Genetic variances analysis of plant height at different
developmental stages
Unconditional genetic variances
The genetic variances VA, VD, VAE and VDE of the
two groups at seven developmental stages were
significant, but VAE and VDE were relatively little
(Table 1). This indicates that the performance of plant
height at different developmental stages was mainly
controlled by the expression of additive and dominant
effects, as well as partially affected by interaction
effects between genotype and environment. In the first
group, VA and VD increased with the developmental
stages, and VA was slightly higher than VD before S4,
but VD was significantly higher than VA after S5. In
addition, the genetic main effects (VA + VD) were over
78.88% in the total genetic effects (VA + VD + VAE +
VDE) through all the stages, and reached 96.22% at S7.
In the second group, VA decreased after an increase
process, and then reached maximum at S7, meanwhile,
VD had been increasing at seven developmental stages,
and was higher than VA at all stages. The ratio of (VA +
VD) to (VA + VD + VAE + VDE) decreased firstly, and
then increased, the minimum was 62.40% at S2, and
the maximum was 92.60% at S7. The above results
show that the plant height was mainly affected by
genetic main effects (VA + VD), and maximized at the
latest stage, but the VA and VD varied with the
genotypes. In the first group, the plant height was
mainly affected by VA at the early stage, but was
subjected to VD at the late stage. In the second group,
the plant height was mainly affected by VD all the time,
and VA was only in the secondary status. In the both
two groups, the ratio of (VAE + VDE) to (VA + VD + VAE
+ VDE) gradually decreased with the plant development
on the whole, and the ratio in the first group was
lower than that in the second group at any time. This
suggests that the influence of interaction effects on
plant height decreased with the developmental process,
and the influence to the first group was less than that
to the second group. Meanwhile, the VA of the first
group was higher than that of the second group, and
the VD of the second group was higher than that of the
first group in the whole process, except for S1.