bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation in Anatomical Characteristics in Leaves of Pecan Seedstocks from Mexico and the United States
Authors: Sagaram Madhulika , Lombardini Leonardo , Grauke L.J.
Published: January 2019

Leaf anatomical traits of Mexican and U.S. pecan [Carya illinoinensis (Wangenh.) K. Koch] seedstocks grown in a single location were studied to determine patterns of ecogeographic variation within the natural range. Stomatal density was uniform among open-pollinated seedlings of a common maternal parent with twofold differences in stomatal density separating some seedstocks. There was an inverse relationship between stomatal density and epidermal cell density. Stomatal density and stomatal index of Mexican seedstocks were related to longitude and annual precipitation of origin. Stomatal density increased along the longitudinal gradient toward the east coast of Mexico; seedstocks originating from areas on the east coast of Mexico had greater stomatal density than seedstocks originating from the drier areas on the west coast. Stomatal density and stomatal index did not follow a pattern along latitude or longitude in the U.S. seedstocks. Although isotopic carbon (13C) discrimination did not vary greatly in Mexican seedstocks, the reduction in stomatal density in pecan trees from areas with reduced annual precipitation suggest the presence of an anatomical feature to reduce water losses.
A Simple Sequence Repeat Marker Linked to the Susceptibility of Apple to Alternaria Blotch Caused by Alternaria alternata Apple Pathotype
Authors: Li Ying , Zhang Liyi , Zhang Zhen , Cong Peihua , Cheng Zong-Ming
Published: January 2019

Alternaria alternata apple pathotype (previously A. mali) causes alternaria blotch disease of apple (Malus ×domestica), which may result in leaf spots and up to 70% premature leaf drop in serious cases. This disease is of worldwide importance but is most serious in eastern Asia (Japan, Korea, and China) and in parts of the United States. The excessive use of fungicides not only adds cost to apple growers, but also pollutes the environment. In this study, we characterized a 5-year F1 population from a cross of a resistant cultivar (Huacui) and a susceptible cultivar (Golden Delicious) consisting of 110 individuals along with 14-year-old parent trees (10 each). A field evaluation of disease severity was conducted in 2008 and 2009 under the natural conditions in Liaoning, China (lat. 40°37′ N, long. 120°44′ E). Based on the field data, 110 F1 plants were divided into five groups. Artificial inoculation was carried out both on the living trees and on the detached leaves in 2009 to ensure that A. alternata apple pathotype was the causative agent. Eighty primer pairs of simple sequence repeat (SSR) were screened against the four genomic DNA pools, respectively, from six highly susceptible F1 plants, six most resistant F1 plants, one tree of the seed parent, and the one tree of the pollen parent. One pair of primers (CH05g07) was shown to be linked to the DNA pools of susceptible F1 and the parent tree, but not to the DNA pools of resistant F1 and parent trees. This primer pair was then used to screen all individual 110 F1 progenies and two parent trees. The differentiation of 103 individuals (97.3%) with the marker matched the field disease resistance rating. This marker was further screened with 20 cultivars with known susceptibility or resistance to A. alternata apple pathotype and its linkage to susceptibility was validated. These results suggest that this marker can be used in marker-assisted selection for resistance/susceptibility to alternaria blotch disease in apple.
Determining Redundancy of Short-day Onion Accessions in a Germplasm Collection Using Microsatellite and Targeted Region Amplified Polymorphic Markers
Authors: Kisha Theodore J. , Cramer Christopher S.
Published: January 2019

The U.S. National Plant Germplasm System is one of the world's largest national genebank networks focusing on preserving the genetic diversity of plants by acquiring, preserving, evaluating, documenting, and distributing crop-related germplasm to researchers worldwide. Maintaining viable germplasm collections is essential to world food security but comes at a cost. Redundancy within the collection can incur needless expense and occurs as a result of donations of similar material under different names from different donors. Alternatively, similarly named accessions from different donors can actually be genetically distinct. We evaluated 35 short-day onion (Allium cepa) accessions using microsatellite and targeted region amplified polymorphic (TRAP) molecular markers to compare newly acquired germplasm with existing accessions in the collection to determine differences and redundancies and to compare the use of each marker type in distinguishing the onion accessions. Both marker types distinguished differences and found similarities, but the results did not always agree. TRAP markers found one of the Italian Torpedo entries to be different, whereas the 10 microsatellite loci analyzed found no differences. In contrast, microsatellite analysis found all three Red Grano entries to be different, whereas TRAP analysis distinguished only one accession. The eight White Grano entries were separated into four groups by microsatellite markers and five groups by the TRAP markers. Discriminating among closely related accessions using molecular markers can require a large number of random marker loci, especially when differences may be limited to a single trait. TRAP markers were more efficient, uncovering ≈10 random polymorphic loci per primer pair, whereas microsatellite markers each uncovered differences at a single locus.
Rapid Assessment of Genetic Variation for Morphological Traits in Sweetbay Magnolia Using a Container Production System
Authors: Zale Peter J. , Struve Daniel K. , Jourdan Pablo , Francis David M.
Published: January 2019

