Lr46: a gene conferring slow-rusting resistance to leaf rust in wheat

Area of Science:

• Plant genetics
• Agricultural science
• Crop pathology

Background:

• Wheat leaf rust (Puccinia triticina) poses a significant threat to global food security.
• Cultivar Pavon 76 exhibits durable slow-rusting resistance effective since 1976.
• Understanding the genetic basis of durable resistance is crucial for breeding resistant wheat varieties.

Purpose of the Study:

• To genetically characterize the slow-rusting resistance in wheat cultivar Pavon 76.
• To determine the chromosomal location of the gene(s) conferring this resistance.

Main Methods:

• Crosses were made between 'Pavon 76' and susceptible cultivars (Jupateco 73S, Avocet S).
• Segregation analysis of F(3) and F(5) lines evaluated adult-plant leaf rust resistance.
• Monosomic analysis using backcrossed populations identified gene location.

Main Results:

• Slow-rusting resistance in 'Pavon 76' is partially dominant and controlled by two additive genes.
• Monosomic analysis located one resistance gene to chromosome 1B of 'Pavon 76'.
• This gene is designated Lr46, the second named slow-rusting gene for wheat leaf rust.

Conclusions:

• The wheat leaf rust resistance in Pavon 76 is conferred by at least two genes with additive effects.
• The identified gene Lr46 on chromosome 1B is a valuable genetic resource for breeding durable leaf rust resistance in wheat.