Abstract:
Most of investigations
showed that nitrogen fertilizers gave
substantial rapeseed yield increases even in
diverse and contradicting conditions but in a
few studies were focused on nitrogen
deficiency stress effects. Some of important
seed yield stress indices based on
application and non application of nitrogen
(N+ and N0) was studied using six spring
rapeseed varieties and their 15 F2 progenies.
Significant mean squares of genotypes
effects were observed for potential yield
(Yp), stress yield (Ys), mean productivity
(MP), geometric mean productivity (GMP),
tolerance index (TOL), stress tolerance
index (STI) and stress susceptibility index
(SSI), indicating significant genetic
differences of the genotypes for the stress
indices. The genotypes including PF7045/91
and RGS003 had the high mean values of
MP and GMP and STI, therefore considered
as high potential parents in both nitrogen
application conditions. On the basis of low
mean value of TOL and SSI indices,
PF7045/91 and 19H were considered as
tolerant to nitrogen deficiency stress. Most
of the crosses with high mean values of MP,
GMP and STI had at least one parent with
high mean values of these stress indices.
Significant positive correlation of Yp and
Ys with MP, GMP and STI, indicating
selection based on these stress indices will
increase the Yp and Ys of the genotypes.
Heterozygosity had important role for
stability of traits in different conditions,
therefore in compare to parents their F2
progenies had low mean values of SSI and
TOL indices.
