54 RESEARCH REPORTS
PNL Volume 12 1980
PEA MUTATIONS OF PRACTICAL VALUE
Monti, L. M., University of Naples, Portici, Italy
F. Saccardo, and P. Vitale Center of Nuclear Studies, Rome, Italy
By comparing mutagenic treatments on seed and on pollen of the canning
variety 'Sprinter', and by classifying all the mutations found in M2 for
chlorophyll and morphological mutations (Table 1), a higher frequency of
the latter types was found after pollen treatments (82.5%) than after seed
treatments (less than 36.5%).
Table 1. Frequency of mutations induced in variety Sprinter after treatment
of uollen and of seed with mutagenic agents.
Irradiation
on
Mutagenic
agent
Mi plant
analyzed
(no.)
Mutations
per Mj plant
(%)
Relative frequency
of mutations
Chlorophyll Morphological
(%) (%)
Pollen
X-rays
271
14.8
17.5
82.5
Seed
X-rays
1107
16.0
80.3
19.7
DS
372
22.3
63.8
36.2
The progenies of the morphological mutants isolated in M2 after seed
and pollen treatments were analyzed in succeeding generations, the same
selection procedure being followed from M2 on. In M3, only mutations which
could have a practical interest were considered, e.g. mutations for height,
flowering time, fertility, pod length, and seed weight and size. From M4
on, only lines with agronomic merit were selected. In M8 only two lines,
both derived from pollen-irradiated material, were superior to the control
varieties in yield (Table 2).
PNL Volume 12 1980
RESEARCH REPORTS 55
Comparative agronomic and technological trials, performed in different
Italian districts, confirmed the improved nature of the two mutant lines,
mainly for some qualities of the processed product, such as taste and color.
The certification procedure has already been started to release the two lines
as new varieties.
Comparison of the results between the two treatments seems to indicate
that pollen treatment probably induces a higher rate of the so-called point
mutations than seed treatments. This is substantiated 1) by the lower rate
of chlorophyll mutations, which are mainly attributed to chromosomal mutations,
and 2) by the higher number of high yielding lines selected from M5, on.
The higher rate of point mutations induced by pollen treatments in comparison
with seed treatments is probably due to the sieve action of the haplontic
selection at the moment of the M1 zygote formation.