# The influence of allelic variants of the Vrn-A1 gene on the duration of the vegetation period in Triticum dicoccoides

## TL;DR

This study explores how different versions of the Vrn-A1 gene affect the growth period of wild emmer wheat, revealing genetic diversity useful for improving wheat crops.

## Contribution

Identification of a new Vrn-A1 allelic variant and evidence of other genetic factors influencing vegetation period in Triticum dicoccoides.

## Key findings

- Five known and one new allelic variant of the Vrn-A1 gene were identified in spring Triticum dicoccoides accessions.
- Accessions with the same Vrn-A1 alleles can show significant differences in vegetation period, indicating other genetic factors are involved.
- A moderate correlation was found between Vrn-A1 allelic variants and vegetation period duration (r = 0.534).

## Abstract

The duration of the vegetation period (DVP) is an important agronomic trait in cereal. Тhe main influence on it in wheat is exerted by Vrn genes, which determine the growth habit (spring vs. winter) and DVP. In the present study, 137 wild emmer Triticum dicoccoides (Körn. ex Aschers. et Graebn.) Schweinf. accessions were evaluated according to the growth habit trait, among which 39 spring ones were identified. The nucleotide sequences of the promoter region of the Vrn-A1 gene were established in the spring accessions by sequencing. Five allelic variants of Vrn-A1 genes previously found in T. dicoccoides were identified, namely Vrn-A1b.1, Vrn-A1b.2, Vrn-A1b.4, Vrn-A1d, Vrn-A1u. Three spring accessions PI355457, PI190919, PI560817 simultaneously contained two alleles of the Vrn-A1 gene: Vrn-A1d and previously undescribed functional allelic variant designated by the authors as Vrn-A1b.8. The promoter region of this allele had several deletions relative to the intact variant. One of such deletions covered 8 bp of the VRN box. In a single experiment, under controlled greenhouse conditions, the relationship between the allelic variants of the Vrn-A1 gene and the duration of the vegetation period of the T. dicoccoides’ spring accessions was studied using the 2B-PLS (Two-Block Partial Least Squares) analysis. The correlation coefficient (r) between these traits was 0.534. The correlation coefficient between the duration of the vegetation period of wild emmer plants and the regions of origin of the studied accessions was also calculated (r = 0.478). It was shown that accessions with identical alleles of the Vrn-A1 gene and originating from the same region can differ significantly from each other in the duration of the vegetation period. The presence of phenotypic differences with the same allelic composition of the Vrn-A1 gene indicates the contribution of other hereditary factors localized in the genomes of these accessions, which determines their value as new donors of genetic resources that contribute to the expansion of the biodiversity of common and durum wheat commercial cultivars.