bluuebunny/crossref_metadata_2025 huggingface dataset:
Inter- and Intraspecific RAPD Variation in Four Ipomoea Species
Authors: Zhang Dapeng , Collins Wanda W.
Published: February 2019

Randomly amplified polymorphic DNA (RAPD) analysis was performed on 18 accessions belonging to four different species of the genus Ipomoea, including sweetpotato and three related species. Twenty-two out of 30 primers tested revealed polymorphisms among these four species. Eight primers were selected on the basis of the number and repeatability of polymorphism produced. With these, a total of 98 different DNA bands were obtained and 85% of them were polymorphic. Based on the presence/absence of the bands, a genetic similarity among accessions and among species was calculated. Unweighted pair-group method with arithmetical averages (UPGMA) based on the similarity coefficients clearly discriminated these four species. Ipomoea trifida and sweetpotato share more genetic similarity. Ipomoea triloba and I. leucantha fall into another cluster. This study demonstrated that RAPD techniques can be a very useful tool for genotype/accession identification and studying the genetic relationship among genotypes/accessions of sweetpotato and among species of Ipomoea.
Genetic Relationships among Accessions and Cultivars of Faba Bean (Vicia faba L.) Based on RAPD Molecular Markers
Authors: Crespo Mario , Nienhuis James , Tivang Jan , Skroch Paul
Published: February 2019

Knowledge of relative genetic distance among genotypes is useful in a breeding program because it permits organization of germplasm resources. Genetic distance (GD) was estimated among 113 faba bean, Vicia faba L. genotypes, which included three botanical varieties from different geographical areas around the world. The genotypes included 87 accessions from Bolivia, 14 accessions from the Middle East and North Africa, five accessions from Australia, and seven commercial varieties from Europe. Twenty-three RAPD primers were scored yielding four to 13 polymorphic bands resulting in a total of 165 bands. Our objective was to determine genetic relationships among accessions and cultivars as measured by RAPD markers. The genetic relationships were estimated using the ratio of discordant to total bands scored. A multidimensional scaling (MDS) plot indicated four clusters corresponding to: i) European commercial cultivars; ii) the Middle East, North Africa, and Australian accessions; iii) the Bolivian highland landraces; and iv) the Bolivian collection maintained in a valley environment. A permutation test confirmed the four clusters (P < 0.01). Sampling variance results indicated that a CV of 10% could be obtained with as few as 148 bands between groups. Selection and drift appears the main cause of divergence of two populations in the Bolivian faba bean collection. The results of this study indicated that RAPDs are a powerful tool for evaluation of germplasm conservation methods in faba bean.
Cold Hardiness in Two Interspecific Populus Hybrids
Authors: McCamant Thaddeus , Black R. Alan
Published: February 2019

Cold hardiness was studied in two interspecific Populus hybrids (P. trichocarpa × P. deltoides, and P. trichocarpa × P. maxomowiscii), using laboratory freezing tests of mid-winter dormant tissues and fully expanded leaves in the autumn. These laboratory measurements were compared to field observations. Hybrids having one parent from southern-source populations and the other parent from northern sources were compared to hybrids in which both parents were from southern-source populations. Populus hybrids with one parent of northern origin were generally hardier than hybrids from parents of southern sources; however, significant differences in cold hardiness were detected between hybrids having the same genetic parents. Field observations generally supported laboratory measurements and showed clonal differences in mid-winter cold hardiness and autumn leaf frost tolerance. Fully expanded leaves of different clones from the same parent also exhibited differences in frost tolerance.
Evaluating the Impact of Transplanting Depth on Tomato Yield
Authors: Vavrina Charles S.
Published: February 2019

Tomato transplants when planted to the cotyledon leaves, or to the first true leaf, yielded more than transplants set to the top of the root ball. Yield increase appears to be a function of increased extra-large fruit number, which suggests advanced maturity. Results held across four widely separated geographic locations for both spring and fall plantings. These data suggest that planting tomato transplants deeper is commercially beneficial in Florida.
DNA Amplification Fingerprinting (DAF) Identifies Closely Related Cultivars in Six Series of Chrysanthemum
Authors: Scott M.C. , Caetano-Anollés G. , Trigiano R.N.
Published: February 2019

The genetic distance of closely related cultivars of Dendranthema grandiflora (chrysanthemum) was assess using DAF. Twenty-three cultivars of chrysanthemum included in the study were members of the following series: Anne (3), Blush (3), Boaldi (4), Charm (5), Davis (4), and Pomona (4). The genetic variability within and between series were evaluated using 11 arbitrary octamer primers. A few polymorphic loci were evident that uniquely identified closely related cultivars within a series. In contrast, many polymorphisms were observed between members of different series. Genetic distances between cultivars within and between series were evaluated using marker comparison and analyzed with PAUP (phylogenic analysis using parsimony) and UPGMA (unweighted pair group cluster analysis using arithmetic means). The average distance between series was 10-fold greater than between cultivars within a series. Furthermore, series with similar flower morphology, pompon or daisy-like, were more closely related than those with different phenotypes. DNA from all cultivars belonging to a series were also bulked to generate DNA profiles containing unique amplified products for each series. Polymorphic loci that were generated by the DAF technique can possibly be used for patent protection and phylogenetic studies, and may be useful in breeding chrysanthemums.
Crop Load Effects on Irrigated and Non-irrigated Vitis vinifera L. cv. Thompson Seedless
Authors: Williams Larry E.
Published: February 2019

