Malting Quality in F₁ Hybrids of Barley¹

Abstract

Seed of 8 varieties of barley and all possible F1 hybrids from crosses among the varieties were malted to obtain data on 8 malting quality characters. On the average, significant heterosis as measured from the mid‐parents was observed in the F1 hybrids for percent extract, percent malt nitrogen, and percent plump kernels. The F1 hybrid average for percent extract was intermediate between the mid‐parent and high‐parent average. F1 hybrid averages for percent malt nitrogen and percent plump kernels were similar to the low‐parent and high‐parent averages, respectively. The average value for the 28 F1 hybrids and average mid‐parent value did not differ for percent wort nitrogen, ratio of wort to malt nitrogen, diastatic power, 6‐amylase, or β‐amylase. For these characters, with only two exceptions, the individual F1 hybrids did not differ significantly from the average of their parents. Only 7 of the 28 F1 hybrids were judged to be acceptable for all 8 malting quality characters. Six of these had an acceptable malting variety as one parent. Malting quality in the F1 hybrids appeared to depend largely on the frequency of favorable genes with additive effects, although for percent extract, percent plump kernels, and percent malt nitrogen there was evidence for genes having dominance and or epistatic effects.

Heterosis and Hybrid Seed Production in Barley

“…Suneson and Dickson (1966) reported that hybrids were intermediate between the parents for most malting quality characters except for protein, which was lower and in the preferred direction. Rasmusson et al (1966) found that only 7 of 28 hybrids were acceptable for all of 8 malting quality characters. Six of the acceptable hybrids had an acceptable malting cultivar as one parent.…”

“…In their studies, heterosis in FI yield was indicated as due to overdominance, but the reduced heterosis that was observed in F2 yield indicated a lack of overdominance. Rasmusson et al (1966) reported that malting quality in F I hybrids appeared to depend largely on the frequency of favorable genes with additive effects, although for percent extract, percent plump kernels and percent malt nitrogen, there was evidence for genes having dominance and/or epistatic effects.…”