bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of Glycolytic Metabolism in Fresh-cut Carrots under Low Oxygen Atmosphere
Authors: Kato-Noguchi Hisashi , Watada Alley E.
Published: January 2019

Carrot (Daucus carota L.) shreds were stored under a continuous flow of air or 0.5% and 2% O2 (balance N,) for 9 days at 5 and 15C. The resulting changes in respiration, levels of glycolytic intermediates, and activities of ATP: phosphofructo kinase (ATP-PFK), and PPi: phosphofructokinase (PPi-PFK) were monitored. Carrots under low O atmosphere exhibited an increase in RQ due to a greater reduction in 02 consumption than in CO2 production, and the increase in RQ was greater at 0.5% than at 2% O2 at both temperatures. Fructose 1,6-bisphosphate (F1,6P) accumulated with decreased O2 atmosphere and was 2-fold greater at 0.5% than at 2% O2 atmosphere at both temperatures. The levels of other glycolytic intermediates were not significantly influenced by low O2. The increase in PPi-PFK activity occurred at the same time as F1,6P accumulation. A similar relationship was not found with ATP-PFK. These results suggest that PPi-PFK may be involved in regulation of glycolysis under low O2 atmosphere.
Lychee Pollination by the Honeybee
Authors: Stern Raphael A. , Gazit Shmuel
Published: January 2019

Pollination of lychee (Litchi chinensis Sonn.) by the honeybee was studied in Israel's two commercial cultivars, `Mauritius' and `Floridian'. Pollination rate, which was determined in a mixed `Mauritius' and `Floridian' plot, followed a consistent pattern: it was low at the first male (M,) `Mauritius' bloom and reached a high value only when the pseudohermaphroditic (M2) `Mauritius' bloom started. Pollen density on bees collected from `Mauritius' inflorescences was very low during the M, bloom and increased to very high values during the M2 bloom. These results indicate that the `Mauritius' M, bloom does not play an important role as a source of pollen for pollination. Pronounced, significant, and consistent differences in nectar volume per flower and sugar concentration in the nectar were found between M1, M2, and female (F) `Mauritius' flowers. Values were very high in F flowers, medium in M2 flowers, and low in M, flowers. Accordingly, the density of bees found on inflorescences was high during the F bloom, intermediate during the M2 bloom, and low during the M1 bloom. The positive correlation between bee density and sugar concentration in the nectar was highly significant for M2 and F `Mauritius' flowers. The nectar contained three sugars: glucose (43%), fructose (39%), and sucrose (18 %). This ratio was the same in nectar from M1, M2, and F `Mauritius' flowers.
Dynamics of Nutrient Uptake from Foliar Fertilizers in Red Raspberry (Rubus idaeus L.)
Authors: Reickenberg Regina L. , Pritts Marvin P.
Published: January 2019

The dynamics of nutrient uptake from foliar applied 15N-urea and Rb (a K analog) were quantified in red raspberries. Both N and Rb in an aqueous solution were absorbed rapidly into the leaf and transported throughout the plant. In the greenhouse, about half of the urea and a third of the Rb were absorbed within 32 hours of application. The addition of a surfactant to the foliar solution reduced uptake, while solution pH, time of application and leaf age had little effect. The lower leaf surface exhibited a faster rate of absorption than the upper surface, but the difference was not large. In the field, some foliar N appeared to have been washed off leaves and taken up by the root system; however, none of the foliar applications affected plant growth. We conclude that significant uptake of foliar applied N and K occurs in raspberry, but the absolute amount delivered through a single foliar application is small. The percentage of total plant nutrient supplied through a foliar application is reduced to < 5% over time as the plant grows, so multiple applications would be required to maintain levels significantly higher than would exist through root uptake alone.
Simultaneous Selection is Effective in Increasing Betalain Pigment Concentration but not Total Dissolved Solids in Red Beet
Authors: Goldman I.L. , Eagen K.A. , Breitbach D.N. , Gabelman W.H.
Published: January 2019

Betalain pigments, composed of the red-violet betacyanins (BC) and the yellow betaxanthins (BX), provide an excellent natural alternative to synthetic red dyes. The objective of this investigation was to evaluate eight cycles of recurrent selection in two red beet (Beta vulgaris L.) populations selected for high total betalain pigment concentration and both high (HPHS) and low (HPLS) total dissolved solids (TDS). Remnant seed was planted in a randomized complete block design in replicated trials at two locations in 1994. Beet roots were sampled at harvest for concentrations of BC, BX, and TDS. Highly significant differences among cycles for BC, BX, BC:BX, total pigment, and TDS were observed. Average gains per cycle were 13.15 and 4.06 mg per 100 g fresh weight for BC and BX in HPHS, and 7.59 and 2.61 mg per 100 g fresh weight for BC and BX in HPLS, respectively. Total pigment increased about 200 % in both populations. Selection for low TDS was ineffective, while only a mild response was detected from selection for high TDS. Since betalain pigments are formed following glycosylation of cyclodopa and betalamic acid, sugar molecules are associated with pigment biosynthesis. Simultaneous selection for high pigment and low TDS may therefore be metabolically incompatible. Our findings demonstrate betalain pigment concentration responds favorably to recurrent selection: however. a concomitant reduction in TDS is not a feasible selection goal.
Backcross Hybrids of Zinnia angustifolia and Z. violacea: Embryology, Morphology, and Fertility
Authors: Boyle Thomas H.
Published: January 2019

