bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors Affecting Photosynthesis, Productivity, and Yield
Authors: Kennedy Robert A. , Fox Theodore C. , Loescher Wayne H. 
Published: September 2022

Abstract
The rate and efficiency of photosynthesis (PS) is unquestionably one of the primary determinants of crop yield. Yet, as this symposium illustrates, many other factors contribute to plant productivity. Indeed, the exact relationship between PS rate and yield remains undefined. For several years we have now been interested in factors that affect PS rate in both C3 and C4 plants, not only within the plant, but also external to it. Internal factors affecting PS that will be discussed include leaf age, leaf canopy, photorespiration, stage of plant development (including both vegetative and reproductive phases), and the occurrence of little-recognized metabolic pathways such as polyol synthesis and transport. External factors that affect PS, in addition to obvious environmental determinants such as temperature, light, and water, include the seasonal growth cycle. While we still do not understand how all of these factors interact to affect yield, we are beginning to understand their singular effects. Control of these factors, once thought to be within reach even before the advent of biotechnology, remains likely, but distant.
Yield and Environmental Stress
Authors: Boyer J. S. 
Published: September 2022

Abstract
Plant development is affected by physical stresses of all kinds. The most sensitive time is during anthesis and early fruit growth, when reproductive structures may fail to develop or embryos may abort. Water limitation can cause both effects, and explanatory theories are based on turgor, photosynthate availability, or hormonal relationships. Data will be presented for maize to show that failure of the female flower accounts for reproductive sensitivity to limited water. There is a correlation between sensitivity and the availability of reserve photosynthate that overrides the effects of turgor. The failure of the female flower is attributable partly to inhibited silk growth and partly to arrested development of the entire seed after fertilization takes place.
History and Evolution of Fruit Crops
Authors: Roach Frederick A. 
Published: September 2022

Abstract
The discovery in Anatolia (western Turkey) of carbonized remains of apples (Malus P.) and at Swiss prehistoric sites of apples, walnuts (Juglans regia L.), bullace (Prunus insititia L.), sweet cherry (Prunus avium L.), and European grapes (Vitis vinifera L.) dating back to 6500 bc shows that man had been collecting and using wild fruits as food for many thousands of years (ref. 1, p. 2 and 3). In Britain, the pollen, wood, and fruits of hazel nut (Corylus avellana L.) frequently have been identified in postglacial deposits (ref. 1, p. 227). Hazel nut is indigenous throughout Europe, western Asia, North Africa, and the Caucasus; it has been suggested that the nuts provided a source of food later replaced by cereals (ref. 1, p. 226).
Molecular Markers as Aids for Germplasm Management and Use in Lycopersicon
Authors: Rick Charles M. 
Published: September 2022

Abstract
The following is a brief review of our investigations on problems of germplasm acquisition, analysis, maintenance, evaluation, and use in the Lycopersicon spp. It is based entirely on our published research; hence, only a synopsis will be presented and appropriate citations made to direct readers to full presentation of results and analysis.
Plant Germplasm Information Management System: Germplasm Resources Information Network
Authors: Perry Mark , Stoner Allan K. , Mowder Jimmie D. 
Published: September 2022

Abstract
A critically important aspect of the management of genetic resources is concurrent management of information pertinent to the preserved seeds or plant materials. An effective information system should: a) aid curators of collections by providing current information on inventories, exchange activities, etc.; b) perm it germplasm users to have rapid access to botanical and horticultural information about specific accessions and thereby encourage more effective use of plant germplasm; and c) allow personnel and organizations within and between countries to coordinate activities related to germplasm collection, exchange, and maintenance.
Genetic Considerations in Germplasm Collection and Maintenance: Introduction to the Symposium
Authors: Wehner Todd C. 
Published: September 2022

Abstract
Agricultural workers in many developed and developing countries are interested in collecting, evaluating, and maintaining germplasm of the crop species used in their particular agricultural production systems. However, opportunities to collect germplasm from centers of origin are being reduced as land is developed for agriculture, roads, housing, and other uses. Of the 240,000 angiosperm species thought to exist currently, it is estimated that 50,000 will become extinct by the year 2000 (2). The urgency to collect accessions of useful or potentially useful plant species is driving many germplasm institutions to expand. Thus, administrators of germplasm institutions are worried about their ability to maintain accessions unchanged for use in solving future problems (1). With such a large effort involved in the areas of germplasm collection and maintenance, it is important to use efficient collection methods, as well as proper means to preserve accessions.
Efficient Sampling from a Collection
Authors: Ryder Edward J. 
Published: September 2022

