# Prebreeding studies of near-isogenic spring bread wheat lines, differing by presence or absence of the 3R(3D) chromosomal substitution from the triticale cultivar Satu

## TL;DR

This study compares wheat lines with and without a specific chromosomal substitution from triticale, assessing their resistance to rust and agronomic traits.

## Contribution

The paper provides new insights into the agronomic and resistance traits of wheat lines with the 3R(3D) chromosomal substitution from triticale Satu.

## Key findings

- Line L16 with the 3R(3D) substitution is highly resistant to Puccinia triticina and P. graminis, including Ug99 race.
- The 3R(3D) substitution reduces ear length and dough elasticity but does not significantly affect grain weight or gluten content.
- L16 requires further breeding improvements to enhance its agronomic value despite its resistance benefits.

## Abstract

One of the sources of resistance to leaf and stem rust pathogens for bread wheat is the Australian spring triticale cultivar Satu, which carries highly effective linked SrSatu/LrSatu genes localized on chromosome 3R. However, they are little used in the practical breeding of Triticum aestivum L. The main reason for that is a low level of knowledge regarding the 3R(3D) chromosomal substitution. This paper presents the results of a comparative study of the agronomic value of near-isogenic spring bread wheat siblings, L16 and L17 = Satu/Saratovskaya 70//Saratovskaya 74/3/Saratovskaya 74, differing by presence (L16 (3R(3D))) or absence (L17 (3D3D)) of chromosome 3R from Satu in 2023–2024. The 3R(3D) chromosomal substitution in L16 was detected by cytogenetic analysis combining GISH with labeled Secale cereale genomic DNA and FISH with probes pSc119.2, pAs1. Line L16 is highly resistant to Puccinia triticina and P. graminis, including the Ug99 race. PCR analysis with DNA markers of Sr genes revealed the non-identity of the resistance gene in L16 to Sr genes: Sr2, Sr24, Sr25, Sr28, Sr31, Sr32, Sr36, Sr38, Sr39, Sr47 and Sr57. L16 was inferior to both L17 and the standard cultivar Saratovskaya 76 in terms of 1,000-grain weight. An analysis of productivity elements of the main ear revealed that the 3R(3D) substitution in L16 significantly reduced the length of the ear, increased the density of the ear and did not significantly affect the number of spikelets and the number of grains per ear and the grain weight per ear. The grain protein content in L16 did not significantly differ from its L17 siblings or Saratovskaya 76. Similarly, there were no significant differences in gluten content. However, gluten in L16 was weaker in comparison with line L17 and Saratovskaya 76. According to the complex trait of SDS sedimentation, L16 was inferior to L17, but did not significantly differ from the standard cultivar. According to the alveograph, L16 had significantly lower dough elasticity and flour strength, but in comparison with the standard cultivar, the decrease in flour strength was not significant. L16 showed a higher bread volume than Saratovskaya 76, but did not significantly differ from its L17 sibling. There was no difference in porosity for all three samples. In general, in terms of the complex of agronomically valuable traits, the spring bread wheat line L16 (3R(3D)) requires further work to improve its breeding value.