bluuebunny/crossref_metadata_2025 huggingface dataset:
Crisphead Lettuce Cultivar Response to Fertilizer Phosphorus
Authors: Nagata R.T. , Sanchez C.A. , Coale F.J.
Published: January 2019

Four field experiments were conducted during 1988 to 1990 to evaluate the response to fertilizer P of six crisphead lettuce (Latuca sativa L.) cultivars grown on Histosols. There were season × cultivar interactions for total mass produced, marketable yield, and P uptake by lettuce. A significant yield response to fertilizer P was demonstrated during all four seasons. The performance of individual cultivars within a given season led to cultivar × P rate interactions for marketable yield. However, there were no significant P rate × cultivar interactions for total mass produced, P uptake, and marketable yield during the one season when growing conditions were near ideal. Calculated critical soil-test P values for both eastern and western lettuce types produced in Florida were all within error currently associated with P fertilizer recommendations for lettuce produced in Florida. Therefore, we conclude that no immediate change in P fertilizer recommendations is required for the new western-type lettuce cultivars produced on Histosols in Florida.
Alleviation of Thermoinhibition in Preconditioned Lettuce Seeds Involves Ethylene, Not Polyamine Biosynthesis
Authors: Huang Xue-Lin , Khan Anwar A.
Published: January 2019

Preconditioning `Mesa 659' lettuce (Lactuca sativa L.) seeds with the moist solid carrier Micro-Cel E at 15C for 20 hours removed thermoinhibition and allowed the seeds to germinate at 35C. Participation of 1-aminocyclopropane-1-carboxylic acid (ACC) and its use in the removal of thermoinhibition were indicated from the following: a) the ACC level in the preconditioned seeds peaked before germination at 35C; b) addition of aminoethoxyvinylglycine (AVG), an inhibitor of ACC synthesis, reduced the ACC level and inhibited germination at 35C; c) response of preconditioned seeds to ethylene at 35C preceded that of ACC; d) exogenous ACC, (2-chloroethyl) phosphonic acid (ETH, ethephon), or ethylene reversed the inhibitory effect of AVG and restored the capability of the seed to germinate at 35C; e) Co+2, an inhibitor of the ACC-to-ethylene step, partially inhibited germination of preconditioned seeds at 35C, and the effect was reversed by ETH. The major free polyamines in dry seed were spermidine (Spd) and putrescine (Put). An increase in polyamine level occurred following transfer of conditioned seeds to 35C. Of the various polyamine biosynthesis inhibitors, difluoromethylarginine and cyclohexylammonium sulfate inhibited an increase in Spd and Put levels only after germination, whereas difluoromethyorinthine had no effect on polyamine biosynthesis. None of these inhibitors affected the relief of thermoinhibition. Thus, the increase in polyamine level during germination at 35C does not appear to be associated with the alleviation of thermoinhibition.
Genetic Variability of Fruit Set, Fruit Weight, and Yield in a Tomato Population Grown in Two High-temperature Environments
Authors: Wessel-Beaver Linda , Scott J.W.
Published: January 2019

Heritabilities (h2) and genetic correlations between percent fruit set, yield, and fruit weight were estimated from one summer planting each in Florida and Puerto Rico of 100 S, tomato (Lycopersicon esculentum Mill.) families from a synthetic population. Single-location h2 was high for all traits. Across-locations h2 was low for yield, intermediate for fruit set, and high for fruit weight. Genotype × environment interaction (G × E) was 1) the only significant component of variance for yield, 2) somewhat important for fruit set, and 3) not an important variance component for fruit weight. The greater importance of genetic variance compared to G × E variance explains why across-location heritabilities for fruit weight and fruit set were high. Genetic correlations between fruit set and weight were strongly negative, while those between yield and set were large and positive. Yields under high temperatures may increase with selection for fruit set, but a reduction in fruit weight would be expected in this population and those with similar genetic correlations.
Genetic Control of Seven Enzyme Systems in Ipomoea Species
Authors: Reyes Luz Marina , Collins Wanda W.
Published: January 2019

Genetic control of seven enzymes in Ipomoea trifida (H.B.K.) G. Don. (diploid, tetraploid, and hexaploid populations) and I. batatas (L.) Lam. was studied by starch gel electrophoresis. Inter- and intraspecific polymorphisms were detected for all enzymes in the populations analyzed, except catalase (CAT, EC 1.11.1.6). Phosphoglucomutase (PGM; EC 2.7.5.1), phosphoglucose isomerase (PGI; EC 5.3.1.9), glutamate oxaloacetate transaminase (GOT; EC 2.6.1.1), menadione reductase (MNR; EC 1.6.99.2), shikimate dehydrogenase (SAD; EC 1.1.1.25), and malate dehydrogenase (MDH; EC 1.1.1.37) collectively were encoded by a minimum of 13 genetic loci resulting in 24 allozymes. Results from the diploid I. trifida were used to infer the genetic basis of these enzymes in the polyploid species. All polyploid populations shared almost the same number of allozymes with diploid I. trifida. PGM and PGI showed evidence of duplicated genes in the polyploid series. A unique allele for MNR was detected only in polyploid series.
Seasonal Variation in Leaf Component Allocation in Normal, Afila, and Afila-tendrilled Acacia Pea Foliage Near-isolines
Authors: Goldman I.L. , Gritton E.T.
Published: January 2019

