Grapevine leafroll‐associated virus 3 (GLRaV‐3; Ampelovirus, Closteroviridae) isolates from Galicia in northwestern Spain were selected to characterize their genetic diversity according to different factors (age, origin, location, variety, etc.). The vines belonged either to local white and red varieties autochthonous to Galicia or to varieties from other Spanish regions but widely used in Galicia. These GLRaV‐3 isolates came from different vineyards in Galicia located in coastal or inner areas. Multiplex RT‐PCR allowed the detection of isolates belonging to groups I, II, III–V and VI. Two genomic regions were studied in the isolates, the HSP70h and the capsid protein, using specific primers that allow the detection of variants from groups I to V. Some possible recombinants could be detected; however, multiple infections with different variants indicated that they were not genuine recombinants. No differences were found in the population structure considering variety or geographical factors. Isolates belonging to four groups were found in the distinct areas surveyed: groups I and II were the most common, followed by groups VI and III, as is the case in the rest of the world. In the same surveys, the presence of insect vectors for GLRaV‐3 was investigated and found lacking in inland areas but present in those with milder climate. Genetic analysis did not support isolation of the GLRaV‐3 isolates in Galicia, suggesting that the uncontrolled exchange of infected vines and/or rootstocks has been a major agent of virus spread.

The detrimental effects of grapevine leafroll disease (GLD) have been documented mainly in young plantsand little data is available on infected grapevines when they reach maturity. This study examined theinfluence of the rootstock on the effect of GLRaV-3 in a 20-year-old Vitis vinifera cv Albariño vineyard inwhich the virus has been spread by Planococcus ficus. Plants grafted on Richter 110 or Castell 196.17 withsimilar development were analysed for grapevine leafroll-associated viruses. In particular, 25 GLRaV-3-infected and 25 leafroll-free and asymptomatic vines were selected and monitored during a period of threeyears to determine grape yield and must components. Although the virus infection affected plants on bothrootstocks, it caused a greater effect on plants grafted onto 110R, with average accumulated yield losses ofup to 33%, relative to losses of 16% for plants on 196.17C. The sugar content was lower in the must frominfected plants on 110R (-2.1ºBrix) than in the must from plants on 196.17C (-1.5ºBrix). The presence ofthe virus was associated with decreased concentrations of primary amino nitrogen (PAN) and ammonium(NH4+), with the greatest effect for 110R (-35%). As 110R is the most used rootstock in Spain, particularcare must be taken to prevent the transmission of GLRaV-3 to certified virus-free plants on 110R in newvineyards. In sensitive varieties such as Albariño, particularly in areas with an active spread of the virusby mealybugs, grafting on 196.17C seems to minimise the effect that GLD has in a medium to long term.

The mealybug Planococcus ficus is one of the main vectors of Grapevine leafroll associated virus-3 (GLRaV-3), which was commonly detected in cv “Albariño” planting material before certified stock was available. Mealybug infestations were rare in vineyards in southern Galicia (NW Spain) during the 1990s (2.2% of the vineyards surveyed) and are still rare in inland zones. However, mealybug infestations have spread since 2000, with 15% of surveyed vineyards infested in 2004 and 80% of surveyed vineyards infested in 2016. The spatial and temporal distributions of plants infected with GLRaV-3 were quantified over a 30-year period in an experimental plot established in 1989. The disease progress curve (DPC) was linear for 25 years, with a slow constant rate of spread of less than one newly infected plant per year (0.6%). Since 1992, >82% of infected plants were located on the west side of the plot as were 84% of newly infected plants. Newly infected plants were in contact with infected plants, suggesting vector-mediated transmission, but no potential vectors were found. In 2013, a small mealybug infestation was detected and identified as Pl. ficus. Between 2014 and 2016, the infection rate increased to >21% per year, and in 2019 all plants tested positive for GLRaV-3. This is a valuable case study illustrating how changes to the vector fauna can increase the rate of spread of an economically important virus of grapevine.

Legumes have an important role in European agriculture. They assimilate N2 to sustainably support maximum crop growth, in turn providing high-protein food for human consumption and livestock feed. However, the extent of the area for legume cultivation in Europe has declined due to the lower economic competitiveness of legumes in relation to other crops, particularly of cereals and oilseed. To increase yields, there is a need to increase the genetic diversity of legumes in terms of adaptation to environmental stresses. We attempted to address this by conducting field and controlled experiments under drought vs. nondrought and different photoperiod conditions. The current study identified the physiological and agronomic traits correlated with productivity and quality performance in five economically important grain legume species (Pisum sativum, Phaseolus vulgaris, Cicer arietinum, Lupinus spp., and Vicia faba). In all species, the days to flowering and seed yield were affected by temperature and photoperiod. For cool-season legume species, long-day photoperiods were favorable and days to flowering was negatively correlated with the average air temperature. For the warm-season legumes, short-day photoperiods and warm temperatures were favorable. Under drought stress, the C/N balance, leaf nutrient (Ca, Fe, and K) concentrations, and yield were significantly reduced, contrary to Zn accumulation, and this information may contribute to improving our understanding and ability to develop sustainable growth. Based on our results, we conclude that the drought-tolerant and photoperiod-insensitive legume genotypes identified in this study constitute valuable starting materials for future programs aimed at improvement of legume productivity at a global/regional scale, which helps to strengthen the competitiveness and economic growth of legumes for European farmers.