Abstract
The similar titles of Namkoong’s paper and this one invite comparison, not so much for their similarity as for the differences in sampling rationale. The main difference is in the nature of the populations that are being sampled. The population in the field is usually far away. Further, it is of unknown size and its genetic makeup and complexity can only be guessed.
Genetic Considerations in Germplasm Collection and Maintenance: A Summary
Authors: Wehner Todd C. 
Published: September 2022

Abstract
There are some 240,000 species of angiosperms in the world, of which 3000 or more have been used for food at one time or another. Of those, only 30 species are produced in quantities of at least 107 t/year, and 12 major crops supply the world's population with most of its plant- and animal-based calorie intake. Thus, humans are dependent for food on only a few species of the many thousands of flowering plants on the earth.
Methods of Screening Blueberry Seedling Populations for Drought Resistance
Authors: Erb W. A. , Draper A. D. , Swartz H. J. 
Published: September 2022

Abstract
Two methods of evaluating seedling drought resistance in Vaccinium (blueberry) spp. were examined. Twenty interspecific populations were greenhouse-grown and either matric-stressed in a dry 1 sand : 1 soil medium or osmotic-stressed in a nutrient solution containing polyethylene glycol (PEG). In both tests, population means were separated statistically by shoot damage ratings. The correlation (r = 0.46) between the two tests was positive and significant. Progenies of clones JU64 and JU62, which are sister seedlings (V. myrsinites Lamark × V. angustifolum Aiton), were the most drought-resistant. The soil screening test appeared more accurate because it grouped populations with common parentage. These tests indicated that the progenies differ in genetic capacity to resist drought.
Comparison of Two Nitrogen Fertilizer Sources for Highbush Blueberries
Authors: Brown Gerald R. , Wolfe Dwight , Rasnake Monroe 
Published: September 2022

Abstract
Highbush blueberries (Vaccinium corymbosum L.) were fertilized with equal amounts of nitrogen from ammonium sulfate (AMS) or sulfur-coated urea (SCU) for 6 years. The plots treated with SCU yielded significantly more than the AMS plots three out of the five harvest years. Except for plant size in 1984, treatments did not significantly affect berry size, plant survival, and other vegetative characteristics. Soil pH after 5 years was significantly lower on the AMS treatments than on the SCU-treated plots (5.4 vs. 5.7). The nutrient content of the leaf tissue did not differ significantly by fertilizer source. At the rate used in this study, SCU would be an acceptable nitrogen source for blueberries compared to AMS, but SCU is less effective in maintaining low soil pH.
Impact of Ten Spray Adjuvants on Leaf Gas Exchange of Pecan, Blueberry, Photinia, and Azalea
Authors: Andersen P. C. , Mizell R. F. , Knox G. W. 
Published: September 2022

Abstract
Three separate factorial experiments were designed to evaluate the effect of 10 adjuvants on net CO2 assimilation rate (A), leaf conductance to water vapor (g1), and transpiration rate (E) of pecan [Carya illinoensis (Wagenh.) C. Koch] ‘Elliott’, blueberry (Vaccinium ashei Reade) ‘Chaucer’, red top photinia (Photinia × Fraseri Dress), and azalea (Rhododendron × ‘Pink Ruffles’). Single applications of Bond, Leaf Act 80A, Nu-Film-17, Ortho X-77, Penetrator 3, Plyac, Sorba Spray ZNP, Sun Spray 7E, Triton CS-7, or Triton B-1956 at recommended rates did not affect A, g1, or E compared to a water spray. The main effect of plant species was highly significant in all three studies without adjuvant-species interactions. A significant adjuvant effect on A occurred with a second application of Nu-Film-17, Plyac, and Triton B-1956. The only significant effect, when treatments were analyzed separately by species, was that A of Plyac-treated blueberry was less than the control.
Effects of Soil Flooding on Leaf Gas Exchange of Seedling Pecan Trees
Authors: Smith Michael W. , Ager P. L. 
Published: September 2022

