SYMPTOM EXPRESSION DUE TO BARLEY YELLOW DWARF VIRUS IN OATS AND WHEAT AND INHERITANCE OF RESISTANCE IN OATS
Abstract
Low (34 kg/ha) and high (78 kg/ha) nitrogen treatments were applied to control and barley yellow dwarf virus (BYDV) infected plants of 5 oat (Avena sativa L.) cultivars, and germplasm lines to determine the effect of nitrogen fertilization on symptom expression. The high nitrogen rate increased plant height and delayed heading date in control and infected plants. Seed yield was reduced by BYDV infection. Ill 70-1297 was most resistant to BYDV compared to CI 9312, Otee, and Noble, in order of decreasing levels of resistance. Control and BYDV-infected plants of 11 oat cultivars were grown in the field to determine the effect of BYDV on yield and other plant characters. Infected plants differed from control plants for symptom score, plant height, seed yield, 200-kernel weight, and percent groat protein in 1978, and for symptom score, heading date, and plant height in 1980. Symptom score of infected plants was positively correlated with percentage reduction due to BYDV for plant height and seed yield. Seed yield reduction was positively correlated with plant height reduction. Symptom score, plant height, and seed yield appeared to be the most effective traits for identifying differences due to BYD. Winter wheats (Triticum aestivum L. em Thell.) were infected or not infected (control) with BYDV to determine the effect of BYDV on yield and other plant characters. Symptom score of infected plants was positively correlated with percentage reduction in number of spikes, plant height, and seed yield. Reduction in number of spikes was correlated with plant height reduction and seed yield reduction. A positive correlation existed between reduction in plant height and reduction in seed yield. BYDV-infected parental and progeny populations of 4 oat crosses were evaluated for 4 traits to determine the inheritance of resistance to BYDV. The mode of inheritance indicated by the data varied from year to year, probably because of effects of different environments on symptom expression or on expression of the alleles themslves, or to differences in virus strains comprising the field collection used for infection.
Degree
Ph.D.
Subject Area
Agronomy
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