Patulin effects on wheat plants in field treatments

Summary Fall field patulin applications (500 µg/g of soil) to Cheyenne winter wheat seedlings at growth stages 0, 1, and 2, decreased germination, plant growth, winter survival, and tillering. Decreased tillering decreased the number of heads and grain yield. Spring patulin application of 250 and 500 µg/g of soil to wheat at growth stages 6, 7, 8, 9, and 10 decreased yields by decreasing the number of heads, kernels per head, and kernel weight. With fall patulin applications, yields were decreased more when patulin was applied near seeding. Spring patulin applications to wheat during sensitive heading stages decreased yield the most.Stages of wheat growth especially susceptible to patulin are the germination, stem-elongation, and flowering, which occur during the fall and spring when soil Penicillium urticae Bainier numbers are maximun and patulin has been extracted from the soil.Contribution from the Soil, Water, and Animal Waste Management Research Unit, North Central Region, Agricultural Research Service, U.S. Department of Agriculture, in cooperation with the Nebraska Agricultural Experiment Station, Lincoln. Published as Paper No. 4071, Journal Series, Nebraska Agricultural Experiment Station.Microbiologist, USDA, A.R.S. University of Nebraska, Lincoln; Soil Scientist, USDA, A.R.S. Fort Collins, Colorado; and Microbiologist, USDA, A.R.S. University of Nebraska, Lincoln, respectively.     

Penicillium urticae Bainier enumeration in soils

Summary A dilution plating method estimatedPenicillium urticae Bainier numbers in soil. This method, which used an agar layering technique and a cyclic incubation of 8 hours at room temperature (about 25°C) and 16 hours at 5°C, permitted the differential growth and sporulation in favor ofP. urticae B. over other common soil fungi.Procedures of extraction, paper chromatography, infrared analysis, and bioassay assayed for accumulated patulin. A combination of these methods routinely estimatedP. urticae B. numbers in soils and authenticated patulin production by selected isolates.Contribution from the Northern Plains Branch, Soil and Water Conservation Research Division, Agricultural Research Service, USDA, in cooperation with the Nebraska Agricultural Experiment Station, Lincoln. Published as Paper No. 2275, Journal Series, Nebraska Agricultural Experiment Station.Soil Scientist, USDA, Grand Junction, Colorado (formerly Chemist, USDA, Lincoln, Nebraska); and Microbiologist, USDA, Lincoln, Nebraska, respectively.     

Ethanol tolerance and carbohydrate metabolism in lactobacilli

Summary This paper describes the ethanol tolerance and metabolism of 31 strains ofLactobacillus on glucose, xylose, lactose, cellobiose and starch. The purpose of this work was to determine the suitability of the 31 strains as potential host for the ethanol producing genes, pyruvate decarboxylase and aldehyde dehydrogenase, fromZymomonas mobilis. The 31 strains were screened for their ability to grow in 0 to 8% v/v ethanol on all five carbohydrates. Those strains that were able to grow to an OD of 1.0 in 8% ethanol were evaluated at ethanol concentrations up to 16%. v/v. The fermentative products from the five carbohydrates were analyzed to determine the ratios of lactic acid, ethanol, and acetic acid.Published as Paper No. 9786, Journal Series Nebraska Agricultural Experiment Station, Lincoln, NE 68583-0704.     

The inhibition of seedling growth by crop residues in soil inoculated withPenicillium urticae Bainer

Summary Laboratory experiments were conducted to determine the effects of crop residues, without and withPenicillium urticae Bainer inoculation, on growth of wheat seedlings in soil. Fifty grams of Sharpsburg silty clay loam soil, containing 1% by weight of incorporated alfalfa, sorghum and corn stover residue, were placed in petri dishes, autoclaved, wetted to 40% moisture, and incubated at 24°C. for periods of 2, 3, and 4 weeks. One-half of the petri dishes were inoculated withP. urticae. Germination and seedling-shoot measurements were taken after 7 days of growth.The results of this study showed that (1) inoculation of soil generally reduced seedling height regardless of the residue treatment; (2) inoculation of soil containing corn and sorghum residues resulted in greater tissue production but reduced height of seedlings as compared to non-inoculated soils; and (3) in the absence of residues, the inoculated control soils were a better growth medium for wheat seedlings than were the non-inoculated control soils. In addition, alfalfa residues, especially in the presence ofP. urticae, were strongly inhibitory to the wheat seedlings, causing curling and reduced wheat-seedling root growth.Joint contribution from University of Nebraska and Soil and Water Conservation Research Division, Agricultural Research Service, U.S. Department of Agriculture, and Nebraska Agricultural Experiment Station, Lincoln, Nebraska, cooperating. Published with the approval of the Director as Paper No. 1242, Journal Series, Nebraska Agricultural Experiment Station.     