A study was conducted to determine the effects of crop removal on gas exchange parameters of `Thompson Seedless' grapevines grown in the San Joaquin Valley of California. Vines were either irrigated at full ET or not irrigated throughout the growing season. Clusters were removed subsequent to veraison, when the fruit soluble solids were ≈15° Brix. Reductions in leaf net CO2 assimilation rate (A) were measured within 1 day of fruit removal for both irrigation treatments and remained such until the end of the experiment. The greatest reduction in A due to crop removal on a diurnal basis was with the non-irrigated vines between 0800 and 1000 hr. The reduction in A subsequent to crop removal was not the result of an accumulation of either starch or sugars in leaf tissue. The greater reduction in A of non-irrigated vines after fruit removal may have been due to the lack of strong, alternate sinks as vegetative growth was minimal due to water stress during the experimental period.
Yield and Dry Matter Partitioning of Strawberry Plants Grown with Three Preplant Soil Fumigation Treatments
Authors: Larson Kirk D. , Shaw Douglas V. , Sterrett Jerry
Published: February 2019

Three preplant soil fumigation treatments were applied to a strawberry fruit production field in Summer 1993: 1) a mixture of 67 methyl bromide: 33 chloropicrin (wt/wt, 392 kg·ha–1) (MBC); 2) chloropicrin (trichloronitromethane, 336 kg·ha–1) followed by metam sodium (935 liters·ha–1) CMS); and 3) nonfumigation (NF). Bare-rooted `Camarosa' strawberry plants were established in each treatment on 1 Nov. in annual hill culture. Plant mortality was <1%; thus, differences in growth and productivity among treatments were due to sublethal effects of competitive soil organisms. Fruit yields were recorded weekly from 14 Jan. to 23 May 1994. For the NF treatment, early season (January–March), late season (April–May), and total yields were 86%, 69%, and 72%, respectively, of those of the MBC treatment. Early season yields were greatest for the MBC treatment, but late and total yields were greatest for the CMS treatment. From Jan. through May 1994, 20 plants were destructively harvested from each treatment at about monthly intervals for determination of leaf (LDW), crown (CDW), and root dry weight (RDW). For a given date, LDW, CDW, and RDW of plants in the MBC and CMS treatments were greater than those of the NF plants. From January to March, plants in the NF treatment allocated a proportionally greater amount of dry matter to roots, and proportionally less dry matter to crowns and leaves than fumigated plants. In April and May, root: shoot ratios were similar for all three treatments. These data demonstrate the marked influence of soil fumigation treatment on yield and dry matter partitioning of strawberry, and suggest that combinations of chloropicrin and metam sodium may be a viable, albeit expensive, alternative to fumigation with methyl bromide.
Developmental and gGenetic Differences in the Fruit-receptacle Separation Zone in Tabasco Pepper
Authors: Motsenbocker Carl E. , Sundberg Marshall D. , Huang Yuehe
Published: February 2019

Two lines of tabasco pepper (Capsicum frutescens) were previously identified that differ significantly in ease of fruit detachment force. Greenhouse-grown plants of these lines, `McIlhenny Select' and `HP', were investigated for differences in cell organization in the fruit-receptacle area and the separation zone at different developmental stages. Histological examination indicated that fruit of `HP', which requires greater force to separate, exhibited a larger region of sclerified cells within the fruit-receptacle area. In contrast, fruit of `McIlhenny Select', the line that detaches easier, had fewer sclerified cells in this region. Cell sclerification increased for both lines with increasing fruit maturity. The fruit-pedicel separation zone in both lines is distal to the sclerified region and is composed of parenchymatous fruit tissue. The separation zone for `HP' includes at least 10 additional distal cell layers in the fruit septal region than `McIlhenny Select'.
Growth and Metabolism of Tomato Seedlings Grown with Roots Warm during the Day and Cold at Night, or Vice Versa
Authors: Ma Yong-Zhan , Gent Martin P.N.
Published: February 2019

Do root temperatures warm during the day and cool during the night benefit plant growth? Tomato (Lycopersicon esculentum Mill.) seedlings were grown at a constant 20C air temperature but with varied root temperature, either 28/12C or 12/28C day/night for 8 days. Eight seedlings were grown in troughs in continuously flowing nutrient solution containing 200 μM \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(^{14}\mathrm{NO}_{3}^{-}\) \end{document} excess amounts of other mineral elements. The flow rate was 0.6 liters/day per trough on the first day, when plants weighed 20 mg, and increased with plant size. After 8 days, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(^{15}\mathrm{NO}_{3}^{-}\) \end{document} was provided for 12 h when roots were warm, and eight plants were harvested at the end of labeling or 12 h later. During the treatments, weight per plant increased more in leaves, 3.5 to 44 mg, than roots, 4.3 to 19 mg, and least for stem, 12 to 30 mg. The whole-plant relative growth rate did not differ among treatments, 0.17 to 0.19/day, but was less than for plants grown at a constant 20C root temperature, 0.22/day. Uptake of \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(^{14}\mathrm{NO}_{3}^{-}\) \end{document} from the media and exudation from the stem of decapitated plants were greater when roots were warm than when roots were cold, regardless of light. After labeling for 12 h at the warm root temperature, 15N enrichment in plant tissues was greater with roots warm during the day, 0.20, 0.15, and 0.16, than in those with roots warm during the night, 0.16, 0.11, and 0.10, for roots, stems, and leaves, respectively. Enrichment with roots warm during the day was 22%, 33%, and 62% greater, for roots, stems, and leaves, respectively, than with roots warm during the night. However, uptake of \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{3}^{-}\) \end{document} at night by roots that were warm during the night was sufficient so that plants grown at out-of-phase root temperature grew as fast as plants grown at in-phase root temperature. Research supported in part by grant 93-37100-9101 from the NRI Competitive Grants Program/USDA.
Sites of Superoxide Production in Mitochondria Isolated from Bell Pepper Pericarp Tissue
Authors: Purvis A.C. , Gegogeine J.W. , Shewfelt R.L.
Published: February 2019

