bluuebunny/crossref_metadata_2025 huggingface dataset:
Inheritance of Green Mature Seed-stage Fruit Color in Cucumis sativus L.
Authors: Peterson Gregory C. , Pike Leonard M.
Published: January 2019

Fruit of TAMU breeding line 830397 are green in contrast to the cream or orange fruit of commercial cultivars at the mature-seed stage (MS-S). Inheritance of this trait for green MS-S fruit color in Cucumis sativus was investigated. A new locus, gn, is proposed as well as the elimination of the C locus. MS-S fruit color is controlled by two major genes, R and Gn. Fruit is orange when the genotype is R_ _ and green when the genotype is rrgngn. The cream MS-S fruit color trait is incompletely dominant over green, as the genotype rrGnGn is cream while rrGngn produces mature fruit from cream to intermediate in color between cream-colored and green fruit. Spine color is pleiotropic with or very tightly linked to the R locus, but heavy netting from PI 165509 appears not to be linked with the orange genotype and is polygenic.
Instantaneous Light Measurements Predict Relative Cumulative Light Levels within an Apple Canopy
Authors: Campbell Richard J. , Marini Richard P.
Published: January 2019

Percent instantaneous incident photosynthetic photon flux density (%INPPFD) was measured within an apple (Malus domestica Borkh.) canopy for various sky conditions and used to predict the percent cumulative incident photosynthetic photon density (PPD) for the last 10 weeks of the growing season (%CPPDLS) and the total growing season (%CPPDTS). Instantaneous measurements from overcast conditions were superior to measurements from clear or hazy conditions for the prediction of %CPPDLS in 1989 and 1990. A one-to-one relationship between %INPPFD and %CPPDLS was found for overcast conditions in both years, even though there was an 11% difference in total cumulative PPD between the years. The models had good predictive accuracy, with prediction coefficients of determination (R2Pred) >0.83 in both years (n = 30). %lNPPFD from overcast conditions also yielded accurate predictive models for %CPPDTS (R > 0.84, n = 30), which differed from the models for %CPPDLS. Predictive models (for both %CPPDLS and %CPPDTS) from %lNPPFD made before the canopy was fully developed differed from the models developed after canopy development was complete. The models still had good predictive accuracy, with R2Pred >0.76 (n = 30). Predictive models developed for cloudless conditions had inferior predictive accuracy (R2Pred = 0.49 to 0.80, n = 30) compared to models for overcast conditions. R2Pred were higher for hazy than for clear conditions. Time of day (1000 to 1400 hr) had no consistent effect on the development of predictive models for any weather condition. The most reliable models resulted from the average of several measurements within a day, particularly for cloudless conditions.
Rootstock-induced Differences in Flower Bud Phenology in Peach
Authors: Durner Edward F. , Goffreda Joseph C.
Published: January 2019

Three peach [Prunus persica (L.) Batsch] rootstock plantings were monitored for date and rate of bloom during Spring 1989 and 1990 to determine if the time of scion bloom on different rootstocks is determined by the date of initiation of bud growth in the spring or by the duration of a particular bud stage. Included were a 1984 planting of `Redhaven' on eight rootstocks, a 1984 planting of `Rio-Oso-Gem' and `Loring', each on 11 rootstocks, and a 1986 planting of `Encore' on 18 rootstocks. The effect of rootstock on bud phenology was consistent within scion cultivar over two extremely different spring temperature profiles. In `Redhaven' and `Rio-Oso-Gem', rootstocks affected the dates but not the rates of bud development. Rootstocks affected both the dates and rates of `Loring' and `Encore' bud development. No consistent effect of rootstock on yield could be associated with delayed bud development in `Rio-Oso-Gem', `Redhaven', or `Loring'; however, delayed bud development of `Encore' on `Okinawa' x `Cardinal' and 62325 resulted in enhanced yield following spring frosts.
An Irrigation Scheduling Model for Summer Squash
Authors: Smittle Doyle A. , Dickens W. Lamar , Hayes M. Jane
Published: January 2019

An irrigation scheduling model for summer squash (Cucurbita pepo L.) was developed and validated during 1986, 1987, and 1989. The model is represented by the equation: 12.7(i - 4) × 0.5ASW = Di-1 + [E(0.14 + 0.015) - P - I]i, where crop age in days is i; effective root depth is 12.7(i - 4) with a maximum of 381 mm; usable water (cubic millimeter per cubic millimeter of soil) is 0.5ASW, deficit on the previous day is Di-1; evapotranspiration is pan evaporation (E) times 0.14 + 0.015i; rainfall (in millimeters) is P; and irrigation (in millimeters) is I. The model was validated during the three years using a line-source irrigation system with irrigation depths ranging from 5% to 160% of the model rates. Nitrogen rates were 50%, 100%, and 150% of the recommended rate. Marketable fruit yields increased as the irrigation depths increased up to the model rate then decreased with greater water application depths. Marketable fruit yields increased as the N rate increased in 1987 and 1989, but yields were similar at all N rates in 1986. The shelf life of marketable fruits was not influenced by irrigation or N rates.
Mineral Concentration of Yellow Squash Responds to Irrigation Method and Fertilization Management
Authors: Clough G.H. , Locascio S.J. , Olson S.M.
Published: January 2019

