IN WESTERN ROMANIA, WHEAT YELLOW DWARF VIRUS BECOME A DISEASE PROBLEM CAUSED BY CHANGING CLIMATE

Abstract

Winter wheat is most susceptible to yellow dwarfed virus and most damaged during its seedling stages and the beginning of stem elongation. Leaf discoloration in shades of yellow, red or purple from the tip down and from the margin to midrib is a typical symptom of BYDV attack. The experiment vas conducted during the year 2019-2020, in the experimental field of wheat breeding laboratory of the Agricultural Research and Development Station Lovrin, placed near the town Oradea, in the North-west of Romania. The autumn of year 2019 were unusually very worm and very humid too, prolonged until the middle of December, favourable the fly of aphides. With a single exception (the cultivar Biharia), all the genotypes that exceed the trial average of yield (Abundent, Bogdana, Otilia, Simnic 60 and F. 14.078 GP 1) had the BYDV average note from 3.2 to 3.6. The best varieties have either cultivar OTILIA or the breeding line Fundulea 14.078 GP 1 in their pedigree. Both of them derived from a triticale/wheat cross. The aphides prefer the grown juicy of leaves of belated genotypes (Bezostaya 1, Dacic, Adelina). The genotypes with good resistance to drought (Bogdana, Ursita, Abundent) are less preferred by aphides. The yield was negative affected by yellowing of leaves, purple leaf coloration and blacken ears of plants. The first simptoms are caused by autumn infection of plants with virions but purple leaf coloration is caused by the new fly of aphides during the earing period. Blacken ears of plants seems to be caused only by the purple leaf coloration. The date of earring correlate negatively with the virus symptoms (yellowing, purple leaf coloration and blacken ears). The genotypes which are earlier are more affected by BYDV.