True-breeding lines of Zinnia marylandica Spooner, Stimart and Boyle [allotetraploids of Z. angustifolia H.B.K. and Z. violacea Cav. (2n = 46)] were reciprocally backcrossed with diploid and autotetraploid forms of Z. angustifolia (2n =22 or 44) and Z. violacea (2n =24 or 48). In most cases, backcrosses were more successful with Z. angustifolia and Z. violacea as autotetraploids than as diploids. Seed-generated, backcross (BC1) families were obtained by crossing Z. marylandica (as female) with autotetraploid Z. angustifolia or autotetraploid Z. violacea. BC1 plants were phenotypically intermediate between the two parental lines for most morphological characters. Crosses between Z. marylandica and autotetraploid Z. angustifolia yielded BC1 plants with 33% stainable pollen, whereas crosses between Z. marylandica and autotetraploid Z. violacea yielded BC1 plants that produced malformed, poorly-stained pollen. No embryos were observed in capitula collected from field-grown BC1 plants. BC1 hybrids of Z. marylandica and autotetraploid Z. violacea produced larger capitula and more ray florets than Z. marylandica, and exhibited novel combinations of floral pigments not observed in Z. marylandica ray florets. BC1 hybrids of Z. marylandica and Z. violacea have commercial potential as seed-propagated, bedding plants.
RAPD Markers Flanking the Are Gene for Anthracnose Resistance in Common Bean
Authors: Young Roberto A. , Kelly James D.
Published: January 2019

Incorporation of the dominant gene Are, of Middle American origin, into commercial cultivars of Phaseolus vulgaris L., has been the main disease control strategy of plant breeders to limit the potential damage of Colletotrichum lindemuthianum (Sacc. & Magnus.) Lams.-Scrib. A random amplified polymorphic DNA (RAPD) marker designated OQ41440, generated by a 5′-AGTGCGCTGA-3′ decamer primer, was found tightly linked in coupling with the Are gene. OQ41440 mapped at 2.0 ± 1.4 centimorgans (cM) from the Are allele in the Andean genetic background and at 5.5 ± 2.3 CM in the Middle American background. A second coupling phase RAPD marker B3551000, generated by the 5′-GTATGGGGCT 3′ primer mapped at 5.4 ± 2.3 cM from the Are allele in the Andean genetic background and at 7.7 ± 2.7 CM in the Middle American background. Based on a recombination distance of 7.0 ± 1.9 cM between the two markers, OQ41440 and B3551000 RAPDs appear to flank the Are gene. The bracketing molecular markers allowed tagging of the Are allele with a selection fidelity of 99%. Use of the OQ41440 and B3551000 RAPD markers for marker-based selection will afford the opportunity to retain the Are anthracnose resistance gene in bean germplasm, as other epistatic resistance genes are characterized, and incorporated into contemporary bean cultivars.
Obtaining Transgenic Anthurium through Agrobacterium-mediated Transformation of Etiolated Internodes
Authors: Chen Fure-Chyi , Kuehnle Adelheid R.
Published: January 2019

Several procedures were tested in development of a gene transfer protocol for anthurium. Etiolated internode segments of anthurium cultivars `Rudolph' and `UH1060' were co-cultured with Agrobacterium tumefaciens LBA4404 carrying the chimeric genes neo, for antibiotic resistance, and att encoding antibacterial attacin. Assays of genomic DNA and RNA from kanamycin-resistant `Rudolph' and DNA from `UH1060' plantlets, recovered as soon as 1 year after culture on selection media, indicated the presence of introduced genes, including neo and att, and transcription of att. Western analysis confirmed the expression of attacin protein in calli induced from laminae of regenerated kanamycinresistant `Rudolph' plantlets. Use of tobacco nurse cells during co-cultivation of internodes with Agrobacterium did not increase recovery of shoots under the regeneration conditions used. Improvements in culture and antibiotic selection conditions during plant development are suggested.
Water Application Scheduling by Pan Evaporation for Drip-irrigated Tomato
Authors: Locascio Salvadore J. , Smajstrla Allen G.
Published: January 2019

Tomatoes (Lycopersicon esculentum Mill.) were grown on an Arredondo fine sandy soil to evaluate the effects of water quantity applied by drip irrigation scheduled by pan evaporation in a 3-year study. Water was applied to polyethylene-mulched tomatoes at 0, 0.25, 0.50, 0.75, and 1.0 times pan evaporation in one application per day. Irrigation was also scheduled with tensiometers to apply water to maintain soil water tension above 10 cb. The response to irrigation varied with rainfall during the three seasons. In an extremely dry season, fruit yields were doubled by irrigation. Total fruit yields were highest with irrigation quantities of 0.75 and 1.0 times pan and significantly lower with 0.25 and 0.50 times pan. In an extremely wet season, fruit yields were not influenced by water quantities from O to 1.0 times pan. In a third season that was wet from the middle to the end of the season, irrigation more than doubled the marketable fruit yield. However, with an increase in water quantity from 0.25 to 0.75 times pan, yield increased only from 65.9 to 74.1 t·ha-1. Water uses during the three seasons with 0.75 pan were 31.8, 31.1, and 29.6 cm, respectively. Fruit yields were similar with the 0.75-pan and 10-cb tensiometer treatments, but water uses with the latter treatment were 15.8, 17.0, and 18.4 cm during the three seasons, respectively. Tomato leaf N concentrations were reduced slightly with each increase in water quantity applied, even though N was applied with drip irrigation. Leaf N concentrations with the 10-cb treatment were generally equal to or higher than the concentrations with 0.75 pan.
Whole-plant Response of Six Poinsettia Cultivars to Three Fertilizer and Two Irrigation Regimes
Authors: Schuch Ursula , Redak Richard A. , Bethke James
Published: January 2019

