M. Ghesquiere et al., BREEDING FOR MANAGEMENT ADAPTATION IN PERENNIAL RYEGRASS (LOLIUM-PERENNE L) .2. GENETIC-VARIABILITY AND HERITABILITY OF LEAF MORPHOGENESIS COMPONENTS, Agronomie, 14(4), 1994, pp. 267-272
A space-limited experimental design was used for estimating the geneti
c parameters of growth components in Lolium perenne. These parameters
might be taken into account in breeding for yield under a given manage
ment. From 58 half-sib families derived from a single polycross, the m
orphogenesis of 3 successive leaves on 1 tiller of 20 individuals per
family was recorded 3 times a week in the spring. Phyllochron, duratio
n of leaf elongation and adult leaf length were measured, and the leaf
elongation rate and the mean number of growing leaves per tiller were
estimated. Leaf length and elongation rate were found to be highly co
rrelated and showed a genetic variability and a narrow-sense heritabil
ity that were definitely higher than phyllochron and duration of leaf
elongation. Compared with controls, the progenies indicated an extende
d genetic variability of morphogenetic traits, mainly towards to genot
ypes with short leaves and/or rapid phyllochron (but to a lesser exten
t). Leaf length therefore appeared as the morphogenetic trait that cou
ld be most modified through selection. This has been used as a selecti
on criterion in breeding for high productivity under infrequent cuttin
g. Conversely, no morphogenetic trait such as phyllochron, which is as
sumed to control yield under frequent cutting, responds so effectively
to selection, which led us to propose that selecting for short-leaved
genotypes could be an alternative approach that should be investigate
d.