Characterization of ploidy levels of wheat microspore-derived plants using laser flow cytometry

Summary The purpose of this study was to determine simply and accurately ploidy levels as estimated by changes in nuclear DNA content of wheat (Triticum aestivum L.) plants regenerated from microspore-derived embryos. Using flow cytometry, the nuclear DNA content of green (83) and albino (222) plants derived using anther culture of ‘Bobwhite’ and ‘Pavon 76’, and of their reciprocal F₁ hydrids was estimated. The average DNA concent of the Bobwhite and Pavon 76 standards was 32.46 and 31.28 per nucleus, respectively. Microspore-derived haploid (3X), doubled-haploid (6X), nanoploid (9X), and dodecaploid (12X) plants contained on average 15.44, 30.56, 45.57, and 60.27 pg of DNA, respectively, at a ratio of 1∶1.98∶2.99∶3.90. The frequency of haploids (43.6%) was similar to that of doubled haploids (43.0%), and much larger than the frequency of endopolyploids [nanoploid (1.3%) and dodecaploid (1.0%)] and various aneuploids (11.1%). In terms of genetic stability, green plants had less chromosomal variation than albino plants. The procedure is suitable for rapid determination of the ploidy levels of wheat microspore-derived plants. The knowledge about DNA content or genome size of plants obtained here provides useful information to plant breeders and geneticists interested in using anther culture. Formerly of the Department of Agronomy, University of Nebraska, Lincoln. NE 68583-0915. Formerly of the Center for Biotechnology, University of Nebraska, Lincoln, NE 68588.     

Variation for improved protein and yield from rice anther culture

Summary The anther culture technique is useful for the recovery of haploids which when doubled provide homozygosity. Additionally, beneficial as well as deleterious genetic and epigenetic changes are promoted by the in vitro procedures. The majority of plants recovered from anther calli of the cultivar Calrose 76 were similar to the starting cultivar but plants regenerated from microspore calli had a wider range of responses than controls for several characteristics. Plants with larger seeds, higher levels of seed protein, shorter stature and more highly tillered than the starting cultivar were obtained from selfed anther-derived plants. The data also support the concept that in vitro procedures including anther culture of specific cultivars of rice promoted the recovery of phenotypes with increased seed storage proteins.Contribution from the U.S. Department of Agriculture, Science and Education, Agricultural Research Service, Plant Physiology Institute, Tissue Culture and Molecular Genetics Laboratory, Room 116, Building 011-A, BARC-West, Beltsville, Maryland 20705, USA     

Characterizing soil fertility by ion diffusive flux measurements

Summary The general acceptance of diffusion as a rate-limiting step in transferring ions to plant roots was considered in characterizing soil fertility. Soil ion diffusive flux measurements to an exchange resin were measured with two soil: resin cells, one with untreated soil, the other with the same soil fertilized with P, K, and Cl. The P, K, and Cl that diffused to the resin of each cell was extracted and determined. Using only these measurements and some simplifying assumptions of diffusion theory, calculations were made of the soil's P and K solution concentration, adsorbed concentration, a capacity factor, transmission factor, and quantity of fertilizer needed to attain any desired flux. Excellent to fair correlations existed between these calculated values and traditionally measured chemical quantities. Plant uptake of P and K was generally well correlated with diffusive flux measurements as well as traditional chemical measurements.Contribution from the Western Region, Agricultural Research Service, U.S. Department of Agriculture; and the Montana Agricultural Experiment Station, Bozeman, Montana, submitted as Station Paper No. 654, Journal Series.Soil Scientist, Snake River Conservation Research Center, Kimberly, Idaho; Professor of Chemistry, and Professor of Soils, Montana State University, Bozeman, respectively.     

