Plant Variety Journal - IP Australia

Plant Varieties Journal Vol. 23 Number 4
produced seed whereas none of the controls plants treated with water rather than colchicine
produced any seed. Ten seeds obtained from a single colchicine treated ‘Grosso’ cutting were
germinated in a petri-dish on filter paper soaked in gibberellic acid to induce germination. All
the seeds germinated and plants were potted up and grown until flowering. The plants were
grown under the same conditions as the parent plants above. Cuttings from individual plants
were propagated and planted in the field collection to observe their morphology and
performance. Of the ten plants grown some morphological variation was seen however most
were more vigorous and much larger plants than the parent variety ‘Grosso’. The plant with
the greatest vigour and largest flowers was selected. This plant was designated ‘Riverina
Thomas’ or CSU150. All plants called ‘Riverina Thomas’ were clonally propagated as
cuttings from the one plant. Characteristics of L.x intermedia ‘Riverina Thomas’ are that it is
a larger plant in the field than ‘Grosso’ with larger leaves and flowers. It has thicker
peduncles and stems, is large but compact and globular in form and flowers slightly earlier
than ‘Grosso’. From chromosome number estimates and flow cytometry analysis of nuclear
DNA content ‘Riverina Thomas’ and the other ‘Grosso’ derived seedlings are approximately
triploid whereas the parent ‘Grosso’ was diploid. ‘Riverina Thomas’ is infertile and did not
produce any seed tested over two seasons in the collection at CSU. In summary, the diploid
L.x intermedia ‘Grosso’ (infertile) was converted to a tetraploid (fertile). Following open
pollination of the tetraploid seeds were collected from these and ‘Riverina Thomas’ is a
seedling selected on the basis of size of the whole plant and various plant organs.
Choice of Comparators Characteristics used for grouping varieties to identify the most similar Variety of
Common Knowledge
Organ/Plant Part Context State of Expression in Group of Varieties
Plant size medium
Most Similar Varieties of Common Knowledge identified (VCK)
Name
Comments
‘Grosso’
Parent.
‘Hidcote Giant’
‘Impress Purple’
‘Seal’
‘Riverina Alan’
Variety Description and Distinctness - Characteristics which distinguish the candidate from one or mo
of the comparators are marked with a tick.
Organ/Plant Part: ‘Riverina
‘Hidcote ‘Impress ‘Riverina
‘Grosso’
‘Seal’
Context
Thomas’
Giant’ Purple’ Alan’
*Plant: growth
habit
globular globular globular globular bushy bushy
*Plant: size medium medium medium medium medium medium
Plant: intensity of
green colour of foliage
Plant: intensity of
grey tinge of foliage
*Plant: attitude of
outer flowering stems
medium medium medium medium medium medium
medium to
strong
medium to
strong
medium to
strong
medium to
strong
medium to
strong
semi-erect semi-erect erect semi-erect erect erect
medium to
strong
*Plant: density medium medium medium medium medium medium
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