Breeding and development of ornamental woody plants for specific ideotypes will provide diverse choices to meet specific needs for natural and constructed landscapes. An F1 half-sib family analysis of Magnolia virginiana generated from controlled pollinations was implemented to identify potential juvenile selection strategies for two mature ideotypes: a compact and rounded shrub form (to 2.5 m tall and wide) and a single-stemmed, small tree form (to 4 m tall), both with abundant flowering. The 2-year test was conducted in a container nursery. Fourteen traits were measured in 2007 and 2008, including height at three intervals (July, August, and September), mean branch length and branch count, early and late flower production, collar sprout formation, stem diameter, and branch angle. There were significant differences between F1 half-sib families (P ≤ 0.0001) for all traits. Phenotypic and genetic correlations and narrow sense heritability were estimated for these traits. Phenotypic and genetic correlations showed favorable associations among branch count, caliper, and early flower production. These traits were used to form a selection index for a shrub ideotype. Also, there were positive phenotypic and genetic correlations between height and late flower production, which were both negatively correlated with collar sprout formation. These traits were used to form a selection index for the single-stemmed, small tree ideotype. Narrow sense heritabilities were high for most traits in 2007 but were lower in 2008. Results suggest that selection of phenotypes ranking highest for the traits of interest may yield the desired ideotypes. However, introduction of additional genetic variation through new germplasm accessions may be necessary to maintain breeding progress.
Rootstocks Modify Scion Architecture, Endogenous Hormones, and Root Growth of Newly Grafted ‘Royal Gala’ Apple Trees
Authors: Hooijdonk Ben van , Woolley David , Warrington Ian , Tustin Stuart
Published: January 2019

‘Royal Gala’ apple scions (Malus ×domestica) were grafted onto 1-year-old rootstock stools of ‘M.9’ (M.9), ‘M.M.106’ (MM.106), ‘Merton 793’ (M.793), and ‘Royal Gala’ [R.G (control)] to elucidate how the dwarfing apple rootstock (M.9) modified scion architecture, the time from grafting when this started, and whether changes in scion architecture were explained by some endogenous hormones present within the scion. At the end of the first season of growth (April), the final length and node number of the primary shoot were similar for scions on M.9 and R.G. However, M.9 appeared to limit the number of secondary shoots formed on the primary shoot during summer. In addition, the proportion of secondary shoots that were actively extending in fall was lower for M.9; consequently, the final mean length of the secondary shoots was slightly shorter for M.9 compared with R.G. Collectively, these subtle effects of M.9 significantly reduced the final total shoot length of the scion compared with R.G. The final dry weight of the scion and root system was also lower for M.9 than MM.106, M.793, and R.G. The mean rate of indole-3-acetic acid diffusing from the apex of the primary shoot progressively declined from February onward irrespective of rootstock, whereas the mean concentration of zeatin riboside (ZR) in the xylem sap increased during the same period, and these events appeared to coincide with cumulative increases in the number of axillary growing points formed on the scion. Despite this general trend, M.9 had a greater concentration of ZR in the xylem sap during February compared with R.G, but the primary shoot on M.9 did not develop more axillary growing points, indicating that other endogenous hormonal signals were also involved in regulating scion branching. By March, M.9 lowered gibberellin A19 (GA19) concentration in the xylem sap of the scion significantly compared with R.G. We conclude that dwarfing apple rootstocks may limit root-produced GA19 supplied to shoot apices of the scion, where GA19 may be a precursor of bioactive gibberellin A1 required for shoot extension growth.
Russeting and Microcracking of ‘Golden Delicious’ Apple Fruit Concomitantly Decline Due to Gibberellin A4+7 Application
Authors: Knoche Moritz , Khanal Bishnu P. , Stopar Matej
Published: January 2019

The effect of four applications of gibberellin A4+7 [GA4+7 (10 mg·L−1 at 10-day intervals beginning with petal fall)] on water-induced russeting, formation of microcracks. and on fruit growth and deposition of the cuticular membrane (CM) was studied in developing ‘Golden Delicious’ fruit (Malus ×domestica Borkh.). Submerging developing apple fruit in deionized water for 48 h induced russeting in untreated control but not in GA4+7-treated fruit. Immersing in water during early fruit development, 19 days after full bloom (19 DAFB), resulted in more russeting than immersions occurring later (139 DAFB). Water on the outer surface of epidermal segments increased the frequency of microscopic cracks in untreated controls but to a lesser degree in GA4+7-treated fruit. The effect of GA4+7 on water-induced russeting and formation of microcracks was larger during early as compared with later stages of fruit development. Fruit treated with GA4+7 consistently had fewer microcracks as compared with non-treated control fruit. GA4+7 had no effect on amounts or rates of cutin or wax deposition, strain, or mechanical properties of the CM as compared with the non-treated control. Thus, the decrease in russeting and formation of microcracks in the cuticle of GA4+7-treated fruit must be accounted for effects on underlying epi- and hypodermal tissues.
Production of Haploids in Persian Walnut through Parthenogenesis Induced by Gamma-irradiated Pollen
Authors: Hosseini Grouh Mohammad Sadat , Vahdati Kourosh , Lotfi Mahmoud , Hassani Darab , Biranvand Nejat Pirvali
Published: January 2019