The effects of root temperature and Ca supply on the growth and transpiration of cotton seedlings (Gossypium hirsutum,L.)

Summary Cotton seedlings were germinated in either tap water or a CaSO₄ solution and then grown for two days in nutrient solutions containing 0.1, 1.0, or 10.0 me Ca/1. They were then transferred to cultures having the same Ca variables and the roots subjected to temperatures of 26, 18, 15 and 12°C for four days. The fresh weight of all plant parts and leaf area increased with increasing root temperatures and with increasing Ca levels, the effect of Ca being most pronounced at the higher temperatures. The dry weight was increased by increasing root temperature; the effect of Ca was rather small. Water use increased with increasing temperature and was higher for the lowest Ca level than for the higher levels. The results emphasize the overriding effect of low temperature on water uptake. Calcium had little effect on the growth depression resulting from low root temperatures. Joint contribution from the Agronomy Department, Mississippi Agricultural Experiment Station, State College and the Soil Science Department, North Carolina Agricultural Experiment Station, Raleigh. Published with the approval of the Directors of Research as Journal Contribution No.1530 and Paper No.2389 of the Journal Series, respectively. This is a report of research conducted while the author was on sabbatical leave at North Carolina State University, February 1–September 10, 1965.     

Effect of 1-aminocyclopropane-1-carboxylic acid on maize kernel development in vitro

Pollination stimulates ethylene production in maize ears, and the application of ethephon during the pollination period can cause kernel abortion. The objective of this study was to determine if kernel abortion could be induced in vitro by the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC). Adding ACC to the culture medium resulted in the evolution of ethylene which caused abortion and reduced mature kernel mass. The effect of ethylene on kernel abortion and dry matter accumulation was partially negated by the addition of the ethylene-binding site inhibitor, 2,5-norbornadiene (NBD). The effect of ethylene on kernel abortion was greatest during the early stage of kernel development and was intensified by an increase in media sucrose concentration. These data suggest that ethylene could regulate kernel abortion in maize.Contribution of the Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108. Paper No. 17,088, Scientific Journal Series, Minnesota Agriculture Experimental Station.     

The allotetraploidization of maize

Summary Allotetraploidization is the creation of artifical allotetraploids from a normally diploid species. The possible value of allotetraploid maize has been discussed in Section I of this series. Allotetraploidization of maize can be achieved by restructuring a maize genome so that its chromosomes will not pair with those of the standard maize genome. This restructuring can be done by concentrating differential pairing affinity (DPA) factors into a single line by a recurrent selection type of breeding program. Because the divergence of the maize genome is a gradual process, it is necessary to devise a model for chromosome pairing and gene segregation in segmental allotetraploids. This has been done by considering pairing in each arm separately and then combining paired arms to form pairing configurations for whole chromosomes. The chromosome disjunction patterns are hypothesized and genetic ratios in relation to different levels of DPA are suggested.Contribution from the Science and Education Administration, U.S. Department of Agriculture, and the Agronomy Department, University of Missouri, Columbia, Missouri, Agricultural Experiment Station Journal Series No. 8090     

Respiration rate of fruit flesh from red and green sides of 'Cortland' apples

Respiration rate of apple flesh from red and green side of ‘Cortland’apples was measured using Gilson respirometer. Respiration fromred side was greater for both pre and post climacteric fruit.Flesh from the red side was also higher in soluble solids, freshweight and dry weight. ¹Contribution No. 1283 of the Rhode Island Agricultural ExperimentStation. ²Present address: Department of Agronomy, U. P. College of Agriculture,College Laguna, Philippines. (Received July 23, 1968; )     