Six cultivars of poinsettia (Euphorbia pulcherrima Wind.), `Angelika White', `Celebrate 2', `Freedom Red', `Lilo Red', `Red Sails', and `Supjibi Red' were grown for 9 weeks during vegetative development under three constant-feed fertilizer treatments, 80,160, or 240 mg N/liter and two irrigation regimes, well-watered (high irrigation) or water deficient (low irrigation). Plants fertilized with 80 or 240 mg N/liter were 10% to 18% shorter, while those fertilized with 160 mg N/liter were 25 % shorter with low versus high irrigation. Leaf area and leaf dry weight increased linearly in response to increasing fertilizer concentrations. Low irrigation reduced leaf area, leaf, stem, and shoot dry weight 3670 to 41%. Cultivars responded similarly to irrigation and fertilizer treatments in all components of shoot biomass production and no interactions between the main effects and cultivars occurred. Stomatal conductance and transpiration decreased with increasing fertilizer rates or sometimes with low irrigation. Highest chlorophyll contents occurred in leaves of `Lilo Red' and `Freedom Red'. Leaves of plants fertilized with 80 mg N/liter were deficient in leaf N and had 40 % to 49 % lower leaf chlorophyll content compared to plants fertilized with 160 or 240 mg N/liter. Irrigation had no effect on leaf N or chlorophyll content. At the end of the experiment leaves of `Supjibi Red' and `Angelika White' contained higher concentrations of soluble proteins than the other four cultivars.
Soil Moisture and Temperature Effects on shrunken2 Sweet Corn Seed Decay and Seedling Blight Caused by Penicillium oxalicum
Authors: Callan Nancy W. , Miller James B. , Mathre Don E. , Mohan S. Krishna
Published: January 2019

Sweet corn (Zea mays L.) seed is commonly infected or infested with fungi that can impair stand establishment. Among these, Penicillium oxalicum Currie and Thorn is known to cause preemergence damping-off or postemergence seedling blight. Supersweet, or shrunken2 (sh2), sweet corn cultivars are particularly affected by seedborne fungal pathogens, although the effects of seed infection on seedling emergence and stand are variable under field conditions. This study was conducted to examine factors that could influence the impact of P. oxalicum on seedling stand, including P. oxalicum inoculum density on seed and in soil, soil moisture, soil temperature, and control of seed decay caused by soilborne Pythium ultimum Trow. Seed surface disinfestation usually had no effect on seedling stand under conditions favoring infection by P. ultimum. Inoculation of sh2 sweet corn seeds or infestation of soil with conidia of P. oxalicum resulted in increasing severity of damping-off and seedling blight as inoculum density increased. In pasteurized soil in the greenhouse, an inoculum density of 102 P. oxalicum conidia per seed reduced emergence and induced seedling blight. In the field, where P. ultimum was also a factor, 106 conidia per seed were needed to reduce emergence and 105 conidia per seed to reduce healthy seedling stand. When pythium seed decay was controlled by metalaxyl seed treatment, seedling emergence and healthy seedling stand were both reduced at 1 × 106 P. oxalicum conidia per seed. When sh2 sweet corn seed was inoculated with conidia of P. oxalicum and incubated in soil at subgermination moisture contents (4.2 to -7.8 MPa) for 2-4 weeks before planting and irrigating, P. oxalicum reduced seedling emergence at all soil moisture levels, but caused the greatest amount of injury after planting when seeds were incubated in soil above -5.1 MPa. As soil temperature increased from 9-25C, seedling emergence from seed inoculated with P. oxalicum was progressively reduced, with a decrease of nearly 50% at 25 C. Penicillium oxalicum has the greatest potential to reduce seedling stand when infected sweet corn seeds are planted in warm, dry soil, but the effects of this and other seedborne fungal pathogens may be masked under conditions favoring infection by P. ultimum.
Activity of 5-Aminolevulinic Acid Dehydratase Declines during Tomato Fruit Development and Ripening
Authors: Kyriacou Marios C. , Polking Gary F. , Hannapel David J. , Gladon Richard J.
Published: January 2019

Activity of 5-aminolevulinic acid (ALA) dehydratase [ALAD, (EC 4.2.1.24)] and soluble protein content were determined in `Rutgers' tomato (Lycopersicon esculentum Mill.) fruit pericarp extracts during development and ripening. ALAD activity in several organs of tomato plant also was determined. Fruit tissue was analyzed at 5-day intervals between days 10 and 60 postanthesis. ALAD activity in fruit tissue declined over time, with the most pronounced decrease occurring between days 10 and 25. At the mature green stage (day 40), and before the breaker stage (day 45), activity of ALAD had declined to a steady-state minimum, and it remained detectable at residual levels throughout ripening (days 40 to 60). Soluble protein content declined less rapidly than did ALAD activity. Immunoblot analysis showed that ALAD protein existed as a doublet of isozymes. One isozyme decreased in abundance, whereas the other isozyme remained constant during development and ripening. ALAD activity was greatest in extracts of chlorophyllous organs (stems, leaves, immature fruit) but only marginally detectable in extracts of nonchlorophyllous organs (roots, overripe fruit). The pH optimum and Km for tomato fruit ALAD were similar to those of ALAD isolated from other sources. Abbreviations: ALA, 5-aminolevulinic acid; ALAD, ALA dehydratase; PBG, porphobilinogen; SDS-PAGE, sodium dodecyl sulfate-polyacry - lamide gel electrophoresis.
Postharvest Longevity of Cut-flower Gerbera. II. Heritability of Vase Life
Authors: Wernett Heidi C. , Wilfret Gary J. , Sheehan Thomas J. , Lyrene Paul M. , Martin Frank G. , White Timothy L. , Powell Gregory L. , Wilcox Charles J.
Published: January 2019

