Research Report

DUS Test Guidelines in Mokara Orchids  

Lakshman De1 , A.N. Rao2 , D.R. Singh1 , S.R. Dhiman3 , R. Prakash4 , Rakesh Singh1
1 NRC for Orchids, Sikkim, India
2 Centre for Orchid Gene Conservation of Eastern Himalayan Region, Senapati District, Manipur State, India
3 Floriculturist, Y.S. Parmer University of Horticulture and Forestry, Nauni, Solan, India
4 PPV & FRA, NASC Complex, New Delhi, India
Author    Correspondence author
International Journal of Horticulture, 2018, Vol. 8, No. 4   doi: 10.5376/ijh.2018.08.0004
Received: 20 Jan., 2018    Accepted: 26 Jan., 2018    Published: 14 Feb., 2018
© 2018 BioPublisher Publishing Platform
This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:

De L.C., Rao A.N., Singh D.R., Dhiman S.R., Prakash R., and Singh R., DUS test guidelines in mokara orchids, International Journal of Horticulture, 8(4): 29-35 (doi: 10.5376/ijh.2018.08.0004)


According to UPOV Convention 1961, DUS (Distinctiveness, Uniformity and Stability) testing is essential to provide and promote an unique way to protect plant varieties with the objective of developing new plant genotypes and for the usefulness of consumers. This provides rights for breeders and farmers to utilize or evolve new strains of plants, to exploit alien genotypes having broad gene pool, to encourage intensive breeding methods and to inhibit exploitations of unauthorized genotypes. In the present study, 8 genotypes of Mokara were evaluated for preparation of DUS test guidelines with a number of morphological characters. Among 61 common descriptors developed, plant width, number of flowers/inflorescence, flower length, flower width, dominant colour of dorsal sepal, dominant colour of lateral sepal, petal dominant colour, dominant colour of lip apical lobe and throat colour of lip were selected for grouping of genotypes.

Hybrids; Characteristics; Descriptors


The orchids are highly diverse, habitat specific and actively evolving plants and popular for their beautiful and long-lasting flowers. Orchids belong to family Orchidaceae, one of the largest family comprises of epiphytic, terrestrial and saprophytic plants. Taxonomically, they belong to the most highly evolved family among monocotyledons having 25,000-30,000 species and cover about 10% of the total flowering plant species. About 300,000 natural and man-made hybrids are found in record and these include several multi generics involving three, four, five, six and even seven genera. In India, the orchids are represented by over 1,300 species distributed mainly in North-Western Himalayas, North-Eastern and Western Ghats and Khasi hills. Orchids flowers are known for their strange shape, longevity, beautiful looks and highly attractive colours. The orchids are cultivated as a cash crop in several countries including India (Vij and Pathak, 2012).


Genera like Paphiopedilum, Vanda, Cattleya, Cymbidium, Oncidium, Phalaenopsis etc. having highly commercial importance are sold as potted plants in the world trade. Besides, Dendrobium, Cymbidium, Orchis, Aerides, Cypripedium, Vanilla etc have unique medicinal importance. Orchids are rich source of alkaloids, flavonoids, glycosides, carbohydrates and other phytochemical contents. Medicinally orchids are rich. They are used for cardiac problem, rheumatic arthritis, respiratory problems etc. Dendrobine alkaloid of Dendrobium sp. is useful in the treatment of pulmonary tuberculosis, night sweats, fever and anorexia. Vanda roxburghii leaf paste is used as application in high fevers. Its leaf juice is used in the treatment of otitis; rheumatic and similar kind of pain; diseases of nervous system and syphilis. Its root is used as antidote against scorpion sting and remedy for bronchitis (Tandon and Kumaria, 2010). Orchids are source of incalculable aesthetic pleasure therefore conservation of orchids in North-eastern India can be closely related to the socio-economic culture of the people of this region. Because of higher socio-economic and cultural importance, the Central Government of India has notified three genera Cymbidium Sw., Dendrobium Sw. and Vanda Jones ex R. Br. for registration on March 27, 2010 under the Protection of Plant Varieties and Farmers’ Rights Act, 2001. Guidelines of two orchid genera 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 fading of colour (b), on the length and width of the flower and parts of the flower at spread out positions (c), the colour of inner side of apex, mid and basal portion of sepal, petal and lip (d) and on the colour of inner side at apex, mid and basal region of column(e). Type of assessment of characteristics as given in column six of the Table 1 were taken by a single observation for a group of plants or plant parts (MG), measurement of a number of individual plants or plant parts (MS), visual assessment by a single observation of a group of plants or plant parts (VG) and visual assessment by observations of individual plants or plant parts (VS).


