Genetic Variability for Grain Yield and Protein Content in Barley and Its Modification by Net Blotch

Abstract

Protein content, yield and 1000-grain weight of healthy and net blotch-diseased plants were studied in a diallel cross programme concerning nine different varieties of barley {Hordeum vulgare L.). Fj hybrids and their parents were grown in the field in two randomized block design experiments each with three replications (three inoculated and three noninoculated plots). General and specific combining abilities were determined for yield, protein percentage, 1000-grain weight, protein yield, and non-protein yield. A high genetic variability for the traits studied was observed. Non-protein yield and 1000-grain weight decreased significantly in inoculated plants where protein yield was not affected. Significant general and specific combining abilities were observed for all traits. Values for general and specific combining abilities were, in some cases, significantly modified by net blotch of barley. This indicates that attention must be paid to the danger of drawing conclusions in quantitative genetics studies dealing with both diseased and healthy plants.

Pathogenic variation in populations of Drechslera teres f. teres and D. teres f. maculata and differences in host cultivar responses

“…Significant interactions, although small, occurred in both experiments carried out. Similar interactions between the net form and host cultivars have been reported by Douiyssi et al (1998), Arabi et al (1992), Jalli and Robinson (2000) and Gupta and Loughman (2001) and these reports indicate the specificity of the host-pathogen relationship (Douiyssi et al, 1998). Such significant interactions suggest that the pathogen may exist as specialised pathological races; this implies that such races exist in the northern European populations.…”

“…This result corresponds with the data from the current experiment; CI 5791 was significantly more resistant to both forms of the pathogen. Arabi et al (1992) also used cv. CI 5791 in their study and found variations in the reaction to net form and spot form isolates on leaves; they found that this previously resistant cultivar was highly susceptible to one net form and one spot form isolate.…”