A general procedure for protoplast recovery,callus and plant regeneration in plants

A portion of this work was supported by NSF grant DCB 8718314 and by the Missouri Agricultural Experiment Station. This research is a joint contribution from the Missouri Agricultural Experiment Station, Journal Series No. 10,789 and from the Massachusetts Agricultural Experiment Station, Amherst, MA 01003; Journal Paper No. MAES 2959. Ousama Zaghmout was supported by the Food for the 21st Century Program, College of Agriculture, University of Missouri, Columbia, MO.     

Sporophytic recognition of pollen S alleles in the gametophytic self-incompatibility system of Nemesia strumosa benth

Summary Several seedlings of Nemesia strumosa with various levels of pseudo-self-compatibility (PSC) often produced more seed after self pollination than when pollinated using pollen from incompatible plants bearing the same S alleles. Sporophytic recognition of self pollen apparently increases PSC levels above those attributable to modifying genes which interfere with normal stylar activity.Scientific Journal Series Paper Number 9546 of the Minnesota Agricultural Experiment Station.     

Sampling variance of the correlation coefficients estimated from analyses of variance and covariance

Summary A generalized sampling variance of correlation coefficients is derived for phenotypic, genetic and en vironmental correlations estimated from nested analyses of variance and covarianee for the equal number case. A numerical example is presented to estimate the sampling variance for the genetic correlation coefficient based on the relationship among full sibs using unequal subclass numbers.Journal Paper No. 3472 of the Purdue University Agricultural Experiment Station. This research was supported, in part, by NIH Biometry Training Grant, GM-00024.     

The translocation of Zn65 and Cs134 between seed generations in soybean (Glycine max (L.) Merr.)

Summary In this study 23.9 per cent of the Zn⁶⁵ and 3.4 per cent of the Cs¹³⁴ contained in the first generation seeds was translocated to the second generation. The advisability of using Zn⁶⁵ or Cs¹³⁴ (and presumably Cs¹³⁷) contaminated soybean seed for crop production, even in uncontaminated soil, is questioned.Paper number 7851 Scientific Journal Series, University of Minnesota Agricultural Experiment Station, St. Paul, Minnesota.     

Microflora of raw cacao beans

Whole non-moldy cacao beans from 14 sources cultured on Czapek's agar with six percent NaCl yielded species ofAspergillus glaucus group,Mucor pusillus and unidentified yeast and bacteria. The average number of bacterial colonies from the 14 sources of non-moldy cacao beans was 32.7 million per gram. The average number of colonies of filamentous fungi in dilution cultures was 57,000 colonies per gram. Yeast colonies were present in the amount of 15.8 million colonies per gram. The moldy beans analyzed contained fungi and bacterial counts in the billions; also, yeast was not isolated from the moldy samples.Paper Number 3170 of the Journal Series of the North Carolina State University Agricultural Experiment Station, Raleigh, North Carolina 27607.     

The inheritance of pseudo-self-compatibility (PSC) in Nemesia strumosa Benth

Summary Pseudo-self-compatibility (PSC) in Nemesia strumosa was determined by recessive modifying genes which interferred with the normal stylar incompatibility reaction. The PSC levels ranged from none or low to amounts resembling full self-compatibility. PSC within a progeny could be maintained at low or high levels by selecting parents either high or low in PSC. Pollen from plants of any PSC level failed to produce seed when placed on other incompatible styles bearing the same S alleles.Scientific Journal Series Paper Number 9420 of the Minnesota Agricultural Experiment Station.     

Plant regeneration from embryogenic callus initiated from immature inflorescences of several high-tannin sorghums

A procedure was established for the induction of regenerable calli from immature inflorescence segments of high-tannin cultivars of sorghum (Sorghum bicolor (L.) Moench). Murashige & Skoog's medium with several components altered was utilized for inducing, maintaining, and regenerating the cultures. Embryogenic calli formed at a frequency of 8–70% depending on the genotype. During a ten-month period, 3600 plants were regenerated from eight genotypes tested. Among the developmental stages of immature inflorescence tested (from differentiation of secondary branch primordia to floret formation) no critical differences were found in potential for callusing, embryogenesis or regeneration. Genotypic differences were observed in pigment production, embryogenic callus formation, shoot differentiation, and in maintenance of regeneration capacity.Abbreviations 2,4-D dichlorophenoxyacetic acid This is Journal Paper Number 11972 from the Purdue University Agricultural Experiment Station     

Single locus heterosis

Summary Experimental evidence is reported in favor of superdominance in over-all vigor inArabidopsis thaliana in connection with two x-ray induced mutants. The tests adopted (outcrossing to unrelated tester, repeated recombination for 15 generations) failed to reveal any additional genetic variation. The genetic and physiolgical mechanism of superdominance is discussed in light of recent information on gene structure and function.Contribution from the Missouri Agricultural Experiment Station. Journal Series Number 2388. Approved by the Director.     