Intensive selection to improve vase life was performed on a sample population of Gerber ×hybrida Hort. from a broad source of germplasm. Progeny of a 5 × 5 diallel cross yielded estimates of narrow sense heritability (h2 = 0.28) and broad sense heritability (H2 = 0.28) for vase life based on a mean of 1.96 measurements per plant. Additive gene action is postulated to control this character since the difference between total genotypic variance and additive genetic variance components was small. Repeatability (r = 0.57) based on a single measurement per plant was moderately high. Heritability estimates were also determined based on 1, 2, 3, 5, and ∞ measurements per plant. Heritability ranged from 22% to 39%.
Isozyme and Morphological Variation in a Cornus florida L. Provenance Plantation Representing Geographically Diverse Populations
Authors: Fernandez Alexander , Schutzki Robert E. , Hancock James F.
Published: January 2019

Starch gel electrophoresis and principal component (PC) analysis were used to determine the levels of genetic variation and the relationship between morphology and geographic origin for Cornus florida (flowering dogwood) populations in a Michigan provenance plantation. The populations are representative of the species' geographic distribution, ranging from Texas to Georgia and north to Connecticut and Michigan. Allelic variation at 11 loci encoded by 5 enzymes was very low in comparison to other plant species. On average, populations displayed 1.16 alleles per locus, 9.89% of loci polymorphic, with an observed heterozygosity value of 0.048. Genetic identify values ranged from 0.961 to 1.00 and displayed no relationship with geographic origin. While the isozyme analysis revealed little genetic variation, the PC analysis revealed a considerable amount of morphological variation. Most variation (83.3%) in leaf and flower bud morphology was explained by three PCs. Leaf characters revealed no relationship with geographic origin. However, flower bud size and number of florets decreased with changes in latitude from northern, central, and southern populations, respectively. The relationship between flower bud size and latitude suggests an adaptive response to photoperiod throughout the species' geographic range.
Mechanical Correction and Chemical Avoidance of Circling Roots Differentially Affect Post-transplant Root Regeneration and Field Establishment of Container-grown Shumard Oak
Authors: Arnold Michael A.
Published: January 2019

Quercus shumardii Buckl. seedlings were grown for 3 or 7 months in 2.3-liter black plastic containers. Containers were either treated or not on interior surfaces with 100 g Cu(OH)2/liter latex carrier. Trees were transplanted in summer or fall to quantify post-transplant responses to mechanical correction or chemical prevention of circling roots. Four treatments were used at each transplant date; nonpruned seedlings from Cu(OH)2-treated or nontreated containers, and seedlings from nontreated containers in which two mechanical root pruning techniques were used, traditional severing of circling roots on the rootball periphery or splitting and splaying the bottom two-thirds of the rootball at transplant (butterfly pruning). Traditional root pruning severed more small-diameter roots (≤0.5 mm), while butterfly pruning severed more large-diameter roots. During the first 21 days following transplant most root regeneration was via elongation of intact root tips. Cu(OH)2-treated seedlings regenerated substantially more roots ≤1.0 mm in diameter and a greater root mass than mechanically root pruned or nonpruned seedlings. Both corrective mechanical pruning techniques resulted in greater predawn water stress during immediate post-transplant (21 days) establishment in October than seedlings chemically treated to prevent circling root development. Treatments that severed more roots and/or removed greater root mass were associated with decreased field performance and increased post-transplant water stress. Increased numbers of small- to medium-diameter new roots were associated with reduced post-transplant water stress and improved post-transplant shoot growth. Nonpruned and traditional root pruned seedlings grew little during the first two post-transplant growing seasons regardless of transplant date. Butterfly pruning resulted in severe dieback of shumard oak seedlings. Cu(OH)2-treated seedlings were the only ones to exhibit a gain in height or stem diameter after 2 years in the field.
Water Relations, Growth, and the Composition of `Braeburn' Apple Fruit under Deficit Irrigation
Authors: Mills T.M. , Behboudian M.H. , Clothier B.E.
Published: January 2019

Three-year-old `Braeburn' apple trees (Malus domestica Borkh.) on MM106 rootstock were studied in a glasshouse to assess the effects of deficit irrigation on fruit growth, water relations, composition, and the vegetative growth of the trees. Trees were assigned to one of three treatments. The control (C) was fully watered. The first deficit treatment (D1) was deficit-irrigated from 55 days after full bloom (DAFB) until final harvest at 183 DAFB. The second deficit treatment (D2) was deficit-irrigated from 105 to 183 DAFB. Compared to C, the D1 and D2 trees developed a lower photosynthetic rate, leaf water potential (Ψl), and stomatal conductance (gs) during the stress period. Trunk-circumference growth was reduced in both D1 and D2 trees, but leaf area and shoot length were reduced in D1 only. Total soluble solids increased in both D1 and D2 fruit. Fructose, sorbitol, and total soluble sugar concentrations were higher in D1 fruit than in C and D2. Titratable acidity and K+ levels were higher in D1 fruit than C and D2. For D1, lowering of fruit water potential (Ψw) was accompanied by a decrease in osmotic potential (Ψs), and therefore turgor potential (Ψp) was maintained throughout the sampling period. Regardless of fruit turgor maintenance, the weight of D1 fruit was reduced from 135 DAFB. Weight, sugar concentration, and water relations of D2 fruit were not affected by deficit irrigation. This indicates that fruit water relations and sugar concentration are modified if water deficit is imposed from early in the season. However, if water deficit is imposed later in the season it has less impact on the composition and water relations of the fruit.
Drought Stress Influences Gas-exchange Responses of Papaya Leaves to Rapid Changes in Irradiance
Authors: Clemente Hiphil S. , Marler Thomas E.
Published: January 2019