Reactive O2 species produced when electron transport is disrupted have been implicated in several environmental stress-induced disorders. Superoxide () is produced at two or more sites in mitochondria isolated from bell pepper fruit supplied with succinate and NADH. SOD and KCN completely inhibited production with both substrates. Antimycin A inhibited production with succinate, but not with NADH. Insensitivity of O2 uptake to KCN increased in mitochondria isolated from bell peppers stored at 2C and their production increased with NADH as substrate, but decreased with succinate. Disrupting the mitochondrial membranes enhanced production with NADH and reduced production with succinate. Greater production with NADH may result from the inability to transfer electrons from NADH through the alternative path. The KCN-insensitive alternative path in some plant tissues appears to reduce the potential production of .
Heat Treatments Extend Shelf-life of Tomato Fruit
Authors: McDonald R.E. , McCollum T.G. , Baldwin E.A.
Published: February 2019

Mature, green tomatoes were either gassed or not gassed with C2H4 for 24 h, immersed in 42C water for 60 min, or held in 38C air for 48 h or not treated, and then stored at either 2C or 13C for 14 days before ripening at 20C. During ripening, the fruit were evaluated for color development, internal quality, and decay and for volatiles when full ripe. Both high-temperature treatments reduced chilling injury and inhibited decay. Days to ripen after removal from storage at 2C or 13C was not influenced by heat treatment method. Color development, lycopene content, and internal quality characteristics of fruit were similar at the ripe stage, irrespective of heat treatment. Of 15 volatiles analyzed, seven showed decreased levels of concentrations as a result of C2H4 gassing, nine showed decreased levels when stored at 2C prior to ripening, and most were unaffected by the heat treatments. Heat treatments appear to be beneficial for maintaining tomato fruit quality.
Effects of Rowcover Microclimate on `Delicious' Apples
Authors: Gatherum Dawn M. , Anderson L. LaMar , Seeley Schuyler D.
Published: February 2019

Plastic covers were placed over rows of `Delicious' apple trees/M.26 to test their effect on canopy temperature and hence on bud phenology and growing season duration. In 1992, plastic covers enclosed the treated plots to within 0.5 m of the soil and the tunnel ends were left open. Average daily temperatures within the rowcovers were 0.1C cooler in April, 0.2C warmer in May, and 0.1C cooler in July than uncovered canopy temperatures. In 1993, rowcovers completely enclosed the treated plots (both ends and sides); average daily temperatures within the enclosed plots were 1.6C warmer in April, 0.1C cooler in May, 0.2C cooler in June, and 1.3C cooler in July. There was no difference in the date of anthesis in 1992; however, within the complete enclosures in 1993, anthesis occurred 7 days earlier than in the uncovered plots. Apple weight and shape were comparable in 1992, but, in 1993, apples in the covered plots average 31.1 g more than fruit in the uncovered trees and had slightly great length/width ratio. Complete and uniform red color development did not occur either year under rowcovers. In addition, rowcovers prevented sunscald and hail damage, and reduced windfall of nearly ripe fruit.
Thinning and Diametric Fruit Growth Response of Apple Trees Treated with Benzyladenine and GA4+7 (Accel®), Carbaryl, and NAA
Authors: Cline John A. , Bom Mary , Elfving Donald C.
Published: February 2019

A series of seven fruit thinning experiments with benzyladenine (BA), benzyladenine and GA4+7 (10:1 BA:GA4+7, Accel), carbaryl (CB), and NAA were conducted at the Horticultural Experiment Station, Simcoe, during the 1993 and 1994 growing seasons. In 1993, BA and Accel at 0, 100, 200, and 300 mg of BA/liter were applied to mature `Redspur Delicious'/M.26 and `Empire'/M.26 trees when fruit were ≈10 mm in diameter. In one set of experiments in 1994, Accel was applied at 0, 25, 50, 100, 150, and 200 mg of BA/liter to mature `McIntosh'/M.26 and `Empire'/M.7 trees. In a second set of experiments in 1994, Accel was applied at 0, 50, and 100 mg of BA/liter to mature `Idared'/M.26, `Empire'/M.26, and `Marshall McIntosh'/Mark trees when fruit were ≈10 mm in diameter. Additional treatments included bloom sprays of Accel at 50 mg of BA/liter, and sprays of BA at 50 mg a.i/liter, NAA at 10 mg a.i./liter, CB at 1000 mg a.i./liter, and a “low” (two fruit remaining/flower cluster) and `”high” (one fruit remaining/flower cluster) rate of hand thinning. In all experiments, thinning response to BA and Accel increased with concentration. Concentrations below 50, 100, and 300 mg BA/liter were generally ineffective for thinning `Empire', `Idared', and `McIntosh', and `Delicious', respectively. Fruit size of `Idared' and `Empire' was increased at rates of 50 mg BA/liter, whereas rates of 100 mg BA/liter were needed to increase fruit size of `McIntosh'. Accel applied to `Empire' at 150 mg BA/liter decreased the number of seeds per fruit and increased fruit length:diameter (L:D) ratios. Concentrations of Accel exceeding 100 mg BA/liter in `Red Delicious' decreased the number of seeds per fruit, while having little effect on fruit L:D ratios even though lower concentrations increased fruit L:D ratios. Diametric fruit growth measurements in 1994 indicated a temporary, but sharp, decline in growth rate immediately following treatment imposition for trees that responded positively to thinning. Additional data describing treatment effects on fruit size distribution, vegetative growth, and fruit maturity will be presented and discussed in relation to crop load.
GA3, GA4+7, and GA7 Inhibit Flower Bud Formation and Reduce Alternate Bearing in Apple (Malus domestic Borkh.)
Authors: McArtney Steven J. , Hua Li Shao
Published: February 2019

