PNL Volume 14
1982
RESEARCH REPORTS 31
INVERSION OF THE ASSOCIATION AMONG PROTEINS AND SUGARS WHEN COMPARING
THE GREEN PEA AND DRY SEED STAGES
Krarup, A. Universidad Austral de Chile, Valdivia, Chile
Previous work (1) indicated that the correlation among protein and
sugar content at the dry seed stage was positive and significant,
whereas that for the green pea stage for the same parameters was nega-
tive, thus indicating a possible Inversion of this association.
This finding was confirmed in a different set of lines by means of
a path-coefficient analysis of proteins vs. sugars. The total correla-
tion for proteins vs. sugars was positive in both stages, but in the
green pea stage there was no detectable correlation at all (r = .0545).
However, in the path-coefficient analysis the direct effects showed a
clear negative (-.4259) relationship, and that pooled indirect effects
of alcohol insoluble solids (AIS) and dry matter (MS) shift the sign to
positive (see Table 1). In the case of dry seed the pooled Indirect ef-
fects have a negative sign, but the direct effect remains positive and
is of great magnitidue (.8445).
Table 2 shows the relations among yields (green and dry) with
sugars, proteins, AIS, and MS. The path coefficient analysis confirms
the signs of the associations between yields with proteins and sugars at
both stages (see signs of direct effects). Thus, as suggested by Pandey
and Gritton (2), and later by the author (3), selections made at the dry
seed stage for high protein content would not necessarily result in
genotypes with low seed yields. To this we can now add that when
selecting for higher protein content, we would be also selecting for
higher sugar content at this stage. This would not be true at the green
pea stage.