Field-grown `Red Lady' papaya (Carica papaya L.) plants were used to measure foliar gas-exchange responses to rapid changes in irradiance levels to determine if papaya stomata are able to track simulated sun-to-cloud cover transitions. Natural sunlight and neutral shade cloth placed over the leaf were used to provide high photosynthetic photon flux (PPF) of about 2000 μmol·m-2·s-1 until leaves reached steady state within the cuvette, followed by three minutes with low PPF of about 325 μmol·m-2·s-1, and a return to PPF of about 2000 μmol·m-2·s-1. Net CO2 assimilation (A) declined from an initial 20 μmol·m-2·s-1 to about 9 μmol·m-2·s-1 within 20 seconds of initiating low PPF, and remained fairly stable for the duration of the three minutes of low PPF. Stomatal conductance (gs) declined within 60 seconds of initiating low PPF, from 385 to about 340 μmol·m-2·s-1 during the three minutes duration of low PPF. Following the return to high PPF, A rapidly increased to about 18 μmol·m-2·s-1, then gradually increased to the original value. After a lag of about 1 minute following the return to high PPF, gs began to increase and returned to the original value after three minutes. Container-grown `Tainung #1' papaya plants were used in a second study to determine the influence of mild drought stress on gas-exchange responses to rapid irradiance transitions. For drought-stressed plants, gs declined to a greater magnitude following the high-to-low PPF transition, and gs and A recovered more slowly following the transition from low-to-high PPF than for well-watered plants. Water use efficiency declined to a minimum immediately following the high-to-low PPF transition for both sets of plants, but recovered more rapidly for drought-stressed plants. These results indicate that papaya stomata are able to track rapid changes in irradiance, and mild drought stress enhances the tracking response.
Changes in Color and Chlorophyll Fluorescence of Broccoli Florets following Hot Water Treatment
Authors: Tian M.S. , Woolf A.B. , Bowen J.H. , Ferguson I.B.
Published: January 2019

Hot water treatments (HWTs), at a range of temperatures (43 to 55C) and durations (10 sec to 30 min), were applied to floret groups of `Shogun' broccoli (Brassica oleracea L. var italica) directly after harvest. Floret groups were then stored at 20C in the dark for 3 days. A range of optimal treatments was found in which yellowing was markedly reduced, and heat damage (water soaking and decay) did not occur. Chlorophyll fluorescence measurements indicated that in the optimum treatment that prevented yellowing the Fv/Fm ratio following HWT decreased immediately and was maintained at a constant level for the next 3 days. A further experiment examined the effect of HWT durations up to 20 min at 47C on fluorescence and yellowing. Longer durations of HWTs (>5 min) progressively reduced yellowing and the Fv/Fm ratio. From these three experiments a HWT of 47C for 7.5 min was selected as the best treatment. This treatment consistently reduced yellowing for up to 5 days. A decrease in the Fv/Fm ratio may be a useful indicator of broccoli florets response to hot water treatments.
No Evidence of Adverse Effects on Germination, Emergence, and Fruit Yield due to Space Exposure of Tomato Seeds
Authors: Kahn Brian A. , Stoffella Peter J.
Published: January 2019

Seeds of `Rutgers California Supreme' tomato (Lycopersicon esculentum Mill.) were exposed to outer space conditions aboard the long duration exposure facility (LDEF) satellite in the space exposed experiment developed for students (SEEDS) project of the National Aeronautics and Space Administration (NASA). Seeds aboard the LDEF were packed in dacron bags forming four layers per sealed canister. Some of these seeds were used in Oklahoma and Florida for studies of germination, emergence, and fruit yield. Among all measured variables in three experiments, there was only one significant main effect of canister 2 versus canister 7 (for mean time to germination) and only one main effect of layer (for seedling shoot dry weight). There also were only two inconsistent canister x layer interactions in the germination tests. The contrast of Earth-based control seed versus space-exposed seed was significant four times: in Oklahoma in 1991 the mean time to germination of space-exposed seeds and the days to 50% of final germination were 0.7 days less than for Earth-based seeds, and in Florida in 1992 seedling percent emergence and shoot dry weight were increased by space exposure. Fruit yield and marketability were unaffected in plants grown from space-exposed seeds. These results support student findings from the SEEDS project, and provide evidence that tomato seeds can survive in space for several years without adverse effects on germination, emergence, and fruit yield.
Seed-producing System in Salvias
Authors: Miyajima Daiichiro
Published: January 2019

