Epistatic and buffering effects in hybrid rye
Geiger, H.H. (Hohenheim Univ. (Germany). Inst. of Plant Breeding. Seed Science and Population Genetics) | Becker, H.C.
To analyse epistatic and buffering effects in rye (Secale cereale L.) 33 double crosses (4W) were each compared with the respective three-way crosses (3W). Epistatic effects were defined by 4W - 3WM, and buffering effects by 3WM -3W, where 3WM denotes the performance of a 1:1 mixture and 3W the mean pure stand performance of the two 3W used for prediction. Data were obtained from yield trials conducted at three locations over two years in the Federal Republic of Germany. Most significant epistatic effects disfavoured the 4W, and nearly all buffering effects favoured the 3WM. Averaged over all crosses and environments only the epistatic effects were significant, leading to a 1.5% yield superiority of the 3WM over the 4W. The variances of the epistatic and buffering effects were in the same order of magnitude. Both types of effects were significantly influenced by environments and genotype/environment interaction. The epistatic and buffering effects for yield were positively associated with the divergence of the respective 3W for yield components. Significant correlations also occurred among the effects and various statistics for the phenotypic stability of the 3W yields. The reliability of predicting 4W yields versus assessing them directly was studied as a function of testing intensity. The disturbing effects of epistasis and buffering turned out to be important under intense testing (over 4 environments) only. Under less intense testing both procedures are almost equivalent, and their reliability is mainly affected by genotype/environment interaction and experimental error. Despite of the significant influence of epistasis and buffering, the prediction of 4W performances is considered reliable enough to be used as a standard routine in hybrid rye breeding.Show more [+] Less [-]