Germination Tests

The International Seed Testing Association (ISTA) has a set of rules pertaining to the testing of germination of a range of plant species. These are contained in the International Rules for Seed Testing which is updated annually. According to ISTA, germination is defined as "the emergence and development of the seedling to a stage where the aspect of its essential structures indicates whether or not it is able to develop further into a satisfactory plant under favourable conditions in the soil". All the information to conduct a germination test for a particular crop is given in detail. This includes what substrate to use to plant the seeds, what temperature/s to incubate the planted seeds, what days to evaluate the seedlings and how to evaluate the seedlings. For example, Pinus radiata should be planted on top paper and incubated at 20°C, the first count to be made at 7 days and the final count to be made at 28 days. Pinus taeda, although also planted on top paper, needs to be incubated at 20 °C for 16 hours and 30 °C for 8 hours. The counts are made on the same days. An additional recommendation is to use a no prechill and a prechill of 28 days at 3 to 5 °C (double test). It is evident then from the above examples that a germination test is not merely placing seeds on blotter paper and then counting how many have emerged. Rules of how to evaluate normal and abnormal seedlings, hard, fresh and dead seeds are given and a handbook on germination with diagrams is available to help with these evaluations.

Germination test on germination paper

Growing media for the germination test

ISTA distinguishes among the following:

Paper substrates

Top of Paper (TP)

Between paper (BP)

Pleated paper (PP)

Sand/Organic growing media

Top of sand (TS)

Top of growing medium (TO)

Sand (S)

Organic growing medium (O)

Paper and Sand

Top of paper covered with sand (TPS)


Vigour Tests

According to ISTA seed vigour is "the sum of those properties that determine the activity and performance of seed lots of acceptable germination in a wide range of environments".Thus a vigorous seed lot should perform well even if environmental conditions are not optimal for growth of that specific species.

Vigour tests include:

The tetrazolium (TTZ) test

The conductivity test

The accelerated ageing test

The cold test

Rapid and slow imbibition test

These tests provide additional information once the germination test has been done. These tests are usually not performed on seed that has a low germination potential. These tests also determine how seeds will perform if stored under sub-optimal conditions.

Seed Health Tests

Seeds may harbour pathogens both inside and on their surfaces. Seeds may be infected with viruses, bacteria, fungi and nematodes which may cause the seed to show various symptoms or may be dormant until the seedling emerges or until a certain plant age is reached. Some of these pathogens may be quarantine pests whilst others may give rise to epidemics. Most, however, are usually the cause of diseases being established in new fields or regions and/or may cause widespread disease to adjacent fields/crops when spores are dispersed from infected plants. ISTA has a range of tests that are used to test for seedborne pathogens. These tests have all been validated and are reviewed every 5 years. All new methods undergo an extensive validation procedure involving several laboratories worldwide before they are published in the ISTA Rules.