Abstract
Roots of 53-day-old pecan seedlings [Carya illinoensis (Wangenh.) C. Koch] were either not flooded or flooded by submerging pots to ≈2 cm above the soil line in containers of water. Leaf gas exchange measurements at 1000 µmol·s–1·m–2 photosynthetic photon flux, 340 µl·liter–1 CO2, and 27°C were made prior to flooding, after 1, 8, or 15 days of flooding, and 7, 14, or 21 days after flooding was terminated. Net CO2 assimilation rate (A) decreased 56% after 1 day of flooding. Flooding 9 or 15 days did not further depress A. Carbon assimilation of trees that had been flooded for 8 days and then returned to nonflooded soil for 7 days were similar to unflooded trees. In contrast, A of seedlings flooded 15 days did not regain the A of unflooded trees 14 days after flooding terminated. Transpiration rates (E) paralleled A in all treatments. Leaf conductance to CO2 (gL) was positively correlated with A (R2 = 0.94). However, leaf internal CO2 (Ci) concentration was not decreased by reduced gL. Water potential (ψl) and turgor potential (ψP) of leaves were higher when trees were flooded, but osmotic potential (ψs) was unaffected.
Verticillium Wilt Resistance in Eggplant, Related Solanum Species, and Interspecific Hybrids
Authors: Alconero R. , Robinson R. W. , Dicklow B. , Shail J. 
Published: September 2022

Abstract
No significant resistance to verticillium wilt (Verticillium dahliae Kleb) was found in 59 eggplant (Solanum melongena L.) accessions, in a sexual hybrid between S. melongena and S. integrifolium, or in eight somatic hybrid clones between S. melongena and S. sisymbriifolium. A relatively high degree of resistance was observed in accessions of S. aculeatissimum, S. scabrum, and S. sisymbriifolium. All 58 accessions of S. gilo tested were susceptible, as were all accessions of S. incanum, S. integrifolium, S. laciniatum, S. macrocarpum, S. mammosum, and S. nodiflorum.
Plantlet Regeneration from Protoplasts of Petunia alpicola
Authors: Ford-Logan Jane , Sink K. C. 
Published: September 2022

Abstract
The isolation, culture, and plant regeneration of protoplasts derived from callus or suspension cultures of Pentunia alpicola Smith and Downs was established. Protoplasts formed macrocalli, at 85% percent plating efficiency, in Murashige and Skoog (MS) liquid medium containing 2,4–D (1.0 mg·liter–1), NAA (0.5 mg·liter–1), BA (0.5 mg·liter–1), and 20% coconut water. Shoot regeneration from macrocalli occurred at 65% frequency on MS containing zeatin (1.0 mg·liter–1), and shoots were readily rooted on either MS containing NAA (0.01 mg·liter–1) or IBA (1.0 mg·liter–1). However, plantlets failed to grow in artificial planting medium. The results provide the basis for somatic cell genetic studies for a Petunia sp. that has distincitive morphology compared to cultivated petunias. Chemical names used: (2,4-dichlorophenoxy)acetic acid (2,4–D), 1-naphthaleneacetic acid (NAA), N-(phenylmethyl)-1H-purin-6-amine (BA), (E)-2-methyl-4-(1H-purin-6-ylamino)-2-buten-l-ol (zeatin), and 1H-indole-3-butyric acid (IBA).
Sugary (su) and sugary enhancer (se) Sweet Corn Inbreds with Resistance to Maize Dwarf Mosaic Virus
Authors: Juvik John A. , D'Arcy Cleora J. 
Published: September 2022

Abstract
Maize dwarf mosaic virus (MDMV), an economically serious viral disease of sweet corn (Zea mays L.) in the United States and other countries of the world, is transmitted primarily by aphid vectors. Early infection by the virus in sweet com can cause stunted growth, delayed maturity, reduced yield, and poor ear quality (11). To provide public and private breeders with germplasm to help alleviate this problem, the Illinois Agricultural Experiment Station announces the release of nine sugary (su) sweet corn inbreds with improved resistance to maize dwarf mosaic virus. These newly developed inbreds have been designated IL793a, IL794a, IL795a, IL796a, IL796b, IL797a, IL798a, IL799b, and IL800a.
Improving Horticulture Internship Programs
Authors: Haque Mary , Lewis Preston 
Published: September 2022

Abstract
In 1980, ASHS completed a survey of internship programs offered at institutions with 2- and 4-year horticulture programs and landscape architecture programs. The results indicated that 50% of 62 responding institutions had internship programs; however, the number of students taking advantage of existing programs was relatively small (1).
Economic Effects of Excessive Vegetative Growth in Deciduous Fruit Trees
Authors: Elfving D. C. 
Published: September 2022

