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.