Two-gene systems of vernalization requirement and narrow-sense earliness in einkorn wheat

The genetic segregation of the heading trait was analyzed using a recombinant inbred line (RIL) of einkorn wheat, RILWA-1, derived from cultivated Triticum monococcum L., and wild-type T. boeoticum Boiss. The latency to heading was examined in 115 lines under controlled environmental conditions, as well as in the field, and the degrees of narrow-sense earliness and vernalization requirement were evaluated for quantitative trait locus (QTL) analysis. Single-marker analysis using 107 RFLP markers segregating in RILWA-1 detected 20 linking markers for heading factors. In all marker loci, the alleles for early heading were conferred by T. monococcum. In interval analysis of chromosome 5A(m), two vernalization genes, Vrn-A(m)1 and Vrn-A(m)2, were precisely mapped to the Xcdo504-Xpsr426 interval on the central region of the long arm and to the Xwg114-Xwec87 interval on its distal region, respectively. Interval analysis also showed that two genes for narrow-sense earliness, designated Nse-3A(m) and Nse-5A(m), were located on chromosome 3A(m) and 5A(m), respectively. It was noticed that heading time in the field was determined mainly by Nse-3A(m), suggesting that narrow-sense earliness is critical for heading in the field in einkorn wheat.