We report the first successful regeneration of haploid lines in persian walnut (Juglans regia) developed by in situ parthenogenesis followed by embryo rescue. Female flowers of cultivars Hartley and Pedro and two native Iranian selections (Z63 and Z67) were pollinated using pollen of selections Z53 and Z30 that had been irradiated with gamma rays at five doses (50, 150, 300, 600, and 900 Gy). Gamma-irradiated pollen induced fruit set and development of some parthenogenetic embryos. The immature embryos were excised 30 and 45 days after pollination, cultured in vitro, and then stratified for 30 days at 4 °C to overcome dormancy. Ploidy level of the resulting plantlets was determined by chromosome counting and flow cytometry. Haploid plants were obtained from ‘Hartley’, ‘Pedro’, Z63, and Z67 after pollination using pollen irradiated at 300 and 600 Gy. Plants obtained from pollen irradiated at 50 and 150 Gy were all diploid. Molecular marker analysis using four simple sequence repeat (SSR) markers also showed that all the diploid plants recovered were zygotic and no spontaneous double haploid plants were obtained in this work. Also, the haploid plantlets presented only one allele of their female parents. These profiles confirmed the parthenogenetic origin of the obtained haploid plants. The techniques used to induce haploid walnut plants by irradiated pollen were successful and could be used in breeding programs and accelerate genome analysis in this plant in which the genome size is approximately three times the size of the human genome.
Identification of Novel Physiological Races of Phytophthora capsici Causing Foliar Blight Using the New Mexico Recombinant Inbred Pepper Lines Set as a Host Differential
Authors: Monroy-Barbosa Ariadna , Bosland Paul W.
Published: January 2019

Phytophthora foliar blight caused by Phytophthora capsici is a serious limitation to pepper (Capsicum annuum) production worldwide. Knowledge of the physiological race composition of isolates causing phytophthora foliar blight is necessary for success in breeding for disease resistance. The New Mexico recombinant inbred lines (NMRILs) effectively differentiated isolates from different geographical locations (i.e., Turkey, The Netherlands, Argentina, and two states in the United States) into 12 physiological races of P. capsici causing phytophthora foliar blight. This research demonstrates the use of the NMRILs to identify P. capsici foliar blight races and the importance of identifying the physiological races occurring in specific regions where a C. annuum cultivar will be grown. Knowing the physiological race(s) in a region will provide valuable information to formulate breeding strategies to deploy durable foliar blight resistance.
Heat-induced Proteome Changes in Tomato Leaves
Authors: Zhou Suping , Sauvé Roger J. , Liu Zong , Reddy Sasikiran , Bhatti Sarabjit , Hucko Simon D. , Yong Yang , Fish Tara , Thannhauser Theodore W.
Published: January 2019

Three tomato (Solanum lycopersicum) cultivars [Walter LA3465 (heat-tolerant), Edkawi LA 2711 (unknown heat tolerance, salt-tolerant), and LA1310 (cherry tomato)] were compared for changes in leaf proteomes after heat treatment. Seedlings with four fully expanded leaves were subjected to heat treatment of 39/25 °C at a 16:8 h light–dark cycle for 7 days. Leaves were collected at 1200 hr, 4 h after the light cycle started. For ‘Walter’ LA3465, heat-suppressed proteins were geranylgeranyl reductase, ferredoxin-NADP (+) reductase, Rubisco activase, transketolase, phosphoglycerate kinase precursor, fructose–bisphosphate aldolase, glyoxisomal malate dehydrogenase, catalase, S-adenosyl-L-homocysteine hydrolase, and methionine synthase. Two enzymes were induced, cytosolic NADP-malic enzyme and superoxide dismutase. For ‘Edkawi’ LA2711, nine enzymes were suppressed: ferredoxin-NADP (+) reductase, Rubisco activase, S-adenosylmethionine synthetase, methioine synthase, glyoxisomal malate dehydrogenase, enolase, flavonol synthase, M1 family peptidase, and dihydrolipoamide dehydrogenase. Heat-induced proteins were cyclophilin, fructose-1,6-bisphosphate aldolase, transketolase, phosphoglycolate phosphatase, ATPase, photosystem II oxygen-evolving complex 23, and NAD-dependent epimerase/dehydratase. For cherry tomato LA1310, heat-suppressed proteins were aminotransferase, S-adenosyl-L-homocysteine hydrolase, L-ascorbate peroxidase, lactoylglutathione lyase, and Rubisco activase. Heat-induced enzymes were glyoxisomal malate dehydrogenase, phosphoribulokinasee, and ATP synthase. This research resulted in the identification of proteins that were induced/repressed in all tomato cultivars evaluated (e.g., Rubisco activase, methionine synthase, adenosyl-L-homocysteine hydrolase, and others) and those differentially expressed (e.g., transketolase).
Inheritance of Carotenoid Content in Tetraploid × Diploid Potato Crosses
Authors: Haynes Kathleen G. , Clevidence Beverly A. , Rao David , Vinyard Bryan T.
Published: January 2019