The allotetraploidization of maize

Summary Allotetraploidization is the creation of synthetic allotetraploids. The allotetraploidization of maize can be accomplished by concentrating DPA (differential pairing affinity) factors into stocks by a recurrent selection breeding system. Selection is based on pairing configuration frequencies and altered genetic ratios that reflect DPA. Both an observed decline in the quadrivalent frequency per meiocyte from 8.10 to 7.31 and genetic data disclosing a reduction in the average frequency of recessive waxy (wx wx) pollen from Wx Wx wx wx plants from 17.48% to 13.35%, indicate considerable progress has been made toward allotetraploidization. A simple model for the effect of DPA on chromosome pairing and genetic ratios is presented.Contribution from the Agricultural Research Service, U.S. Department of Agriculture, University of Missouri, Missouri Agricultural Experiment Station, Journal Series No. 9806     

Peripheral reticulum in chloroplasts of plants differing in CO2 fixation pathways and photorespiration

Summary The development of peripheral reticulum (PR) in chloroplasts varies in C₃ and C₄ plants. In general, PR is more extensive in C₄ plants, but PR is also seen in the chloroplasts of some C₃ plants. Within some C₄ plants, PR is seen in the bundle sheath cells which predominantly use the C₃ pathway. Thus, PR is not associated directly with the presence of the C₄ pathway on a cellular basis. Its predominance in C₄ plants must be related to some characteristic other than the method of CO₂ fixation. Ultrastructural evidence suggests that PR is associated with the rapid transfer of substances into and out of chloroplasts and from mesophyll to bundle sheath cells.Cooperative investigations of the Department of Agronomy, University of Georgia, Athens, Georgia; Department of Agronomy, University of Florida, Gainesville, Florida; and the Plant Science Research Division, Agricultural Research Service, USDA, Gainesville, Florida. The mention of specific products is for the purpose of clarity and does not imply endorsement by the USDA. Journal Series No. 977 of the Georgia Agricultural Experiment Station, and Journal Series No. 3870 of the Florida Agricultural Experiment Station.     

Effects of nitrogen: phosphorus supply ratios on nitrogen fixation in agricultural and pastoral ecosystems

An analysis of data compiled from the literature confirms a strong inverse relationship between annual rates of nitrogen fixation and the soil nitrogen content in agricultural and pastoral ecosystems. However, this inverse relationship is strongly modified by the rate of application of phosphorus fertilizer, which strongly influences the activities of both symbiotic and non-symbiotic nitrogen fixing organisms. In the case of symbiotic legumes, the response of N-fixation to N and P is in part a result of changes in legume dominance within the plant community. These results, as well as supporting data presented from a review of experiments on nitrogen fixation in a variety of other terrestrial and aquatic ecosystems, provide important support for the hypothesis that phosphorus availability is a key regulator of nitrogen biogeochemistry. Published as Paper No. 9950, Journal Series, Nebraska Agricultural Research Division, University of Nebraska, Lincoln, NE, USA.     

Biological transformations of phosphorus in soil

Summary Mathematical expressions were developed for calculating (1) the availability of soil phosphorus and nonradioactive inorganic fertilizer phosphorus to soil organisms, the measurements being expressed in terms of a standard source of inorganic phosphorus containing P³² added to the soil prior to incubation, and (2) the amounts of synthesized and mineralized organic phosphorus present in soils after incubation. Analytical procedures for obtaining the necessary data were described.Soil Phosphorus Research Project of the North Central Region. Contribution from the B.P.I.S.A.E., U.S. Department of Agriculture, and the Iowa Agricultural Experiment Station. Journal Paper No. J-2302 of the Iowa Agricultural Experiment Station, Ames, Iowa. Project No. 1183.Formerly Soil Scientist, U.S.D.A., and Collaborator, Iowa Agricultural Experiment Station; now Soil Scientist, Dow Chemical Co., Seal Beach, California. The author is indebted to Dr. L. A. Dean and Dr. C. A. Black for their many helpful suggestions in planning these investigations and preparing the data for publication.     