Squash (Cucurbita pepo L. var. melopepo) was grown at two locations with different soil types as a second crop in a succession cropping study that used previously cropped polyethylene-mulched beds. Squash was produced with drip or overhead irrigation and with concurrent N-K fertilization or residual fertilizer from the previous crop. Tissue mineral concentration responses to irrigation method were variable; in early fruit, N and K concentrations were higher with overhead than for drip, but leaf Ca and Mg concentrations were higher with drip than with overhead irrigation. Concentrations of N and K were higher with concurrent than with residual fertilization and increased with an increase in application rate. In contrast, concentrations of P, Ca, and Mg decreased with concurrent fertilization and an increase in application rate.
Growth Suppression and Raised Tissue Cl- Contents in NH4+-fed Marigold, Petunia, and Salvia
Authors: Jeong Byoung Ryong , Lee Chiwon W.
Published: January 2019

Ageratum houstanianum Mill. (tolerant), Tagetes patula L. (French marigold, very sensitive), Petunia hybrida Vilm. (sensitive), and Salvia splendens F. Sellow et. Roem & Schult. (very sensitive) were grown with NO3-, NH4+NO3-, or NH4+ as the N source to examine whether NH4+-related growth suppression (NH4+-RGS) in the NH, -sensitive species was associated with excessive Cl- absorption from the nutrient solution. Amounts of Cl- applied were 4 or 11 meq·liter-1 (Expt. 1) and 0 or 4 meq·liter-1 (Expt. 2). When fertilized with NH4+ as a sole N source, marigold, petunia, and salvia showed NH4+-RGS symptoms with yield reduction regardless of altered Cl- levels in the nutrient solution, while ageratum showed no such symptoms. When grown with NH4+ solution, these sensitive plants had shoot fresh and dry weight reductions of ≈ 50% compared to those grown with the NH4+ + NO3- solution. Plants fertilized with NH4+ showed more severe NH4+-RGS symptoms when grown in rockwool (RW) than in peat-lite mix (PL). The NH4+-grown plants contained more NH4+ and much more Cl- in the tissue than plants fertilized with NO3- or NH4+ + NO3-, irrespective of the Cl- level in the nutrient solution. However; NH4+-RGS symptoms in marigold, petunia, and salvia appear to be caused by the uptake of NH4+, but not in association with Cl- from the nutrient solution.
Rednecked Cane Borer Galling Affects Blackberry Growth and Yield
Authors: Johnson Donn T.
Published: January 2019

Thorny erect blackberries (Rubus spp.) were evaluated for yield and cane vigor as affected by galls produced by the rednecked cane borer Agrilus ruficollis (F.). Galling in `Cherokee' significantly (P < 0.001) decreased the count of berries and the weight of berries per centimeter of live cane. Winter injury, water stress, and nutritional stress induced by galls increased the amount of dead wood per cane. Galling did not affect the length of live laterals per `Cherokee' cane. For `Comanche' and `Cheyenne', the amount of dead wood per cane increased as gall counts increased. In contrast, the length of live laterals per cane increased for `Comanche' and decreased for `Cheyenne' as gall counts increased. The weight of berries and the count of berries per centimeter of live cane for `Comanche' and `Cheyenne' were not related to the count of galls. Of the four cultivars, `Shawnee' produced the most berries and greatest weight of berries per centimeter of live cane when canes were free of galls. Conversely, when galls exceeded two per cane, `Shawnee' yielded least, followed by `Comanche', `Cheyenne', and `Cherokee'.
Water Relations of Fruit End Cracking in French Prune (Prunus domestica L. cv. French)
Authors: Milad Rémy E. , Shackel Kenneth A.
Published: January 2019

Irrigation of previously water-stressed French prune trees is known to induce fruit end cracking. The relationships between end cracking, water relations, and mechanical properties of the skin of French prune were studied as a function of irrigation regimes under field conditions. Water stress resulted in the accumulation of solutes in the fruit of nonirrigated trees. A gradient in osmotic potential (ΨS) existed along the vertical axis of fruit from all treatments; ΨS was always lower at the stylar than stem end. Irrigation of previously water-stressed trees (irrigated-dry treatment) resulted in ΨS gradients exceeding those of all other treatments. Moreover, estimated turgor (ΨP) at the stylar end of the fruit increased 2-fold within 24 hours after irrigation. These changes were accompanied by the onset of fruit end cracking, and neither the well-watered controls nor the continuously droughted fruit exhibited such changes. During the 24 hours following irrigation, the overall ΨS of irrigated-dry treatment fruit was diluted by the same amount as the calculated increase in fruit volume. However, during the same period, ΨS at the stem end of the fruit showed more dilution than expected, and ΨS at the stylar end of the fruit concentrated, indicating a redistribution of solutes. There were no differences in skin mechanical properties along the fruit vertical axis and, hence, this could not have accounted for the observed changes in ΨS and ΨP. Thus, when previously stressed French prune trees were irrigated, the overall recovery in water potential (Ψ) and the subsequent movement of solutes to the stylar end of the fruit resulted in apparently excessive turgors in this region and hence the observed pattern of end cracking.
Foliar Raffinose and Sucrose in Four Conifer Species: Relationship to Seasonal Temperature
Authors: Hinesley L.E. , Pharr D.M. , Snelling L.K. , Funderburk S.R.
Published: January 2019

