Improved method for detectingUstilago nudain barley seed

Abstract

Loose smut of barley (Ustilago nuda) is a seed-borne fungal disease in which the fungus is located inside the embryo. The transmission of this disease is highly likely in the field through seed exchange because the seed is symptomless. Therefore, increasing seed movement necessitates specific solutions to guarantee smut-free seed and reduce the unnecessary use of seed treatment. The International Centre for Agricultural Research in the Dry Areas (ICARDA) Seed Health Laboratory, like most seed health and quarantine laboratories, detects U. nuda using the International Seed Testing Association method 7-013. This method is sensitive and reliable, but requires 2 days to complete the assay. A new and more rapid detection method for barley loose smut was developed at ICARDA -reducing the test period to just 5 h. The methodology involved soaking 2000 barley seeds in sodium hydroxide and then heating them at 40°C for 3.5 h. This was followed by pre-separation with sodium chloride (NaCl) solution for 15 min and then collecting the embryos on 0.71 mm mesh. Afterwards, the embryos were separated using a NaCl solution, with a mixture of 1:1 glycerol and water. The new method was fast, simple, reliable and very sensitive. This test can be used by seed health laboratories and regulatory and quarantine authorities to ensure that only smut-free loose seed are introduced.

Development of a marker within the candidateUn8true loose smut resistance gene for use in barley breeding

“…Barley was domesticated approximately 10.000 years ago (Andersen et al, 2016) and now it is the fourth most important crop in the world (Nadolska-Orczyk1 et al, 2017, Asaad et al, 2013. Barley is one of the most adaptable cereal crops (Zhou, 2010), and is cultivated over a wide range of latitudes (Haas et al, 2019, Gürel et al, 2016.…”

“…Currently most grown cultivars are susceptible to loose smut. Disease controlling is done by mainly using uninfected seed or seed coated with systematic fungicides (Asaad et al, 2013;Eckstein et al, 2002). If infected seed is treated with fungicide, it reduces crop quality and quantity.…”

“…Infection effectively takes place immediately before pollination until 4-8 days after (Pedersen, 1960;Wunderle et al, 2012). Infection rates are increased in cool high-rainfall areas and the year following a wet spring (Asaad et al, 2013).…”

Development of a Marker within the Candidate Un8 True Loose Smut Resistance Gene for Use in Barley Breeding

“…Barley was domesticated approximately 10,000 years ago (Andersen et al, 2016) and now it is the fourth most important crop in the world (Asaad et al, 2013;Nadolska-Orczyk1 et al, 2017). Barley is one of the most adaptable cereal crops (Zhou, 2010), and is cultivated over a wide range of latitudes (Gürel et al, 2016;Haas et al, 2019).…”

“…(U. nuda) infects barley in all cultivation areas worldwide (Eckstein et al, 2002;Asaad et al, 2013). In epidemic years, U. nuda has caused yield losses of more than 30% (Asaad et al, 2013). Currently most grown cultivars are susceptible to loose smut.…”