Mn. Uddin et al., THE PERFORMANCE OF PURE LINES DERIVED FROM HETEROTIC BREAD WHEAT HYBRIDS, Australian Journal of Agricultural Research, 45(3), 1994, pp. 591-600
Comparisons of the grain yields of pure lines derived from heterotic h
ybrides were made with those of the F1 hybrids and their parents for f
our hand-made crosses, and with the hybrid in the case of the commerci
al hybrid cultivar Comet. Seventy-five F7 (F6 in the case of Comet) si
ngle seed descent lines from each cross were evaluated in hill plot ex
periments containing five plots of each parent and hybrid per replicat
ion. Mid-parent and high-parent heterosis averaged 17% and 10.7% respe
ctively in the four hand-made hybrids. Thus hybrid breeding of wheat c
ould achieve a significant yield advance because the parental genotype
s were advanced breeding lines or commercial cultivars. The estimated
genotypic value for grain yield of the best pure line derived from eac
h cross was 98, 96, 94, 91 and 85% of the corresponding hybrid mean yi
eld, and even higher yields could be expected from a larger sample of
derived pure lines. A hybrid breeding program cannot therefore be just
ified solely on the basis of yield comparisons between hybrids and pur
e lines.