Foliar raffinose and sucrose concentrations in eastern white pine (Pinus strobus L.), eastern redcedar (Juniperus virginiana L.), Leyland cypress (×Cupressocyparis leylandii Dallim.), and Virginia pine (Pinus virginiana L.) were measured monthly over 2 years. During cold weather, foliage of white pine and redcedar contained higher concentrations of raffinose and sucrose than did Leyland cypress and Virginia pine. Rafflnose concentrations were highest during winter and were best correlated with the frequency of occurrence of daily minima ≤ 1.7C during the 30 days before sampling. Sucrose concentrations, which also reached maximum levels during the winter, were best correlated with the frequency of occurrence of daily minima ≤ 7.2C in the prior 30 days. Sucrose concentrations were relatively high during fall and spring. Raffinose and sucrose concentrations increased in response to recurring low temperature, with correlations highest for raffinose.
Breeding Strawberries at the Decaploid Level
Authors: Ahmadi Hamid , Bringhurst Royce S.
Published: January 2019

Two groups of Fragaria decaploid (2n = 70, x = 7) breeding populations were studied. The first was derived from pentaploid (2n = 35) and hexaploid (2n = 42) natural or synethetic interspecific hybrids between octoploid (2n = 56) F. chiloensis (L.) Duch. or F. virginiana Duch. both from California, and various Fragaria diploids (2n = 14). Their chromosome number was doubled with colchicine or through the naturally generated unreduced gametes. They were selfed repetitively, intercrossed, and open pollinated. Gametic viability of the hermaphroditic and female decaploid hybrids exceeded 50%. The hybrids exhibited heterosis for runner production and vegetative vigor. Fragaria chiloensis bred for large fruit and desirable fruit qualities, and, in combination with diploids F. vesca L. and F. viridis Duch., resulted in hybrids that produced a single early spring crop and prolific runner production throughout the summer. Fragaria virginiana L. derivatives were characterized by high pollen fertility, and by day neutrality (photo-insensitivity). Together, they may contribute genes for adaptation to various regions and climates of the world and for pest and disease resistance. The second and most important group of decaploids involved here were those derived from hybrids between day-neutral octoploid cultivars (F. ×ananassa) crossed to F. vesca or F. viridis. This group of decaploids combined the genomes of the best octoploid cultivars with those of the above diploid species: facilitating the incorporation of genes responsible for high yield, day neutrality, and excellent fruit quality into the decaploid strawberries.
Expression of a Chimeric Tobacco Peroxidase Gene in Transgenic Tomato Plants
Authors: Lagrimini L. Mark , Vaughn Jill , Finer John , Klotz Karen , Rubaihayo Patrick
Published: January 2019

Tomato plants (Lycopersicon esculentum cv. OH 7814) were transformed via Agrobacterium tumefaciens with a chimeric tobacco anionic peroxidase (EC 1.11.1.7) gene joined to the cauliflower mosaic virus (CaMV) 35S promoter. Transgenic plants obtained by selection on kanamycin were found to have more than five times the total leaf peroxidase activity of control plants. Transformed tomato plants chronically wilted upon reaching sexual maturity. Two independently selected transformants were self-fertilized, and progeny were obtained that were homozygous for the foreign gene. Isoelectric focusing gels stained for peroxidase activity revealed a new tomato leaf peroxidase isoenzyme with a pI of 3.75, which is similar to that seen in Nicotiana sylvestris L. Mature tomato fruit were found to have up to 1600-fold higher peroxidase activity in transformants expressing the tobacco anionic peroxidase (TobAnPOD) than control plants. Tissue blots showed the tobacco enzyme evenly distributed throughout the tomato fruit tissue. Progeny plants possessing the tobacco peroxidase gene (now homozygous) showed stunting, and fruit size was reduced by >80%. However, fruit set was normal and the rate of ripening was not altered from control plants. Fruit from transformed plants were found to have normal pigmentation, but the soluble solids concentration was 400% higher than in control tomato fruit. This result was predicted from the peroxidase-induced water stress. Possible roles for the tobacco anionic peroxidase in growth, development, and stress resistance are discussed.
Micropropagated Raspberry Plant Establishment Responds to Weed Control Practice, Row Cover Use, and Fertilizer Placement
Authors: Trinka David L. , Pritts Marvin P.
Published: January 2019

Micropropagated (MP) raspberries (Rubus idaeus L. var. idaeus) are sensitive to moisture and temperature extremes and to certain preemergent herbicides used at transplanting. We examined fertilizer placement and row covers in conjunction with various weed management strategies to identify beneficial practices for newly planted, MP primocane-fruiting `Heritage' raspberries. Uncontrolled weed growth during plant establishment inhibited raspberry cane growth and production into the second and third growing seasons. Handweeding and herbicide treatments successfully controlled weeds, but soil moisture was apparently insufficient for optimum growth of the MP raspberries when these treatments were imposed, even with normal rainfall in early summer and drip irrigation in late summer. Polyethylene and straw mulches during the establishment year provided both weed control and adequate soil moisture, resulting in more cane growth in the first and 2nd year, and higher yields the 2nd year. Primocane density after the third growing season still was influenced by first-year weed management practices. Raspberry plants responded best to straw mulch without row covers as plant growth was better in both years. Canes were thicker, yields were higher, and a larger portion of the total crop was harvested early. Row covers were beneficial only in bare-soil treatments, and method of fertilizer placement had no effect on any measured variable. Mulching newly transplanted MP raspberries is an alternative to herbicide use that also provides physiological benefits to the plant through microclimate modification.
Heat Tolerance and Holding Ability in Broccoli
Authors: Heather D.W. , Sieczka J.B. , Dickson M.H. , Wolfe D.W.
Published: January 2019