Isozyme genotype-environment relationships in natural populations of the harvester ant,Pogonomyrmex barbatus,from Texas

Three different allelic isozyme systems (two esterases, ESH and ESR, and a malic dehydrogenase, MDH) were analyzed in population samples of a species of ant, Pogonomyrmex barbatus, from Texas. Allelic frequencies were determined for several collection localities, and a number of significant differences were found. Principal component analysis was used to compare the patterns of variability of the allelic frequencies with environmental factors. Significant correlation was particularly evident with respect to weather and the pattern of variability in both esterases, and it is therefore suspected that natural selection is important in determining the allele frequency patterns. Observed and expected genotypic proportions were found in good agreement, generally, but in some localities homozygotes appeared in significantly greater numbers than expected. Heterotic selective maintenance was thus not indicated. Correlation found between patterns of variability in the enzyme systems themselves was consistent with the hypothesis that all three enzyme systems were affected by the environmental factors.Supported in part by USPHS Research Grants No. GM 15769, GM 11609, and GM 11546 and Texas A & I University Faculty Research Grant No. 449-N-68. The field work and laboratory analyses in this investigation were done while the senior author was at the University of Texas, and the data were analyzed at North Carolina State University. The computing was supported by Grant FR-00011 of the National Institutes of Health. Paper number 2784 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, North Carolina.     

Isozyme variability in species of the genus Drosophila. VII. Genotype-environment relationships in populations of D. melanogaster from the eastern United States

Collections of D. melanogaster were analyzed for genetic variation at nine enzyme loci. Allelic frequencies were determined, and comparisons between observed phenotypic proportions and those expected under equilibrium conditions were made. A significant tendency toward homozygote excess was noted. Relationships between patterns of genetic variability and between patterns of genetic and environmental variability were examined by the method of principal components and correlation analysis. Several of the loci showed a clinal pattern in gene frequencies, and overall there was an appreciable amount of genetic-genetic and genetic-environmental association.This work was supported by PHS Research Grant No. GM 11546 and AEC Contract No. AT-(40-1)-3980. Paper No. 4026 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, North Carolina.     

Genetic correlation and response to selection in simulated populations

Summary One of two quantitative traits was selected and correlated response in the other trait was measured in each of 30 generations for models of additive genes and of complete dominance. Each trait was controlled by 48 loci with equal effects, segregating independently from frequencies of 0.5 in the initial generation. Intensity of selection regulated the number of offspring from randomly mating 24 males and 24 females each generation. Three each of genetic correlations between traits, intensities of selection, and amounts of environmental variation were simulated.In the additive model correlated responses of the unselected trait to selection of the primary trait agreed closely with responses expected from theoretical considerations. In the model of complete dominance, responses of genotypic means of the unselected trait to selection of the primary trait in opposite directions were quite symmetrical for the first few generations but became distinctly asymmetrical in later generations. With little selection, response was fairly linear but became distinctly curvilinear as intensity of selection increased and environmental variance decreased. Between 15th and 30th generations some gains in the correlated trait to the 15th generation were lost.Michigan Agricultural Experiment Station Journal Article 4847. Part of North Central Regional Project NC-2.     

Restoration of pseudo-self-compatibility (PSC) in derivatives of a high-PSC × no-PSC cross in Nemesia strumosa Benth

Summary Mean PSC increased following each generation of recurrent selection in F₁, F₂ and F₃ Nemesia strumosa families derived from a cross of a 100% PSC plant to an unrelated 0% PSC plant. The first 100% PSC individuals occurred in the F₄. Populations derived through sib pollination tended to have higher PSC means than lines derived through self pollination. One F₃ family showed a three-fold higher PSC level when pollinated in the green-house than when pollinated in the growth chamber, while another F₃ family similarly pollinated showed no change in PSC.Scientific Journal Series Paper Number 10,356 of the Minnesota Agricultural Experiment Station     

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.     

