•Chemical and sensory quality of ciders made using two yeasts and 11 apple cultivars.•S. cerevisiae ciders differed from S. pombe ciders in chemical composition.•Apple cultivar had less influence on ...volatile profile of ciders than yeasts.•S. pombe reduced malic acid content of ciders resulting in lowered sourness.•S. pombe resulted in ‘floral’ flavors compared to ‘cider-like’ in S. cerevisiae.
Composition of volatile compounds and concentrations of sugars and organic acids were studied in apple ciders produced with Saccharomyces cerevisiae and Schizosaccharomyces pombe yeasts using eleven different Finnish apple cultivars. Moreover, sensory quality of selected ciders was studied using check-all-that-apply test with untrained panelists. Seventy-seven volatile compounds were detected in the samples using HS-SPME-GC-MS. In general, the ciders had higher concentrations of higher alcohols, aldehydes, and acetals whereas the juices contained higher contents of C6-alcohols. Simultaneously, fermentation using S. pombe resulted in lower concentrations of malic acid, ethyl pentanoate, ethyl hexanoate, and volatile acids and higher concentrations of residual sugars compared to S. cerevisiae. Ciders made using S. cerevisiae were characterized as ‘alcoholic’ and ‘yeasty’ while S. pombe ciders were more frequently described as ‘sweet’, ‘honey-like’, and less rated as sour. Besides the strong effect by the yeasts, apple cultivars had significant effects on the compositional and sensorial properties of apple ciders.
The preference and behavioral mechanism of the feeding behavior of the woolly apple aphid, Eriosoma lanigerum (Hausmann), on Chinese apple cultivars was investigated using the electrical penetration ...graph (EPG) technique. Feeding of adult aphids was assessed for the four main cultivars of apple in China (Red Fuji, Ralls Genet, Starkrimson, and Jonagold) over an 8-h monitoring period, what that of fourth-instar nymphs was assessed for 8 h on Jonagold only. EPG waveforms representing the details of probing behaviors, parameters were measured for analysis. We found that at the nonphloem phase, the total duration of the nonpenetration (np) waveform and the total duration of the stylet pathway phase (the ‘C wave') on Ralls Genet and Starkrimson were significantly longer than on Red Fuji. In addition, the phloem-feeding phase, the total duration of ‘release of saliva into the phloem’, (the E1 waveform) was significantly longer on Ralls Genet and Jonagold than on Red Fuji. The total duration of the ‘ingestion from sieve cells’ phase (the E2 waveform) on Red Fuji, meanwhile, was significantly longer than on Ralls Genet or Starkrimson. At the same time, when combined with EPG parameters, Red Fuji was found to have no obvious resistance to woolly apple aphid and to be a susceptible cultivar. This experiment also recorded the feeding waveform of fourth-instar aphid nymphs. Based on the phloem and nonphloem parameters recorded in this study, it was inferred that adult aphids are more likely than nymphs to feed on apple trees.
► European apple cultivars vary in polyphenol content and profile. ► Folin-Ciocalteu, TEAC and FRAP are useful screening methods for polyphenols. ► Cultivars can be classified based on the polyphenol ...profile. ► Flavan-3-ols rich apples may cause health benefits comparable to that of chocolate. ► Phenolic acid rich apples may cause health benefits comparable to that of coffee.
It has been reported that polyphenolic compounds from various plant foods produce physiological effects beneficial to health. Nevertheless, comprehensive evaluations of the polyphenol content and profile of different apple cultivars are scarce. This study examined 104 European apple cultivars for 12 polyphenols by UHPLC–MS, total polyphenol content (TPC) by Folin-Ciocalteu and antioxidative potential by Trolox® equivalent antioxidative capacity (TEAC) and ferric reducing antioxidant power (FRAP). The highest concentrations of individual polyphenols were found for epicatechin, procyanidin B2 and chlorogenic acid. Individual apple polyphenols ranged from below the limit of detection (LOD) to 70mg/100g FM, and varied strongly between the different cultivars. The TPC varied from 49mg to 377mg catechin equivalents (CE) per 100g, and was much higher than the sum of the 12 individual polyphenols. TPC as well as the antioxidative potential correlated well with the sum of individual polyphenols as quantified by UHPLC–MS. Based on this polyphenol profiling, apples can be divided into flavan-3-ol predominant or phenolic acid predominant cultivars. Both classes of polyphenols are reported in the literature as having physiological effects beneficial to health.