Abstract
Excessive vegetative growth and its control remain significant and often costly problems facing deciduous fruit growers. The term “vegetative growth” is often understood to mean “shoot growth”, since the most visible manifestation of vegetative growth is the development of new shoots each year. Other forms of vegetative growth also occur in deciduous fruit trees, although their impact on productivity is less clearly understood. In this paper, “excessive vegetative growth” will refer to any condition that results in an undesirable amount of shoot growth.
Comprehensive Extension System—The Land-grant Example
Authors: Larsen R. Paul 
Published: September 2022

Abstract
From colonial times to the present, America has prized education as the provider of individual opportunity, as well as our national progress. The value of practical education was delineated clearly with the passage of the Land-grant “Morrill Act” by the U.S. Congress, signed by Abraham Lincoln in 1862. The Land-grant Act provided grants of federal land to every state that agreed to establish at least one college to teach agriculture and the mechanic arts along with other scientific and classical subjects. This and subsequent legislation to support research and extension developed the “trilogy of American ingenuity”—the blended roles of teaching, research, and public service that form both the mission and strength of America's land-grant universities.
Cultural Practices for Using True Seed in Potato Production under Temperate Climates
Authors: Martin Mark W. 
Published: September 2022

Abstract
Potatoes (Solanum tuberosum L.) normally are propagated vegetatively by tubers and produce a uniform, productive, high-quality crop. However, tubers accumulate systemic diseases, which greatly reduce their productivity and quality. Many countries control these diseases with complex and expensive seed certification programs. Such control methods are not available in many other countries where potatoes are an important part of the diet.
Gene Expression in Embryogenesis
Authors: Sung Z. R. , Smith J. M. , Choi J. H. , Krauss M. , Borkird C. , Liu L. -S. 
Published: September 2022

Abstract
The objective of our research is to understand the genetic basis of embryogenesis. Somatic embryogenesis from carrot culture was chosen as the experimental system because of its simplicity and the ease with which it lends itself to obtaining a large number of embryos for genetic and biochemical experiments. Our general philosophy is to avoid media manipulation and to focus on gene expression during embryogenesis. One approach is to isolate genes preferentially expressed at specific stages of embryogenesis, and then to study the role of these genes in development.
Role of ABA in the Regulation of Somatic Embryogenesis
Authors: Ammirato Philip V. 
Published: September 2022

Abstract
Abscisic acid (ABA), a naturally occurring plant growth inhibitor, exerts a number of striking effects on the development of somatic embryos grown in suspension cultures. When added at moderate concentrations to populations of proembryos, ABA permits normal embryonic growth and maturation but inhibits diversions from this pathway. It prevents the initiation and growth of new embryonic centers and the malformation of cotyledons and shoots. In fully formed embryos, it inhibits their germination or conversion into plantlets. ABA also influences cellular differentiation, affecting both anatomy and biochemistry. Its role is to permit the normal progression of the embryonic programs. With ABA, somatic embryos closely resemble zygotic embryos in both structures and behavior. Practically, the manipulation of endogenous or exogenous ABA levels in populations of somatic embryos increases the frequency of embryos that reach maturity and facilitates their manipulation in large scale propagation and mechanized delivery.
Germplasm Determination of in Vitro Somatic Embryogenesis in Alfalfa
Authors: Brown Daniel C. W. 
Published: September 2022

Abstract
More than 1000 higher plant species have been reported to regenerate in vitro via either somatic embryo formation or shoot formation (1, 9, 11, 12, 16, 27, 40, 42, 45, 46). Although many reports of plant regeneration are not accompanied by the necessary developmental or histological evidence for verification, it is apparent that most successes follow an organogenic rather than an embryogenic route. However, regardless of which developmental pathway is followed or the complexity of the protocol that is used ultimately to recover a complete plant, much of the work on in vitro regeneration can be described as empirical in nature.
Introduction to the Symposium
Authors: Anderson George 
Published: September 2022

Abstract
Urban horticulture is an emerging area of interest to the researcher, teacher, landscape architect, city planner, forester, nurseryman, and the public. In today's society, demands are made on plants and man which are often above and beyond anything that could be considered normal for the species. The human animal is expected to work efficiently and effectively amidst austere surroundings of glass and concrete of major cities and to “relax” in busy, often sunless streets. In order to improve this working environment, planners and architects recommend a greater use of plants, the benefits of which have been provided for us by many of the early researchers in design and greenspace architecture. Trees and other woody plants improve the urban environment by screening unwanted views, by reducing noise and air pollution, and by generally improving the well-being of the individuals who come in contact with them. However, we often fall short of success in our search for suitable plants for use in the urban environment.
Ecophysiology of Urban Trees and Their Management—The North American Experience
Authors: Whitlow Thomas H. , Bassuk Nina L. 
Published: September 2022

