Influence of genetic background on the expression of wheat leaf rust resistance gene Lr22a

F4 families homozygous for Lr22a, derived from crosses between the wheat genotypes RL6044 (Thatcher:Lr22a) and Zaragoza or SST33 (leaf rust-susceptible) were developed. Quantitative assessment of latent period of Puccinia recondita f. sp. tritici and number of uredinia per centimeter of square leaf...

Full description

Saved in:
Bibliographic Details
Published in:Phytopathology 1990-06, Vol.80 (6), p.579-584
Main Authors: Pretorius, Z.A. (University of the Orange Free State, Bloemfontein, South Africa), Rijkenberg, F.H.J, Wilcoxson, R.D
Format: Article
Language:English
Subjects:
Agronomy. Soil science and plant productions
Biological and medical sciences
Fundamental and applied biological sciences. Psychology
GENE
GENES
Genetics and breeding of economic plants
GENOTIPOS
GENOTYPE
HEREDITE
HERENCIA (GENETICA)
INFECCIONES
INFECTION
Pest resistance
Plant pathogens
PRODUCTOS DEL CRUZAMIENTO
PRODUIT DE CROISEMENT
PUCCINIA
RESISTANCE AUX MALADIES
RESISTENCIA A LA ENFERMEDAD
TRITICUM AESTIVUM
Varietal selection. Specialized plant breeding, plant breeding aims
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:F4 families homozygous for Lr22a, derived from crosses between the wheat genotypes RL6044 (Thatcher:Lr22a) and Zaragoza or SST33 (leaf rust-susceptible) were developed. Quantitative assessment of latent period of Puccinia recondita f. sp. tritici and number of uredinia per centimeter of square leaf surface of these families indicated significantly different levels of resistance. Although infection types, resulting from inoculations with different isolates of known virulence, denoted the presence of Lr22a, certain F4 families exhibited a latent period statistically equal to that of the susceptible control. Other F4 families showed resistance superior to that of RL6044. Selected F5 families indicated that levels of adult-plant resistance superior to that of the parent could be maintained in a selection program. Enhanced levels of resistance were apparently not caused by the combination of Lr22a with other known, but ineffective genes for hypersensitive seedling resistance in the susceptible parents, or by the growth stage of plants in families segregating for maturity. It is hypothesized that modifying genes, which cannot be detected qualitatively, interacted with Lr22a to produce different levels of resistance. These modifying genes were not associated entirely with Lr22a since F4 families without the gene also varied for latent period and the number of uredinia
ISSN:0031-949X
1943-7684
DOI:10.1094/Phyto-80-579