In addition to validating southwestern Ethiopia as a center of origin, the above results have suggested Yemen as one of the centers of domestication of C. arabica. If indeed Yemen were a center of domestication, today’s cultivated varieties of C. arabica should be genetically similar to Yemen cultivars. As predicted, Anthony et al found a number of AFLP and SSR markers present in Yemen cultivars to be similar in the Typica- and Bourbon-derived accessions. Their results fit accordingly with the historical data—that Typica and Bourbon genetic bases diffused from Ethiopian coffee introduced to Yemen , a center of domestication for C. arabica and the primary center of dispersal for coffee .While multiple types of evidences have been analyzed to trace the Ethiopian origin of C. arabica, archaeological evidence is still lacking. On the one hand, multiple sources affirm the strong linkage between coffee consumption and tiny porcelain/earthenware coffee cups, but on the other hand, recovery of such cups is rare. Not only would the sources of these cups help us trace the dissemination of coffee, but the cups themselves could be dated, confirming important dates in coffee history provided by other types of evidence. In addition to cups, other tools used to prepare coffee, such as a mortar and pestle to grind coffee beans, could carry valuable archaeological data. Promising excavation sites would include villages near the rainforests in southwestern Ethiopia, the Sufi monasteries of Yemen, and the trading ports of Yemen . Archaeobotanical evidence, such as seeds, pollen, phytoliths, etc., is almost nonexistent for C. arabica, nft channel which is unfortunate because these remains would prove crucial in verifying conclusions drawn from genetic evidence.Grapevine is an economically important crop worldwide with a global surface area of 7.45 million ha, which is mainly cultivated for wine making.

Califtornia stands out as the fourth leading wine producer in the world with 257,784 ha of wine grapes and 4.28 million tons of grapes harvested in 2018, leading to an annual economic impact of $57.6 billion . Nevertheless, winegrowers face the challenge of replanting their vineyards when grapevines are not producing due to diseases such as grapevine red blotch virus, trunk diseases, or other viral diseases such as leaf roll disease, or because the plant material is producing substandard fruit and consequently compromising the wine quality. However, several factors need to be taken into account when replanting, as improper establishment during this stage causes considerable economic loss to the industry. Arbuscular mycorrhizal fungi are soil-borne fungi that form mutualistic relationships with 80% of the superior plants . In viticultural regions, the AMFgrapevine symbiosis was pointed out as a key component of the vineyard system . Recent research suggested the key role that this symbiosis might play in facing environmental constrains . The application of mycorrhizal inocula has emerged as a reliable technique to enhance the agricultural productivity whereas reducing environmental costs . Frequently, these commercial inoculants consist of a single or few AM fungal isolates grown in plant culture or greenhouse conditions with annual grasses or forbs , hence they might not establish on woody grapevines that have different ecosystem preferences . It is well established that under controlled conditions AMF inoculation of grapevines promotes increased growth , drought tolerance , and nutrient uptake . Moreover, AMF protect grapevines grown in controlled conditions against pathogens through stimulation of key genes of the phenylpropanoid biosynthesis in leaves and inhibit their transmission by impairing the growth of nematode vectors in roots and their reproduction in soils . Although it is widely accepted that AMFgrapevine association improves grapevine growth and mineral uptake in vineyards , contradictory results were recently reported when studying the protective role of the symbiosis against pathogens such as Ilyonectria . Similarly, AMF inoculation may affect berry primary and secondary metabolism in response to environmental stresses when grapevines were cultivated under controlled conditions but little is known about their effect under natural conditions.

Additionally, rootstock genotype and type of inoculum could also influence the effectiveness of mycorrhizal inoculation and therefore the response of young vines to the environment . On the other hand, most wine grape producing regions are subjected to seasonal drought, but based on the global climate models an increase in aridity is predicted in the future. Hence, an optimized irrigation schedule would still be one of the most desirable tools to improve crop productivity and quality in historically non-irrigated viticulture areas where irrigation is expanded fast to mitigate environmental stress . In addition, in warm and hot viticultural regions such as Califtornia that rely on irrigation for crop production, water resources, especially groundwater, are becoming scarce due to extended drought periods and overuse by irrigated agriculture . Currently, winegrowers are aware of the importance of a sustainable viticulture that ensures the profitability in the future, without compromising berry quality. However, to the best of our knowledge little is known about the contribution AMF inoculation may have for implementing the effects of different irrigation amounts on the performance and berry quality of young grapevines under field conditions. Therefore, the aim of this study was to characterize the response of young Merlot grapevines to AMF inoculation subjected to two different irrigation amounts in their first productive year. This study was conducted in the Oakville Experimental Station . The vineyard was planted to Merlot clone 181 on 3,309 C rootstock in 2018 at 3 m × 2 m spacing in E–W orientation. The grapevines were spur pruned and trained to quadrilateral trellis system 1.38 m above vineyard floor with catch wires at 1.68 m. The experimental vineyard was drip-irrigated with one or two emitters spaced every 2 m along the drip line and with the capacity of deliver 3.8 L of water per hour. Natural vegetation was allowed to grow in alleys and mowed according to vineyard manager’s discretion, with a no-till system in place. The experiment consisted in a 2 × 2 factorial design with four replications of seven grapevine plots arranged in a split plot design. The commercial Myco Apply Endo Maxx inoculum consisted in a suspendable powder containing living propagules of Rhizophagus intraradices , Funneliftormis mosseae, Glomus aggregatum, and Glomus etunicatum containing 5,625 propagules/g.