In pea (Pisum sativum L.) the af gene replaces leaflets with tendrils, and the tac gene restores small leaflets to the terminal portion of the tendrils of afaf plants. Normal (AfAf-TacTac), afila (afaf-TacTac), and afila-tendrilled acacia (afaf-tactac) near-isogenic lines in three genetic backgrounds were evaluated for 2 years in two locations to determine allocation of foliage area and weight of foliage components throughout the growing season. The percentage of total leaf area and weight due to stipule, tendril, leaflet, and tac leaflet were measured three times during the growing season in each environment. Highly significant foliage-type effects were detected for the percentage of leaf area and weight due to stipule and tendril at each sampling date. The pea leaf canopy exhibits large fluctuations in area and weight component allocation throughout the growing season. At 28 days after planting, stipules comprised 34%, 76%, and 53% of the total leaf area, and tendrils comprised 6%, 24%, and 13% of the total leaf area in normal, afila, and afila-tendrilled acacia types, respectively. At harvest, stipules composed 43%, 60%, and 53% of the total leaf area and tendrils composed 15%, 40%, and 22% of the total leaf area in normal, afila, and afila-tendrilled acacia types, respectively. Results from this study demonstrate that significant seasonal variation in allocations of foliage area and weight components exists among these three foliage types.
Storage Atmospheres Influence Chilling Injury and Chilling Injury-induced Changes in Cell Wall Polysaccharides of Cucumber
Authors: Mercer M. Darlene , Smittle Doyle A.
Published: January 2019

`Gemini II' cucumber (Cucumis sativus L.) fruits were stored for 2, 4, or 6 days at 5 and 6C in 1989 and for 5 days at SC or 10 days at 3C in 1990. Chilling injury (CI) symptoms were rated after 2 to 4 days at 25C. Cell wall polysaccharide concentrations in the peels and in injured and noninjured portions of the peels were determined only in 1990. High CO2 and low O2 delayed the onset of CI symptoms, but did not prevent symptom development. Chilling injury symptoms increased with longer exposure to chilling temperatures. Solubilization of cell wall polysaccharides was associated with development of CI symptoms. Variations in low methoxyl pectinates accounted for 70% of the variation in CI.
Supercooling and Extracellular Ice Formation in Differentiating -Buds of Eastern Thornless Blackberry
Authors: Warmund Michele R. , Takeda Fumiomi , Davis Glen A.
Published: January 2019

`Hull Thornless' and `Black Satin' blackberry (Rubus spp.) canes were collected from Sept. 1989 through Mar. 1990 to determine the hardiness and supercooling characteristics of buds at various stages of development. Anatomical studies were also conducted to examine the location of ice voids in buds frozen to -5 or -30C. Differentiation of the terminal flower occurred in `Black Satin' buds by 6 Nov., whereas `Hull Thornless' buds remained vegetative until early spring. As many as nine floral primordia were observed in both cultivars by 12 Mar. The hardiness of the two cultivars was similar until February. Thereafter, `Black Satin' buds were more susceptible to cold injury than those of `Hull Thornless'. Flora1 and undifferentiated buds of both cultivars exhibited one to four low temperature exotherms (LTEs) from 9 Oct. to 12 Mar. in differential thermal analysis (DTA) experiments. The stage of flora1 development did not influence the bud's capacity to supercool. The number of LTEs was not related to the stage of floral development or to the number of floral primordia. Extracellular voids resulting from ice formation in the bud axis and scales were observed in samples subjected to -5 or -30C.
In Vivo Characterization of a Graft-transmissible, Free-branching Agent in Poinsettia
Authors: Dole John M. , Wilkins Harold F.
Published: January 2019

The free-branching poinsettia (Euphorbia pulcherrima Willd. ex. Klotzsch) cultivar Annette Hegg Brilliant Diamond (BD) contained a free-branching agent that was graft-transmissible to the restricted-branching cultivar Eckespoint C-1 Red (CR). CR plants were transformed by the agent regardless of whether BD plants were used as scion or stock, indicating that the agent moved basipetally and acropetally through the graft union. The agent was repeatedly transmitted to a CR plant by serial grafting with a free-branching poinsettia plant. A minimum of 10 days contact through grafting was required for BD plants to transmit the agent to CR plants. Percentage of CR plants exhibiting the free-branching characteristic increased from 0% for < 10 days of graft contact with BD plants to 100% after 30 days.
Inheritance of Tolerance to the Herbicide Bentazon in Peppers (Capsicum annuum L.)
Authors: Wolff David W. , Collins Wanda W. , Monaco Thomas J.
Published: January 2019

Several inheritance experiments with bentazon herbicide-tolerant Capsicum annuum `Bohemian Chili' (BCH P1) and susceptible `Keystone Resistant Giant' (KRG, P2) and `Sweet Banana' (SB, P2) were conducted. Populations of plants at the three- to five-leaf stage were treated with a bentazon rate of 4.5 kg·ha-1. Tolerance expression was affected by environment and varied across experiments. F2 and BCP2 generations from both susceptible parent crosses fit the expected ratios for a single, dominant gene conferring tolerance. Reciprocal F1s showed a maternal effect on tolerance intensity not consistently observed in reciprocal BCP2s or at all in reciprocal F2s. Segregation ratios of reciprocal crosses, however, were not heterogeneous, based on x2 tests of observed ratios in seven of eight cases. Variable tolerance expression in expected homogeneous populations (P1, P2, and F1) and lower tolerance in BC3 families suggested that modifying factors affected tolerance. Analysis of genetic components of shoot height and fresh weight generation means showed significant digenic epistasis, primarily additive × dominance. Modifying genes that affect the major gene controlling tolerance in BCH are, therefore, present. The simple inheritance of bentazon tolerance, even though modifying factors were present, facilitated transfer of bentazon tolerance into KRG via backcrossing. Chemical name used: 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide (bentazon).
Contribution of Storage and Currently Assimilated Nitrogen to Vegetative and Reproductive Growth of Rabbiteye Blueberry
Authors: Birkhold Keith T. , Darnell Rebecca L.
Published: January 2019

