Exploiting intra-cultivar variation to select forBarley yellow dwarf virus-PAV(BYDV-PAV) resistance in barley

Abstract

Selection within elite barley cultivars is assumed to be ineffective due to the belief that inbred cultivars are highly homogeneous. The objective of the present work was to evaluate a selection procedure (Honeycomb design) applied within five barley cultivars (Manel, Rihane, Kounouz, Lemsi, and Imen) and two Tunisian landraces (Ardhaoui and Djebali) under ultra-low plant density (1.2 plants m−2) towards selecting high-performance lines with resistance to Barley yellow dwarf virus-PAV (BYDV-PAV). Lines selected through this process were further field-evaluated in hill plots under artificial BYDV-PAV inoculation and uninoculated control conditions during the 2016–2017 cropping season. Artificial inoculation in the field caused a severe reduction in agronomic performance traits, with yield loss reaching around 60%. However, two lines (IH16-H1 and IH4-L0) originating from cultivar Imen were significantly superior over the mother variety in the control field, showing at the same time minimum yield loss after BYDV-PAV inoculation not exceeding 10%, similar to the resistant check. Genotyping of the lines for the Ryd2 and Ryd3 resistance genes and assessment of visual symptoms in the field associated with reduction in yield revealed an additive effect of the genes conferring resistance to BYDV-PAV. However, there were lines with genotypic patterns that did not match the patterns of the source material, providing insights for exploitable intra-cultivar diversity within the barley cultivars and landraces assessed.

Crop resilience via inter-plant spacing brings to the fore the productive ideotype

“…Other reports of successful selection exist in snap bean ( Phaseolus vulgaris L.; Traka-Mavrona et al, 2000 ), tomato ( Solanum lycopersicum L.; Christakis and Fasoulas, 2002 ; Avdikos et al, 2021 ), and barley (Tsivelikas et al, 2022 ). Nil-competition, accentuating the interplant phenotypic differences, allowed the method to exploit narrow genetic variation of commercial varieties and upgrade yield performance, e.g., in crops of wheat (Fasoula, 1990 ; Tokatlidis et al, 2006 ), maize (Tokatlidis, 2000 ), cotton (Tokatlidis et al, 2011b ), barley (Ben Ghanem et al, 2018 ), and soybean (Fasoula and Boerma, 2007 ; De Almeida Lopes et al, 2020 ). Tokatlidis and Vlachostergios ( 2016 ) also suggested a conservation honeycomb breeding procedure for sustainable stewardship of the landrace diversity and continuous adaptation to an ever-changing environment.…”

Single-Plant Selection at Ultra-Low Density Enhances Buffering Capacity of Barley Varieties and Landraces to Unpredictable Environments and Improves Their Agronomic Performance

“…The whole procedure resulted in 12 first cycle lines (8 high yielding and 4 low yielding) and 38 second cycle lines (30 high yielding and 8 low yielding) to be assessed in the next seasons' dense stand trials. The honeycomb experimental field layouts and the selection procedure applied for two consecutive years are described in detail by Ben Ghanem et al (2018). A summary of the selection history of the progeny lines is given in Table 1.…”

“…In the 2016 growing season, the 50 first and second cycle selected lines along with five checks (source seed lots of Imen, Ardhaoui, Djebali, Manel, and Rihane) were planted as dense stand field trials at the National Agricultural Research Institute of Tunisia (INRAT) experimental stations in El Kef (36 Ghanem et al, 2018). The coding of lines is based on two letters and the number of the selected plant.…”