A single spray of either GA3 or GA4+7 at full bloom reduced the severity of the alternate bearing cycle of `Braeburn' apples, measured as the proportion of flowering spurs over the 2 years following treatment. Increasing the concentration of GA3 applied in the light-flowering year linearly reduced the proportion of flowering spurs in the following year and linearly increased the proportion of flowering spurs 2 years after treatment. Application of GA3 or GA4+7 at full bloom inhibited flower bud formation on spurs only, whereas, in a separate experiment, GA3 or GA7 applied later than 8 weeks after bloom inhibited flower bud formation on 1-year wood only. Thus, delayed GA treatments may provide suitable technology for the selective removal of fruit from 1-year wood in apple.
Analysis of Anther-derived Potato by RAPDs and SSRs
Authors: Veilleux R.E. , Shen L.Y. , Paz M.M.
Published: February 2019

RAPD and SSR analyses were used to characterize the genetic composition of anther-derived plants of a diploid potato clone, CP2 (S. chacoense 80-1 × S. phureja 1-3). The ploidy of anther-derived plants was first determined by flow cytometry. A total of 44 decamer primers was screened for polymorphism. The loci that segregated were selected and scored. The monoploids had only half as many loci carrying RAPD markers compared to the anther donor. Among the 13 anther-derived diploids, four were identified as homozygous by marker frequency similar to monoploids and nine as heterozygous. Five of seven SSRs obtained from published potato sequences were polymorphic in CP2. CP2 was found to be heterozygous with two alleles at four SSR loci (TC/TA, AAG, AGA, CTT), and three alleles at an ACTC locus. Primer pairs flanking each of the five polymorphic SSRs revealed that monoploids had only the allele contributed by chc 80-1. Homozygous diploids had only one band per SSR locus, whereas heterozygous diploids displayed more than one allele for at least one SSR locus. Results of the SSR analysis supported the findings based on RAPD markers; the same diploid clones were characterized as homozygous by both SSR and RAPD markers.
Screening Fine Fescues for Aluminum Tolerance
Authors: Liu H. , Heckman J.R. , Murphy J.A.
Published: February 2019

The fine fescues are generally considered to be acid-tolerant compared to many other cool-season turfgrasses. However, there is a lack of documentation on aluminum tolerance of fine fescues at both the species and cultivar levels. A total of 58 genotypes belonging to five species or sub-species were screened under greenhouse conditions using solution culture, sand culture, and acid Tatum subsoil. This soil had 69% exchangeable Al and a pH of 4.4. An Al concentration of 640 μM and a pH 4.0 were used in solution screening and sand screening. Differences in Al tolerance were identified at both species and cultivar levels based on relative growth. The genotypes with endophyte infection generally exhibited greater Al tolerance than endophyte-free genotypes. The results indicate that fine fescues vary in Al tolerance and there is potential to improve Al tolerance with breeding and to refine management recommendations for fine fescues regarding soil pH.
Accumulation of Possible Potato Tuber-inducing Factor in Continuous-use Recirculating NFT sSystem
Authors: Wheeler R.M. , Stutte G.W. , Mackowiak C.L. , Yorio N.C. , Ruffe L.M.
Published: February 2019

Potatoes (Solanum tuberosum L.) have been grown successfully with a recirculating nutrient film technique (NFT) when a fresh nutrient solution is used for each planting. During the past year, we conducted two studies in which the same nutrient solution was used for successive plantings (EC and pH were maintained at 0.12 S·m–1 and 5.8). Results showed that successive plantings became prematurely induced (tubers initiating near 20 days after planting–DAP), causing stunted shoot growth and reduced yields per plant. When “old” nutrient solution from a continuous production system was regularly added to a newly started plant system maintained under a non-inductive environment (12-h photoperiod with night break of 6 h into dark), tubers formed on “old” nutrient solution plants (24 DAP), but not on “new” solution plants. When charcoal water filters were placed on the systems, plants grown on either “old” or “new” nutrient solutions showed no tuber initiation (plants harvested at 42 DAP). Results suggest that a tuber-inducing factor(s) emanating from the plants accumulates in the nutrient solution over time and that the factor(s) can be removed by charcoal absorption.
Continuous Production of Potato in an AFT System
Authors: Stutte G.W. , Mackowiak C.L. , Yorio N.C. , Wheeler R.M. , Ruffe L.M.
Published: February 2019