Forty hybrid broccoli [Brassica oleracea L. (Italica Group)] accessions were screened for heat tolerance and holding ability over three planting dates in 1988 at the Long Island Horticultural Research Laboratory in Riverhead, N.Y. Holding periods were quantified using the number of consecutive days between the time individual heads reached 10 cm diameter and cutting, which occurred when the sepals had fully expanded and had just begun to separate. In 1989 and 1991, heat stress was applied at various weeks during maturation to determine the most sensitive stage or stages of plant development in terms of reduction in holding period and head weight. Field studies and heat stress experiments indicate that heat stress may be most critical during the time the immature inflorescence measures 5 to 10 mm in diameter. This stage corresponds to ≈ 3 weeks before harvest for summer plantings in the northeastern United States.
Cell Wall Modification during Ripening of `Keitt' and `Tommy Atkins' Mango Fruit
Authors: Mitcham Elizabeth J. , McDonald Roy E.
Published: January 2019

`Keitt' and `Tommy Atkins' mango (Mangifera indica L.) fruit were evaluated for selected ripening criteria at six ripening stages, from mature green to overripe. `Tommy Atkins' mangos developed more red and yellow pigmentation (CIE a* and b*) in peel and mesocarp tissues than `Keitt'. The outer mesocarp of `Keitt' remained firm longer than `Tommy Atkins', and the inner mesocarp was softer than the outer at each stage in both cultivars. Cell wall neutral sugars, particularly arabinosyl, rhamnosyl, and galactosyl residues, decreased with ripening in both cultivars. `Keitt' had more loosely associated, chelator-soluble pectin, accumulated more soluble polyuronides, and retained more total pectin at the ripe stage than `Tommy Atkins'. Both cultivars had similar polygalacturonase (EC 3.2.1.15) activity which increased with ripening. The amount and molecular weight of cell wall hemicellulose decreased with ripening in both cultivars. These data indicate that enzymatic and/or nonenzymatic processes, in addition to polygalacturonase activity, are involved in the extensive softening of mango fruit.
Respiration Rate of Blueberry in Modified Atmosphere at Various Temperatures
Authors: Song Yoonseok , Kim Hyun Ku , Yam Kit L.
Published: January 2019

Respiration rates of three blueberry (Vaccinium corymbosum L.) cultivars (Coville, Blueray, and Jersey) were measured as a function of O2, CO2, and temperature using the closed system method. The data conformed well to a recently proposed Michaelis-Menten type respiration (r) model (r = Vm [O2]/{Km + (1 + [CO2]/Ki)[O2]}), where Vm was maximum respiration rate, Km was Michaelis-Menten constant, and Ki was inhibition constant. The model predictions were used to examine the behavior of respiration rates. In general, the respiration rates decreased with increasing CO2, but were little affected by changes in O2. `Coville' blueberries had the highest respiration rate, followed by `Blueray' and `Jersey'. The temperature dependence of the respiration rates followed the Arrhenius relationship.
Alteration of Cellular Compartmentation and Membrane Permeability to Sugars in Immature and Mature Apple Fruit
Authors: Yamaki Shohei , Ino Migifumi
Published: January 2019

A study was conducted to determine the distribution of sugars in vacuoles, cytoplasm, and free space in apples (Malus domestica Bork) picked at the immature and mature stage of maturity. The volumes of free space and air space were 13.4% and 14.5%, respectively, in immature fruit, and 14.6% and 25.6%, respectively, in mature fruit. The inner cellular volume (vacuole + cytoplasm) was 72% and 60% for immature and mature fruit, respectively. About 90% of each sugar (glucose, fructose, sucrose, and sorbitol) was found in the vacuole. The concentration of total sugar in the inner cell or free space was 326 or 128 mm each in immature fruit and 937 or 406 mm each in mature fruit. Permeability to sugars across the plasma membrane and tonoplast also increased with fruit maturation, 7- to 30-fold for the tonoplast and 4- to 5-fold for the plasma membrane in mature compared to immature fruit. Cells in immature fruit apparently enlarge through higher turgor pressure from sequestering of sugars into vacuoles, and cease to enlarge in mature fruit as the amount of sugar unloading into the fruit is reduced due to the accumulation of sugar in the free space or cytoplasm.
Gibberellins and Temperature Influence Long-day Floral Initiation in Poinsettia
Authors: Evans Michael R. , Wilkins Harold F. , Hackett Wesley P.
Published: January 2019

Exogenous foliar spray applications of gibberellic acid (GA3) applied at 7- or 14-day intervals providing 50 or 125 μg per plant inhibited long-day (LD) floral initiation in poinsettia [Euphorbia pulcherrima (Willd. ex. Klotzsch)]. Periodic application of GA3 resulted in an additional number of nodes being produced by the plant before floral initiation equivalent to the number of nodes over which GA3 was applied. Further, GA, application eliminated the nodal position dependence of the long-day node number (LDNN) of axillary meristems observed in control plants. It was concluded that GA3 application inhibited the inclusion of nodes into the LDNN count and thus inhibited ontogenetic aging of the meristem. Exogenous application of GA, also inhibited LD floral initiation, while application of GA4 had no effect. Application of GA7 delayed LD floral initiation, but plants did initiate cyathia by the termination of the experiment. All gibberellins increased the average internode lengths similarly. The gibberllin-biosynthesis inhibitors chlormequat and paclobutrazol had no effect on LD floral initiation when applied as single or multiple foliar sprays or as soil drenches, although heights and internode lengths were reduced by application of the inhibitors. The LDNN of plants grown at 31C was significantly higher than of plants grown at 16, 21, or 26C. All plants eventually initiated cyathia regardless of temperature. When plants were grown under a range of day/night temperatures, an increase in the LDNN occurred only when plants were grown at 31C during the day. Chemical names used: 2-chloroethyl-trimethyl-ammonium chloride (chlormequat); (+/-)-(R*,R*)-β -(4-chlorophenyl)methyl-α -(1,1-dimethylethyl)-1-H-1,2,4-triazole-1-ethanol (paclobutrazol).
The Genetics of the Juvenile Phase in Avocado and its Application for Breeding
Authors: Lavi Uri , Lahav Emanuel , Degani Chemda , Gazit Shmuel
Published: January 2019