Abstract
Only a few species are capable of colonizing extreme environments, whereas more moderate environments can support many more. The diversity of species in a habitat is thus controlled by the environment, whether by soil fertility, altitude or any other factor. This diversity reflects the number of species adapted to grow in a habitat, and the nature of this adaptation must be examined in light of the physiological effect of the environmental factors making up the habitat, and their variation in time and space (11).
Scale Propagation as a Method of Measuring Summer-sprouting Tendency in Easter Lily
Authors: Matsuo E. , Ohmachi K. , Arisumi K. , Sakata Y. , Kobayashi M. 
Published: September 2022

Abstract
Summer-sprouting in Easter lily (Lilium longiflorum) occurred more frequently in scale-propagated plantlets than in yearling planting stock. Cultivars without summer-sprouting in scale-propagated plantlets had no summer-sprouting in yearling planting stock. Cultivars having high percentages of summer-sprouting in scale-propagated plantlets also had high percentages of summer-sprouting in yearling planting stock.
‘Park’ Kentucky Bluegrass Response to Foliarly Applied Urea
Authors: Wesely R. W. , Shearman R. C. , Kinbacher E. J. 
Published: September 2022

Abstract
This study was conducted on ‘Park’ Kentucky bluegrass (Poa pratensis L.) established on a Sharpsburg silty clay loam (Typic Argiudoll). Urea was applied at 0, 0.8, 1.6, 2.4, and 3.2 g N/m2 in 35 ml·m–2 of distilled water. Treatments were applied at 3-week intervals beginning 29 Apr. 1980 and ending 2 Sept. 1980. Turfgrass color, quality, clipping yield, total N percentage in clippings, and tissue succulence were highest for 3.2 g N/m2. Maximum N-rate responses occurred during spring and fall and were highest 1 week after treatment. Acceptable turfgrass quality was maintained at 1.6 g N/m2 per application. Nitrogen recoveries based on clipping removal were 49%, 60%, 59%, and 59% for 0.8, 1.6, 2.4, and 3.2 g N/m2, respectively.
Enhancing Seed Germination of Sand Blackberry
Authors: Campbell Peta L. , Erasmus D. J. , Staden J. van 
Published: September 2022

Abstract
Germination was greater for seeds scarified manually or with 15% NaOCl than for those scarified with concentrated H2SO4. Fifteen percent NaOCl for 18 hr scarified the seed endocarp and negated the need for stratification. Germination of 85% was attained after 8 weeks incubation in the light at alternating 15°/30°C. This percentage compared favourably with 82% germination resulting from manual scarification techniques. Electron microscopy revealed that endocarp degradation was much more extensive after 18 hr in 15% NaOCl than after 4 days in a 1% solution.
Effect of Shoot Vigor on Pistillate Flower Production and Abortion in ‘Stuart’ Pecan
Authors: Sparks Darrell 
Published: September 2022

Abstract
In pecan [Carya illinoensis (Wangenh.) C. Koch)], pistillate flower production is positively and abortion is inversely correlated with growth of the supporting shoot. Shoot growth from 1-year-old branches of 4- and 8-cm lengths was increased by pruning all other branches from the supporting limb. Pistillate flower production increased and subsequent abortion decreased with increasing shoot vigor. The results demonstrate a cause-and-effect relationship between shoot vigor and pistillate development and abortion.
Effect of High Temperature on Fruit Set in Tomato Cultivars and Selected Germplasm
Authors: Berry S. Z. , Uddin M. Rafique 
Published: September 2022

Abstract
Selected F3 and F4 lines of different origin were evaluated at high temperature (26° night and 35°C day) in the greenhouse along with several known heat-sensitive and heat-tolerant tomato (Lycopersicon esculentum Mill.) cultivars. A number of the selected lines had fruit set comparable to the tolerant cultivars Saladette, Ohio 7663, BL 6807, and Chico III. The expected greater fruit set of the tolerant cultivars vs. that of the sensitive cultivars was observed. High fruit set in this study was not associated with high seed number in the majority of tolerant cultivars evaluated.