The relative contribution of storage and currently assimilated N to reproductive and vegetative growth of `Bonita' and `Climax' rabbiteye blueberry (Vaccinium ashei Reade) was estimated immediately before and during the fruit development period. Total and storage N decreased in roots and shoots of both cultivars during dormancy and early fruit development. The principle N storage form appeared to be protein, as indicated by a significant decline in total shoot and root protein during this same period. Storage N from roots and shoots in both cultivars was remobilized to flowers and/or fruit and new vegetative growth. At anthesis, 90% of the total N present in reproductive organs was estimated to come from storage N. By fruit maturity, ≈ 50% of the accumulated N was derived from storage pools. Storage N contributed 90% of the total N in developing vegetative growth of `Bonita' at leaf budbreak, which is concomitant with floral budbreak for this cultivar. Developing vegetative growth of `Climax' at leaf budbreak, which occurs ≈ 4 weeks after floral budbreak, derived ≈ 65% of its total N from storage and 35% from currently assimilated N. By fruit maturity, contribution of storage N to new vegetative growth had decreased to ≈ 20% in both cultivars, indicating that currently assimilated N became the principal N supply as vegetative growth became more established. Differences in timing of floral and vegetative budbreak between the two cultivars did not appear to affect allocation of either storage or currently assimilated N to new vegetative or reproductive growth.
Pollen Parent Effect on Outcrossing Rate, Yield, and Fruit Characteristics of `Floridian' and `Mauritius' Lychee
Authors: Stern R.A. , Gazit S. , El-Batsri R. , Degani C.
Published: January 2019

Fruits produced in two orchards, each consisting of adjacent blocks of `Floridian' and `Mauritius' lychee (Litchi chinensis Sonn.), were unequivocally identified as selfed or outcrossed by phosphoglucose isomerase (PGP; EC 5.3.1.9) isozyme analysis. The average rate of hybrid production in each orchard was 69% and 87% for `Floridian' and 17% and 65% for `Mauritius', respectively. The percentage of hybrids produced on trees adjacent to those of the other cultivar was invariably significantly higher than that produced on the more distant trees. However a significant correlation between hybrid percentage and proximity to the other cultivar, as well as between hybrid percentage and yield, was found only for `Floridian' in one of the orchards. A significant correlation was found between pollen source and the weights of fruits and seeds in both cultivars. Fruits originating from cross-pollination were heavier and contained heavier seeds than selfed fruits. The most pronounced effect of pollen parent on seed weight was found in `Floridian', which appears to exhibit inbreeding depression.
Genetic Diversity of Red Raspberry Varieties throughout the-World
Authors: Dale Adam , Moore Patrick P. , McNicol Ronald J. , Sjulin Thomas M. , Burmistrov Leonid A.
Published: January 2019

Pedigrees of 137 red raspberry (Rubus idaeus L.) varieties released throughout the world since 1960 were used to calculate: 1) the genetic contribution of founding clones to these varieties; 2) genetic relatedness among them; and 3) their inbreeding coefficients. Fifty founding clones contributed to the pedigrees of these varieties with a mean genetic contribution ranging from <0.1% to 21%. Varieties were clustered according to the genetic contribution into groups strongly related to geographical origin. Varieties developed in the former USSR and derived from `Novost Kuzmina' formed a distinct cluster. The remaining varieties were clustered in groups based mainly on whether they were of North American or European origin. Varieties were clustered also on the basis of Wright's coefficient of relationship-a measure of genetic relatedness. Cluster groups were related to their geographical origin and the varieties within the groups could be traced to similar intermediate parents. Inbreeding coefficients ranged from 0.0 to 0.625 and were related, in part, to the numbers of generations of controlled hybridization from common ancestors. The British group, with the largest number of generations of breeding, had a low mean inbreeding coefficient, indicating that inbreeding can be minimized with attention to the mating system. Strategies are suggested for maintaining and increasing the genetic diversity in the world's red raspberry breeding populations.
Primocane Development and Early Yield of `Heritage' Red Raspberry in Relation to Initial Plant In-row Spacing
Authors: Myers S.C.
Published: January 2019

Micropropagated plants of `Heritage' primocane-fruiting (PF) red raspberry (Rubus idaeus L.) were planted at in-row spacings of 100, 50, or 25 cm. Yield per unit area during the first season was positively correlated with initial plant in-row spacing. During the first season of growth, initial plant in-row spacing did not affect the total number of primocanes that developed but was positively associated with the numbers of primocanes that fruited. Yield per primocane, primocane yield efficiency, total nodes per primocane, and number of fruiting nodes per primocane were not affected by plant in-row spacing in the first year. Average fruit weight and fruiting primocane diameter in the first year were negatively associated with plant in-row spacing. Photosynthetic photon flux density (PPFD) penetrating the row canopy as measured in the first season was not affected by treatment. Treatment did not influence percentage of fruit exhibiting solar injury, shattering, or infection by Botrytis cinerea. Plant in-row spacing did not influence yield during the second and third production seasons.
Efficacy, Fruit Residues, and Soil Dissipation of the Herbicide Metolachlor in Processing Tomato
Authors: Gaynor J.D. , Hamill A.S. , MacTavish D.C.
Published: January 2019

