The relationship between root system development and vernalization under contrasting irrigation in bread wheat lines with the introgressions from a synthetic hexaploid

The properties of the root system are especially important under drought, which is currently the most significant climate threat worldwide. The aim of this work was to investigate the relationship between the root system development and vernalization requirements under contrasting irrigation conditions in bread wheat using lines with alien introgressions. A set of single chromosome substitution lines Chinese Spring (Synthetic 6x, AABBDD) and D-genome derived introgression lines were used to study the relationships. It was found that 1A substitution resulted in a substantial reduction of root length and weight while 5D substitution, on the contrary, led to a significant increase compared to the recipient and the donor under both irrigation regimes. The greatest root weight, root length, and number of days to flowering were detected in the lines carrying a common introgression fragment of the 5D chromosome connected with the molecular marker Xgwm292 and the Vrn-D1 gene. The lines with the introgression in this region had a significantly larger root length and weight compared with the recipient and donor under all conditions of irrigation. The combination of prolonged vernalization and drought negatively affected the development of roots in all lines with the most pronounced effect on root weight. With the use of monosomic analysis, it was shown that the Vrn-A1 gene has a substantial reducing effect on the root length and weight. The revealed relationship between the flowering time and root system development can be used for breeding of wheat cultivars more adapted for growing in arid conditions.