The functional response of natural enemies and their interactions may be affected by host plant characters. Functional response of the adult females of the predatory mite, Typhlodromus bagdasarjani ...Wainstein and Arutunjan to protonymphs of Eotetranychus frosti (McGregor) on four apple cultivars Imperial Gala, Kohanz Golab, Granny Smith and Lebanon Red was investigated. The protonymphs of E. frosti were offered to the adult female of the predator at densities of 2, 4, 8, 16, 32, 64 and 128 on apple leaf discs (4 cm2). The number and length of trichomes on the lower surface of each apple cultivar were measured. The highest and lowest number of trichomes were observed in Granny Smith and Kohanz Golab, respectively. Typhlodromus bagdasarjani adult females exhibited the type II functional response on E. frosti protonymphs regardless of apple cultivars. Also, the values of attack rate (a) and handling time (Th) were determined using the Rogers's type II model. Adult females of T. bagdasarjani had the highest attack rate (a) (0.0747 h1) and the shortest handling time (0.7005 h) on Kohanz Golab, and the lowest attack rate (0.0334 h1) and the longest handling time (1.1189 h) was on Granny Smith. The theoretical maximum predation rate (T/Th) on Kohanz Golab, Imperial Gala, Lebanon Red and Granny Smith were 34.26, 33.79, 26.85 and 21.45 prey/day, respectively. The estimated value of a/Th indicated that T. bagdasarjani was most effective against E. frosti on Kohanz Golab with lowest number of trichomes. The finding of this study shows that the predation and searching activity of the predator was affected by trichome density and length of the apple leaves.
Apple cultivar classification is challenging due to the inter-class similarity and high intra-class variations. Human experts do not rely on single-view features but rather study each viewpoint of ...the apple to identify a cultivar, paying close attention to various details. Following our previous work, we try to establish a similar multiview approach for machine-learning (ML)-based apple classification in this paper. In our previous work, we studied apple classification using one single view. While these results were promising, it also became clear that one view alone might not contain enough information in the case of many classes or cultivars. Therefore, exploring multiview classification for this task is the next logical step. Multiview classification is nothing new, and we use state-of-the-art approaches as a base. Our goal is to find the best approach for the specific apple classification task and study what is achievable with the given methods towards our future goal of applying this on a mobile device without the need for internet connectivity. In this study, we compare an ensemble model with two cases where we use single networks: one without view specialization trained on all available images without view assignment and one where we combine the separate views into a single image of one specific instance. The two latter options reflect dataset organization and preprocessing to allow the use of smaller models in terms of stored weights and number of operations than an ensemble model. We compare the different approaches based on our custom apple cultivar dataset. The results show that the state-of-the-art ensemble provides the best result. However, using images with combined views shows a decrease in accuracy by 3% while requiring only 60% of the memory for weights. Thus, simpler approaches with enhanced preprocessing can open a trade-off for classification tasks on mobile devices.
Fire blight is a devastating disease of apple, pear and quince caused by the Gram-negative bacterium
Erwinia amylovora
. As antibiotics are not allowed against fire blight in Switzerland, ...optimization of alternative plant protection strategies is required. In this context, fire blight tolerant cultivars become of higher importance to control the disease. A plant protection product efficacy trial against fire blight with the susceptible cultivar ‘Gala Galaxy’ and the tolerant cultivar ‘Ladina’ bred at Agroscope was set up at the Agroscope Steinobstzentrum Breitenhof in 2018. Four different treatment strategies, including an untreated control, were tested on both cultivars after inoculation with
Erwinia amylovora
. ‘Ladina’ showed less fire blight blossom cluster infection in untreated and treated plants compared to ‘Gala Galaxy’. Blossom cluster infection rates following different plant protection treatments did not differ significantly from each other in ‘Gala Galaxy’ whereas they did in ‘Ladina’.
