Wu et al. (1999) discussed several difficulties in
investigating the inheritance of allelochemicals, for
example, phytochemical analysis of plant material from
genetically diverse genotypes. To have qualitative and
quantitative data on allelochemicals, sophisticated
techniques of natural product chemistry are needed.
The nature of inheritance of allelochemicals may be
complex. There may be more than two genes responsible
for the production of an allelochemical. Furthermore,
there are chances that allelopathic activity, due to
several genes, is not/weakly correlated to yield of the
crop (Olofsdotter et al., 1995). Another problem is the
isolation of chemicals from the substratum. Even if a
crop cultivar has high allelochemical levels and releases
allelochemicals in large quantities, substratum ecology
plays an important role by influencing the qualitative
and quantitative availability of allelochemicals