Platte Valley Yellows,a chlorotic condition of soybeans: Symptoms and preliminary chemical analyses

Summary A chlorotic condition of soybeans in the river valleys of eastern Nebraska was studied. The pattern of chlorosis, presence of petiolar necrosis, reductions in rhizobial and mycorrhizal infection, and plant and soil chemical analyses suggest that the condition is more complex than normal iron deficiency chlorosis or other mineral deficiencies or toxicities. Nodulation is almost totally inhibited in affected plants. Mycorrhizal fungi, while able to infect early in the season, do not persist on affected plants. Breakdown of endodermis was observed in the roots of affected plants. The factors contributing to this condition have not yet been determined. Published with the approval of the director as Paper No. 5672, Journal Series, Nebraska Agricultural Experiment Station.     

Effect of aluminum on growth and mineral elements of al-tolerant and Al-intolerant corn

Summary Growth and P, K, Ca, Mg, Mn, Zn, Fe, and Cu concentrations and contents were determined in Al-tolerant and Al-intolerant corn (Zea mays L.) inbreds when grown at various levels of Al. B57 was more tolerant to Al than was Oh40B. Relatively low Al levels (up to 5 mg/l) enhanced B57 growth but inhibited Oh40B growth. With few exceptions, Oh40B root and leaf concentrations of the elements decreased with added Al. The decreases in element concentrations were not as large for B57 as they were for Oh40B. The Mg concentrations and contents decreased more than the other elements in all inbreds with added Al. Root Mg decreased more than leaf Mg. Total uptake of some elements were higher at low Al than with no Al. Inasmuch as Mg has a pronounced effect on root growth, low Mg may be an important response in plants sensitive to Al.Journal article No. 82-75 of Department of Agronomy, Ohio Agricultural Research and Development Center, Wooster, Ohio.Journal article No. 82-75 of Department of Agronomy, Ohio Agricultural Research and Development Center, Wooster, Ohio.     

The allotetraploidization of maize

Summary Allotetraploidization is the creation of artificial allotetraploids. Allotetraploidization of maize can be achieved by restructuring a maize genome so that its chromosomes will not pair with those of the normal maize genome. The restructuring can be done by concentrating induced or naturally occurring visible and cryptic chromosome aberrations and qualitatively different genetic material into a single line by a recurrent selection type of breeding program. The basis of allotetraploidization is the presence of differential pairing affinity between normal and restructured chromosomes. Experiments demonstrate that differential pairing affinity factors occur naturally in exotic races and in standard corn belt inbred lines and that they may be readily induced by X-irradiation and chemical mutagens.Contribution from the Science and Education Administration, U.S. Department of Agriculture, and the Agronomy Department, University of Missouri, Columbia, Missouri, Missouri Agric. Exp. Sta. Journal Series No. 8092     

Choosing plant cultivars based on the probability of outperforming a check

Summary A major consideration in most plant breeding programs is the development of cultivars that have high probabilities of outperforming the check cultivar in a broad range of environments. Methods are presented for estimating and testing hypotheses regarding these probabilities, which are termed reliabilities. Reliabilities are shown to be directly related to several commonly used stability parameters. Data from international maize yield trials are used to illustrate and evaluate the repeatability of the approach. Results indicate that reliabilities can be useful aids to plant breeders since they (1) are easy to understand and compute, (2) are indices that weigh the importance of the difference in performance relative to stability, and (3) are potentially useful as genetic parameters since they are generally repeatable across randomly sampled sets of environments.Contribution from the Agricultural Research Division, University of Nebraska, Lincoln, Neb., Paper no. 9653     

Effect of moisture and oxidation status of alkaline rice soils on the adsorption of soil phosphorus by an anion resin

Summary Considerable effort was devoted to experimentally explaining the greater amount of anion resin-adsorbable P (ARAP) in water-saturated alkaline soils relative to moist soils with the purpose of explaining the phenomenon of increased P availability in flooded rice soils. ARAP increased when waterlogged conditions were imposed on soils, but the increase in ARAP occurred before reducing conditions were obtained. Reducing conditions did not increase ARAP. The increase in ARAP in the water-saturated alkaline soils was attributed to the enhanced P diffusion resulting from a decrease in tortuosity, thus indicating that increased P availability upon flooding could be due to increased P diffusion.Paper number 4533 of the Journal Series of the North Carolina Agricultural Experiment Station.Paper number 4533 of the Journal Series of the North Carolina Agricultural Experiment Station.