PISUM GENETICS
2010-VOLUME 42
BRIEF COMMUNICATION
Yellow green (ygl) mutation in Pisum
Ambrose, M.J. John Innes Centre, Norwich, UK
The yellow green mutant was first described by Kellenbarger in 1953 (1). The mutation arose as a single
plant (KE
s1
) in a crop of Alaska. Seedlings bearing the mutation were reported as being of uniform
yellowish green when they emerge with growth becoming a normal green over time. In 1953 Lamprecht
notes the work of Kellenberger and reassigns the mutation as vil (2). Blixt, in his 1971 thesis on mutations
in Pisum (3), designated the mutation as chlorina-virescens and lists it under vil but goes on to comment
that the question of reinstating the yg symbol should be discussed. While Blixt was aware of the mutant
the line does not appear in the Weibullsholm collection and the mutation is logged as extinct in the gene
database at the time of writing (4).
As part of the regular regeneration of germplasm against wire in the field, the abnormally pale foliage
colour of one particular accession was noticable. The tops of the plants were all yellowish green
becoming a mid green lower down the plant. Documentation associated with this line showed it was
received at the John Innes in 1964 from Robert Lamm. A letter from Lamm that accompanied the material
states that this line originated from Kellenbarger and included alongside the symbols ygl and virl.
The chlorophyll content of leaf tissue was measured using a portable Minolta SPAD 502 chlorophyll
meter which determines the relative chlorophyll in leaf tissue by measuring absorbance at two
wavelengths, namely in the regions of 400-500nm and 600-700nm which are characteristics of
chlorophyll absorption peaks. Readings from the leaflets and stipules from the top of the plant gave
readings of 18.5 SPAD units which doubled to 34.0 SPAD units seven nodes further down the plant.
While the reading obtained from foliar tissue lower down the plant is in the mid range of values
measured in other pea germplasm, the value of the younger foliage is at the low end (5).
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PISUM GENETICS
2010-VOLUME 42
BRIEF COMMUNICATION
It should be noted that the line differed from the founder line Alaska in one further respect in having
reduced wax on the stipules. This was not noted by Lamm in the accompanying notes associated with
the line. The genetic relationship between the yellow green foliage and reduced stipule wax awaits
further study.
As the line has not been studied or published on for such a long period of time, I propose to reinstate the
original gene symbol yg as valid and vil as a synonym in the PGene database (4). The status of the
mutation moves from extinct to valid and seed is now available from the John Innes Pisum Collection.
References
1. Kellenbarger, S. 1953. J. Genetics 51: 41-46.
2. Lamprecht, H. 1953. Agri. Hort. Sci 21: 40-54.
3. Blixt, S.1972. Agri Hortique Genetica 30: 1-293.
4.
PGene: http://www.jic.ac.uk/GERMPLAS/pisum/Zgc4g.htm.
5. Ambrose, M.J. 2010. Pisum Genetics 42: 7-10.
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