Carotenoids have a wide range of human health benefits. Yellow-fleshed tetraploid potato (Solanum tuberosum) cultivars have more than twice the concentration of carotenoids as white-fleshed cultivars. However, carotenoid concentrations in some diploid potatoes have been reported to be up to 13 times higher than in ‘Yukon Gold’, the most popular yellow-fleshed potato cultivar grown in the United States, and up to 22 times higher than in white-fleshed potatoes. The purpose of this study was to determine the feasibility of using these high-carotenoid diploids to develop high-carotenoid tetraploid germplasm. Three diploid clones with high (dark yellow-flesh), moderate (moderate yellow-flesh), and low (white–cream-flesh) carotenoid levels that produced 2n pollen were crossed with a light yellow-fleshed tetraploid advanced breeding selection to determine the inheritance of carotenoid content. Twenty-six to 43 progeny from these three 4x-2x families were grown in a replicated field experiment in Presque Isle, ME, for 2 years. After harvest, carotenoids were extracted and quantified by high-performance liquid chromatography in 13 to 14 randomly selected clones from each family; however, flesh color was scored as white or yellow in all progeny. A continuous distribution of carotenoid concentration with high- and low-carotenoid segregants was observed in all three families. There were no significant differences among these three families for individual or total carotenoid concentrations; however, there were significant differences among clones within families. Broad-sense heritability estimates were high for total carotenoid (0.81), lutein (0.77), zeaxanthin (0.73), and the lycopene beta-cyclase pathway carotenoids (0.73); moderate for neoxanthin (0.42); and low for violaxanthin (0.21) and antheraxanthin (0.13). Based on flesh color segregation, the two yellow-fleshed diploid parents were heterozygous for the Chy2 allele governing yellow-flesh and produced 2n gametes by a second division restitution mechanism. It appears that selection for high-carotenoid tetraploid germplasm can be made from within any family with at least one yellow-fleshed parent. Selections will have to be made on an individual clonal basis rather than on a family basis.
Genetic Diversity of Iraqi Date Palms Revealed By Microsatellite Polymorphism
Authors: Khierallah Hussam S.M. , Bader Saleh M. , Baum Michael , Hamwieh Alladin
Published: January 2019

Genetic diversity in 30 date palm (Phoenix dactylifera L.) cultivars in Iraq representing 24 female and six male cultivars was investigated using 22 microsatellite [simple sequence repeat (SSR)] primers. The tested SSR markers showed a high level of polymorphism. A total of 188 alleles were detected at the 22 loci ranging from three to 21 with an average of 8.54 alleles per locus. The average of heterozygosity for all cultivars was 0.503; genetic distance among cultivars varied from 0.171 to 0.938 indicating diverse relationships. The cultivar Ghanami Akhder was highly divergent from ‘Ghnami Ahmer’, whereas ‘Jamal Al-Dean’ was very closely related to ‘Qitaz’. Unweighted pair group method arithmetic average ordered date palm cultivars into two main clusters. Principal coordinate analysis exhibited the similar clusters of cultivars as in the dendrogram.
Identification of Salt-induced Changes in Leaf and Root Proteomes of the Wild Tomato, Solanum chilense
Authors: Zhou Suping , Sauvé Roger J. , Liu Zong , Reddy Sasikiran , Bhatti Sarabjit , Hucko Simon D. , Fish Tara , Thannhauser Theodore W.
Published: January 2019

This article reports salt-induced changes in leaf and root proteomes after wild tomato (Solanum chilense) plants were treated with 200 mm NaCl. In leaf tissues, a total of 176 protein spots showed significant changes (P < 0.05), of which 104 spots were induced and 72 spots suppressed. Salt-induced proteins are associated with the following pathways: photosynthesis, carbohydrate metabolism, glyoxylate shunt, glycine cleavage system, branched-chain amino acid biosynthesis, protein folding, defense and cellular protection, signal transduction, ion transport, and antioxidant activities. Suppressed proteins belong to the following categories: oxidative phosphorylation pathway, photorespiration and protein translational machinery, oxidative stress, and ATPases. In root tissues, 106 protein spots changed significantly (P < 0.05) after the salt treatment, 63 spots were induced, and 43 suppressed by salt treatment. Salt-induced proteins are associated with the following functional pathways: regeneration of S-adenosyl methionine, protein folding, selective ion transport, antioxidants and defense mechanism, signal transduction and gene expression regulation, and branched-chain amino acid synthesis. Salt-suppressed proteins are receptor kinase proteins, peroxidases and germin-like proteins, malate dehydrogenase, and glycine dehydrogenase. In this study, different members of proteins were identified from leaf and root tissues after plants were subjected to salt treatment. These proteins represent tissue-specific changes in salt-induced proteomes. When protein expression was compared in the context of metabolic pathways, the branched-chain amino acid biosynthesis, glucose catabolism toward reducing cellular glucose level, and the antioxidant, detoxification, and selective ion uptake and transport were induced in both root and leaf tissues. These changes appear to be associated with salt tolerance in the whole plant.
Floral Scent in Wisteria: Chemical Composition, Emission Pattern, and Regulation
Authors: Jiang Yifan , Chen Xinlu , Lin Hong , Wang Fei , Chen Feng
Published: January 2019

Volatile chemicals emitted from the flowers of chinese wisteria (Wisteria sinenesis) and japanese wisteria (W. floribunda) were collected using a dynamic headspace technique and identified using gas chromatography–mass spectrometry; 28 and 22 compounds were detected from chinese wisteria and japanese wisteria flowers, respectively. These chemicals can be classified into four major classes, including fatty acid derivatives, benzenoids/phenylpropanoids, terpenoids, and nitrogen-containing compounds. Two monoterpenes, (E)-β-ocimene and linalool, belonging to the class of terpenoids, were the most abundant compounds emitted from both species. Despite strong similarity, the floral volatile profiles of the two species displayed variations in both quality and quantity. Chinese wisteria was selected as a model for further study of volatile emission from different parts of flowers, emission dynamics, and regulation of floral scent production. Although floral volatiles were detected from all flower parts, petals emitted the most. The emission of floral volatiles displayed a diurnal pattern with the maximal emissions occurring during the daytime. This rhythmic pattern was determined to be light-dependent. Regulation of floral volatile emission by exogenous chemicals, including silver thiosulphate (an ethylene inhibitor), salicylic acid, and jasmonic acid, also was analyzed. Generally, jasmonic acid promoted the emission of floral volatiles. In contrast, neither silver thiosulphate nor salicylic acid showed a significant effect on floral volatile emission. The results presented in this article suggest that wisteria can serve as a useful system for exploring novel biochemistry of floral scent biosynthesis. They also build a foundation for the study of the biological/ecological significance of floral volatiles on the reproductive biology of wisteria species.
Silicon Differentially Influences Copper Toxicity Response in Silicon-accumulator and Non-accumulator Species
Authors: Frantz Jonathan M. , Khandekar Sushant , Leisner Scott
Published: January 2019

