Heliyon (Nov 2024)
Adult-plant resistance to leaf scald and net form net blotch in food barley genotypes at a hot spot location in Ethiopia
Abstract
Globally, the fungal pathogens Rhynchosporium graminicola and Pyrenophora teres f. teres produce foliar diseases that significantly reduce barley yield. These diseases are known as leaf scald and net form net blotch, respectively. One hundred food barley genotypes in reaction to the diseases were assessed in Ethiopia’s natural environment. Since Ethiopia is a secondary center of genetic diversity in barley and consequently its pathogens, this assessment is certainly of interest in identifying new sources of resistance and using the identified genotypes in breeding. In addition, effect of the diseases on yield and yield components of food barley and the association between the parameters were studied. A simple lattice design was used for the field testing. Ten center rows (5 m2) were assessed for grain yield, and the results were converted to t ha−1. Eyal classes and Eyal and Brown reaction types were used to evaluate the reactions of barley genotypes in one year breeding scheme. The association between the independent and dependent variables was examined using Pearson correlation in ellipses predictor. The Logistic and Gompertz models were employed to analyses disease rates. The maximum grain yield (6.7 t ha−1) and lowest grain yield (1.7 t ha−1) were recorded by genotypes HB#P356 and SARC#P42, respectively. Among evaluated genotypes, 21 % were susceptible, 44 % were moderately susceptible, 20 % were moderately resistant, and 15 % were resistant to leaf scald disease. Genotypes like HB#P1235, HB#P1244, HB#P1251, HB#P386 and the other 11 demonstrated resistance reactions to leaf scald disease. In reverse, the 17 genotypes, including HB#P394, SARC#P5, SARC#P29, and SARC#P12, were susceptible to scald disease. The reactions of genotypes to net form net blotch disease were as follows: 12 % were susceptible, 77 % were moderately susceptible, 8 % were moderately resistant, and 3 % were resistant. A few genotypes, including HB#P340, SARC#P10, and SARC#P14, were susceptible to net form net blotch. Genotypes, HB#P1319, HB#P825, and HB#P830, showed resistance to net form net blotch disease. Consequently, in later breeding schemes, these genotypes, which are resistant to leaf scald and net form net blotch, can be utilized as a parental genotype for crossing and variety development. Moreover, these genotypes can also be important as a genetic resource for future breeding and genetic research. Plant height and the severity of both diseases showed an adverse association (r = −0.1), suggesting that barley breeders should take these two factors into account when designing targeted their breeding program.