This study analyzed factors influencing cultivation area of two major apple cultivars, Fuji and Hongro, applying the panel SUR model to survey data from farms. Characteristics of farms, distribution ...factors, and weather factors were the independent variables of the model. The analysis indicated that characteristics of farms, distribution factors, and weather factors influence the cultivation area of Hongro and Fuji. The independent variables were also found to have different levels of influence on increase and decrease of the cultivated area. Helping predict changes in cultivation area of Hongro and Fuji, the research results can be used as primary data to support efforts to prevent price fluctuations due to changes in supply.
During gene transfer in apple, optimization of antibiotics concentration in post co-cultivation process is critical for the establishment of an efficient transformation system. Keeping in view, the ...doses of kanamycin (5–25 mg/l) and cefotaxime (100–500 mg/l) alone or in combinations were evaluated for their effects on callus induction and shoot regeneration. Cefotaxime at 100–500 mg/l was also tested for the inhibition of Agrobacterium tumefaciens strain EHA105 following co-cultivation with leaf explants of apple cv. Red Chief. In this study, leaf explants were found highly sensitive to kanamycin, a widely used antibiotic in transformed plant selection and recovery of transgenic plants. Low kanamycin doses of 5–8 mg/l resulted in callus induction and shoot regeneration. Maximum shoot regeneration frequency (60.56%) was obtained on 5 mg/l kanamycin and gradually reduced (12.84%) upto 8 mg/l. It reduced callus induction, completely inhibited the regeneration at 9–25 mg/l and developed chlorosis of leaves. Cefotaxime at 100–200 mg/l enhanced the regeneration rate (95–100%) from leaves comparable to control while higher concentrations gradually reduced the frequency of regeneration with decreased number of shoots per explant. However, no callus and regeneration were observed when kanamycin was combined with cefotaxime at various concentrations. Omission of kanamycin from initial regeneration phase for few days resulted in shoot induction. To eliminate the Agrobacterium overgrowth from cultured leaves, 500 mg/l cefotaxime was found effective. As this concentration inhibited the shoot induction, it was gradually reduced to 200 mg/l over a period of 7 weeks, which stimulated morphogenesis and later formed shoots. Thus, the optimized doses established in the present study could be applicable to suppress the excess Agrobacterium growth and to generate transformed shoots in further genetic transformation work on ‘Red Chief’.
Tracking newly emergent virulent populations in agroecosystems provides an opportunity to increase our understanding of the co-evolution dynamics of pathogens and their hosts. On the one hand host ...plants exert selective pressure on pathogen populations, thus dividing them into subpopulations of different virulence, while on the other hand they create an opportunity for secondary contact between the two divergent populations on one tree. The main objectives of the study were to explore whether the previously reported structure between two Venturia inaequalis population types, virulent or avirulent towards Malus x domestica cultivars carrying Rvi6 gene, is maintained or broken several years after the first emergence of new virulent strains in Poland, and to investigate the relationship between 'new' and 'native' populations derived from the same commercial orchards. For this purpose, we investigated the genetic structure of populations of the apple scab fungus, occurring on apple tree cultivars containing Rvi6, Rvi1 or Rvi17 resistance gene or no resistance at all, based on microsatellite data obtained from 606 strains sampled in 10 orchards composed of various host cultivars.
Application of genetic distance inferring and clustering methods allowed us to observe clear genetic distinctness of the populations virulent towards cultivars carrying Rvi6 gene from the Rvi6-avirulent populations and substructures within the Rvi6-group as a consequence of independent immigration events followed by rare, long-distance dispersals. We did not observe such a structuring effect of other genes determining apple scab resistance on any other populations, which in turn were genetically homogenous. However, in two orchards the co-occurrence of strains of different virulence pattern on the same trees was detected, blurring the genetic boundaries between populations.
Among several resistance genes studied, only Rvi6 exerted selective pressure on pathogens populations: those virulent toward Rvi6 hosts show unique and clear genetic and virulence pattern. For the first time in commercial Malus x domestica orchards, we reported secondary contacts between populations virulent and avirulent toward Rvi6 hosts. These two populations, first diverged in allopatry, second came into contact and subsequently began interbreeding, in such way that they show unambiguous footprints of gene flow today.
PDF