The use of copper (Cu) in agriculture is widespread as a pesticide, and it is present in high concentrations in certain types of manures. As the use of Cu continues and manure management is incorporated into sustainable systems, the likelihood of Cu toxicity increases. Supplemental silicon has been used to successfully counteract potential micronutrient toxicity. There is currently considerable debate regarding the value of including silicon (Si) as a nutrient in fertility programs and as such, it is not part of a typical management practice in floriculture crop production in the United States. We investigated the potential for Si to ameliorate the effects of Cu toxicity in both a Si-accumulating [zinnia (Zinnia elegans)] and a Si-non-accumulating [snapdragon (Antirrhinum majus)] species. Using visible stress indicators and dry weight analysis, it initially appeared that Si was a significant benefit to only zinnia under Cu toxicity. Enzymatic assays and elemental analysis of leaves, stems, and roots revealed that both species responded to supplemental Si, showing evidence of reduced stress and nutrient concentrations more similar to healthy, control plants than plants exposed to Cu toxicity. Although there appear to be differences in the extent of Si-mediated amelioration of Cu toxicity between these two plants, both responded to supplemental Si. This adds to the growing body of evidence that all plants likely have Si-mediated responses to stress, and its inclusion into fertility programs should be more broadly considered than current practices.
Assessment of the Genetic Diversity and Population Structure of Lotus Cultivars Grown in China by Amplified Fragment Length Polymorphism
Authors: Fu Jie , Xiang Qiaoyan , Zeng Xianbao , Yang Mei , Wang Ying , Liu Yanling
Published: January 2019

To assess the genetic diversity among lotus (Nelumbo) accessions and evaluate the correlation between genetic variation and morphological classification, we sampled 138 accessions: two of N. lutea, 112 of N. nucifera, 17 of hybrids between N. nucifera and N. lutea, and seven Japanese cultivars. The 11 selected combinations of amplified fragment length polymorphism (AFLP) primers produced 138 polymorphic loci, and the percentage of polymorphism was 28.7%. The unweighted pair group method with arithmetic mean (UPGMA) dendrogram clustered all the accessions into two groups: Group I comprised N. lutea and its hybrids with N. nucifera; Group II included N. nucifera and its hybrids with N. lutea and Japanese cultivars. Population structure analysis identified four main clusters: N. lutea clustered mainly in C1, whereas N. nucifera clustered in C2, C3, and C4, which was consistent with the UPGMA and principal coordinate analysis results. The Japanese cultivars were related more closely to N. nucifera (genetic similarity coefficient = 0.74) than to N. lutea (0.46); hence, the Japanese cultivars can be classified as N. nucifera. Moreover, rhizome lotuses formed a separate subclade, whereas seed lotuses were interspersed among flower lotuses, which demonstrated that rhizome lotuses were distinct from flower and seed lotuses. Plant size, flower color, and other morphological criteria used commonly to classify lotuses were correlated with genetic variation to a certain extent but not sufficiently for accurate classification. It appears that it is necessary to use both DNA markers and morphological characteristics to classify lotus species and cultivars.
DNA Markers Linked to Eastern Filbert Blight Resistance from a Hazelnut Selection from the Republic of Georgia
Authors: Sathuvalli Vidyasagar R. , Mehlenbacher Shawn A. , Smith David C.
Published: January 2019

The hundred-year history of the european hazelnut (Corylus avellana L.) industry in the Pacific northwestern United States is threatened by eastern filbert blight (EFB) caused by the fungus Anisogramma anomala (Peck) E. Müller. Marker-assisted selection has been extensively used for ‘Gasaway’ resistance in the hazelnut breeding program at Oregon State University. Concern over possible breakdown of this single resistance gene provides an incentive to look for new sources of resistance. OSU 759.010, a selection from the Republic of Georgia, has remained free of EFB after inoculations over several years. Random amplified polymorphic DNA (RAPD) markers linked to resistance were identified by screening primers against three resistant seedlings, three susceptible seedlings, and the parents of a segregating seedling population. For the progeny OSU 759.010 × OSU 653.068, 13 linked markers were identified. The markers most closely linked to resistance were 695-1800 on the proximal side and H12-640, 373-700, 349-450, and F08-700 on the distal side. Four of the five markers also segregated in the progeny OSU 759.010 × OSU 665.076, whereas H12-640 was monomorphic. Segregation for disease response in the first population showed a surplus of resistant seedlings, approaching a 3:1 ratio, with closely linked RAPD markers showing similar ratios. In the second population, the observed segregation for disease response and associated markers did not deviate from the expected 1:1 ratio. Based on cosegregation with simple sequence repeat (SSR) markers, resistance from OSU 759.010 was assigned to linkage group 2. Resistance to EFB from ‘Gasaway’ and ‘Ratoli’ was previously mapped to linkage groups 6 and 7, respectively. Therefore, OSU 759.010 provides a novel source of EFB resistance and markers 695-1800, 373-700, 349-450, and F08-700 have potential for use in marker-assisted selection to pyramid EFB resistance alleles.
Lack of Fruit Set Caused by Ovule Degeneration in Japanese Plum
Authors: Guerra María Engracia , Wünsch Ana , López-Corrales Margarita , Rodrigo Javier
Published: January 2019