New Publications

Aveling TAS, De Ridder K, Olivier NA, Berger DK. (2020) Seasonal variation in mycoflora associated with asymptomatic maize grain from small-holder farms in two provinces of South Africa. Journal of Agriculture and Rural Development in the Tropics and Subtropics (JARTS) 121(2):265-275. 10.17170/kobra-202011262275 PDF
Berger DK, Mokgobu T, De Ridder K, Christie N, Aveling TAS. (2020) Benefits of maize resistance breeding and chemical control against northern leaf blight in smallholder farms in South Africa. South African Journal of Science 12(11) 10.17159/sajs.2020/8286
Godfrey, Aveling, B. Flett, M. Truter. (2020) Control of Alternaria leaf blight caused by Alternaria alternata on sunflower using fungicides and Bacillus amyloliquefaciens. Crop Protection 132:1-7. https://doi.org/10.1016/j.cropro.2020.105146 PDF
T.A.S. Aveling , Chirwa P, Edgar Mangwende. (2020) Evaluation of seed treatments against Colletotrichum kahawae subsp. cigarro on Eucalyptus spp.. Crop Protection PDF
Zelda, Zelda, Terry, D.A. Cowan, A. Jacobs. (2020) Diversity and seasonality of fungal communities in soil from the SucculentKaroo biodiversity hotspot, South Africa. Journal of Arid Environments 172:1-7. https://doi.org/10.1016/j.jaridenv.2019.104020 PDF
Mangwende E, Kritzinger Q, Aveling TAS. (2019) Control of Alternaria leaf spot of coriander in organic farming. European Journal of Plant Pathology 10.1007/s10658-019-01682-6 PDF
Mandiriza G, Kritzinger Q, Aveling TAS. (2018) The evaluation of plant extracts, biocontrol agents and hot water as seed treatments to control black rot of rape in South Africa. Crop Protection 114:129-136. 10.1016/j.cropro.2018.08.025 PDF
Mandiriza G, Kritzinger Q, Aveling TAS. (2018) Seed health and germination of Brassica spp. from seed companies in South Africa. Acta horticulturae :171-176. 10.17660/ActaHortic.2018.1204.22 PDF
Pieterse E, Aveling TAS, Jacobs A, Cowan DA. (2018) Seasonal variability in fungal endophytes from Aizoaceae plants in the Succulent Karoo biodiversity hotspot, South Africa. Journal of Arid Environments 156:19–26. 10.1016/j.jaridenv.2018.05.004
Mangwende E, Aveling TAS, Kritzinger Q, Truter M. (2018) Alternaria alternata: A new seed-transmitted disease of coriander in South Africa. European Journal of Plant Pathology 152(2):409-416. 10.1007/s10658-018-1484-x PDF
van den Berg N, Christie JB, Engelbrecht J, Aveling TAS. (2018) Callose and β-1,3-glucanase inhibit Phytophthora cinnamomi in a resistant avocado rootstock. Plant Pathology 67(5):1150-1160. 10.1111/ppa.12819
Terry Aveling, Truter M, Ramusi TM, Flett B, Godfrey Kgatle. (2018) Alternaria alternata, the causal agent of leaf blight of sunflower in South Africa. European Journal of Plant Pathology (151):677 – 688. 10.1007/s10658-017-1402-7 PDF
Appolinaire A., Thierry R., Theresa A.S. Aveling. (2017) Phenolic content as an indicator of resistance of cowpea seedlings to Sclerotium rolfsii.. European Journal of Plant Pathology 149(2):245-251. 10.1007/s10658-017-1178-9 PDF
Ramusi TM, Van Der Waals JE, Labuschagne N, Aveling TAS. (2017) Evaluation of mefenoxam and fludioxonil for control of Rhizoctonia solani, Pythium ultimum and Fusarium solani on cowpea.. South African Journal of Plant and Soil 34(1):27-33. 10.1080/02571862.2016.1155764 PDF
Masangwa J, Kritzinger Q, Aveling TAS. (2017) Germination and seedling emergence responses of common bean and cowpea to plant extract seed treatments.. The Journal of Agricultural Science 155(1):18-31. 10.1017/S0021859616000113 PDF
Kandolo SD, Thompson AH, Calitz FJ, Laurie SM, Truter M, Van Der Waals JE, Aveling TAS. (2016) Field tolerance of selected varieties to and fungicide efficacy against Alternaria blight of sweet potato.. African Crop Science Journal 24(3):331-339. 10.4314/acsj.v24i3.9 PDF
