Vineyard management practices have an impact on grape berry development in ways that influence the quality of wine made from those grapes. The goal of this study was to determine whether exogenous applications of marine extracts on Syrah grapes can influence yield components, harvest juice quality parameters, and nutrient uptake. From 2009 to 2011, Syrah grape vines at the Trestle Vineyard on the California Polytechnic State University, San Luis Obispo campus received individual doses of marine extract via fertigation at berry set and veraison proportional to the amount they would receive on an annual per-acre basis based on the extract manufacturer’s recommended rate of application. In a separate experiment conducted in 2011, marine extracts were applied as foliar treatments. Treatments were analyzed for their effects on berry juice TSS, pH, TA, anthocyanins, tannins, and fruit yield per vine, clusters per vine, average berry weight, cluster weight, berries per cluster, vegetative yield, and foliar nutrient concentration. The marine extracts did not have any significant effects on yield components, harvest juice quality, or foliar nutrient concentration at any point in this experiment, except for a marginally significant increase in copper uptake with seaweed extract application as compared to the untreated control. Seaweed extract fertigation did result in a significant decline in net photosynthesis shortly after application as compared to control, while fish/seaweed extract blend fertigation resulted in a significant increase in net photosynthesis after application as compared to control. Though some minor effects of marine extracts were detected, there appears to be no benefit or drawback to applying these products in Syrah grapes growing in heavy clay soil in cool-climate conditions.

Determination of phylogenetic relationships among ancestral species of Rubus has been elusive. Most Rubus species (including blackberries and raspberries), representing nine of the 12 subgenera, occur in a large, well supported clade named 'A' for reference). The remaining nine species are excluded from this group and represent three subgenera: subg. Anoplobatus (R. bartonianus, R. deliciosus, R. neomexicanus, R. odoratus, R. parviflorus, R. trilobus), subg. Chamaemorus (R. chamaemorus), and subg. Dalibarda (R. lasiococcus, R.pedatus). In addition, Rubus dalibarda L. is often treated in its own monotypic genus as Dalibarda repens L. Phylogenetic analyses of DNA sequence data from chloroplast regions and the nuclear ribosomal DNA internal transcribed spacer ITS 1 - 5.8S - ITS 2; ITS) region have not resolved basal relationships in Rubus and the position of Dalibarda repens has varied from being the sister group to Rubus to nested within it. However, monophyly of American subg. Anoplobatus species is supported by both genomic regions. Our goal was to clarify ancestral relationships, investigate the position of Dalibarda repens relative to Rubus, and examine the origin of the circumboreal, octoploid species R. chamaemorus using sequence data from one additional chloroplast DNA region, trnS-trnG, and the singlecopy nuclear gene Granule-Bound Starch Synthase (GBSSI-1). Parsimony analyses of trnS-trnG sequences indicate a basal trichotomy, while R.chamaemorus is strongly supported as sister to R. pedatus. A combined cpDNA (trnS-trnG and three other regions) parsimony analysis indicates that subg. Anoplobatus is sister to clade A, and strongly supports Dalibarda repens as sister to R. lasiococcus. This suggests that Dalibarda repens be classified as R. dalibarda consistent with Linnaeus (1762) and Focke (1910). Parsimony analyses of GBSSI-1 sequences result in a large polytomy and do not recover clade A. The presence of three (GBSSI-la, GBSSI-1 (3 and GBSSI-ly) putative forms of the gene is observed. However, separate parsimony analysis of GBSSIly sequences demonstrates strong support for clade A and the monophyly of ubg. Anoplobatus. In this analysis, two different alleles are present in R. chamaemorus; one occurs outside clade A (sister to R. lasiococcus) and the other nests within clade A (sister to R. arcticus). Thus these data suggest that R. chamaemorus may be an ancient allopolyploid. The phylogenetic position of Dalibarda repens relative to Rubus cannot be resolved by existing GBSSI-1 data.

