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Characterization of radish genetic resources

Contributors to this page: CAAS, China (Qiu Yang, Li Xixiang); Bioversity International, Italy (Imke Thormann, Ehsan Dulloo); CGN, Netherlands (Noortje Bas); IPK, Germany (Andreas Börner, Ulrike Lohwasser); AVRDC, Taiwan (Andreas Ebert); USDA, USA (Larry Robertson); NBPGR, India (Chitra Pandey); SASA, UK (George Campbell); University of Warwick, UK (Charlotte Allender).

Contents:
Cultural practices
Descriptors
Recording information

Cultural practices

Environment

Choose a field in which the previous crop was not a crop belonging to the Brassicaceae family.
Light soils are preferable e.g. sandy loam, silt loam, or soils with high organic matter with good drainage and deep soils with a pH of 6.0-7.0 and uniform fertility.
Surrounding climate (temperature, light, etc.) should meet the requirement of radish plant growth and development.

Season

For vegetative growth

Radish is a cool-weather, short-season vegetable crop. It grows best in cool and moist weather (15-22°C for leaf, 13-18°C for root).
It is grown during spring and autumn in temperate zone and during the cooler parts of the year in the tropics.

For reproductive growth

Radish flowers (bolt) initiate after vernalization. It is important to expose plants to cool outside temperatures below 15°C for at least 20 days.
Another option is to store the germinating seeds or radish seedlings with two leaves in a cool room at 2-5°C for 14 to 40 days. A few accessions need 2-5℃ for more than 60 days.
Temperature at flowering and seed set is optimal at 25± 3 °C. Radish may be sown at the end of winter (January) in a non-heated greenhouse and planted in the field in spring (mid-March In North China).

Plot size

Row to row distance 30-60 cm – 90 cm are used in AVRDC, 3-45 cm between plants depending on the radish type and the vegetative or reproductive growth.
Plant border rows around the plot.

Replications

No replications are needed.

Standard check cultivars

Use standard varieties for all characterizations.

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Descriptors for characterization

A set-up for photographing radish from a CGN characterization field in 2007. (photo: M.Thomas)

Morphological descriptors for characterization

See list for radish descriptors developed by IBPGR, (now Bioversity International, 1990), CAAS descriptors, or UPOV (such as the ‘UPOV Guidelines for the Conduct of Tests for Distinctness, Uniformity and Stability’ for Black Radish (TG/63/6), Fodder Radish (TG/178/3) and Radish (TG/64/6), used by SASA).

Pictures for characterization

Sufficient detail should be captured in images to taxonomically identify the plant and demonstrate the traits that show variation.

Take images for character(s) which may be difficult to describe verbally or to score.
Images of whole plant, racemes (if applicable), flowers, siliques.
Store pictures in a database file linked to other characterization data.

Molecular markers for characterization

SSR, EST-SSR, AFLP, RAPD (more efficient techniques).

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Recording information during characterization

The following information should be recorded for each trial:

Observation location
Culture season and condition
Sowing and planting date.
Bolting date
Fleshy root harvest date
Bolting date
Data collector (full name).
Date of data collection (this may be done several times, record the date of each time for specific character in remarks)
All data of morphological or molecular characterization for each accession

System for characterization data

All basic information, morphological data and pictures should be stored in one of the modules of the genebank documentation system.

References and further reading

Beattie JH. 1882. Production of radishes. [online]. Washington, D.C.. UNT Digital Library. Available from: http://digital.library.unt.edu/ark:/67531/metadc1562/m1/1/. Date accessed June 8, 2010.

Cornell University. 2006. Growing guide: Radishes. [online] Cornell University. Available from http://www.gardening.cornell.edu/homegardening/scene341b.html. Date accessed June 8, 2010.

Dainello FJ. 2003. Radish. Texas Cooperative Extension, Horticulture Crop Guides Series. Available from http://aggie-horticulture.tamu.edu/extension/vegetable/cropguides/radish.html. Date accessed June 8, 2010.

IBPGR. 1990. Descriptors for Brassica and Raphanus. International Board for Plant Genetic Resources, Rome, Italy. Published in association with the Commission of the European Communities. Available here (1.5 MB).

Li XX, Shen D, Wang HP, Song JP et al. 2008. Descriptors and Data Standard for Radish (Raphanus sativus L.). Beijing: Chinese Agricultural Press.

Radish. [online] New world Encyclopedia. Available from http://www.newworldencyclopedia.org/entry/Radish. Date accessed June 8, 2010.

Shippers RR. 2004. Raphanus sativus L. [online] Record from Protabase. Grubben GJH, Denton OA, editors. PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. Available from: http://database.prota.org/search.htm. Date accessed: 22 January 2010.

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