Ndunguru J, Ascencio-Ibáñez JT, Aveling TAS, Tohme J, Thompson G, Legg JP, Plata G, Sseruwagi P, Doyle CD, De León L, Hanley-Bowdoin L. (2016) Two Novel DNAs That Enhance Symptoms and Overcome CMD2 Resistance to Cassava Mosaic Disease. Journal of virology 90(8):4160-4173. 10.1128/JVI.02834-15 PDF
Mandiriza G, Kritzinger Q, Aveling TAS. (2016) A survey of brassica vegetable smallholder farmers in the Gauteng and Limpopo provinces of South Africa.. Journal of Agriculture and Rural Development in the Tropics and Subtropics 117(1):35-44. PDF
Rudolph N, Aveling TAS, Labuschagne N. (2015) The effect of plant growth promoting rhizobacteria on seed germination, vigour and seedling growth of maize. Seed Science and Technology 43(3):507-518. 10.15258/sst.2015.43.3.04
Mangwende E, Kabengele JBK, Truter M, Aveling TAS. (2015) First Report of White Rust of Rocket (Eruca sativa) Caused by Albugo candida in South Africa. Plant Disease 99(2):290. 10.1094/PDIS-09-14-0947-PDN
Bekker TF, Aveling T, Labuschagne N, Regnier T, Kaiser C. (2014) Effects of soil drenching of water-soluble potassium silicate on commercial avocado (Persea americana Mill.) orchard trees infected with Phytophthora cinnamomi Rands on root density, canopy health, induction and concentration of phenolic compounds. South African Journal of Plant and Soil 31(2):101-107. 10.1080/02571862.2014.912687 PDF
Aveling TAS. 2014. Global Standards in Seed Health Testing. In: Global Perspectives on the Health of Seeds and Plant Propagation Material. Springer, Netherlands, pp 17-28.
Aveling TAS, Govender V, Kandolo DS, Kritzinger Q. (2013) The effects of treatments with selected pesticides on viability and vigour of maize (Zea mays) seeds and seedling emergence in the presence of Fusarium graminearum. Journal of Agricultural Science 151:474-481. 10.1017/S0021859612000457 PDF
Govender V, Kandolo DS, Kritzinger Q., Aveling TAS. (2013) The effects of treatments with selected pesticides on viability and vigour of maize (Zea mays) seeds and seedling emergence in the presence of Fusarium graminearum. Journal of Agricultural Science 151(4):474-481. 10.1017/S0021859612000457 PDF
Masangwa JIG, Aveling TAS, Kritzinger Q. (2013) Screening of plant extracts for antifungal activities against Colletotrichum species of common bean (Phaseolus vulgaris L.) and cowpea (Vigna unguiculata (L.) Walp). Journal of Agricultural Science 151:482-491. 10.1017/S0021859612000524 PDF
Thompson RS, Aveling TAS, Prieto RB. (2013) A new semi-selective medium for Fusarium graminearum, F. proliferatum, F. subglutinans and F. verticillioides in maize seed. South African Journal of Botany 84:94-101. 10.1016/j.sajb.2012.10.003 PDF
Domola MJ, Thompson GJ, Aveling TAS. (2008) Sweet potato viruses in South Africa and the effect of viral infection on storage root yield. African Plant Protection 14:15-23. PDF
Govender V, Aveling TAS, Kritzinger Q. (2008) The effect of traditional storage methods on germination and vigor of maize (Zea mays.) from northern Kwazulu-Natal and southern Mozambique. South African Journal of Botany 74:190-196. 10.1016/j.sajb.2007.10.006 PDF
Adandonon A, Aveling TAS, Labuschagne N, Tamo M. (2006) Biocontrol agents in combination with Moringa oleifera extract for integrated control of Sclerotium caused cowpea damping-off and stem rot. European Journal of Plant Pathology 10.1007/s10658-006-9031-6 PDF
Kritzinger Q, Aveling TAS, van der Merwe CF. (2006) Phytotoxic Effects of Fumonisin B1 on Cowpea Seed. Phytopathological/Mycology 34(2):178-186. PDF
Ndunguru J, Legg JP, Fofana IBF, Aveling TAS, Thompson G, Fauquet CM. (2006) Identification of a detective molecule derived from DNA-A of the bipartite begomovirus of East African cassava. Plant Pathology 55:2-10. 10.1111/j.1365-3059.2005.01289.x PDF