Strawberries are a rich source of polyphenols which contribute to berry color and plant disease resistance, and have been shown to lower the risk of many chronic when consumed. While a considerable body of work exists on the polyphenolic composition of commercial strawberry (Fragaria x ananassa Duch.), less information is available concerning polyphenols in Fragaria vesca, or Alpine strawberry, considered a model system for the Rosaceae family of crop species. The study of natural and genetically-engineered F. vesca mutants with white fruit can provide unique insight into regulation of metabolic flux through the complex branched phenylpropanoid/flavonoid biosynthetic pathway. Thus, the identity and quantity of major phenolic-derived anthocyanins, flavonols, flavan-3-ols, hydroxycinnamic acids, and ellagic acid (EA)-derived compounds, of red-fruited versus white-fruited genotypes of F. vesca and F. x ananassa were compared by high performance liquid chromatography-mass spectrometry. Due to the unknown origin of all but one white-fruited mutant of F. vesca, it was assumed that each resulted from independent mutation events and would exhibit different flavonoid profiles. A total of 27 phenolic-derived compounds were identified. The white genotypes of both species had very low anthocyanin levels. Total content of free EA and its conjugated forms were generally higher in white than in red F. vesca, but were the opposite in F. x ananassa, more in red than in white berries. Differences in content of individual flavonoids and in group totals among the white F. vesca genotypes suggested that they may represent different mutations affecting flavonoid production. Polyphenol profiles of a red and a white cultivar of F. vesca during four fruit developmental stages were determined along with transcriptional analyses of key structural and regulatory genes of the phenylpropanoid/ flavonoid biosynthesis. The final concentration of polyphenolic groups in red versus white F. vesca was due to the differential expression patterns of key pathway genes, especially dihydroflavonol-4-reductase, anthocyanidin synthase, and UDP-glucose-flavonoid-3-O-glucosyltransferase. The efficacy of phenolic compounds were evaluated in an in vitro study for inhibiting growth of Colletotrichum spp. associated with anthracnose fruit rot of strawberry. Only trans-cinnamic, p-coumaric, and ferulic acid inhibited isolates of the pathogen.

Temperate Region fruit and nut trees, and many other perennial plants, require cool winter temperatures (chilling hours) to ensure leaf and flower bud production in the following season. Temperate Regions are characterized by variable winter and spring temperatures. Failure of meeting sufficient chilling requirement results in deformed fruits, unequal maturation, and other plant deformities, thereby reducing quality and yields. Chilling requirements are expressed as number of accumulated hours within a range of approximately 32º to 45ºF or 0º to 7.2ºC. These requirements are specific for level of temperature, length of temperature period, and species and cultivar of plants. Information on chilling hour production by the diverse Kentucky environments and chilling requirements of its plants is limited. Global warming is reducing the occurrence and length of chilling conditions, thereby negatively impacting perennial fruit production (IPCC, 2014). There is increasing interest in fruit crops by the state’s producers and consumers. The Kentucky Mesonet Weather System provides temperature data, which can readily be converted to chilling units. Also, commercial nurseries are beginning to publish chilling requirement data for their fruit stocks. The present study included data collected over A 5-years period at 33 Mesonet sites. The average number of chilling hours overall years and sites was 1544, year means ranged from 1427 to 1842, sites means ranged from 1422 to 1682. Chilling hour production exceeded chilling requirements of fruit and nut crops commonly grown in Kentucky.