The seed-producing system of salvias (Salvia splendens Sello) was investigated. The number of florets opening per day per plant increased with the increase in days from anthesis. Pollinators that effectively worked were small-sized insects. High pollen viability was observed on the stigmatic surface, and pollen tubes reached the ovules within 3 hours after pollination. Fertilized ovules became mature seeds within 25 days after fertilization. Pollination within 1 day after opening of florets resulted in a high percentage of seed setting. The pollen-ovule ratios indicated that salvias were facultative xenogamous. Actually, the salvias had heterostyle florets and the ability to set seeds without pollinators.
Indole-3-acetic Acid (IAA) Content and Axillary Bud Development in Relation to Russet Spotting in Harvested Iceberg Lettuce
Authors: Ritenour Mark A. , Sutter Ellen G. , Williams David M. , Saltveit Mikal E.
Published: January 2019

This study was undertaken to determine if endogenous IAA content and axillary bud development correlate with phenylalanine ammonia-lyase (PAL) induction and russet spotting (RS) susceptibility among RS susceptible and resistant cultivars of Iceberg lettuce (Lactuca sativa L.). Final levels of ethylene-induced PAL activity and RS development were highly correlated among cultivars, field conditions, and harvest dates. Harvested Iceberg lettuce midribs contained relatively low amounts of free IAA (maximum of 5.2 ng·g-1 fresh weight). There was poor correlation between free IAA content in lettuce leaf midribs and final RS development among all cultivars, growing conditions, and harvest dates. Axillary bud development, as measured by the number of visible buds per head, bud weight, or bud length, were not significantly correlated with final RS development or midrib IAA content. Cultivars with higher initial free IAA content lost much of their IAA after 8 days storage at 5C in air ± ethylene.
Pecan Kernel Color: Standards Using the Munsell Color Notation System
Authors: Thompson Tommy E. , Grauke L.J. , Young E.F.
Published: January 2019

The Munsell Color System was used to define pecan [Carya illinoinensis (Wangenh.) K. Koch] kernel colors and color changes for 21 clones, 11 locations, and 4 storage methods for nuts collected over a 4-year period. Hue readings ranged from 10.0 (10 red) to 22.5 (2.5 yellow). Value readings ranged from 2.5 to 8.0, and chroma readings ranged from 1.0 to 8.0. A total of 91 color chips (individual combinations of hue, value, and chroma) were needed to describe kernel color variability. In 1987 and 1988, one color [15.0/5/4 (hue/value/chroma)] accounted for 3,979 of the 32,078 readings taken, and the 15 most common colors accounted for 80.7% of all the readings. The Munsell system of color determination was well suited for pecan color determinations. A simplified color rating system with only six color classes was developed for general use by the pecan industry. This system is also routinely used in our breeding and genetics program to define this very important quality trait in pecan.
Rye (Secale cereale L.) and Hairy Vetch (Vicia villosa Roth) Intercrop Management in Fresh-market Vegetables
Authors: Mwaja Vasey N. , Masiunas John B. , Eastman Catherine E.
Published: January 2019

The effect of cover-crop management on growth and yield of `Bravo' cabbage (Brassica oleracea var. Capitata L.), `Market Pride' tomato (Lycopersicon esculentum Mill.), and `Mustang' snap bean (Phaseolus vulgaris L.) was determined. Each fall, `Wheeler' winter rye (Secale cereale L.) and `Oregon Crown' hairy vetch (Vicia villosa Roth) were interseeded. The following spring, the cover crops were killed by either applying glyphosate and mowing (CC-G) or mowing and disking (CC-D). Trifluralin was preplant incorporated into bare ground as a conventional tillage (CT) treatment. In 1992 and 1993, a chicken (Gallus gallus L.) based fertilizer was applied to half the subplots. The greatest snap bean and cabbage yields were in CT. The system with the greatest tomato yields varied. In 1991, the greatest tomato yields were in the CT treatment, while in 1992 yields were greatest in the CT and CC-D treatments, and in 1993 the greatest yields were in CT and CC-G. Cabbage yields were greater in the fertilized than the unfertilized treatments. In 1992, infestations of diamondback moth, imported cabbageworm, and cabbage looper were greater in CT than in the CC-G treatment. Three years of the CC-G treatment increased soil organic matter from 3.07% to 3.48% and increased soil pH from 6.30 to 6.51, while neither changed in the CT. Chemical names used: N-(phosphonomethyl) glycine (glyphosate); 2,6-dinitro-N,N-dipro`pyl-4-(trifluoromethyl) benzenamine (trifluralin).
Producing Transgenic `Thompson Seedless' Grape (Vitis vinifera L.) Plants
Authors: Scorza R. , Cordts J.M. , Gray D.J. , Gonsalves D. , Emershad R.L. , Ramming D.W.
Published: January 2019

Transgenic grape plants were regenerated from somatic embryos derived from leaves of in vitro-grown plants of `Thompson Seedless' grape (Vitis vinifera L.) plants. Somatic embryos were either exposed directly to engineered Agrobacterium tumefaciens or they were bombarded twice with 1-μm gold particles and then exposed to A. tumefaciens. Somatic embryos were transformed with either the lytic peptide Shiva-1 gene or the tomato ringspot virus (TomRSV) coat protein (CP) gene. After cocultivation, secondary embryos proliferated on Emershad/Ramming proliferation (ERP) medium for 6 weeks before selection on ERP medium containing 40 μg·mL-1 kanamycin (kan). Transgenic embryos were identified after 3 to 5 months under selection and allowed to germinate and develop into rooted plants on woody plant medium containing 1 μm 6-benzylaminopurine, 1.5% sucrose, 0.3% activated charcoal, and 0.75% agar. Integration of the foreign genes into these grapevines was verified by growth in the presence of kanamycin (kan), positive β-glucuronidase (GUS) and polymerase chain-reaction (PCR) assays, and Southern analysis.
Genetic Variation for Field Resistance to Verticillium dahliae Evaluated Using Genotypes and Segregating Progenies of California Strawberries
Authors: Shaw Douglas V. , Gubler W.D. , Larson Kirk D. , Hansen John
Published: January 2019

