Origin and evolution of the bread wheat D genome.

Bread wheat (Triticum aestivum) is a globally dominant crop and major source of calories and proteins for the human diet. Compared with its wild ancestors, modern bread wheat shows lower genetic diversity, caused by polyploidisation, domestication and breeding bottlenecks. Wild wheat relatives represent genetic reservoirs, and harbour diversity and beneficial alleles that have not been incorporated into bread wheat.

First Report of Rust Caused by on Creeping Fig, , in South Africa.

has recently been reported as the causal organism of rust on edible fig, in South Africa (SA) (Boshoff et al. 2022). This contradicted reports by Doidge (1927, 1950) and Verwoerd (1929) who listed as the causal organism of the disease in SA.

Genome-Enabled Analysis of Population Dynamics and Virulence-Associated Loci in the Oat Crown Rust Fungus f. sp. .

f. sp. () is an important fungal pathogen causing crown rust that impacts oat production worldwide.

Identification and introgression of a novel leaf rust resistance gene from Thinopyrum intermedium chromosome 7J into wheat.

A novel leaf rust resistance locus located on a terminal segment (0-69.29 Mb) of Thinopyrum intermedium chromosome arm 7JS has been introduced into wheat genome for disease resistance breeding. Xiaoyan 78829, a wheat-Thinopyrum intermedium partial amphiploid, exhibits excellent resistance to fungal diseases in wheat.

Wheat Stem Rust Surveillance Reveals Two New Races of f. sp. in South Africa During 2016 to 2020.

Stem rust, caused by f. sp. (), is an important disease of wheat in South Africa (SA) and is primarily controlled using resistant cultivars.

Breeding oat for resistance to the crown rust pathogen Puccinia coronata f. sp. avenae: achievements and prospects.

Crown rust, caused by Puccinia coronata f. sp. avenae (Pca), is a significant impediment to global oat production.

The life cycle of on and species in South Africa.

Rust fungi are important plant pathogens and have been extensively studied on crops and other host plants worldwide. This study describes the heterecious life cycle of a rust fungus on (finger grass) and the species (large yellow bitter apple), (bitter apple), and (eggplant) in South Africa. Following field observations, inoculation studies involving telial isolates collected from plants produced spermogonia and aecia on , and .

Long-read genome sequencing of bread wheat facilitates disease resistance gene cloning.

The cloning of agronomically important genes from large, complex crop genomes remains challenging. Here we generate a 14.7 gigabase chromosome-scale assembly of the South African bread wheat (Triticum aestivum) cultivar Kariega by combining high-fidelity long reads, optical mapping and chromosome conformation capture.

A recombined Sr26 and Sr61 disease resistance gene stack in wheat encodes unrelated NLR genes.

The re-emergence of stem rust on wheat in Europe and Africa is reinforcing the ongoing need for durable resistance gene deployment. Here, we isolate from wheat, Sr26 and Sr61, with both genes independently introduced as alien chromosome introgressions from tall wheat grass (Thinopyrum ponticum). Mutational genomics and targeted exome capture identify Sr26 and Sr61 as separate single genes that encode unrelated (34.

Chromosomal composition analysis and molecular marker development for the novel Ug99-resistant wheat-Thinopyrum ponticum translocation line WTT34.

A novel Ug99-resistant wheat-Thinopyrum ponticum translocation line was produced, its chromosomal composition was analyzed and specific markers were developed. Stem rust caused by Puccinia graminis f. sp.

Historical Development of the Population in South Africa.

In contrast to many other countries, the virulence and genetic diversity of the South African population before 1980 is unknown, because of the absence of regular and systematic race analysis data and viable rust cultures. Herbarium specimens housed at the National Collection of Fungi, Biosystematics Unit, Plant Health and Protection, Agricultural Research Council, Pretoria, South Africa (SA), provided the opportunity to investigate the genetic development of the population using isolates collected between 1906 and 2010. Five subpopulations that survived between 21 and 82 years in the field were found.

Phenotypic and Genotypic Variation of in South Africa.