Avocado (Persea americana Mill.) progeny that originated from 11 crosses (both self-pollinations and crosses between cultivars) were evaluated for the length of their juvenile period. Time to first flowering, “flowering age,” and time to first fruit production, “fruiting age,” were recorded for each progeny. The mean values for both ages, the sd, and the progeny distribution were calculated. Significant statistical differences in flowering age and fruiting age between various progeny populations were detected. No differences were detected between self-pollinated plants and crosses. The time until first flowering was found to be the limiting factor in evaluation of seedlings.
Growth and Mineral Composition of Newly Planted Apple Trees Following Fertigation with N and P
Authors: Neilsen G.H. , Parchomchuk P. , Wolk W.D. , Lau O.L.
Published: January 2019

Newly planted `Jonagold' and `McIntosh' apple (Malus domestica Borkh.) on M.26 fertigated with Ca(N03)2 showed increased early tree vigor and leaf Ca concentration but decreased leaf Mg and Mn compared to trees fertigated with urea or NH4N03. Fertigation with P increased early tree vigor, leaf and fruit P concentration, and decreased leaf Mn in the first year relative to a single planting hole application of granular P. Increased fruit Ca concentration in `Jonagold' in one year was associated with the use of Ca(N03)2 and fertigation of P. Fruit quality was generally unaffected by the experimental treatments.
A Two-dimensional, Dynamic Model for Root Growth Distribution of Potted Plants
Authors: Chen De-Xing , Lieth J. Heinrich
Published: January 2019

A two-dimensional mathematical model was developed to describe the time course of root growth and its spatial distribution for container-grown plants, using chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] as the model system. Potential root growth was considered as consisting of several concurrent processes, including branching, extension, and death. Branching rate was assumed to be related sigmoidally to existing root weight density. Root growth extension rate was assumed to be proportional to the existing root weight density above some threshold root weight density in adjacent cells. The senescence rate of root weight density was assumed to be proportional to existing root mass. The effects of soil matric potential and temperature on root growth were quantified with an exponential function and the modified Arrhenius equation, respectively. The actual root growth rate was limited by the amount of carbohydrate supplied by the canopy to roots. Parameters in the model were estimated by fitting the model to experimental data using nonlinear regression. Required inputs into the model included initial root dry weight density distribution, soil temperature, and soil water potential data. Being a submodel of the whole-plant growth model, the supply of carbohydrates from canopy to roots was required; the total root weight incremental rate was used to represent this factor. Rather than linking to a complex whole-plant C balance model, the total root weight growth over time was described by a logistic equation. The model was validated by comparing the predicted results with independently measured data. The model described root growth dynamics and its spatial distribution well. A sensitivity analysis of modeled root weight density to the estimated parameters indicated that the model was more sensitive to carbohydrate supply parameters than to root growth distribution parameters.
Polyethylene Mulch Stimulates Early Root Growth and Nutrient Uptake of Transplanted Tomatoes
Authors: Wien H.C. , Minotti P.L. , Grubinger V.P.
Published: January 2019

Tomato (Lycopersicon esculentum Mill.) plants grown on polyethylene (PE) mulch in New York State frequently have more branches and increased mineral nutrient uptake and yield than plants not mulched. In four field experiments conducted on a silt loam soil, clear PE mulch stimulated root extension shortly after transplanting. One week after transplanting, roots were significantly longer for mulched than for unmulched plants in all four experiments, whereas aboveground dry matter differences did not become significant until 14 days after transplanting in two of four trials. Mulching increased branching, hastened flowering on basal branches, and increased concentration of major nutrients in the aboveground parts. In the field, stimulation of aboveground growth due to mulch might be brought about by warming of the stem by air escaping from the planting hole in the mulch. However, an experiment with black, white, or clear mulch, in which the planting hole was either left uncovered or covered with soil, showed no effect of hole closure on branching even though air temperature near the stem was increased when holes were left uncovered. The results taken together imply that the increased aboveground growth observed with mulching is a consequence of enhanced root growth and nutrient uptake.
Relationship between a Reduced Aroma Production and Lipid Metabolism of Apples after Long-term Controlled-atmosphere Storage
Authors: Brackmann A. , Streif J. , Bangerth F.
Published: January 2019