An experiment was conducted in the Biomass Production Chamber (BPC) at Kennedy Space Center to determine the feasibility of continuous steady-state production of potato (Solanum tuberosum L.). Plants were grown in a “batch” or continuous production mode using either 0.5 × modified Hoaglands or effluent from aerobically processed inedible potato biomass as a nutrient source. EC and pH were controlled to 0.12 S·m–1 and 5.8, respectively. The batch harvest occurred after 104 days and continuous harvest occurred every 26 days, with replanting occurring in the same solution. Continuous production on “aged” solution resulted in earlier tuber initiation, reduced plant height, and smaller canopies than the “batch” treatment. Planting density of the continuous treatment was increased from eight to 16 plants/m2. Because one quarter of the planting area was harvested and replanted every 26 days, a steady-state of canopy coverage between 60% to 75% of the chamber was maintained. Steady-state of CO2 fixation was also maintained in the continuous treatment. There was no effect on either quantum efficiency, tuber yield, or harvest index of the plants grown in continuous production. Although replanting into “aged” nutrient solution resulted in earlier tuber initiation and reduced plant size, the system reached a steady state of production, which is desirable for advanced life support system.
A Heat Unit Model to Predict Growth and Development of Muskmelon (Cucumis melo var. reticulatus Naud.) to Anthesis
Authors: Jenni S. , Cloutier D.C. , Bourgeois G. , Stewart K.A.
Published: February 2019

Plant dry weight of muskmelon transplants to anthesis could be predicted from a multiple linear regression based on air and soil temperatures prevailing under 11 mulch and rowcover combinations. The two dependent variables of the regression model consisted of a heat unit formula for air temperatures with a base temperature of 14C and a maximum-reduced threshold at 40C, and a standard growing-degree-day formula for soil temperatures with a base temperature of 12C. Based on 2 years of data, 86.5% of the variation in the dry weight (on a log scale) could be predicted with this model. The base temperature for predicting time to anthesis of muskmelon transplants was established at 6.8C and the thermal time ranged between 335 and 391 degree-days during the 2 years of the experiment.
The Maintenance of Charge Balance and pH in Hydroponic Solutions by Stock Nutrient Addition: A Possibility?
Authors: Lea-Cox John D. , Stutte G.W. , Berry W.L.
Published: February 2019

The maintenance of pH in unbuffered nutrient solutions has important consequences for the hydroponic industry and proposed nutrient delivery systems for plants in space. The requirement for charge balance by a model plant system, dwarf wheat (Triticum aestinum cv. Yecora rojo), is largely a function of the uptake ratio of four cation species (, Ca2+, and Mg2+) and two anion species ( and ) up to anthesis. The change in electrical conductivity (EC) and pH of the nutrient solution over time integrates the overall influx:efflux process of the plants. Solutions with three different NH4:NO3 ratios were sampled at 15-min intervals over a 12-h period at 9, 10, 16, 17, 23, 24, 37, and 38 days after planting. Exhaustion of N in the solution at all stages of ontogeny resulted in a 2- to 3-fold reduction in ΔpH/Δt, despite high plant tissue N and irrespective of the concentration of other charge balance ions in solution. These data, combined with a plant nutrient uptake database (normalized for plant relative growth rate per mole PPF), suggest that a system can be developed to control pH by direct supply of various alternative nutrient stock solutions, rather than by the addition of H+ or OH– from acid or base.
Tissue Nutrient Content Dynamics of Wheat and Potato Grown under Highly Productive Field and Hydroponic Conditions
Authors: Matar A. , Berry W.L. , Mackowiak C.L. , Stutte G.W. , Wheeler R.M. , Sager J.C.
Published: February 2019

Tissue nutrient (element) content profiles were determined for wheat and potato plants grown hydroponically (NFT) in NASA's Biomass Production Chamber (20 m2) using a complete nutrient solution with electrical conductivity maintained at 0.12 S·m–1. Profiles were compared to patterns of nutrient accumulation during vegetative stages reported for highly productive wheat and potatoes grown in the field under a wide range of conditions. Among the essential elements, differences between the hydroponically and field-grown crops were observed only for Ca, Mg, and Mn in the recently mature leaves, and these differences were related to changes in growth phase and/or consistency of nutrient supply during plant growth. Nutrient profiles for both hydroponically and field-grown crops were also compared to deficiency and toxicity critical levels compiled by various workers. As expected for high-yielding crops, the profiles for both crops were well within the sufficiency ranges for all evaluated nutrients.
Effects of Postharvest Prestorage Hold Temperatures Followed by Cold or CA Storage on the Quality of `Bartlett' Pears
Authors: Chu C.L.
Published: February 2019

`Bartlett' pears were harvested from four commercial orchards at their optimum harvest date and 3 or 7 days later (depending on grower orchard). Samples were held for 3 or 7 days before stored in cold storage and two controlled-atmosphere conditions: 1) cold storage at 1C; 2) regular CA storage (2.5% O2 + 1.0% CO2 at –1C); 3) low-oxygen CA (1.0% O2 + 0.2% CO2 at –1C). After 2 months of cold and CA storage, pears showed that postharvest prestorage holding temperature, affected the rate of change in weight loss, firmness, ground color, and senescent breakdown. After 4 months of CA storage, `Bartlett' pears maintained their quality at about 53–58 N of firmness. Firmness loss, peel ground color change, and senescent breakdown of `Bartlett' pears were affected by the holding temperature and the length of the holding period between harvest and storage. In conclusion, pear quality was reduced depending on the holding temperature and holding period between harvest and storage. CA storage maintained better pear quality than cold storage. Fast oxygen pulldown in order to establish CA condition sooner was essential to maintain better pear quality.
Performance of `Gala' Apple Grown on Seven Rootstocks in Illinois
Authors: Kushad Mosbah M.
Published: February 2019

