Inheritance of Resistance to Barley Yellow Dwarf Virus Detected by Northern Blot Analysis
- G. F. Lorens ,
- C. O. Qualset and
- B. W. Falk
Development of wheat (Triticum aestivum L.) cultivars tolerant to the barley yellow dwarf virus disease (BYD) has been limited by lack of precision in rating plants for response to infection, usually done by visual scoring of plant symptoms under field conditions. Other methodologies have been developed to study the host/pathogen relationship and to assess resistance or susceptibility. In this study northern dot blot analysis was used to determine barley yellow dwarf virus (BYDV) UNA concentrations of six wheat cultivars that differed in visual BYD symptom expression. Plants were infected with the NYPAV (PAY) isolate of BYDV in the greenhouse. At several dates after inoculation crude plant extracts were blotted on nitrocellulose and hybridized with a 32P-labeled probe of the pPA8 cDNA clone of BYDV. Scintillation counts of a dilution series of purified plasmid were used to determine PAY RNA concentration (PRC). Seri 82, a susceptible cultivar, had statistically greater PRC than NS 879/4, a cultivar showing tolerance based on symptom expression in the field. The frequency distribution for PRC for 122 F2 plants from the cross of these two cultivars was multimodal, but showed no discrete classes. The F2 mean PRC was greater than the mean of either parent. Selection of F2 plants with either high PRC or low PRC resulted in good bidirectional response to selection in the F3 generation, demonstrating genetic control of PRC. The F3 data also indicated that variation for greater susceptibility than either parent in the F2 generation was genetically controlled. Both NS 879/4 and Seri 82 appear to each have genes for reduced PRC and these genes are probably at different loci. The distribution of PRC for the F2 population was compared to the distribution of BYD visual symptom scores for 403 F2 plants of a similar F2 population of NS 879/4 ✕ Seri 82 under field conditions. The results were qualitatively similar, suggesting that northern dot blot analysis to measure PRC may be useful in understanding the genetics of resistance to BYD. This technique, when incorporated into breeding programs, could be important in the development of highly tolerant wheat cultivars with reduced losses to BYD.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 1989.