`Golden Delicious' apples (Malus domestica Borkh.) harvested at the preclimacteric and climacteric stages of ripening were stored for up to 8 months at 1C in air and under various controlled atmosphere(s) (CA), including ultralow oxygen (ULO) storage conditions. Aroma volatiles were measured at 2-month intervals in fruit ripened for 10 days at 20C. Fruits harvested at the climacteric stage produced more volatiles during all storage conditions than preclimacteric fruit. All CA storage treatments suppressed aroma production compared to cold storage. The greatest reduction was found under ULO (1% O2) and high CO2 (3%) conditions. A partial recovery of aroma production was observed when CA fruits were subsequently stored for 14 days under cold storage conditions. Suppression of aroma production under ULO conditions seems to be related to low fatty acid synthesis and/or degradation, and is restricted to volatiles having a straight C chain. Production of branched C-chain aroma compounds was suppressed by high CO2 concentrations. The reduced capacity of aroma production during shelf life after ULO storage is confined to apple cultivars producing mainly ester compounds with a straight C-chain, e.g., `Golden Delicious'.
Accumulation of the Components of Total Solids in Ripening Fruits of Tomato
Authors: Young T.E. , Juvik J.A. , Sullivan J.G.
Published: January 2019

To identify qualitative and quantitative chemical variation in tomato fruit dry matter, crosses were made between the high soluble solids concentration (SSC) line LA 1501 (6.3% SSC when red-ripe) and the nearly isogenic commercial tomato cultivar VF 145B-7879 with a lower SSC (4.4% when red-ripe). Fruit samples from the parents and the reciprocal F1 hybrids were collected at 3-day intervals, from 25 to 52 days after anthesis, to evaluate the accumulation of various quality components throughout the development of the fruit from immature-green to red-ripe stage. Fructose and glucose concentrations, titratable acidity, pH, and percent dry weight (pulp and serum) were determined for each sample on a fresh basis. Fruit maturity was evaluated by puree color using Hunter `a' colorimeter values. Changes in most of the chemical constituents of the fruit were found to regress linearly with changes in fruit color. Regression of puree color against fruit SSC, and fructose, glucose, and total sugar concentrations described more of the observed variability in these components than days after anthesis, indicating that Hunter `a' colorimetric values provide a more precise measurement of fruit physiological age. The variation between the parents in fruit dry matter was found to be primarily due to differences in SSC. The ratio of fruit soluble to total solids concentration increased 23.7% in LA 1501 (from 61.6% to 85.3%) throughout ripening compared to-an increase of only 8.9% (from 66.3% to 75.2%) in `VF 145B-7879'. At the red ripe stage, LA 1501 possessed a 44% higher SSC than `VF 145B-7879'. Differences in fructose and glucose accounted for 41% of the variation in SSC between the two lines. An unidentified component(s) was responsible for the residual variation. Application of the genetic and physiological information generated from this study can be used to isolate and select for genes controlling accumulation of tomato fruit dry matter.
Seed Germination of Three Flower Species following Matriconditioning under Various Environments
Authors: Madakadze Rufaro , Chirco Ellen M. , Khan Anwar A.
Published: January 2019

The effect of preplant conditioning on germination of three flower seeds, Bupleurum griffithii (Tourn.) L. (thorough-wax), Ammi majus L. (greater ammi), and Cirsium japonicum DC. Per. (Japanese thistle), were studied. Seeds were osmoconditioned with -1.2 MPa polyethylene glycol 8000 (PEG) solution and matriconditioned with moist Micro-Cel E (ratio of 2 seed: 0.6 carrier: 3 water by weight for Bupleurum and Cirsium; for Ammi the ratio was 2:1.4:6) and moist expanded vermiculite #5 (the ratio was of 2 seed: 0.6 carrier: 2 water for Bupleurum). In some treatments, water in the matriconditioning mixture was replaced with 1 mm gibberellin A4+7 (GA) or 0.2 % KNO3. In Bupleurum, matriconditioning with Micro-Cel E was generally superior to matriconditioning with vermiculite or osmoconditioning with PEG. A 4-day matriconditioning with Micro-Cel E and germination in the dark reduced the period required for 50% (T50 of final germination by 4 days and improved the percentage germination at 20C (73 % vs. 95%), compared to nonconditioned seeds germinated in the dark. The treatment also improved the percentage of germination at 15C (68% vs. 95%) and effectively removed the thermoinhibition of germination at 25 and 30C. Germination was inhibited to a greater extent for seeds kept in the light during matriconditioning and germination than for seeds conditioned in darkness and germinated in light or conditioned in light and germinated in darkness. Nitrate added during conditioning in light prevented inhibition of germination, provided seeds were kept in darkness during germination. In A. majus, germination in light after 4-day matriconditioning reduced the T50 by ≈2 days, but had little effect on percentage germination. Both GA and irradiance equally promoted germination when added during osmoconditioning, with nitrate having no effect. In C. japonicum, a 4-day matriconditioning or a 7-day osmoconditioning reduced the T50 of germination by -2 days and improved the percentage germination to some extent. Neither irradiance nor nitrate had any significant effect.
Root Development Patterns in Field Grown Peach Trees
Authors: Glenn D.M. , Welker W.V.
Published: January 2019

The objective was to determine the interrelationship between root growth and plant available soil water (PAW) for young, nonbearing, and mature fruiting peach trees (Prunus persica L. Batsch) over 7 years. Root growth observed with minirhizotrons indicated that young, nonbearing trees developed new white roots throughout the growing season. The pattern of new white root growth became bimodal when the trees fruited. White root production in mature trees appeared in March, preceding budbreak, ceased in June, resumed following fruitremoval in August, and persisted through January. The appearance of white roots was inversely related to the presence of fruit and was not correlated to PAW levels in the 0 to 90 cm depth. The lack of root growth response to PAW levels was attributed to a root system that penetrated the soil to depths beyond our zone of sampling. Circumstantial evidence suggests that deep roots help maintain the surface root system when the surface soil dries.
Chloroplast DNA Diversity in Raspberry
Authors: Moore Patrick P.
Published: January 2019