Metolachlor was evaluated for annual grass and eastern black nightshade (Solarium ptycanthum Dun.) control in processing tomato (Lycopersicon esculentum Mill.). Metolachlor applied preplant incorporated provided excellent (> 88%) control of annual grasses and eastern black nightshade. The metolachlor, metribuzin plus trifluralin tank mix applied preplant and incorporated into the soil provided better annual grass and eastern black nightshade control than the metolachlor plus metribuzin tank mix in two of three years. Nonincorporated and posttransplant treatments of metolachlor provided good annual grass control but failed to control eastern black nightshade. Tomato yield in all herbicide treatments was similar to that from hand weeded controls. Metolachlor dissipated from the soil throughout the growing season so that at the time of harvest <10% of that applied was recovered. Metolachlor residues in the fruit were hydrolyzed to deacylated (CGA 37913) or hydrolyzed conjugated (CGA 49751) metolachlor metabolizes. Analyses of extracts from treated fruits were found to be less than the detection limit of 50 ppb in the whole fruit harvested from selected metolachlor treatments. Chemical names used: 2-chloro-N -(2-ethyl-6-methylphenyl)-N -(2-methoxy-1-methylethyl) acetamide (metolachlor); 2,6-dinitro-N,N -dipropyl-4-(trifluromethyl)benzenamine (trifluralin); 4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-tlriazin-5(4H)-one (metribuzin); 2-(2-ethyl-6-methylphenyl)amino-1-propanol (CGA 37913); 4-(2-ethyl-6-methylphenyl)-2-hydroxy-5-methyl-3-morphol. inone (CGA 49751).
Characterization of the Kentville Stock Clone Apple Rootstocks. II. Precocity and Productivity
Authors: Lesser B.H. , Embree C.G. , Crowe A.D.
Published: January 2019

The precocity and productivity of 30 Kentville Stock Clone (KSC) apple (Malus domestica Borkh.) rootstocks, with `McIntosh' and `Delicious' as scion cultivars, were assessed independently of each other using a procedure involving computer-aided fitting of curves to yearly production data. A good fit to the data was obtained after biennial fluctuations in yield were removed by using a weighted, 3-year running average. For all 30 rootstocks combined, `McIntosh' was more precocious and reached a higher level of productivity compared to `Delicious'. There was poor correlation between precocity and productivity.
Characterization of the Kentville Stock Clone Apple Rootstocks. III. Quality and Overall Performance
Authors: Embree C.G. , Lesser B.H. , Crowe A.D.
Published: January 2019

The effects of 30 Kentville Stock Clone (KSC) selections on fruit size and color of `McIntosh' and `Delicious' apples (Malus domestica Borkh.) were monitored over 5 years. Fruit size was influenced by the rootstock and, when averaged over the duration of the study, ranged from 108 to 132 g and 131 to 161 g for `McIntosh' and `Delicious', respectively. Variation in fruit size due to crop load (CL) was greater for `McIntosh' than for `Delicious'. Fruit color was influenced by the rootstock in all years for `McIntosh' and in 3 of 5 years for `Delicious'; it was strongly associated with tree size for `Delicious' only. An overall performance index, which also included price based on quality, was developed, and the best performers in each size group were: semidwarf KSC 18 and 28; semivigorous KSC 7, 11, and 24; and vigorous KSC 3 and 6.
Genetic Similarity Among Brassica oleracea L. Genotypes as Measured by Restriction Fragment Length Polymorphisms
Authors: Nienhuis James , Slocum Mary K. , DeVos Dawn A. , Muren Roger
Published: January 2019

Genetic similarities were calculated among 89 Brassica oleracea L. genotypes, which included 62 broccolis (var. italica), 16 cauliflowers (var. botrytis), and 11 cabbages (var. capitata). These entries represented a wide range of commercially available germplasm, including open-pollinated cultivars, commercial hybrids, the inbred parents of several hybrid cultivars, and 27 entries that were provided as unknowns. Sixteen random genomic clones were used as probes in Southern hybridizations to detect restriction fragment length polymorphism (RFLP). From each of the random probes, an average of four polymorphic bands were classified as to their presence or absence for each genotype. The genetic similarity between ail pairs of genotypes was calculated. A multidimensional scaling (MDS) plot indicated that the broccoli, cauliflower, and cabbage groups were clustered with very little overlap. Within groups, genetic similarity corresponded to relationships based on available pedigree information. Comparison of banding patterns between hypothetical and actual hybrids was used to correctly identify the parents of several parent-hybrid combinations. The RFLP pattern of a hybrid and one of the parents (female) were used to predict the genotype and identity of the other parent (male).
The Role of Aminoglycoside Antibiotics in the Regeneration and Selection of Neomycin Phosphotransferase-transgenic Apple Tissue
Authors: Norelli John L. , Aldwinckle Herb S.
Published: January 2019

Regeneration from apple (Malus × domestica Borkh.) M.26 leaf tissue was completely inhibited by (μg·ml-1) 1 geneticin, 5 kanamycin, 10 to 25 paromomycin, and 100 neomycin. nptII-transgenic M.26 had an increased tolerance to all four of the antibiotics tested, with inhibition of regeneration occurring at (μg·ml-l) 2.5 geneticin, 100 kanamycin, 375 paromomycin, and 375 neomycin. Paromomycin (100 to 250 μg·ml-l) and neomycin (250 μg·ml-1) significantly increased the amount of regeneration from nptII-transgenic M.26 apple leaf tissue. p35SGUS-INT, a plasmid with a chimeric b -glucuronidase gene containing a plant intron, was useful for studying the early events of apple transformation by eliminating GUS expression from Agrobacterium tumefaciens. It was used to determine that the optimal aminoglycoside concentrations for the selection of nptII-transgenic M.26 cells were (μg·ml-1) 2.5 to 16 kanamycin, 63 to 100 neomycin, and 25 to 63 paromomycin. Geneticin was unsuitable as a selective agent.
A Functional and Exploratory Approach to Studying Growth: The Example of the Peach Fruit
Authors: Génard Michel , Bruchou Claude
Published: January 2019