Yield performance and postharvest quality of `Gala' apple on Mac.39, P.1, Mark M.26E, M.9E, B.9, and M.27E were evaluated. Trees on B.9 and Mark had the highest yield efficiency, while trees on P.1 and M.9E had the lowest yield efficiency. Trees on P.1 were most vigorous, while trees on B.9 and M.27E were least vigorous. Trees and fruit buds survived a –32C during Jan. 1994. Fruit firmness, soluble solids, starch, and ethylene production rate were similar in fruits from all seven rootstocks at harvest. However, after 3 months in storage, fruits from trees on M.27E, P.1, and Mark rootstocks were less firm than fruits from trees on the other four rootstocks. Glucose, fructose, sucrose, and sorbitol levels at harvest and after storage were similar in fruits from all rootstocks.
Variation for Calcium Concentration among 64 Genotypes of Snap Bean (Phaseolus vulgaris)
Authors: Quintana Juan M. , Harrison Helen C. , Nienhuis James
Published: February 2019

Calcium is an essential element for human nutrition. The lack of it causes various problems, such as osteoporosis. Snap beans rank as good sources of calcium among vegetables and are well-liked by most teenagers. In this study, pod yield and Ca concentration were analyzed for 64 genotypes of snap beans, plus four checks. The experimental design was a 8 x 8 double lattice, repeated at two locations (Arlington and Hancock, Wis.). Snap beans were planted in June 1993 and machine-harvested 67 days later, in Aug. 1993. Calcium analyses were made using an Atomic Absorption Spectometer. Results indicated significant differences for pod Ca concentration and yield. Pod size and Ca concentration showed a strong negative correlation (R = 89.5). Clear differences among the locations were also observed. Results were consistent—high-Ca genotypes remained high regardless of location or pod size. Selected genotypes appeared to have the ability to absorb Ca easier than others, but this factor was not related to yield.
Pest Control with Proteinase Inhibitors: Is It Compatible with IPM Strategies?
Authors: Michaud Dominique , Vrain Thierry C. , Raworth David A. , Daubeny Hugh A.
Published: February 2019

In recent years, several studies have demonstrated the potential of proteinase inhibitors (PIs) for the control of various pests and pathogens. Used as a component of an integrated pest management program, such an approach must, however, be carefully considered, given the possible risks of interference with other control methods. For example, we are analyzing the effect of oryzacystatins (OCI and OCII), two cysteine PIs naturally occurring in rice grains, against digestive proteinases of Amblyseius californicus (AC), a native predator of the two-spotted spider mite (SM; Tetranychus urticae). Electrophoretic analyses have shown the existence in SM extracts of a major cysteine proteinase form strongly inhibited by OCI, indicating the potential of this inhibitor for SM control. However, similar analyses revealed a strong affinity between proteinases from AC extracts and OCs. Thus, despite their potential for SM control, plant cystatins may represent growth-suppressing compounds for AC. Work is currently underway to determine the usefulness of OCI-expressing transgenic plants for SM control, and to assess the compatibility of this control with an AC-based biological control strategy.
Nodal Propagation Reduces Genetic Variability in Sweetpotato Clones
Authors: Villordon Arthur Q. , LaBonte Don R.
Published: February 2019

Our research examined whether plants originating from adventitious sprouts from fleshy sweetpotato roots are genetically more variable than plants that arise from pre-existing meristematic regions, i.e., nodes. Our study compared one plant each of `Jewel', `Sumor', and L87-95 clonally propagated for seven generations both nodally and through adventitious sprouts. PCR-based analysis of 60 samples (10 nodal and 10 adventitiously derived plants/genotype) showed 20% polymorphism among adventitious materials vs. 6% among nodally derived plants. An “analysis of molecular variance” showed that differences between propagation methods accounted for 30% of the total marker variability. Our results support previous findings that, relative to non-meristematic materials, meristematic regions strictly control cell division and DNA synthesis that exclude DNA duplication and other irregularities.
juvenile albino, a Virescent Mutant in Watermelon: Inheritance and Expression
Authors: Zhang X. , Rhodes B.B. , Baird W.V. , Skorupska H.T. , Bridges W.C.
Published: February 2019

juvenile albino (ja) is a spontaneous mutant, first observed in 1992. Hypocotyls, new young leaves, shoot tips, tendrils, and flowers on the main shoot of the ja mutant are all albino during early spring and late fall. The interior of the albino leaves gradually become green, while the margins remain albino. Fruit rind color of the mutant is variegated. Growth of the ja mutant is severely impaired in the early spring and late fall. However, the mutant grows almost normal in the summer, and produces fruits of almost normal size. Genetic analysis of F1, F2, and BC1 populations derived from the ja mutant showed that ja mutant is inherited as a single, recessive, nuclear gene. The segregation ratios in the F2 and BC1 progenies derived from the cross between the previously reported dg virescent mutant and the ja mutant indicated that both are inherited independently. Experiments with temperature (3–5C vs. 20–22C at night), day length (8 vs. 15 h), and red and/or far-red light (15 vs. 0 min) at the end of an 8-h day were performed to investigate the regulation of ja trait expression. Temperature and red/far-red light had no differential effect on mutant and wild-type plants. However, significantly increased fresh weight and chlorophyll content were observed in the ja mutant over the wild-type when grown under long-day conditions. In addition, chlorophyll synthesis or accumulation in the mutant is severely impaired under short-day conditions. To our knowledge, this is the only virescent mutant in Cucurbitaceae whose expression is regulated by day length.
A Genetic Model for Resistance to Root-knot Nematode (Meloidogyne hapla Chitwood) in Carrot (Daucus carota L.)
Authors: Wang Min , Goldman I.L.
Published: February 2019