Part 1. Formation and control of chlorophyll, solanine alkaloids, and sprouts of potato (Solanum tuberosum L.) tubers Incorporation of radioactive carbon from acetic acid-2-14C (sodium salt), β-hydroxy-β-methylglutaric acid (HMG)-3-14C, L-leucine-U-14C, L-alanine-U14C, and D-glucose-U-14C into the predominant glycosidic steroidal alkaloids, &alpha-chaconine of potato sprouts was 4.88, 9.0, 15, 24, and 20 times less than that of mevalonic acid (MVA=2-14C (DBED salt), respectively. The efficiency ratio revealed that β-hydroxy-β-methylglutaric acid (HMG)-3-14 was incorporated via acetate or acetoacetate. The distribution of radioactivity originated from D-glucose-U-14C was nearly nine times higher in the glycoside moiety than that in the aglycone part of the glycoalkaloids. Apparently, Alar( succinic acid 2,2-dimethylhydrazide), Ethrel or Ethephon (2-chloroethylphosphonic acid), and Telone (1 ,3-dichloropropene and related chlorinated hydrocarbons) significantly reduced the rate of incorporation of β-hydroxy-β-methylglutaric acid (HMG)-3-14C into the alkaloids. A catalytic conversion of solanidine and UDP-glucose-U-14C to β-glucoside by the enzymatic system in a suspension of potato slices and the enzyme preparation from sprouts demonstrated the presence of β-glucosyltransferase in Solanum tuberosum L. Stepwise synthesis of α-solanine and α-chaconine from solanidine in potato tubers or sprouts seems possible. Formation of solanine alkaloids in peeled potato slices was stimulated when stored at 15 and 24 C in dark or light (200 foot-candles). The slices held under light developed nearly three to four times more alkaloids than those held in the dark. Significantly higher concentrations of solanine alkaloids were formed in the late stage (after 24 hours) than in the early stage of the storage period . Hence, it can be concluded that when potatoes are sliced for chips or French fries, they should be processed immediately, before the glycoalkaloids are synthesized in higher concentrations. Post-harvest application of chemicals, such as Phosfon (tributyl 2,4-dichlorobenzylphosphonium chloride), Phosfon-S (tributyl 2,4-dichlorobenzylammonium chloride), Amchem 72-A42 [2-(p-chlorophenylthio)- triethylamine], Amchem 70-334 or CPTA [2-(p-chlorophenylthio)-triethylamine hydrochloride], Nemagon (1,2-dibromo-3-chloropropane), and Telone (1,3-dichloropropene and related chlorinated hydrocarbons) at the concentrations of 250, 500, and 100 parts per million (ppm) in water; glycerin (10, 20, and 30 percent weight by volume [w/v] in water); and mineral oil (1.25, 2. 5, 5, 10, 15, 20, and 100 percent [w/v] in ether or petroleum ether) significantly inhibited the formation of chlorophyll and solanine alkaloids in the peripheral (periderm and outer parenchyma) zone of potato tubers exposed to a fluorescent light (200 foot-candles) for 6 or 7 days at 16 C and 60 percent relative humidity. The rates of inhibition increased with concentration of chemicals studied. A 10 percent solution of mineral oil was the minimum required concentration for effective control of chlorophyll and solanine alkaloids. The tubers dipped in 10 percent mineral did not develop chlorophyll on exposure to light (200 foot-candles) for 4 weeks, while the overall rate of inhibition of alkaloids was significantly high. In general, oil treatments were the most effective in controlling the formation of chlorophyll, solanine alkaloids, and sprout growth. Part II . Formation and control of carbonyl compounds of tomato (Lycopersicon esculentum Mill.) fruits Incubation of unsaturated fatty acids such as linoleic and linolenic acids with the crude soluble extract from tomato fruits produced carbonyl compounds. The enzyme preparations did not catalyze the conversion of saturated or monounsaturated fatty acids to carbonyls. Inability of potassium cyanide to inactivate the crude soluble extract proved that degradation of these fatty acids was mediated by lipoxidase and nonenzymatic oxidation by heme compounds was eliminated. These findings were supported by the fact that hydrogen peroxide, an inhibitor of lipoxidase enzyme, had inhibitory effects on the degradation of linoleic and linolenic acids by the tomato extract. Hexanal was found to be one of the products of the enzyme reaction. The identity of hexanal was confirmed by comparing the physical properties such as retention time, infra-red and ultra-violet absorption bands, and Rf value with those of an authentic sample . Biogenesis of hexanal from linoleic or linolenic acid was further substantiated by the use of uniformly labeled 14C isotopes of these fatty acids with the crude soluble extract, filtered homogenate, and tissue slices. Maximum activities (as evidenced by the production of carbonyls) were observed in the extract prepared with and incubated in a buffer medium of pH 7.5 (0.l M, Tris-HCl). The degradation of linoleic and linolenic acids was maximum at 30 C when incubated for 4 hours with 1 ml of the crude soluble extract. The enzymatic activity was enhanced by metal ions and compounds containing free -SH groups. Increase in the production of carbonyls by addition of citric and L-ascorbic acid may result from their metabolism. In general, ripe fruits contained greater enzymatic activities but smaller amounts of linoleic and linolenic acids than green fruits . The activity of the crude extract was increased by dialysis and the ammonium sulfate fractionation between 30 and 70 percent saturation. The rates of degradation of linoleic and linolenic acids catalyzed by the insoluble fractions of tomato extracts were more than those by the corresponding soluble fractions. Tomato fruits (green-wrap or large green) stored under hypobaric or sub-atmospheric pressures were analyzed for their volatiles after ripening. The concentrations of selected carbonyls (acetaldehyde, 2-methyl propanal, butanal, 3-methyl butanal, and hexanal) and some other volatiles decreased substantially with decrease in storage pressure.

‘MidSouth’, a relatively low maintenance interspecific hybrid bunch grape currently grown in South Mississippi, has low sugar and high acid levels for red wine use. Two studies, conducted at the Mississippi State University McNeill Research Unit in 2020 and 2021, determined the effects of pruning timing, leaf removal, and shoot thinning on ‘MidSouth’ development and fruit and wine quality. Treatments in the first study included early versus normal pruning timing, both with and without leaf removal, and treatments in the second study included leaf removal, shoot thinning, and control vines. Cluster temperatures, leaf chlorophyll, berries per cluster, berry and cluster weights, crop yield, Ravaz index, total soluble solids, titratable acidity, juice pH, monomeric anthocyanin pigment, and total phenolic content data were collected. It was determined that ‘MidSouth’ fruit quality can be altered through canopy manipulation, but not enough of a desired effect was achieved for these practices to be recommended.

