season for the seed germination period of 30 days. The QTL x E effect was also observed for this QTL, however it was very small.