Adandonon A, Aveling TAS, Labuschagne N, Ahohuendo BC. (2005) Etiology of and effect of environmental factors on damping-off and stem rot of cowpea in Benin. Phytopathological/Mycology 33(1):65-72. PDF
Adandonon A, Aveling TAS, van der Merwe NA, Sanders G. (2005) Genetic variation among Sclerotium isolates from Benin and South Africa, determined using mycelial compatibility and ITS rDNA sequence data. Australian Plant PAthology 34:19-25. 10.1071/AP04071 PDF
Aveling TAS, Powell AA. (2005) Effect of seed storage and seed coat pigmentation on susceptibility of cowpeas to pre-emergence damping-off. Seed Science and Technology 33:461-470. PDF
Kritzinger Q, Lall N, Aveling TAS. (2005) Antimicrobial activity of cowpea (Vigna unguiculata) leaf extracts. South African Journal of Botany 71(1):45-48. PDF
Ndunguru J, Taylor NJ, Yadav J, Aly H, Legg JP, Aveling TAS, Thompson G, Fauquet CM. (2005) Application of FTA technology for sampling, recovery and molecular characterisation of viral pathogens and virus-derived transgenes from plant tissues. Virology Journal 2:45-57. 10.1186/1743-422X-2-45 PDF
Ndunguru J, Legg JP, Aveling TAS, Thompson G, Fauquet CM. (2005) Molecular biodiversity of cassava begomovirus in Tanzania: evolution of cassava geminiviruses in Africa and evidence for East Africa being a center of diversity of cassava geminiviruses. Virology Journal 2(21):1-23. 10.1186/1743-422X-2-21 PDF
Adandonon A, Aveling TAS, Tamo M. (2004) Occurence and distribution of cowpea damping-off and stem rot and associated fungi in Benin. Journal of Agricultural Science 142:561-566. 10.1017/S0021859604004629 PDF
Kritzinger Q, Aveling TAS, Marasas WFO, Rheeder JP, Van Der Westhuizen L, Shephard GS. (2003) Mycoflora and Fumonisin Mycotoxins Associated with cowpea [Vigna unguiculata (L.) Walp] seeds. Journal of Agricultural and Food Chemistry 51(8):2188-2192. 10.1021/f026121v PDF
van der Waals JE, Korsten L, Aveling TAS, Denner FDN. (2003) Influence of Environmental Factors on Field Concentrations of Alternaria solani Conidia above a South African Potato Crop. Phytopathological/Mycology 31(4):353-364. PDF
van den Berg N, Venter SL, Aveling TAS . (2003) Infection studies of Alternaria cassiae on cowpea. Australasian Plant Pathology 32 10.1071/AP02056
Kritzinger Q, Aveling TAS, Marasas WFO. (2002) Effect of essential plant oils on storage fungi, germination and emergence of cowpeas. Seed Science and Technology 30:609-619. PDF
Pakela YP, Aveling TAS, Coutinho TA. (2002) Effect of plant age, temperature and dew period on the severity of anthracnose of cowpea caused by Colletotrichum dematium. African Plant Protection 1 PDF
van den Berg N, Aveling TAS, Venter SL. (2002) The evaluation of six fungicides for reducing Alternaria cassiae on cowpea seed. Crop Protection 21:501-505. PII:S0261-2194(01)00140-5 PDF
van den Berg N, Aveling TAS, van der Merwe CF. (2002) Conidial morphology and development of Alternaria cassiae from cowpea. African Plant Protection 8(1):69-74. PDF
Adandonon A, Aveling TAS, Labuschagne N, Ahohuendo BC. (2001) Pythium/Rhizoctonia complex causing damping-off of cowpea in South Africa. African Plant Protection 7(2):111-113. PDF
Henning BJ, Snyman HG, Aveling TAS. (2001) Plant soil interactions of sludge-borne heavy metals and the effect on maize (Zea mays L.) seedling growth. Water SA 27(1):71-78. ISSN 0378-4738 PDF
van der Waals JE, Aveling TAS, Korsten L. (2001) A review of early blight of potato. African Plant Protection 7(2):1-12. PDF
Smith JE, Korsten L, Aveling TAS. (1999) Infection process of Colletotrichum dematium on cowpea stems. Mycological Research 103(2):230-234. PDF