Some japanese plum (Prunus salicina) cultivars are particularly prone to erratic fruit set showing very low or even null fruit set for reasons that are not clear. To ascertain the causes of lack of fruit set in some of them, different factors intervening in the reproductive process have been evaluated using flowers of three cultivars, Angeleno, Rubirosa, and Sweet August, from commercial orchards with records of very low fruit set in previous seasons and compared with a producing cultivar, Simka. Different cultivars coincident at flowering with the cultivars studied were evaluated as adequate pollenizers in each orchard. To determine which factors that intervene in the reproductive process could be related to the lack of fruit set, microscopic observations of pollen germination, pollen tube growth, pollen–pistil incompatibility, and ovule development were analyzed in flowers of different pollination treatments. Results allowed dismissal of pollen viability, pollen transfer, and pollen–pistil incompatibility as the cause of lack fruit set. However, the observation of ovule development revealed a high incidence of premature ovule degeneration on final fruit set in the three low-producing cultivars. The lack of fruit set in orchards with no apparent adverse environmental conditions is traditionally studied by analyzing the pollination process and the pollen–pistil incompatibility relationships, but the stage of development of the ovules is not usually considered. The approach used in this work may prove valuable to other species and situations of lack of fruit set, which could help to identify the causes for premature ovule degeneration.
The Rare-earth Metallome of Pecan and Other Carya
Authors: Wood Bruce W. , Grauke Larry J.
Published: January 2019

We report the composition of the rare-earth (REE) metallome component of the foliar ionomes of pecan (Carya illinoinensis) and other North American Carya and how accumulation of specific REEs relate to ploidy level and to accumulation of essential divalent nutrient elements. REE accumulation within the foliar ionomes of 12 Carya species, growing on a common site and soil, indicates that REEs accumulate according to the Oddo-Harkins rule with Ce, La, Nd, and Y (Ce > La > Nd > Y) being the dominant REEs with accumulated concentration typically being La > Ce > Nd > Y > Gd > Pr > Sm > Dy > Er > Yb > Ho > Tb >Tm > Sc >Lu. Carya species quantitatively differ in accumulation of REEs with all but C. aquatica accumulating at much greater concentrations than non-Carya tree species and with tetraploid Carya accumulating to approximately twice the concentration as diploid Carya. Carya tomentosa was an especially heavy accumulator of REEs at 859 μg·g−1 dry weight, whereas C. aquatica was especially light at 84 μg·g−1. Accumulation of REEs was such that any one element within this elemental class was tightly linked (generally r ≥ 0.94, but 0.81 for Ce) to all others. Accumulation of REEs is negatively correlated with Ca accumulation and positively correlated with Mn and Cu accumulation in diploid Carya. In tetraploid Carya, accumulated Mg, Ca, and Fe is positively associated with foliar concentration of REEs. Total concentration of REEs in pecan's foliar ionome was 190 μg·g−1, about equivalent to that of Mn. Circumstantial evidence suggests that one or more of the physiochemically similar REEs increases physiological plasticity and subsequent adaptive fitness to certain Carya species, especially tetraploids. Because all tetraploid Carya are high REE accumulators and are native to more xeric habitats than diploids, which typically occupy mesic habitats, it appears that REEs might play a role in Carya speciation and adaptation to certain site-limiting environmental stresses. REEs appear to play an unknown metabolic/physiological role in pecan and most Carya species, especially tetraploids; thus, their nutritional physiology merits further investigation.
Nitrogen Deficiency-induced Protein Changes in Immature and Mature Leaves of Creeping Bentgrass
Authors: Xu Chenping , Jiang Zhongchun , Huang Bingru
Published: January 2019

Nitrogen (N) deficiency inhibits plant growth and induces leaf senescence through regulating various metabolic processes. The objectives of this study were to examine protein changes in response to N deficiency in immature and mature leaves of a perennial grass species and determine major metabolic processes affected by N deficiency through proteomic profiling. Creeping bentgrass (Agrostis stolonifera cv. Penncross) plants were originally fertilized with a diluted 36N–2.6P–5K fertilizer. After 14 days acclimation in a growth chamber, plants were grown in a nutrient solution containing 6 mm nitrate (control) or without N (N deficiency). Immature leaves (upper first and second not yet fully expanded leaves) and mature leaves (lower fully expanded leaves) were separated at 28 days of treatment for protein analysis. Two-dimensional electrophoresis and mass spectrometry analysis were used to identify protein changes in immature and mature leaves in response to N deficiency. The abundance of many proteins in both immature and mature leaves decreased with N deficiency, including those involved in photosynthesis, photorespiration, and amino acid metabolism (hydroxypyruvate reductase, serine hydroxymethyltransferase, alanine aminotransferase, glycine decarboxylase complex, glycolate oxidase), protein protection [heat shock protein (HSP)/HSP 70, chaperonin 60 and FtsH-like protein], and RNA stability (RNA binding protein). The reduction in protein abundance under N deficiency was greater in mature leaves than in immature leaves. The abundance of small HSP and metalloendopeptidase increased under N deficiency only in immature leaves. These results suggest that N deficiency accelerated protein degradation in immature and mature leaves of creeping bentgrass, particularly those proteins associated with energy and metabolism, but to a lesser extent in immature leaves. Immature leaves were also able to accumulate proteins with chaperone functions and for N reutilization, which could protect leaves from senescence under N deficiency.
Prediction of Genotypic Values for Apple Fruit Texture Traits in a Breeding Population Derived from ‘Honeycrisp’
Authors: McKay Steven J. , Bradeen James M. , Luby James J.
Published: January 2019

