Authors: K Kóti I Karsai P Szűcs Cs Horváth K Mészáros G B Kiss Z Bedő P M Hayes
Publish Date: 2006/09/02
Volume: 152, Issue: 1, Pages: 17-24
Abstract
A two gene epistatic model in which a dominant “winter growth habit” allele at VrnH2 encodes a repressor with a corresponding binding site in a recessive vrnH1 allele explains the vernalization response phenotypes in an array of barley germplasm In order to validate the model genetically we developed an F 2 population and F 2derived F 3 families from the cross of Hardy winter × Jubilant spring Using genespecific primers we determined the VrnH1 and VrnH2 allele architecture of each F 2 plant and we measured the growth habit phenotype of each F 2 plant via phenotyping of its F 3 progeny under controlled environment conditions We used a set of treatments involving plus/minus vernalization under long photoperiod and vernalization under short photoperiod Alleles at the two loci showed expected patterns of segregation and independent assortment Under long day conditions the two Vrn genes were the primary determinants of heading date regardless of the vernalization treatment Under short photoperiod the effects of these loci were not significant There was incomplete dominance at VrnH1 heterozygotes were significantly later to head than VrnH1VrnH1 genotypes VrnH2 genotypes were also significantly later to head even when plants were vernalized These results validate the twogene epistatic model for vernalization response under longday conditions The results under short photoperiod and the variance in flowering with vernalization confirm that while the two Vrn genes are the primary determinants of vernalization response they are part of a larger interactome that determines the timing of the vegetative to reproductive transition
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