Table 1 Some grouping characteristics in Mokara


2 Results and Discussion

In the present study, all total 61 common descriptors were developed for development of DUS test guidelines in Mokara and those are plant width (cm), internode length (cm), leaf type, leaf attitude (Figure 1), leaf length(cm), leaf width(cm), leaf emarginated tip, leaf folding, inflorescence length (cm), number of flowers/inflorescence, inflorescence branching, inflorescence orientation, peduncle length (cm), pedicel length (cm), flower length (cm), flower width(cm), flower fragrance, dorsal sepal length (cm), dorsal sepal width (cm), dorsal sepal shape (Figure 2), dorsal sepal curvature of longitudinal axis, dorsal sepal apex, dorsal sepal colour pattern, dorsal sepal dominant colour, curvature of lateral sepal, length of lateral sepal (cm), width of lateral sepal (cm), shape of lateral sepal, apex of lateral sepal, colour pattern of lateral sepal, lateral sepal dominant colour, petal shape, petal length (cm) (Figure 3), petal width (cm), petal curvature of longitudinal axis (Figure 4), petal apex, petal number of colours, petal colour pattern, petal dominant colour, lip length of apical lobe (cm), lip width of apical lobe (cm), lip lobbing of apical lobe apex (Figure 5), protrusion of ventral side of apical lobe of lip, dominant colour of apical lobe of lip, colour pattern of apical lobe of lip, no. of colours of apical lobe of lip, length of lateral lobe of lip (cm), width of lateral lobe of lip (cm), colour pattern of lateral lip lobe, dominant colour of lateral lip lobe, No. of colours of lateral lobe of lip, colour of throat of lip, keel nos., column length (cm), column width (cm), column dominant colour, column colour pattern, no of colours of column, spur type and spur length.


Out of 61 common descriptors developed, plant width, number of flowers/inflorescence, size, flower length, flower width, dorsal sepal dominant colour, lateral sepal dominant colour, petal dominant colour, dominant colour of apical lip lobe and throat colour of lip were used for grouping of genotypes.


Figure 1 Leaf attitude



Figure 2 Length and width of Dorsal sepal, Lateral sepal & Petal



Figure 3 Dorsal sepal, Lateral sepal and Petal: shape



Figure 4 Dorsal sepal, Lateral sepal and Petal: curvature in longitudinal axis



Figure 5 Lip: apical lobe: length, width and lobing of apex



A genotype becomes eligible for registration under the Act if it essentially fulfils the criteria of Distinctiveness, Uniformity and Stability (DUS) which means that the candidate genotype must be distinguishable by at least one essential characteristic from a genotype of common knowledge in any country at the time of filing application, sufficiently uniform in expression of its essential characteristics which should remain fixed even after repeated multiplication. The genotype should also have a single and distinct denomination (Greef, 2008).


Mokara hybrids showing significant variation in morphological vegetative and floral characters could be used as parents for developing new hybrids. Vanda ‘Miss Joaquim’ is said to have taken the form of V. hookeriana and the colour of V. teres as reported by Fuchs R.F. (1997) and Tim Wing Y.T. (2001) reported that Vanda sanderiana and V. coerulea are the two important vanda species found in the background of most of the vandaceous hybrids. V. sanderiana gives full form, whereas V. coerulea imparts the rich blue violet colouration, lobely tessellation as well as the long inflorescence. Examples of Vanda hybrids exploited as parent plant for evolvement of new hybrids are “Amoene’, ‘Betsy Summer’, ‘Bull Sutton’, ‘Eisenhower’, ‘Ellen Noa’, ‘Emily Notley’, ‘Ernest’, Fujinaga’, ‘Frank Crook’, ‘Haledena’, ‘Helen Reynolds’, ‘Hilo Blue’, ‘Honolulu’, ‘Jennie Hashimoto’, ‘Josephine Van Bero’, ‘Kapolio’, ‘Manila’, ‘Manisaki’, ‘Miss Joaquim’, Noel’, ‘Nora Potter’, ‘Norbert Alphanso’, Onomea’, ‘Poepoe’, ‘Rubella’, ‘Ruby Prince’, ‘Tan Chay Yan’, ‘Tatzeri’, ‘Trimerrill’, ‘Trisher’, ‘Venus’ and ‘Waipuna’ (De and Bhattachrjee, 2011).


Thomas (2001) viewed the requirements for flower forms of commercial growers of Phalaenopsis like strong self -supporting erect inflorescences, long duration of blooms, compact plant size, wide temperature tolerance, disease resistance, firm substances and consistency of colours.



The authors are thankful to the Director, ICAR-NRC for Orchids, Pakyong, Sikkim, India for kind permission to carry out the research work and for providing the facilities during the period.



De L.C., and Bhattacharjee S.K., 2011, ‘Ornamental Crop Breeding’, Pp. 438, Published by Aavishkar Publishers & Distributors, Jaipur, Rajasthan


Fuchs R.F., 1997, Fabulous Vandaceous Intergenerics, Orchids, 66: 350-357


Greef H.D., 2008, Details about D.U.S., Testing for Plant Breeders Rights in Orchids in Europe, Abstracted in Taiwan International Orchid Symposium


Rao A.N., Rajeevan P.K., Srivastav M., Dhiman S.R., and De L.C., 2012, Guidelines for the Conduct of Test for Distinctiveness, Uniformity and Stability on Orchid Cattleya and Phalaenopsis Orchids, Protection of Plant Varieties and Farmers Rights Authority, NASC Complex, New Delhi-110012, Plant Variety Journal of India, 6 (11): 7-116


Tandon P., and Kumaria S., 2010, Orchids Resources of the North East India and their Sustainable Utilization, Biotechnology for Sustainable Development: Achievements and Challenges, Mc Graw Hill Education, India


Thomas F.O.H., 2001, Modern White Phalaenopsis: Origin and Current Status, Orchid Digest, 65(4): 148-154


Wing Y.T., 2001, Vanda ‘Miss Joaquim’, c, Orchid Review, 109 (1237): 25-27


Vij S.P., and Pathak P., 2012, Orchid Diversity: Conservation and Utilization, Proc. Natl. Acad. Sect. B Biol. Sci. (November 2012) 82 (S2): 295


International Journal of Horticulture
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