The commercially successful apple (Malus pumila Mill.) cultivar Honeycrisp is known for its high degrees of crispness and juiciness. This cultivar has been incorporated into numerous breeding programs in an effort to duplicate its desirable texture traits in conjunction with such other traits as reduced postharvest disorders, disease resistance, and improved tree vigor. This study characterizes variability and estimates heritability for several apple fruit texture traits within a large breeding population over several years. Five full-sib families, all sharing ‘Honeycrisp’ as a common parent, were assayed with respect to crispness, firmness, and juiciness using sensory evaluation panels and total work required to fracture tissue using instrumental methods. The incomplete block design of the sensory panels, coupled with best linear unbiased prediction, facilitated the evaluation of a large number of genotypes with small numbers of fruit per genotype while accounting for individual sensory panelist effects. Broad-sense heritability estimates exceeded 0.70 for all four traits. Principal component analysis, applied to the phenotypic data, characterized ‘Honeycrisp’ as having average crispness and low firmness (53rd percentile relative to its offspring) but also as being a relatively extreme example of high juiciness and low work to fracture (first percentile). The improved characterization of desired fruit texture phenotypes and the high levels of broad-sense heritability provide valuable tools for the further development of new, high-quality apple cultivars.
Genetic Variation in Pawpaw Cultivars Using Microsatellite Analysis
Authors: Lu Li , Pomper Kirk W. , Lowe Jeremiah D. , Crabtree Sheri B.
Published: January 2019

Pawpaw (Asimina triloba) is a tree fruit native to eastern North America, which is in the early stages of domestication. Most early 20th century pawpaw cultivars have been lost; however, recent cultivar releases and potential new releases may have enhanced genetic diversity. The objective of this study was to compare the genetic variation exhibited among older and new pawpaw cultivars and Kentucky State University (KSU) advanced selections using simple sequence repeat (SSR) markers. Polymorphic microsatellite marker analysis was conducted with nine older pawpaw cultivars, six recently released PawPaw Foundation (PPF) cultivars, and nine KSU advanced selections. Using 18 microsatellite loci, a total of 179 alleles were amplified in the set of 24 genotypes. The major allele frequency (0.13 to 0.96), number of genotypes (two to 23), and allele size (96 to 341 bp) varied greatly by locus. Eighteen loci were highly polymorphic, as indicated by high expected heterozygosity (He = 0.71) and observed heterozygosity (Ho = 0.65) values as well as high polymorphism information content (polymorphism information content = 0.69). The dinucleotide SSR (GA and CA motifs) loci were more polymorphic than trinucleotide (ATG and AAT motifs) SSRs. The PPF cultivars and KSU advanced selections were more closely grouped genetically than with older cultivars. Older cultivars displayed the greatest genetic diversity (Ho = 0.69). The pawpaw cultivar base of older and PPF cultivars does appear to be genetically diverse. However, KSU advanced selections contain unique pawpaw germplasm that should enhance the genetic base of cultivars if these selections are released to the public.
Changes in Free Amino Acid Content in ‘Jonagold’ Apple Fruit as Related to Branched-chain Ester Production, Ripening, and Senescence
Authors: Sugimoto Nobuko , Daniel Jones A. , Beaudry Randolph
Published: January 2019

The relationship among the free amino acid content, the expression of genes related to branched-chain amino acid metabolism {branched-chain aminotransferase [BCAT], α-keto acid decarboxylase [pyruvate decarboxylase (PDC)], and threonine deaminase [TD]}, and the production of branched-chain (BC) esters during ripening and senescence in ‘Jonagold’ apple fruit (Malus ×domestica) was studied. Eighteen amino acids were measured by liquid chromatography coupled with tandem mass spectrometry. The content for all amino acids changed with developmental stage and some shared similar patterns of accumulation/diminution. The pattern for isoleucine differed from all other amino acids, increasing more than 20-fold during the ripening process. The onset of the increase was concomitant with the onset of increasing ethylene and BC ester production and the content remained elevated even during senescence. The elevated isoleucine levels are consistent with an increase in the flux through the pathway leading to the formation and degradation of the isoleucine precursor α-keto-β-methylvalerate, which is used for production of BC esters containing 2-methylbutanol and 2-methylbutanoate moieties. Unexpectedly, the content of threonine, the amino acid from which isoleucine is thought to be derived in plants, did not change in concert with isoleucine, but rather declined somewhat after ripening was well underway. Patterns in the expression of some, but not all, of the putative BCAT and PDC genes appeared to reflect the rise and fall in ester formation; however, the expression of putative TD genes did not change during ripening. The patterns in gene expression and amino acid content are interpreted to suggest that the synthesis of α-keto-β-methylvalerate and isoleucine during apple ripening may depend on an as yet uncharacterized pathway that bypasses threonine, similar to the citramalate pathway found in some bacteria.
Hot Water Treatment Delays Ripening-associated Metabolic Shift in ‘Okrong’ Mango Fruit during Storage
Authors: Yimyong Sarunya , Datsenka Tatsiana U. , Handa Avtar K. , Seraypheap Kanogwan
Published: January 2019