An approach to studying fruit growth is presented for peach fruit (Prunus persica L. Batsch). It combines a functional description of growth curves, multivariate exploratory data analysis, and graphical displays. This approach is useful for comparing growth curves fitted to a parametric model, and analysis is made easier by the choice of the model whose parameters have a meaning for the biologist. Growth curves were compared using principal component analysis (PCA) adapted to the table of estimated parameters. Growth curves of 120 fruits were fitted to a model that assumes two growth phases. The first one described the pit growth and the first part of the flesh growth. The second described the second part of the flesh growth. From PCA, firstly it was seen that fruit growth varied according to cumulated growth during both growth phases and to date of maximal absolute growth. Secondly, fruit growth varied according to cumulated growth and relative growth rates during each phase. Further examples are presented where growth curves were compared for varying fruit number per shoot and leaf: fruit ratio, and for different sources of variation (tree, shoot, and fruit). Growth of individual fruit was not related to fruit number per shoot or to leaf: fruit ratio. Growth variability was especially high between fruit within shoots.
Growth, Yield, and Fruit Quality of Nucellar Frost `Marsh' Grapefruit on Fifteen Rootstocks in Cyprus
Authors: Economides C.V. , Gregoriou C.
Published: January 2019

Tree growth, yield, and fruit quality of nucellar `Frost Marsh Seedless' grapefruit (Citrus paradisi Macf.) on 15 rootstocks were evaluated under Cyprus conditions. Over the 9-year production period, trees on Palestine sweet lime, the group of rough lemon, and Citrus volkameriana Pasq. were more productive per unit of tree size, and their cumulative yields per tree were significantly higher than those of trees on sour orange, which is the standard rootstock commercially used in Cyprus. Rootstocks affected fruit size and weight, rind thickness, juice content, total soluble solids concentration (SSC), and total acids, but the differences were not large enough to affect the market value of the fruit, On the basis of the results of this trial and because sour orange is highly susceptible to tristeza, the C. volkameriana and rough lemon group, which are tolerant to tristeza, should be included in further trial plantings as a potential commercial rootstock.
Performance of Three Primocane-fruiting Red Raspberry Cultivars in Ontario and Québec
Authors: Privé Jean-Pierre , Sullivan J.A. , Proctor J.T.A. , Allen O.B.
Published: January 2019

The influence of genotype x environment interactions on the performance of `Autumn Bliss' `Heritage' and `Redwing' primocane-fruiting (PF) red raspberry (Rubus idaeus L.) cultivars was studied at six sites across Ontario and Quebec during 1989 and 1990. Cultivar × location × year interactions were found for most vegetative and reproductive components analyzed. `Autumn Bliss' had the most consistent performance of the three cultivars in all location/year combinations, while `Redwing' varied greatly between environments. `Heritage' was always the latest-bearing of the three cultivars and failed to achieve its maximum yield potential in many of the northern locations.
Breeding Tomatoes for Salt Tolerance: Variations in Ion Concentrations Associated with Response to Salinity
Authors: Saranga Y. , Zamir D. , Marani A. , Rudich J.
Published: January 2019

Accessions of four tomato species, Lycopersicon esculentum Mill. (Le), L. pennellii (Corr.) O'Arey (Lpen), L. cheesmanii Riley (Lc), and L. peruvianum (L.) Mill., (Lper), and interspecific populations were irrigated with saline water under field conditions and concentrations of Na, K, Cl, Ca, and Mg in leaves and stems were determined. Potassium: sodium ratios in leaves and stems of salt-tolerant genotypes were higher under salinity and were moderately changed by salinity compared to the sensitive genotypes. In the tolerant wild accessions and F1(Le × Lpen), Cl concentrations in leaves and the ratio between Cl in leaves to Cl in stems were lower than in the sensitive Le cultivar. Regulation of the K: Na ratio was found in tolerant wild accessions and tolerant Le cultivars, while regulation of Cl concentration in leaves was found only in the wild germplasm. The effects of ion concentrations on dry matter of interspecific segregating populations, F2(Le × Lpen) and BC1(Le × (Le × Lpen)), were studied by regression analyses. Dry matter was positively correlated with the K: Na ratio in stems and negatively correlated with the Cl concentrations in leaves and stems, thus confirming the results obtained by comparison between the tolerant and sensitive accessions.
Growth and Mineral Content of St. Augustinegrass Cultivars in Response to Salinity
Authors: Peacock C.H. , Dudeck A.E. , Wildmon J.C.
Published: January 2019

This investigation documented growth and nutritional responses of St. Augustinegrass `Floralawn', `Floratam', `Floratine', and `Seville' in salinized (conductivity = 1.1 to 41.5 dS·m-1) solution cultures. Averaged over all cultivars' tissue, Cl concentrations increased linearly as salinity increased, while Na concentrations reached a threshold at 10 dS·m-1 during 3 months of growth. Tissue K concentration decreased nonlinearly with increased salinity to 10 dS·m-1, with `Floratine' being the least affected. All cultivars apparently substituted Na for K until an optimum level was reached. Leaf tissue concentration of P decreased linearly, while Ca and Mg decreased nonlinearly with increased salinity. The salinity level that caused a 50% reduction in Ca concentration was 24% lower for `Floratine' than for other cultivars. Tissue color differences were more strongly correlated with Ca and Mg levels in `Floratine' than `Seville'. Differences in cultivar response were noted for K, P, Ca, and Mg, with `Seville' being the most salt-tolerant among those evaluated, based on overall nutritional and growth responses.
Temperature Conditioning and Surface Treatments of Grapefruit Affect Expression of Chilling Injury and Gas Diffusion
Authors: McDonald Roy E. , McCollum T. Gregory , Nordby Harold E.
Published: January 2019