The relationships among raspberry (Rubus spp.) clones were investigated using southern hybridization. Total DNA from 22 clones were digested with Bam III and Eco RI and hybridized with two sequences from a Pst I tomato (Lycopersicon esculentum Mill.) chloroplast library. A total of 40 different restriction fragments were distinguished for the four enzyme probe combinations. These fragments distinguished seven groups of clones with members of each group having identical fragment patterns. Clones with R. idaeus L. maternal ancestry were distinct from those with R. occident&s L. or R. parvifolius L. ancestry. Differences were detected between R. idaeus vulgatus Arrhen. and R. idaeus strigosus (Michx.). No commercial cultivars had chloroplast DNA patterns that were the same as an accession of the R. idaeus strigosus subspecies.
Preharvest Watersprout Removal Influences Canopy Light Relations, Fruit Quality, and Flower Bud Formation of `Redskin' Peach Trees
Authors: Myers Stephen C.
Published: January 2019

Three separate blocks of mature, nonirrigated trees of `Redskin' peach [Prunus persica (L.) Batsch] on `Lovell' rootstock, all uniformly dormant-pruned to an open center, were summer pruned 43, 31, and 21 days before harvest (DBH) in 1988, 1989, and 1990, respectively, and compared to unpruned controls in respect to light penetration and fruit characteristics. Summer pruning consisted of watersprout removal (WSR), selectively including all shoots more upright than 45° on scaffolds from the crotch to the top of the tree. WSR increased photosynthetic photon flux density (PPFD) in the center of the fruiting zone of the canopy to four times the level measured in unpruned trees, but only to an average of 16% of above-canopy PPFD. The greatest effect of WSR on PPFD occurred in the center of the tree, increasing light levels from <10% full sun before WSR to 90% full sun following WSR. WSR resulted in higher PPFD in the center of the tree for the remainder of the season. Fruit ground color and red pigmentation were not affected by WSR. WSR increased the percentage of fruit that exceeded 62 mm in diameter and decreased the percentage of fruit < 55 mm in diameter in 1988 and 1990. In 2 of the 3 years, WSR increased flower count per cm shoot length in the fruiting zone of the canopy.
Respiratory Oxygen Response and Respiratory Quotient of Apple Stem Sections during Chilling
Authors: Young Eric
Published: January 2019

During natural leaf abscission, 2-year-old potted apple trees (Malus domestica Borkh. cv. MM.111 EMLA) were placed in a room at 6C for chilling [0,600, 900, or 1400 chilling units (CU)]. After each chilling treatment, respiration of shoot segments was measured as CO2 evolved and O2 consumed at 22C in several O2 concentrations. Respiration increased with oxygen concentration after all CU treatments. Carbon dioxide evolved at the several O2 levels did not show a pattern related to CU, but O2 consumed decreased at a decreasing rate with additional CU. Respiratory quotient was <1 at 0 and 600 CU and equal to 1 at 900 and 1400 CU, indicating a possible shift in respiratory substrate with chilling.
Isolation and Initial Characterization of cDNAs for mRNAs Regulated during Peach Fruit Development
Authors: Callahan Ann M. , Morgens Peter H. , Cohen Reuben A.
Published: January 2019

Peach [Prunus persica (L.) Batsch] cDNA libraries have been constructed from RNA isolated from immature (30 days after bloom) and ripe fruit. cDNA clones of interest have been identified by differential hybridization among the cDNAs of various peach cultivars or from several stages in fruit development. In addition, several clones were isolated by low stringency hybridizations with oligonucleotides derived from a tomato polygalacturonase cDNA sequence and a cucumber peroxidase amino acid sequence. The pattern of accumulation of the corresponding mRNAs during fruit development was examined by RNA gel-blot analyses in the commercial cultivar Suncrest. Three cDNA clones, pch201, pch307, and pch313, were related to mRNAs that accumulate during the softening stage of fruit development. cDNA clones pchl03, pch205, and pch306 were related to an mRNAs that increase in abundance throughout development, with maximum levels in ripe fruit. cDNA clones pch104 and pch202 were related to mRNAs that exhibit maximum abundance in midfruit development, and clone pch108 was related to mRNA that decreases as the fruit matures. Southern analyses indicated that seven of the cDNAs are represented by only a few genes, while pch104 detects a repetitive family, and pch307 detects a small family of genes. These clones will provide the initial source of genes to manipulate and affect fruit development.
Sinapine Leakage from Brassica Seeds
Authors: Taylor A.G. , Paine D.H. , Paine C.A.
Published: January 2019