Resistance to wilt caused by Verticillium dahliae Kreb. was evaluated for 41 strawberry genotypes from the Univ. of California breeding program and 1000 offspring from crosses among 23 of these genotypes. Runner plants from these genotypes and seedlings were inoculated with a conidial suspension containing a mixture of five isolates of V. dahliae from strawberry. Symptoms were scored as the number of dead or seriously stunted plants per plot, or based on a subjective phenotypic resistance score assigned to each plot on five dates during the spring after planting. Most of the California germplasm is highly susceptible to V. dahliae, with an average resistance score of 2.1 (±0.10) and 84.1% (±2.1) plants stunted or dead compared with a score of 3.2 (±0.24) and 57.4% (±4.9) of plants stunted or dead for a control set of six non-California genotypes identified previously as resistant. However, a broad range of intermediate resistance was detected, and 4 of the 41 California genotypes evaluated had resistance scores superior to the mean score for the non-California resistant checks. Plot-mean heritabilities for resistance and stunting scores estimated using genotypic, full-sib family, and offspring-parent analyses ranged from 0.44 to 0.88. Comparison of different estimates of variance components suggests that half or more of the genotypic variance for resistance traits detected is due to the additive effects of genes. There appears to be sufficient variation within the California population to proceed with an effective selection program, despite the absence of directional selection for resistance during the past 3 decades. However, developing cultivars with adequate resistance will ultimately depend on the recovery of transgressive segregants from superior parents, as even the most resistant genotypes from all sources showed some disease symptoms.
Developing a Slow-release Nitrogen Fertilizer from Organic Sources: I. Using Nonviable Bacteria
Authors: Choi Jong-Myung , Nelson Paul V.
Published: January 2019

Mineralization of N from nonviable cells of Brevibacterium lactofermentum (Okumura et al.) mixed into soilless substrate in elution columns occurred largely during the first 5 weeks with a peak between 2 and 3 weeks. Over a 12-week period, 73% of the total N was recovered in the eluent. To prolong the period of N release to meet the requirements of a slow-release fertilizer, the bacterium was bonded to kraft lignin, a polyphenolic substance highly resistant to degradation. To retard mineralization further, the bacterium-lignin mixture was reacted with formaldehyde to form amino cross-links within and between protein chains. Bonding to lignin was undesirable because N release occurred during the same period as from the bacteria unbound to lignin and the total amount of N recovered was reduced to only 42%. Cross-linking with formaldehyde was less desirable since N was released mainly during the first 4 weeks with a peak during the first elution (0 time) and the total amount of N released was even lower than for the bacterium-lignin mixture. Additions of urea to the latter reaction did not satisfactorily improve subsequent N mineralization. In a second set of treatments lignin was withheld and the bacterium was reacted with weights of formaldehyde (a.i.) equivalent to 0.1%, 0.5%, 1.0%, 5.0%, and 10.0% of the dry weight of bacterium. Formaldehyde quantities ≤1.0% either had no effect or lowered the mineralization of N without altering time of release. Five percent and 10% formaldehyde successfully reduced release of N during the first 4 weeks and increased it thereafter. The best rate was 5%. In this treatment N was released from week 2 through the end of the test (12 weeks). Peak release occurred at 6 weeks. This resulting N source, while not a stand alone product, does have a slow-release property that could lend itself to use in combination with other slow-release N sources.
Developing a Slow-release Nitrogen Fertilizer from Organic Sources: II. Using Poultry Feathers
Authors: Choi Jong-Myung , Nelson Paul V.
Published: January 2019

The structure of feather keratin protein was modified in attempts to develop a slow-release N fertilizer of 12 weeks duration or longer by steam hydrolysis to break disulfide bonds, enzymatic hydrolysis with Bacillus licheniformis (Weigmann) to break polypeptide bonds, and steam hydrolysis (autoclaving) to hasten mineralization followed by cross-linking of the protein by a formaldehyde reaction to control the increased rate of mineralization. Release of N in potting substrate within elution columns from ground, but otherwise untreated, raw feathers occurred mainly during the first 5 weeks with a much smaller release occurring from weeks 8 to 12. Steam hydrolysis resulted in an increase of N during the first 5 weeks and a decrease during weeks 8 to 11. Cumulative N release over 11 weeks increased from 12% in raw feathers to 52% for feathers steam hydrolyzed for 90 minutes. This favored an immediately available fertilizer but not a slow-release fertilizer. Microbial hydrolysis with B. licheniformis resulted in a modest reduction of N release during the first 5 weeks and a small increase during weeks 8 to 11. Both shifts, while not desirable for an immediately available fertilizer, enhanced the slow-release fertilizer potential of feathers but not sufficiently to result in a useful product. Steam hydrolyzed feathers cross-linked with quantities of formaldehyde equal to 5% and 10% of the feather weight released less N during the first 5 weeks, more during weeks 6 and 7, and less during weeks 9 to 12 compared to raw feathers. The first two shifts were favorable for a slow-release fertilizer while the third was not.
Developing a Slow-release Nitrogen Fertilizer from Organic Sources: III. Isolation and Action of a Feather-degrading Actinomycete
Authors: Choi Jong-Myung , Nelson Paul V.
Published: January 2019

