Primary hexaploid synthetics: Novel sources of wheat disease resistance

Abstract

Climate change is leading to increased occurrence of and yield losses to wheat diseases. Managing these diseases by introducing new, effective and diverse resistance genes into cultivars represents an important component of sustainable wheat production. In 2016 and 2017 a set of primary hexaploid synthetic wheat was studied under high disease pressure: powdery mildew, leaf and stem rust in Omsk; Septoria tritici and S. nodorum in Moscow. A total of 28 synthetics (19 CIMMYT synthetics and 9 Japanese synthetics) were selected as having combined resistance to at least two diseases in both years of testing. Two synthetics (entries 13 and 18) originating from crosses between winter durum wheat Ukrainka odesskaya-1530.94 and various Aegilopes taushii accessions, and four synthetics (entries 20, 21, 23 and 24) from cross between Canadian durum wheat Langdon and Ae. taushii were resistant to all four pathogens. Pathological and molecular markers evaluation of resistance suggests presence of new genes and diverse types of resistance. The novel genetic sources of disease resistance identified in this study can be successfully utilized in wheat breeding.

Stable sources of resistance to yellow rust and powdery mildew in Indian and exotic wheat germplasm

“…As has been observed in the present studies, sources and genes for APR against leaf rust, yellow rust, black rust and powdery mildew resistance i.e. Lr34/Yr18/ Sr57/Pm38, Lr46/Yr29/Sr58/Pm39, Lr67/Yr46/ Sr55/ Pm46 have been identified and well characterized (Sheikh et al, 2019), yellow rust and powdery mildew (Shamanin et al, 2019). Therefore, the availability of genetically diverse germplasm with broad resistance to multiple diseases is important to the success of wheat improvement programs (Polak and Bartos, 2002).…”

Mechanisms of powdery mildew resistance of wheat – a review of molecular breeding

“…It is well accepted that the mechanism of race‐specific resistance is due to the presence of a major resistance gene ( R gene) and cognate pathogen avirulence gene ( Avr gene) (Flor, 1971), and this has proved to be an integral part of crop breeding for resistance in wheat for many decades (Wang et al , 2005; Lillemo et al , 2010; Shamanin et al , 2019). The plant R gene codes for a receptor that is activated by a pathogen effector, irrespective of plant stage.…”

Abscisic Acid—Enemy or Savior in the Response of Cereals to Abiotic and Biotic Stresses?

“…Moreover, there is limited genetic diversity of resistance genes available for use in breeding programs. The monoculture of modern wheat cultivars with low genetic diversity has resulted in pathogen resurgences, threatening wheat supplies [ 170 ]. Therefore, understanding mechanisms of biotic stress responses in plants is of paramount importance in the current situation.…”

“…It is clearly visible that in most of the described cases, ABA acts as disease susceptibility factor in wheat and barley plants, especially in relation to pathogenic fungi [ 188 ]. In general, pathogenic fungi can be roughly classified into two categories—biotrophic and necrotrophic—on the basis of their lifestyle; however, deviations from this rule are sometimes observed [ 170 ]. It seems that that the impact of ABA on the resistance of cereals to fungus is dependent on a few factors, like the intensity of increase of this phytohormone, the type of pathogen, the source of ABA (endogenous or exogenous), or the method of application.…”