Effect of genotype, environment, and their interaction on malting barley characteristics in a 25 cultivar x 27 environment study.

 

Mario C. Therrien

 

As part of a six-row malting breeding program, twenty-five malting and feed barley cultivars, which were used as check varieties, were grown in 27 environments (9 sites x 3 years) across western Canada. Though not intentionally a part of a genotype x environment study on malting quality, this serendipitous study provided the opportunity to examine a large number of genotypes over a wide range of environments. Although not a rigourous study, the information presented may give some insight into genotypic-environmental effects on some of the major malting quality traits used for selection in a breeding program.

 

 Samples of grain (350 g) from each variety, at each environment, were malted and analyzed for Crude Protein (CP), Alpha Amylase (AA), Diastatic Power (DP), Malt Extract (MEX) and Soluble Protein (SP). Variance attributed to genotypic (g), environmental (e), and g x e effects, as a percent of total variance, was calculated for each trait.

 

GP was found to have a moderate environmental and genotypic effect, as well as a relatively large g x e interaction (Table 1). While environment has the largest effect (55%), the effects of genotype and g x e were relatively large, indicating that this trait is complex and subject to much interaction between genotype and environment. AA demonstrated a nearly equal effect of genotype and environment (58 vs. 41%), with little g x e interaction (Table 1). This would make any future potential genetic gain rather problematic. DP, on the other hand, had a strong genotype effect (66%), with almost no g x e interaction. Thus, this trait is reliable over environments and genetic gains, through breeding, would meet with a high likelihood of success. MEX demonstrated a strong environmental component (66%), with some appreciable g x e interaction (5%). Unfortunately, this economically important trait appears to be largely influenced by environment. Finally, SP showed a strong genotype effect (61%) and a fair degree of g x e interaction (8%). There appears to be good prospects for genetic advance and improving this trait, with a caveat that some genotypes may not respond.

 

 

 

 

Table 1. Statistical analysis of 5 malting traits for 25 barley genotypes over 27 Environments.