Effects of hot water treatment (HWT) on metabolism of mango (Mangifera indica cv. Okrong) fruit during low-temperature storage (LTS) and subsequent room temperature fruit ripening (RTFR) were examined. Mature-green ‘Okrong’ mango fruit were treated by immersing in hot (50 ± 1 °C) or ambient (30 ± 1 °C) water for 10 min, stored either at 8 or 12 °C for 15 days, followed by transfer to room temperature (30 ± 2 °C) for 5 days. Rate of ethylene production was significantly reduced by HWT during LTS and RTFR in all treatments. HWT increased catalase activity, suppressed ascorbate peroxidase activity, and had no effect on glutathione reductase activity during the ripening phase but showed a slight stimulatory effect during LTS. HWT altered RNA transcripts of manganese–superoxide dismutase, pectate lyase, β-galactosidase, and β-1,3-glucanase, which exhibited increases during LTS. RTFR of LTS fruit caused reduction in transcript levels of these genes, except pectate lyase. Total protein patterns were altered by all treatments during LTS and RTFR, but HWT arrested loss of several proteins during RTFR. Taken together, results provide strong evidence that HWT increases the storage period of mango by extending fruit shelf life through the regulation of a myriad of metabolic parameters, including patterns of antioxidant and cell wall hydrolase genes and protein expression during storage at low and ambient temperatures.
Cold-hardiness, Acclimation, and Deacclimation among Diverse Blueberry Genotypes
Authors: Ehlenfeldt Mark K. , Rowland Lisa J. , Ogden Elizabeth L. , Vinyard Bryan T.
Published: January 2019

Cold injury to plants can occur by early fall freezes before cold acclimation, by severe midwinter freezes that exceed the limits of the plant's tolerance, or by hard freezes in late winter or early spring after partial or complete deacclimation. Ideally, blueberry (Vaccinium L.) cultivars for temperate regions should acclimate to cold quickly in the fall, have a high midwinter-hardiness, and deacclimate late and/or slowly during spring or during unseasonably warm spells in winter, and do all of this without adversely delaying time of fruiting. Until recently, only limited evaluations have been done on the acclimation and deacclimation process in blueberry, although it is an integral part of flower bud survival and, thus, is directly related to potential yield. In this study, we have measured the timing and rate of acclimation and deacclimation in seven blueberry genotypes with different amounts of diverse species germplasm in their backgrounds. Primary differences observed among the seven genotypes were differences in maximum hardiness levels and the date at which they were reached, and differences in the date at which maximum acclimation levels were no longer sustained and deacclimation started. Highbush cultivars Bluecrop and Legacy (V. corymbosum L.), rabbiteye cultivar Tifblue [V. ashei Reade (= V. virgatum Aiton)], and two rabbiteye hybrid derivatives (US 1043 and US 1056) all reached maximum or near maximum cold-hardiness by late December with temperatures causing 50% lethality (LT50) in a range from –22 to –27 °C. The half-high, ‘Northsky’, and a hybrid of V. constablaei Gray × V. ashei ‘Little Giant’ both achieved cold acclimation of –28 °C or below (the lowest value we could measure) by the end of November. After reaching their maximum hardiness in late December, ‘Legacy’, ‘Tifblue’, and US 1043 began a sustained and relatively linear deacclimation, whereas US 1056, ‘Bluecrop’, ‘Northsky’, and ‘Little Giant’ sustained their acclimation for longer intervals. ‘Bluecrop’ and US 1056 did not begin to deacclimate until early March, and ‘Little Giant’ and ‘Northsky’ had no LT50 values higher (warmer) than –25 °C until late March. As concerns about climate change increase, knowledge of the ability of breeding germplasm to tolerate greater temperature extremes and fluctuations will prove increasingly valuable.
Diallel Analysis of Floral Longevity in Impatiens walleriana
Authors: Howard Nicholas P. , Stimart Dennis , de Leon Natalia , Havey Michael J. , Martin William
Published: January 2019

Impatiens (Impatiens walleriana) are currently among the most valuable and widely cultivated floriculture crops in the world. Attractive floral display is a primary goal for breeders of impatiens. Although breeders have selected for this trait, little consideration has been given to floral longevity as a means to increase the floral display of bedding crops. In this study, 259 commercial inbred lines of impatiens were grown in a greenhouse and evaluated for floral longevity as defined by the time between when a flower was completely open to when all of the petals abscised from the pedicle. Mean floral longevity of inbreds ranged from 3.3 ± 0.4 to 15.8 ± 2.5 days. Twelve inbreds (six with long floral longevity and six with short floral longevity) were chosen and crossed in a half diallel to create 66 hybrids that were analyzed for floral longevity in three greenhouse environments. Mean floral longevity of hybrids across greenhouse environments ranged from 2.8 ± 0.4 to 14.1 ± 2.8 days. Significant general (GCA) and specific (SCA) combining abilities for floral longevity were detected. GCA mean squares were 37 times larger than SCA mean squares, revealing that additive genetic effects play a more important role in the inheritance of floral longevity in impatiens. This information, coupled with the significant amount of variation for floral longevity among inbreds, indicates that there is good potential for breeding for floral longevity in impatiens to improve the floral display of hybrids.