`Marsh' Grapefruit (Citrus paradisi Macf.) were temperature conditioned (7 days at 15C), wiped with hexane, treated with squalene, squalane, or safflower oil (all 10% in hexane), or waxed with a commercial fruit wax (Flavorseal) to determine their effects on weight loss, chilling injury (Cl) symptoms on the peel, and gas exchange. Following 3 weeks of storage at SC, wiping fruit with hexane resulted in a significant decrease in weight loss, but not CI. Temperature conditioning and Flavorseal independently inhibited weight loss and Cl development. Squalene inhibited CI development, but not weight loss. Chilling injury on fruit treated with squalene or Flavorseal was similar in appearance, but significantly less common than that on nontreated fruit. Grapefruit peel accounted for 92% of the gas diffusion of fruit, and resistance coefficients for peel and whole fruit were similar. Less ethane diffused into fruit that were: temperature-conditioned compared with nonconditioned, hexane wiped compared with nonhexane-wiped, and squalene-treated compared with nonsqualene treated fruit. Ethane influx was significantly restricted into squalane- and squalane-treated fruit compared with Flavorseal- or safflower oil-treated fruit. Oxygen and CO2 influx was significantly reduced by Flavorseal, safflower oil, squalene, and squalane. Squalane was the most restrictive of ethylene efflux followed by safflower oil, squalene, and Flavorseal. All of these surface treatments are known to reduce CI on grapefruit. These data indicate that water loss is less important to the development of Cl than has been previously suggested, and that the beneficial effects of squalene are not the result of an inhibition of water loss. Permeability of grapefruit peel to gases other than H2O vapor may also influence the expression of Cl.
Postharvest Performance Evaluation of Plum (Prunus salicina Lindel., `Casselman') Fruit Grown under Three Ozone Concentrations
Authors: Crisosto C.H. , Retzlaff W.A. , William L.E. , DeJong T.M. , Zoffoli J.P.
Published: January 2019

We investigated the effects of three seasonal atmospheric ozone (0,) concentrations on fruit quality, internal breakdown, weight loss, cuticle structure, and ripening characteristics of plum fruit from 3-year-old `Casselman' trees in the 1991 season. Trees were exposed to 12-hour daily mean O3 concentrations of 0.034 [charcoal-filtered air (CFA)], 0.050 [ambient air (AA)], or 0.094 [ambient plus O3 (AA+O)] μl·liter-1 from bloom to leaf-fall (1 Apr. to31 Oct. 1991). Fruit quality and internal breakdown incidence measured at harvest and after 2, 4, and 6 weeks of storage at 0C were not affected by any of the O3 treatments. Following an ethylene (C2H4) preconditioning treatment, the rate of fruit softening, C2H4 production, and CO, evolution was higher for plums harvested from the AA + O than from those grown in CFA. Weight loss of fruit from the AA + O exceeded that of fruit from CFA and AA. Anatomical studies of mature plums indicated differences in wax deposition and cuticle thickness between fruit grown in AA + O, AA, and CFA. Differences in gas permeability, therefore, may explain the difference in the ripening pattern of `Casselman' plum fruit grown in high atmospheric O3 partial pressures.
Juvenility, Flowering, and the Effects of a Limited Inductive Photoperiod in Coreopsis grandiflora and C. lanceolata
Authors: Damann M. Peggy , Lyons Robert E.
Published: January 2019

Juvenility and flowering requirements of Coreopsis grandiflora Hogg ex Sweet. `Sunray' and C. lanceolata L. `Early Sunrise' were examined by growing plants under short days (SD) and transferring them to long days (LD) upon reaching the designated true leaf stages. Neither cultivar flowered in continuous SD, and `Sunray' remained vegetative in LD. However, LD induced flowering in `Early Sunrise' plants in each leaf count treatment and the loss of juvenility was gradual, with most rapid flowering occurring when plants were transferred to LD at the 16 leaf stage. The limited inductive photoperiod (LIP) inhibited stem elongation of `Early Sunrise' plants in all LD treatments and selectively inhibited axillary flower bud development compared to plants grown in continuous LD. LIP did not affect scape length at first flower even though plant height was significantly diminished if given relatively few LD before transfer to SD. Height reduction was attributed to LIP inhibition of stem elongation with no significant loss of axillary flower bud potential.
Analysis of Peach Germplasm in Mexico
Authors: Pérez S. , Montes S. , Mejía C.
Published: January 2019

A wide range of peach [Prunus persica (I,.) Batsch] germplasm was collected from the most important peach growing regions in Mexico and some Latin American countries, as well as from breeding programs in the United States, Europe, and South Africa. Budded trees, seedlings derived from selfing cultivars and selections, and seed samples from various growing regions were propagated and planted in central Mexico. Twenty eight morphological or phenological variables were recorded on 52 accessions representing different geographic regions. The highest degree of variability was observed for traits related to bud density and distribution, and to phenological variables associated with temperature requirements such as budbreak and harvest seasons, leaf fall, fruit development, and seed stratification period. Principal component analysis (PCA) integrated groups of phenotypes based mainly on growth habit, shoot diameter, bud and leaf size, as well as resistance to powdery mildew, rust, and frost. PCA provides support for the development of objectives and breeding strategies in the search for germplasm and cultivars for nontraditional peach growing regions.
Production and Postharvest Characteristics of Rosa hybrida L. `Meijikatar' Grown in Pots under Carbon Dioxide Enrichment
Authors: Clark David G. , Kelly John W. , Rajapakse Nihal C.
Published: January 2019