The mycorrhizal inoculum was diluted in water to final concentration of 5.3 mg/L in order to achieve the manufacturer’s recommended rate of 10 g each 1,000 plants. The diluted AMF inoculum was applied in-field drench during 50 s around the trunk of each vine at the beginning of the growing season by using a 56 L spot sprayer. Although the inoculum manufacturer did not report other microorganisms accompanying AMF1 , it is known that commercial AMF inocula, obtained following industrial production processes, are home of a large and diverse community of bacteria with important functional plant promoting growth traits, that may act insynergy with AMF providing additional services and benefits . Therefore, non-inoculated vines received the same amount of a filtrate inoculum with the objective of restoring rhizobacteria and other soil free-living microorganism accompanying AMF and that play an important role in the uptake of soil resources as well as in the infectivity and efficiency of AMF isolates . The filtrate was obtained by passing diluted mycorrhizal inoculum through a Whatman filter paper Grade 5 with particle retention of 2.5 µm . Phosphorus amounts in the vineyard soil was measured before the experiment and was low, thus, that phosphorus level was sufficient to ensure adequate development of non-inoculated plants, even under water deficit and not excessive enough to decrease the mycorrhizal diversity in the vineyard and thereby the root colonization . Irrigation treatments started at the beginning of summer until harvest . Vineyard crop evapotranspiration was calculated by multiplying the reference evapotranspiration and the crop coefficient . Thus, hydroponic nft half of the inoculated and non-inoculated vines were irrigated to ensure the full of expansive growth that corresponded with the amount of water needed to restore the 100% of the ETc . The other half of inoculated and non-inoculated vines received half of the amount of water received by FI plants . Irrigation was applied weekly. Each treatment had four replicates consisting in 7 grapevines, 3 of which were sampled and the 4 on distal ends were treated as border plants. Intraradical AMF colonization was estimated before treatment application , 3 months after treatment application , and at harvest . Root samples from three grapevines per replicate were collected at a depth of 15 and 20 cm away from the vine trunk by using a fork, and stored in zip bags for further analysis. Then, each replicate root sample was washed with water in the sink, cleared, and stained according to methods described in Koske and Gemma . AMF colonization was determined by examining 1-cm root segments under the microscope . Then, intensity of the intraradical mycorrhizal colonization was calculated for each treatment/replicate as described previously by Torres et al. . Briefly, the extension of mycorrhizal colonization was determined by estimating the product of the mycorrhizal colonization in width and length according to a scale range between 0 and 10 where 0 is complete absence of fungal structures. The extension of each treatment/replicate was calculated as the sum of the product of mycorrhizal colonization in width and length divided to the number of root segments. Then, the incidence of mycorrhizal colonization was estimated by dividing the number of root segments with presence of fungal structures and the total observed segments.

Finally, the intensity of the colonization was calculated as the product between the extension and incidence, and the result was expressed as percentage of colonization. Relative mycorrhizal dependency index was calculated following Bagyaraj : RMD = Leaf fresh weight of I vines × 100/Leaf fresh weight of NI vines. This index allows establishment of the crop dependency upon the mycorrhizal symbiosis for reaching its maximum growth for given environmental conditions. All the growth parameters were measured on the three middle vines in each replicate and the values were averaged for the replicate value. Green pruning was carried out before the cluster development to avoid the excessive vegetative growth and ensure a good balance between the growth of vegetative and reproductive organs of the grapevines. Removed shoots from the three middle grapevines were weighed. Trunk diameter was measured with a carbon fiber composite digital caliper . At harvest, leaves were removed and leaf area was measured with a LI- 3100 Area meter . Clusters were harvested and weighted to obtain the yield per vine. Measurements were performed on the three middle grapevines within each replicate and averaged.Thirty berries were randomly collected from the middle vines within each replicate and immediately processed. Berries were weighed and gently pressed by hand to squeeze the juice. Total soluble solids were determined using a temperature compensating digital refractometer . Must pH and titratable acidity were determined with an autotritrator . TA was estimated by titration with 0.1 N sodium hydroxide to an end point of 8.3 pH and reported as g/L of tartaric acid. For flavonoid analysis 20 berries were randomly collected from each treatment-replicate and after gently peeling, skins were freeze-dried . Dried Thissues were ground with a Thissue lyser . Fifty mg of the resultant powder was extracted in methanol: water: 7 M hydrochloric acid to simultaneously determine flavonol and anthocyanin concentration and profile as previously described by MartínezLüscher et al. . Briefly, extracts were filtered and analyzed using an Agilent 1260 series reversed-phase high performance liquid chromatography system coupled to a diode array detector. Separation was performed on a reversed-phase C18 column LiChrospher R100, 250 mm × 4 mm with a 5 µm particle size and a 4 mm guard column of the same material at 25◦C with elution at 0.5 mL per minute. The mobile phase was designed to avoid co-elution of anthocyanins and flavonols and consisted in a constant 5% of acetic acid and the following gradient of acetonitrile in water: 0 min 8%, at 25 min 12.2%, at 35 min 16.9%, at 70 min 35.7%, 65% between 70–75 min, and 8% between 80–90 min. The identification of flavonoid compounds was conducted by determining the peak area of the absorbance at 280, 365, and 520 nm for flavan-3-ols, flavonols, and anthocyanins, respectively. Identification of individual flavan-3- ols, anthocyanins, and flavonols were made by comparison of the commercial standard retention times found in the literature.