The genetics of resistance to root-knot nematode (M. hapla Chitwood) was studied in crosses of three carrot inbred genotypes, two resistant genotypes (R1 and R2) and one susceptible genotype (S1) identified in previous screening tests. Seedlings of three parental genotypes, six F1 crosses including three reciprocal crosses, two BC1 populations, and three F2 populations were evaluated for their resistance and susceptibility to infestation of M. hapla Chitwood based on gall number per root, gall rating per root, and root rating per root in a greenhouse experiment carried out in 1994. All six F1 plants were susceptible, which indicated a lack of heterosis for resistance in these F1s. The R1 × S1 cross segregated 3 susceptible: 1 resistant in the F2, 1 susceptible: 1 resistant in the BC1R1, and did not segregate in the BC1S1. The R1 × R2 cross yielded 44 susceptible: 36 resistant seedlings in the F2 (R1R2), and 48 susceptible: 32 resistant in the reciprocal cross of R1 and R2, both of which closely fit a 9: 7 ratio (P ≤ 0.001). These results indicate these two resistant genotypes carry two different homozygous recessive genes conditioning root-knot nematode resistance. We propose a model of duplicate recessive epistasis control the reactions of host plants and nematode in these crosses.
Physiological and Chemical Changes during Ripening of Costa Rican Bananas Harvested at Four Different Seasons
Authors: Marin D.H. , Blankenship S.M. , Sutton T.B. , Swallow W.H.
Published: February 2019

Mature-green `Grande Naine' bananas (Musa AAA) were harvested 13 weeks after flowering, in June and Sept. 1993, and Feb. and Mar. 1994. Fruit were 1) held in storage for 36 days at 14C and 80% to 90% RH, or 2) after 8 days of storage, fruit were treated with ethylene, and held at 17C until color 6 of the standard color scale was observed. Although a similar grade and age, the length of the preclimacteric phase was different among months, which reflected different physiological maturities at harvest. Rate of respiration, pulp pH, and soluble solids were the most-useful variables to characterize the fruit. Increases in respiration after ethylene treatment varied from 4- up to 14-fold the respiratory level under storage conditions. The climacteric occurred at any point during ripening, ranging from color 2 to 5, except at very early stages. Ethylene increases were short in duration and magnitude, and occurred earlier than the respiratory peak. Sometimes, internal and external ripening stages did not match. The most dramatic seasonal effects were observed in CO2 evolution, pulp-to-peel ratio, and starch conversion.
Influence of Stock Plant Nitrogen Fertilization on Rooting Stem Cuttings of Loblolly Pine
Authors: Rowe D.B. , Blazich F.A. , Wise F.C. , Warren S.L.
Published: February 2019

Containerized, 1.5-year-old, hedged stock plants of four full-sib families of loblolly pine (Pinus taeda L.) were fertilized daily with a complete nutrient solution containing 9 ppm P, 38 ppm K, and either 0, 5, 10, 20, or 40 ppm N. Softwood cuttings were removed in May and July 1994, and placed under intermittent mist at two locations: Raleigh and Summerville. Overall rooting was significantly greater at Summerville (49%) than in Raleigh (37%). Cuttings taken in May rooted at significantly greater percentages than the July cuttings (57% vs. 29%). Overall rooting (56%) and root area (12 cm2) were greatest at 40 ppm N, whereas root number (two), root dry weight (66 mg), and total root length (108 cm) were maximized at 20 ppm N. Although family was not significant, a family × nitrogen interaction occurred. For both rooting trials, maximum rooting (83%) was noted for May cuttings rooted in Summerville, which were taken from stock plants of one family fertilized with 20 ppm N.
Penetrating Agents for Liquid Quick-dip Rooting Hormones
Authors: Vandergriff David , Witte Willard T.
Published: February 2019

Fifteen-cm terminal cuttings of llex × `Nellie R. Stevens' were harvested 28 Nov. 1993. Basal leaves were stripped with five to six terminal leaves remaining. Groups of 10 cuttings were treated with a 5-s quick-dip by inserting stem bases to a depth of 2.5 cm into the treatment solution. Treated cuttings were immediately inserted into 12-cm-deep nursery flats containing moist 40% Pro-Mix/60% perlite. Hormone treatments were dilutions of Dip'N Grow formulation (10,000 ppm IBA + 5000 ppm NAA). IBA/NAA levels were set at 3000, 6000, and 9000 ppm and combined in a factorial arrangement with penetrating agents of 20% dimethylformamide and 20% triethanolamine with water as a control for nine treatment combinations. Ten replications were placed on a propagation bench with bottom heat (25C) and intermittent mist. When most cuttings were well-rooted, each cutting was rated on a scale of 1 (no or little rooting) to 5 (heavy rooting). Analysis of variance showed each level of rooting hormone to be different from every other level, with best rooting at 9000 ppm (3.80). Penetrating agent treatments were different from each other, with best rooting in triethanolamine treatments (3.54), followed by dimethylformamide treatments (3.29), and controls (2.65).
Early Development of a Free-standing Tree Wall for `Mcintosh' and `Empire' Apples
Authors: Embree Charlie
Published: February 2019

Spur-type growth habit, among other factors, is known to reduce vigor in apple trees. High-density orchards can, therefore, be designed with more vigorous rootstocks, which do not require support systems. Trees were planted in a latin square design and trained to modified vertical axis system which, encouraged maximum limb development. Growth response of the spur McIntosh strains; `MacSpur', `Hartenhof', `Stirling', `Chick-a-dee'; and for `Empire' are compared for each of the five rootstocks MM.106, Alnarp 2, MM.111, KSC13, and KSC3. `Empire' on KSC13 grew the largest, the smallest were `Stirling', `Chick-a-dee', and `Empire' on KSC3.
Leaf Appearance Rate of Summer Squash as a Function of Thermal Time
Authors: NeSmith D. Scott
Published: February 2019