The effects of carbon dioxide enrichment on growth, photosynthesis, and postharvest characteristics of `Meijikatar' potted roses were determined. Plants were grown in 350, 700, or 1050 μl CO2/liter until they reached 50% flower bud coloration and then were placed into dark storage for 5 days at 4 or 16C. Plants grown in 700 or 1050 μl CO2/liter reached the harvest stage earlier and were taller at harvest than plants produced in 350 μl CO2/liter, but there were no differences in the number of flowers and flower buds per plant among CO2 treatments. Plants grown in early spring were taller and had more flowers and flower buds than plants grown in late winter. Shoot and root growth of plants grown in 700 or 1050 μl CO2/liter were higher than in plants produced in 350 μl CO2/liter, with plants grown in early spring showing greater increases than plants grown in late winter. Immediately after storage, plants grown in 350 μl CO2/liter and stored at 4C had the fewest etiolated shoots, while plants grown in 1050 μl CO2/liter and stored at 16C had the most. Five days after removal from storage, chlorophyll concentration of upper and lower leaves had been reduced by ≈50% from the day of harvest. Carbon dioxide enrichment had no effect on postharvest leaf chlorosis, but plants grown in early spring and stored at 16C had the most leaf chlorosis while plants grown in late winter and stored at 4C had the least leaf chlorosis.
Orchard Floor Management Affects Peach Rooting
Authors: Parker M.L , Hull J. , Perry R.L.
Published: January 2019

The root distribution of peach trees [Prunus persica (L.) Batsch cv. Redhaven/Halford] as affected by six orchard floor management treatments was evaluated after 3 years of growth. Two treatments were maintained vegetation-free and four had vegetative covers in the alleyway with a 1.2-m-wide herbicide strip in the tree row. The profile wall method was used to determine root distribution. Trees maintained vegetation-free with herbicide had the most roots. Trees in the vegetation-free plots, maintained with herbicide or cultivation, produced more roots 1.2 m from the tree than trees in the vegetative covers. The number of roots, 1.2 m from the tree, was lowest in the tall fescue treatment. The number of roots were higher in the Kentucky bluegrass (Poa pratensis L.) or alfalfa (Medicago sativa L.) than with tall fescue (Festuca arundinacea, Schreb.).
Drought and Flood Stress Effects on Plant Development and Leaf Water Relations of Five Taxa of Trees Native to Bottomland Habitats
Authors: Nash Lenore J. , Graves William R.
Published: January 2019

Responses of five bottomland tree taxa to drought and flooding were studied to identify those adapted to urban environments. During one experiment, containerized `Franksred' red maple [Acer rubrum L. `Franksred' (trademark = Red Sunset)], sweetbay magnolia (Magnolia virginiana L.), black tupelo (Nyssa sylvatica Marsh.), bald cypress [Taxodium distichum (L.) Rich.], and pawpaw [Asimina triloba (L.) Dunal.] were treated with various irrigation regimes for up to 118 days. Net assimilation rate (NAR) and relative growth rate (RGR) were reduced more by flooding than by drought for plants of all taxa, except pawpaw, which showed similar NAR and RGR during flooding and drought. Only sweetbay magnolia and bald cypress maintained positive NAR and RGR during flooding, and sweetbay magnolia was the only taxon that did not produce significantly less leaf surface area, shoot dry mass, and root dry mass during flooding and drought. Apparent morphological mechanisms of stress resistance included an increase in specific mass of leaves (mg·cm-2) during drought for red maple and bald cypress and a 385% increase in the root: shoot mass ratio for droughted plants of pawpaw. Leaf water relations of drought- and flood-stressed `Franksred' red maple and sweetbay magnolia were determined in a second experiment. Predawn and mid-day leaf water potential (ψ) decreased with decreasing root-zone matric potential for both taxa, and transpiration rate was reduced by drought and flooding. Pressure-volume analysis showed that leaves of `Franksred' red maple responded to drought by shifting symplastic water to the apoplast. Leaves of drought-stressed sweetbay magnolia adjusted osmotically by reducing osmotic potential (ψπ) at full turgor by 0.26 MPa. Our results suggest that sweetbay magnolia and bald cypress will perform well at urban planting sites where episodes of drought and flooding regularly occur.
Reduced Incidence of Lesser Peachtree Borer and Leucostoma Canker in Peach-Almond Hybrids
Authors: Puterka G.J. , Scorza R. , Brown M.W.
Published: January 2019

Damage by lesser Peachtree borer (LPB) (Synanthedon pictipes Grote & Robinson) and Leucostoma canker that had accumulated during 6 (Orchard A) and 8 (Orchard B) years were compared in peach (Prunus persica L.) and peach-almond [P. amygdalus (Mill.) D. A. Webb] hybrids. Afterward, the main trunk and scaffold limbs of the trees received 10 wounds 26 mm in diameter and a subset of these trees in Orchard A had wounds inoculated with Leucostoma persoonii Hohn. Before wounding, Leucostoma canker infection and LPB infestations that had accumulated for 6 to 8 years on peach-almond hybrids was ≈60% and 98% less than on peach in Orchard A and B, respectively. One month after wounding the trees, no significant differences in Leucostoma canker infection and LPB infestations were found among the peach-almond hybrids, treated or not treated with L. persoonii, or untreated peach. Yet, Leucostoma- treated and untreated peach-almond hybrids had 33% and 25% less Leucostoma canker and LPB, respectively, when compared with Leucostoma- treated peach. Ten months after wounding, peach-almond hybrids treated with L. persoonii still had significantly less Leucostoma canker (60%) and LPB (25%) when compared with Leucostoma- treated peach. Wound gumming and wound closure rates seemed to influence the degree of LPB infestation and Leucostoma canker. Based on these data, peach-almond hybrids could be valuable sources of resistance to LPB and Leucostoma canker.
A New Gene for Flower Color Pattern, White Banner (wb), in Progeny of an Interspecific Hybrid between Common and Scarlet Runner Beans
Authors: Bassett Mark J.
Published: January 2019

