International Journal of Horticulture, 2018, Vol.8, No.4, 29-35
30
namely
Cattleya
and
Phalaenopsis
are finalized, published in PVJ of India and notified for registration during
April, 2014 (Rao et al., 2012) and DUS test guidelines for
Oncidium
is published in PVJ of India in April, 2014
and notified in October, 2014.
1 Materials and Methods
In the present study, 8 hybrids of
Mokara
(
Arachnis
x
Ascocentrum
x
Vanda
) were studied for preparation of DUS
test guidelines with morphological characters. These test guidelines can be applied to all vegetatively propagated
genotypes of
Mokara
, belonging to the family Orchidaceae. For all genotypes, 20 flowering size plants (10 for
each Centre) were needed for developing DUS test guidelines. Usually, insect pest and disease free, healthy plants
are chosen for testing for taking morphological parameters without any biochemical and physical treatment.
1.1 Conduct of test
The test was carried out for two similar growing seasons at two different locations. The genotype would be
considered for further experimentation at another suitable test location or under special test protocol on request of
the applicant if any essential characteristic of the genotype is not expressed for visual parameters at these locations.
Testing should be done with at least 10 plants under protected culture to ensure satisfactory growth for the
expression of the relevant characteristics of the genotype. All parameters were taken by measuring or counting
made on 10 plants or parts taken from each of 10 plants. Additional tests could be carried out for special purposes.
Usually, plant hormones are not applied.
1.2 Parameters
The characteristics used for testing of genotypes for preparation of DUS test guide lines are given in Table 1. For
Distinctiveness and Stability assessment, all parameters were taken from 10 plants or plant parts taken from each
of 10 plants. For Uniformity assessment, a population standard of 1% and an acceptance probability of at least 95%
was adopted. In the case of a sample size of 10 plants, the maximum permissible number of off-types was
considered as 1. All parameters were taken on the flowering shoot, on the longest leaf of a flowering shoot, of the
inflorescence and the flower at 50% opening of the flowers on the inflorescence and on fully opened flower on the
inflorescence before fading of colour, length and width of the flower and parts of the flower in the spread out
position, colour of inner side of sepal, petal, lip and column. The Royal Horticultural Society (RHS) colour chart
was utilized for the assessment of colour characters.
1.3 Grouping of genotypes
The genotypes of common knowledge were chosen to be grown in the experiment along with the candidate
genotypes and the process in which these genotypes are divided into groups for easy assessment of distinctiveness
is supported by the use of grouping parameters. Grouping descriptors are defined as the documented states of
expression, even where grown at different places, can be used, either individually or in combination with other
such parameters: (a) by selecting genotypes of common knowledge that can be excluded from the growing trial
used for testing of distinctiveness; and (b) by conducting the growing trial so that similar genotypes are grouped
together.
1.4 Characteristics and symbols
A table of characteristics was used to study Distinctiveness, Uniformity and Stability of the morphological
parameters and their states. Notes 1-9 (numbers) were used to describe the state of each character for easy
electronic data processing. (*) Characteristics was found in every growing season for genotypes and included in
the description of the genotypes, except when the state of expression of any of these characters is rendered
impossible by a preceding phenological characteristic or by the environment conditions of the testing locations.
Under such exceptional situation, adequate explanation is required. (+)
indicates the explanations on the Table of
Characteristics. Characteristics denoted with symbols QL, QN and PQ in the first column of the Table of
Characteristics were taken as Qualitative characteristic, Quantitative characteristic and Pseudo-qualitative
characteristic, respectively. Characteristics indicated with (a), (b), (c), (d) and (e) in the first column of the Table
of Characteristics (Table 1) were observations on the longest leaf of flowering plant (a), on the inflorescence and
the flower at 50% opening of the flowers on the inflorescence and fully opened flower on the inflorescence before