An actinomycete designated Streptomyces cn1 with a high proteolytic activity and capacity to degrade feather keratin was isolated and its effectiveness for altering feathers to yield a slow-release N fertilizer was evaluated. The pattern of N release in column elution tests from feathers ground to a particle size ≤1 mm, but otherwise unaltered, was characterized by a first period of release from weeks 2 through 5 with a high peak at week 3 and a second period of release from 14 to 20 weeks. The release of N during the first period was 10.5% and during the second period it was 7.3% for a total of only 17.8% of the N contained in these feathers. Grinding feathers to a finer particle size ≤0.5 mm caused increases in N release during the two periods to 14.7% and 15.8% N, respectively, for a total of 30.5% and second period N release began 5 weeks earlier at week 9. Microbial hydrolysis with Streptomyces cn1 for 1 though 5 days resulted in an adverse reduction in total N released, due in part to drying of feathers after hydrolysis. Hydrolysis of feathers for 7 days resulted in 42.6% of total N released over 20 weeks with 77.0% of this released during weeks 6 through 20. The second period of release began at week 8. Hydrolysis of feathers for 9 days was best for purposes of a slow-release fertilizer. Forty five percent of total N was released over 20 weeks with 89.3% of this released during the second period that began in week 7. Root substrate pH was increased in all treatments where feathers were applied. This would require a reduction in the rate of limestone incorporated into a commercial substrate when feather N is used. Pepsin digestibility and ninhydrin tests provided some insight into the N release mechanism but did not effectively predict N release from the feather products.
Tomato Root Distribution under Drip Irrigation
Authors: do Rosário G. Oliveira Maria , Calado António M. , Portas Carlos A. Martins
Published: January 2019

Tomato (Lycopersicon esculentum Mill.) root distribution was evaluated by the trench profile wall method at four trickle irrigation regimes (irrigation at soil water potential -10, -20, -40, and -60 kPa) in a 2-year field trial. Total root length intensity (m·m-2), final yield (t·ha-1) and fruit size (g/fruit) decreased with decrease in amount of water applied. In both years, tomato water use efficiency (kg·ha-1·mm-1) was significantly lower with irrigation at -10 kPa than with any other irrigation regime studied. The largest proportion of tomato roots, 88% for 1989 and 96% for 1990, was found in the top 40 cm of the soil and rapidly decreased with depth. The high concentration of roots in the 30 to 40 cm layer was attributed to an horizon with high soil bulk density values, immediately below 40 cm, impeding deeper root penetration. Most roots occurred in the emitter area, close to the plant. In rows 1.5 m apart, between 12% and 21% of total root length was found more than 0.5 m from the stem, which may have resulted from the interpenetration of roots from plants of adjoining rows.
Sod Competition in Peach Production: II. Establishment Beneath Mature Trees
Authors: Glenn D.M. , Welker W.V.
Published: January 2019

Planting sod beneath peach trees (Prunus persica) to control excessive vegetative growth was evaluated from 1987 to 1993 in three field studies. Peach trees were established and maintained in 2.5-m-wide vegetation-free strips for 3 years, and then sod was planted beneath the trees and maintained for 5 to 7 years. Reducing the vegetation-free area beneath established peach trees to a 30- or 60-cm-wide herbicide strip with three grass species (Festuca arundinacae, Festuca rubra, Poa trivialis), reduced total pruning weight/tree in 5 of 16 study-years and weight of canopy suckers in 6 of 7 study-years, while increasing light penetration into the canopy. Fruit yield was reduced by planting sod beneath peach trees in 5 of 18 study-years; however, yield efficiency of total fruit and large fruit (kg yield/cm2 trunk area) were not reduced in one study and in only 1 year in the other two studies. Planting sod beneath peach trees increased available soil water content in all years, and yield efficiency based on evapotranspiration (kg yield/cm soil water use plus precipitation) was the same or greater for trees with sod compared to the 2.5-m-wide herbicide strip. Planting sod beneath peach trees has the potential to increase light penetration into the canopy and may be appropriate for high-density peach production systems where small, efficient trees are needed.
Postharvest Browning of Rambutan is a Consequence of Water Loss
Authors: Landrigan Margaret , Morris Stephen C. , McGlasson Barry W.
Published: January 2019

Rambutan (Nephelium lappaceum L.) rapidly lose their attractive appearance after harvest due to a superficial pericarp browning. Storage at high humidity minimizes fruit desiccation and may, therefore, delay browning onset. This paper examines the effect of reduced water loss rate on browning that may occur with time. Rambutan fruit pericarp browning beyond a commercially saleable level occurred at a weight loss of 25% to 40%. This depended on duration and storage relative humidity (RH). Skin browning was 50% greater on the red (R 134) than the yellow (R 156) cultivar at 60% RH. There was a storage time × RH interaction in the development of browning such that browning was observed earlier at lower RHs. Skin browning and spintern (soft spine) browning developed independently. Cracks appeared on the surface of fruit with increased weight loss. Browning occurrence was consistent with increased total phenolic compound levels in the pericarp. Water loss precedes browning occurrence and, over time, water loss is related to browning. Water stress appeared to affect rambutan pericarp tissue in much the same manner as senescence.