A new gene for flower color pattern, designated white banner (WB), appeared in material derived from the cross `Harvester' snap bean (Phaseolus vulgaris L.) × Plant Introduction (PI) accession 273666 of scarlet runner bean (P. coccineus L.). The WB character has a white banner petal and pale violet wings (veronica-violet 639/2). The inheritance of the mutant was studied in crosses involving dry bean breeding line 5-593, which has bishops-violet (wild-type) flowers, and genetic stocks v BC2 5-593 (white flowers) and blu BC2 5-593 (blue flowers). Segregation in F2 and F3 progenies from the cross v BC2 5-593 × WB supported the hypothesis that WB is controlled by a single recessive gene that is nonallelic with the V locus. An allelism test with blu BC2 5-593 gave evidence that WB is not allelic with the blu locus. The gene symbol wb is proposed for the gene producing WB.
Skin Color in Apples—Influence of Copigmentation and Plastid Pigments on Shade and Darkness of Red Color in Five Genotypes
Authors: Lancaster Jane E , Grant Jan E. , Lister Carolyn E. , Taylor Michael C.
Published: January 2019

The biochemical and cytological mechanisms responsible for the differences in red color quality of apples (Malus domestics Borkh.) were investigated. Copigmentation, the increase in absorbance maxima (λ max) from anthocyanin and flavonoid interactions, is known to be a mechanism for producing variation in shade of red in flowers. In intact apple skin cells, the mean λ max was 550 nm, with no significant difference between genotypes. Furthermore, the ratio of flavonols and proanthocyanidins to anthocyanins was similar for all genotypes. Therefore, copigmentation is not a mechanism producing different shades of red in apples. Darkness of red skin was positively related to the proportion of red cells in the skin and the size of the vacuoles containing anthocyanins. Measurements of plastid pigments, chlorophyll, and carotenoids, compared with L*, a*, b* measurements, indicated that the visual blending of plastid pigments and anthocyanins has an important influence on red coloration of apple skin.
Effects of Chilling on Episcia and Dieffenbachia
Authors: McMahon Margaret J. , Pertuit A.J. , Arnold James E.
Published: January 2019

Leaves of chilled `Moss-Agate' Episcia (Mart.) plants exhibited direct chilling injury (i.e., watersoaked browning of leaf blade interveinal areas within 24 h of exposure to low temperature) immediately following exposure in darkness to 10C for 0.5 or 1.0 h. Chlorophyll fluorescence peak: initial ratios and terminal: peak ratios of chilled Episcia were -reduced 20% and 25%, respectively, 3 h after chilling, a result suggesting possible photosystem II damage. Total leaf chlorophyll content was reduced by 17% within 3 h of chilling and CO2uptake also was reduced at this time. Leaves of chilled `Rudolph Roehrs' Dieffenbachia maculata (Lodd.) (D. Roehrsii Hort.) plants expressed no visible injury within 24 h of 1.2C chilling in darkness for 36,48, or 60 h, but CO2uptake was reduced by 70% compared to the control 3 h after chilling. Visible injury began to appear 27 h after chilling, and the older leaf blades of all chilled plants exhibited a watersoaked appearance 75 h after chilling. Chlorophyll fluorescence peak: initial ratios of chilled Dieffenbachia did not vary, and terminal: peak ratios were not reduced until 147 h after chilling, when the injured tissue was extremely flaccid and translucent. Chilling reduced the chlorophyll content of Dieffenbachia by 10% in some plants 27 h after chilling and by 35%. in all plants 75 h after chilling. Transpiration rate was reduced and stomata] diffusive resistance increased 27 h after chilling.
Carbon Exchange Rate and Accumulation in Limbs of Fruiting and Nonfruiting Apple Trees
Authors: Schechter Ido , Proctor J.T.A. , Elfving D.C.
Published: January 2019

Mature `Sturdeespur Delicious' apple (Malus domestica Borkh.) trees on MM.106 rootstocks were hand-deblossomed or hand-pollinated in 1989 and 1990. Two representative limbs were chosen at bloom on each tree in 1989, one of which was girdled (G) while the other served as a control. One representative limb was selected at bloom in 1990. Three leaf types were studied: shoot (SH) leaves, leaves on nonfruiting (NF) spurs (S-F), and leaves on fruiting (F) spurs (S + F). The presence of fruit did not affect C exchange rate (CER). Girdling fruiting limbs reduced CER by ≈10%. Girdling NF limbs resulted in starch accumulation in the leaves and low CER. SH leaves had the highest CER per unit leaf area, while S + F leaves had the lowest. Total seasonal dry weight (DW) accumulated in leaves, fruit, and wood, normalized per square centimeter limb cross-sectional area (LCSA), was higher in F trees. Roots were longer and DW of roots extracted from soil core samples was higher in NF trees. NF trees had significantly more vegetative growth in new shoots and dry-matter increment in wood than F trees.