Fungal diseases pose significant challenges for grapevine producers in Kentucky due to the region’s abundant moisture and relative humidity. Methods to reduce fungicide application frequency would prove both economically and temporally valuable to producers. A field experiment was established in Bowling Green, KY in 2017 to investigate Bacillus mycoides isolate J (LifeGard) as a supplement to a fungicide program for systemic acquired resistance (SAR). Three fungicide treatment regimens were implemented consisting of a program modelled from the Midwest Fruit Pest Management Guide (2017) and an identical program supplemented with 140 g ha-1 LifeGard per application (both applied on 14 day intervals), a reduced frequency application every 28 days supplemented with 140 g ha-1 LifeGard, and an untreated control. Treatments were applied to 9-year-old French-Hybrid grapevines (cv. Chambourcin); each treatment was replicated 3 times in a randomized complete block design. All treatments were applied with a backpack sprayer delivering 150 L ha-1 at 2 Bar pressure. Canopy management, fertility, herbicide, and insect management were standardized across treatments and no supplemental irrigation was applied. Data collected included fruit yield, pH, ºBrix, and titratable acidity (TA). Data were analyzed with SAS PROC GLIMMIX; differences in means were determined at  < 0.05. Plots supplemented with B. mycoides had lower fruit pH than untreated plots but higher fruit pH than the traditional fungicide program. Treatment regime did not influence Brix, TA, or total yield; however, all treated plots yielded more high quality fruit than the untreated control.

In many areas, over half of all diverted water is used for irrigation. Tree fruit crops use a lot of water, but water productivity can be increased using properly-timed precision water stress. In addition to water conservation, increases in water productivity arise from better fruit quality, increased storage life and reductions in pruning and maintenance. One major hurdle to applying precision water stress in orchards is the lack of a reliable, automated method of determining tree water status. However, the influence of physiological characteristics such as rootstock vigor on water productivity are also important. Selecting the most appropriate rootstocks and accurately determining the water status of orchard trees can increase water productivity. Research has shown that some rootstocks can more effectively extract water from soil. In this research, the response to water stress of three different Gisela tart cherry dwarfing rootstocks was compared using a weighing lysimeter system. Gisela 12 and Gisela 3 rootstocks recovered from drought stress more quickly and had higher trunk diameter growth rates than drought-stressed Gisela 5 rootstocks. Two potential methods of determining tree water status were also evaluated. Trunk hydration was measured using electromagnetic sensors and canopy temperature changes were detected using infrared radiometry. Electromagnetic techniques, including time domain reflectometry, can be used to determine the water content of wood. Until recently, the cost of this technology has inhibited its widespread use, but new affordable commercial electromagnetic soil moisture sensors have created renewed interest in this technique. In this research five different types of electromagnetic soil moisture sensors were inserted into the trunks of fruit trees and were monitored over two growing seasons. Maximizing exposure of waveguides to the sapwood increased the response of these sensors to changes in stem water potential. Infrared measurements of canopy temperature have successfully been used with field crops. However, the heterogeneity of orchard canopies makes this technique more difficult in orchards. Here, the efficacy of aiming radiometers at single trees versus at entire orchards was compared over multiple growing seasons. Neither single tree measurements nor whole orchard techniques produced a sufficiently robust signal to recommend them for general use.

Fleshy fruits in different species can display large variation in color. A link between fruit color and seed dispersal success is suggested by previous studies showing that high intensity of fruit color increases the visitation rate in seed-dispersing birds. Wild tomato species (Solanum spp.) are excellent model organisms for research on genetic basis of differential fruit color development during the ripening process. Despite polymorphism in fruit color, all tomato species have yellow flowers due to accumulation of carotenoid pigments, which suggests that the carotenoid pathway is intact. Thus, regulatory changes controlling enzymes activity during fruit maturation are likely to have played a role in fruit color evolution. Our transcriptome analysis of wild tomato species revealed that differences in cyc-b and crtr-b2 expression could explain the diversity of fruit color. Additionally, co-expression analysis elucidated regulators of the carotenoid pathway. Combined with Sanger sequencing of carotenoid pathway genes, we identified genes that may underlie differences in fruit color during tomato evolution.

A variety of plants synthesize and store oil in the form of triacylglycerols (TAG) in their seed and nonseed tissues that are commonly used as vegetable oils. In seed tissues, an acyl CoA-dependent diacylglycerol (DAG) acyltransferase (DGAT) and/or -independent phospholipid:DGAT (PDAT) catalyze the conversion of DAG to TAG. In avocado fruit, which stores up to 70% oil by dry weight in mesocarp, it is hypothesized that both DGAT and PDAT are likely involved in TAG synthesis. To investigate, TAG content and composition and transcript levels for the acyltransferases in avocado fruit were quantified by gas chromatography and real-time polymerase chain reaction, respectively. Temporal, tissue-specific and phenotypic comparisons revealed that while DGAT1 gene expression was specifically associated with TAG accumulation, PDAT also correlated with higher levels of polyunsaturated fatty acid; DGAT2 was barely detectable. These studies suggest that TAG biosynthesis in nonseed tissues of avocado involves acyl CoA-dependent and -independent reactions.