Sunflower ( L.) is the third largest grain crop by area planted in South Africa (SA). The annual yield is negatively affected by sunflower rust caused by Schw.

South African competition policy on excessive pricing and its relation to price gouging during the COVID-19 disaster period.

The declaration of a state of national disaster in South Africa, due to the COVID-19 pandemic, was followed by excessive-pricing regulations pertaining to certain consumer and medical products and services. The regulations and their application suggest an intertemporal benchmark to judge excessive pricing, deviating from previous practice. Intertemporal comparisons assume a structural shift during COVID-19 that changes competitive conditions, related to changes in consumer behaviour.

Mapping a Resistance Gene to f. sp. in the Bread Wheat Cultivar 'Matlabas'.

f. sp. race TTKSF+ was collected from the South African wheat cultivar 'Matlabas' in 2010.

Additive Manufacturing of Devices Used for Collection and Application of Cereal Rust Urediniospores.

Optimized inoculation procedures are an important consideration in achieving repeatable plant infection when working with biotrophic rust fungi. Several plant pathology laboratories specializing in rust research employ a system where the collection and application of fungal spores are accomplished using an exchangeable gelatin capsule. Urediniospores are collected from erumpent pustules on plant surfaces into a capsule fitted to a cyclone collector controlled by a vacuum pump.

Point Inoculation Method for Measuring Adult Plant Response of Wheat to Stripe Rust Infection.

Depending on the pathogenicity of the stripe rust fungus f. sp. , the nature of resistance in the wheat host plant, and the environment, a broad range of disease phenotypes can be expressed.

First Report of a New TTKSF Race of Wheat Stem Rust (Puccinia graminis f. sp. tritici) in South Africa and Zimbabwe.

Seven races have been described in the Ug99 race group of Puccinia graminis f. sp. tritici (2).

A genetic analysis of adult plant resistance to stripe rust in the wheat cultivar Kariega.

The wheat cultivar Kariega expresses complete adult plant resistance to stripe rust in South Africa. The aim of this investigation was to determine the extent and nature of variability in stripe rust resistance in a population of 150 doubled haploid lines generated from a cross between Kariega and the susceptible cultivar Avocet S. Analysis of field data for adult plant stripe rust resistance identified two major QTLs and two minor QTLs in the resistant cultivar Kariega.

First Report of Virulence in Puccinia graminis f. sp. tritici to Wheat Stem Rust Resistance Genes Sr8b and Sr38 in South Africa.

During the 2000 to 2001 season, 27 stem rust samples were collected from wheat (Triticum aestivum), barley (Hordeum vulgare), and triticale (× Triticosecale) cultivars and lines in the Western Cape, South Africa. Following inoculation and multiplication on McNair 701 seedlings, 40 single pustule isolates of P. graminis f.

Establishment, Distribution, and Pathogenicity of Puccinia striiformis f. sp. tritici in South Africa.

Stripe rust, caused by Puccinia striiformis Westend. f. sp.

Pathogenic Variability of Puccinia coronata f. sp. avenae and P. graminis f. sp. avenae on Oat in South Africa.

Although crown rust (caused by Puccinia coronata f. sp. avenae) and stem rust (caused by Puccinia graminis f.

Occurrence and Pathogenicity of Puccinia hordei on Barley in South Africa.

Although leaf rust, caused by Puccinia hordei, is considered an important disease of barley (Hordeum vulgare) and regularly reaches epidemic proportions, pathogenic variability has never been studied in South Africa. From 1994 to 1997, only one pathotype (SAPh 3231) was identified with virulence to resistance genes Rph1, Rph4, Rph5, Rph10, and Rph11. During 1998, a second pathotype (SAPh 7321) was identified, differing from pathotype SAPh 3231 only in virulence to Rph12.

A New Pathotype of Puccinia striiformis f. sp. tritici on Wheat in South Africa.

Following the detection of Puccinia striiformis f. sp. tritici for the first time on wheat (Triticum aestivum) in the Western Cape in August 1996, stripe rust has spread to all the important wheat production areas in South Africa.