Recurrent Selection for Tolerance to Barley Yellow Dwarf Virus in Oat

Abstract

Two cycles of recurrent selection were conducted to determine the feasibility and effectiveness of this breeding strategy for improving tolerance to barley yellow dwarf virus (BYDV) in an oat (Avena sativa L.) population. The base population (C0) originated from 57 crosses between eight winter and nine spring oat lines selected for their good agronomic traits and BYDV tolerance and/or crown rust resistance (Puccinia coronata Cda.) A cycle of recurrent selection involved random intermating of the population twice followed by selection of BYDV tolerant plants to provide parents for the next cycle of random intermating. Selection for BYDV tolerance was among single S0 plants that were infected with BYDV isolate PAV and transplanted to the field for observation of BYDV symptoms. To evaluate progress for BYDV tolerance, 300 randomly selected plants from the unselected C0, C1, and C2 populations were grown to one‐leaf stage in transplanting flats and infested with viruliferous Rhopalosiphum padi L. aphids carrying the PAV isolate of BYDV. Plants were transplanted into the field in a completely randomized design with subsampling. A wooden frame cage covered with a nylon net was erected over the experimental area to exclude natural populations of aphids. Heading date and BYD sympton score were recorded for each plant. Based on the mean BYD symptom scores (0 to 9 scale) for the C0, C1, and C2 populations, progress for BYDV tolerance was made after two cycles of recurrent selection. The mean symptom score for C0 was 5.2; that for C1 was 5.0; and the mean symptom score for C2 was 4.3, significantly reduced from that of C0. Thus recurrent selection for BYDV tolerance is effective and feasible in oat.