The purpose of this project was to study factors that influence the leakage rate and develop methods to enhance leakage of sinapine from Brassica seeds. Six seedlots (two seedlots of one cultivar each of cabbage (Brassica oleracea L., Capitata group), broccoli, and cauliflower (B. oleracea L., Botrytis group) were studied. Leakage was quantified spectrophotometrically by measuring the absorbance of the soak water at 330 nm. The onset of sinapine leakage was determined from single seeds by the visual presence (yellow soak water) caused by soaking seeds in a biological buffer adjusted to pH 10. The leakage pattern from heat-killed seeds of all seedlots was sigmoidal with a distinct lag phase followed by a rapid efflux and final slower rate. The duration of the lag phase and the total amount of sinapine leaked after 24 hours was not the same for all seedlots after adjusting for seed count, seed weight, or sinapine content. Therefore, another factor was responsible for differences measured in leakage. Embryos or seeds with cracked testas leaked faster than intact seeds, and the leakage pattern without testa integrity was biphasic. From these studies, we conclude that the testa was a major factor regulating sinapine leakage. Pretreating heat killed seeds, with up to 1.0% NaOCl for 10 minutes, accelerated the onset of leakage. The time for 50 percent of the seeds to leak (T50) decreased as NaOCl concentration increased. Leakage uniformity, as measured by the standard deviation of the distribution, generally increased as NaOCl concentration increased. The sigmoidal leakage pattern from heat-killed Brassica seeds may be attributed to seedcoat cracking associated with imbibitional swelling. A NaOCl pretreatment may have increased the permeability of the testa and, thereby, enhanced the leakage rate.
Estimates of Marketable Yield in Asparagus using Fern Vigor Index and a Minimum Number of Daily Harvest Records
Authors: Wolyn D.J.
Published: January 2019

Fern vigor indices and estimates of percent marketable yield (PMY) were used to determine alternative measures of asparagus (Asparagus officinalis L.) marketable yield. Total yield was highly correlated (0.75 ≤ r ≤ 0.91), and marketable yield was not correlated with fern vigor indices. The products of fern vigor indices and seasonal PMYs were highly predictive of marketable yield (r 20.95). When the products of each daily PMY estimate and fern vigor index for the same season were determined, then averaged over years, <30% of correlations with marketable yield were ≥0.90, and r values varied considerably during the season. The products, averaged for 2 years, of fern vigor index and mean PMY estimated from combinations of three harvest dates during the season, except from the first harvest week, were associated with marketable yield. For the 40 3-day average estimates of PMY examined, 95% of Pearson correlation coefficients were ≥0.90 and all were ≥0.88. Thus, fern vigor index and PMY estimates from three harvest dates may be used to predict temperate zone marketable yield, decreasing labor requirements for yield trials, and facilitating evaluation of many experimental hybrids.
Ice Distribution in `Earliglow' Strawberry Crowns and Tissue Recovery following Extracellular Freezing
Authors: Warmund Michele R.
Published: January 2019

`Earliglow' strawberry (Fragaria xananassa Duchesne) plants were frozen to -5 or -50C to examine the distribution of ice in the crowns. Anatomical studies were also performed to characterize tissue growth in a greenhouse at 4, 8, and 15 weeks after freezing to -5C. Ice masses observed in fresh crown tissue corresponded to the presence of extracellular tissue voids in specimens fixed for scanning electron microscopy (SEM). Voids were present near the peduncle and adjacent to the vascular system in crown tissue. After plants were grown in the greenhouse, cell division and enlargement were observed near the voids in crowns subjected to -5C. By 15 weeks after freezing, a few small extracellular voids remained in the crowns. Tissue voids were also present in crowns of plants frozen rapidly to -50C and subsequently thawed. Cells in the crown of these plants were intact and did not appear collapsed after exposure to -50C, a lethal temperature.
Influence of Inverse Day/Night Temperature on Ozone Sensitivity and Selected Morphological and Physiological Responses of Cucumber
Authors: Agrawal Madhoolika , Krizek Donald T. , Agrawal Shashi B. , Kramer George F. , Lee Edward H. , Mirecki Roman M. , Rowland Randy A.
Published: January 2019

Cucumis sativus L. (cvs. Poinsett and Ashley) plants were grown from seed in a growth chamber at a +10C (28/18) or a -10C (18/28) difference (DIF) between day temperature (DT) and night temperature (NT) on a 12-hour photoperiod for 24 days prior to ozone (O3) fumigation (3 hours at 0.5 umol·mol-1). Negative DIF, compared to +DIF, reduced plant height, node count, fresh weight, dry weight, and leaf area in both cultivars. Photosynthetic rate (Pn), chlorophyll concentration, and variable chlorophyll fluorescence (Fv) were lower and O3 injury and polyamine concentrations were higher at -DIF than at +DIF. Ozone fumigation generally increased leaf concentration of polyamines and reduced Pn, stomatal conductance, and chlorophyll fluorescence. `Poinsett' generally had a higher specific leaf mass and higher concentrations of chlorophyll a and polyamines than did `Ashley', but there was no cultivar difference in O3 injury, growth response, Pn, or stomatal conductance.
Field Plot Technique Affects Snap Bean Yield Evaluation
Authors: Sills Gavin R. , Nienhuis James
Published: January 2019

The interactive effects of genotypes, plant population densities, and harvest methods on snap bean (Phaseolus vulgaris L.) yield evaluation were investigated using a split-split plot factorial arrangement of treatments at two locations Six snap bean processing cultivars were grown at 5.5, 11, and 22 plants/m2 and harvested either by machine or by hand. Each' of three commercial seed companies provided two cultivars, one of which was described as “good” and the other as “poor” for machine harvesting. Genotype × harvest method interactions were not significant for pod count, but were significant when yield was evaluated as pod weight. This latter interaction was explained by a single-degree-of-freedom contrast of genotypes × (“good” vs. “poor” harvestability). Genotype × density and genotype × density × location interactions were significant for both pod count and weight. The density × harvest method interaction was nonsignificant for both yield variables. These results suggest that breeders can evaluate yield of genotypes using either hand or machine harvest but should use plant population densities appropriate to commercial production. Optimum plot size for snap bean yield evaluations at these locations under the various conditions imposed were estimated.