Different planting dates were used to study the influence of thermal time on leaf appearance rate of four summer squash (Cucurbita pepo L.) cultivars. During the first year (1991), thermal time or growing degree days (GDD) were calculated using a base temperature of 8C and a ceiling temperature of 32C for several planting dates. Leaf numbers per plant were determined every 2 to 3 days. Leaves that were beginning to unfold with a width of 2 cm or greater were included in the counts. The relationship between leaf number and GDD was established from the initial data set, and data from subsequent years were used for model validation. Results indicated that single equation could be used to predict leaf appearance of all four cultivars in response to thermal time. The response of leaf appearance to GDD was curvilinear, with a lag over the first five leaves. After five leaves, the increase in leaf number per plant was linear with increased GDD. Segmented regression with two linear functions also fit the data well. With this approach, leaf 5 was the node, and a separate linear function was used to predict the leaf number below five leaves and above five leaves. The results of this model should prove to be useful in developing a model of leaf area development, and eventually a crop growth model, for summer squash.
Peanut Production using Recirculating Nutrient Film Technique (NFT)
Authors: Mackowiak C.L. , Wheeler R.M. , Stutte G.W. , Yorio N.C.
Published: February 2019

As part of NASA's effort with bioregenerative life support systems, the growth of candidate crops is being investigated in controlled environments. Peanut (Arachis hypogaea L.) was selected for the high oil and protein content of its seed. Peanut cvs. Pronto and Early Bunch were grown from seed, using recirculating nutrient film technique (NFT) in 6-cm-deep, trapazoidal culture trays. The trays were fitted with slotted covers, which allowed developing pegs to reach the root zone. Use of a separate moss-filled pegging compartment above the root zone (tray within a tray) had little effect on seed yield, but resulted in a 60% increase in the nitric acid requirements for pH control. Yields from both cultivars were equivalent to field values on an area basis; however, harvest indices were lower than field values due to the luxuriant canopy growth under controlled environment conditions. Proximate analysis of seeds was similar to field values, with the exception of fat, which was ≈15% lower, and ash, which was ≈30% greater under controlled environment conditions, regardless of cultivar.
Evaluation of Iron Nutritional Quality of Two Amaranth Species sing Hemoglobin Repletion in Rats
Authors: Rangarajan Anusuya , Chenoweth Wanda , Kelly John F. , Agee Karen
Published: February 2019

Studies have been underway to evaluate the genetic variation in iron nutritional quality of the green leafy vegetable Amaranthus. Initial screening of 35 lines of amaranth from 12 species indicated wide variation in total iron, and small, but significant, differences in bioavailable iron, as determined by an in vitro assay. To verify if the differences in bioavailable iron detected by the in vitro assay were biologically significant, two lines of amaranth, A. tricolor Ames 5113 and A. hypochondriacus Ames 2171, were evaluated using a hemoglobin repletion assay in rats. Weanling Sprague-Dawley rats were made anemic by feeding an ironfree casein-based diet for 4 weeks. The anemic animals were fed treatment diets in which all Fe was provided by the amaranth lines. Hemoglobin levels were measured at the start and end of the treatment period to determine bioavailability. Although A. tricolor contained a higher concentration of total iron (670 ppm), the bioavailability of this iron to rats was lower than from the A. hypochondnacus line (total Fe = 210 ppm). Similar amounts of either amaranth line added to the diet produced similar changes in hemoglobin, although total iron concentrations were significantly different, confirming results observed with in vitro assays.
RAPD Analysis of Hosta Species and Cultivars
Authors: Ling Jing-Tian , Gawel Nick , Sauve Roger J.
Published: February 2019

The genus of Hosta (plantain lily) is a shade-loving herbaceous plant with attractive foliage. Confusion exists in the genus regarding nomenclature and taxonomy. In this study, the possibility of application of RAPD markers to characterize Hosta species and cultivars was investigated. DNA was extracted from 28 Hosta species and cultivars. Thirty-six of 37 primers generated RAPD markers. Phylogenic analysis and principal components analysis showed groupings among cultivars. Results indicated that H. plantaginea and H. ventricosa were the most distant from the other tested species and cultivars. These results suggest RAPDs may be useful in the identification and analysis of relationships among Hosta.
Growth of Sugar Maple Taxa in Tennessee
Authors: Witte W.T. , Sauve R.J. , Flanagan P.C.
Published: February 2019

Commercially available Acer saccharum cultivars, and some closely related species accessions (floridanum, leucoderme, macrophyllum, and nigrum `Greencolumn'), were established as 10 single-plant replications in a cultivar trial at the TSU–NCRS in 1993 and Spring 1994. Plants were regularly fertilized and drip irrigation was begun Summer 1993. Growth data were recorded each fall and height and caliper increment calculated for the 1994 season. In the group with most height growth were: `Bonfire', `Majesty', nigrum `Greencolumn', leucoderme, `Sweet Shadow', `Fairview', and macrophyllum. These, except for `Fairview' and macrophyllum, differed significantly from a group of seven slower growing cultivars. With some exceptions, cultivars with the most height growth tended to have the most caliper growth, while those with the least height growth tended to have the least caliper growth. Data will also be presented on insect and disease ratings.