Sporophytic-gametophytic herbicide tolerance in sugarbeet

Summary In vitro selection procedures for herbicide tolerance were initially developed in the sporophytic generation of sugarbeet (Beta vulgaris L.), and then tested in the gametophytic generation. The primary objective of our study was to develop and evaluate in vitro techniques for identifying genotypes within heterogeneous seedling populations tolerant to specific herbicides, and to use meristematic cloning procedures to synthesize clones genetically tolerant to the herbicide. Seed from cloned selections tolerant to the herbicide ethofumesate were obtained and compared to plants from seed of the original population (using germination, central bud development, and root dry weight). Verification for in vitro selection accuracy was accomplished by pollen germination studies in the gametophyte. The results indicate that in vitro selection of germinated seedlings in the presence of the proper concentration of challenging agent can be effective in identifying genotypes tolerant to ethofumesate. Such identification was accomplished in fully differentiated tissue, but without the necessity of mature plants. Gametophytic studies, via pollen germination, indicated an association between genes operating in the sprophyte and those in the gametophyte. Cloning the seedlings identified as tolerant genotypes, and subsequent intercrossing of these clones provided a convenient method of synthesizing populations with gene frequencies shifted in the direction desired.Joint contribution of the Agricultural Research Service, USDA, and the Colorado State University Experiment Station. Published with the approval of the Director of the Colorado State University Experiment Station as Scientific Series Paper No. 2952     

Inheritance of somatic embryogenesis and plantlet regeneration from primary (type 1) callus in maize

Summary Genetic factors controlling the differential expression of somatic embryogenesis and plant regeneration of maize from tissue culture were studied in two crosses. Inbred, hybrid, F2 and backcross generations developed from crossing maize inbred A188 with two commercially important inbred maize lines (B73 and Mo17) demonstrated genetic and environmental effects on somatic embryogenesis and plant regeneration when immature zygotic embryos were cultured on MS medium. Additive gene effects were more important in both crosses than dominant gene effects for precent somatic embryogenesis and percent or number of plants regenerated per embryo when generation means were analyzed. In backcross generations of each cross, cytoplasmic, maternal and/or paternal effects were significant for frequency of somatic embryos three weeks after culture as well as frequency, or number of plants regenerated per embryo, nine weeks after culture. Analysis of genetic variances suggests at least one gene (or block of genes) controls the expression of the frequency of somatic embryogenesis in these crosses. Differences in somatic embryogenesis and plant regeneration between B73 and Mo17 are discussed. This is Journal Paper No. 11,435 of the Purdue University Agricultural Experiment Station.     

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.     

Effects of mating system in Japanese quail

Summary A 17-generation selection experiment was conducted to study direct and correlated responses to mass selection under a mating system with alternating generations of full-sib inbreeding and wide outbreeding (population I) as compared with a mass selected, randomly mated population (population II). The selection criterion was an index of total egg mass to 78 days divided by adult female body weight. Estimates of heritabilities and genetic correlations are reported. Estimated heritabilities for the index were 0.38±0.04 and 0.29±0.05 in population I and II, respectively. Realized heritabilites were 0.10±0.05 and 0.12±0.03. For most traits studied the mean phenotypic values in the cyclic mated population decreased for inbred generations. Increased inbreeding levels also caused outbred generation means of population I to decrease through the first six or seven generations. After this period of adaptation to inbreeding selection response was positive for the index and positively correlated traits. Total response to selection under the cyclic inbred-outbred mating system did not exceed selection response made under random mating. However, the rate of response in the cyclically mated population exceeded that in the randomly mated population in later generations when the cyclically mated population had apparently adapted to inbreeding.Published with approval of the Director of the Montana Agricultural Experiment Station, Journal Series No. 1221     

Increased P diffusion as an explanation of increased p availability in flooded rice soils

Summary Phosphorus supply factors (capacity, kinetic, intensity, and diffusivity) and plant growth were the approaches used to assess P supply of flooded rice soils. Increases in the capacity, intensity, and kinetic factors, as measured by E-value, solution P concentration, and soil P release rate to a distilled water sink respectively, were unpronouced and infrequent upon water-saturation of ten soils. However, increases in the diffusitivity factor, as measured by ³²P diffusion coefficients, were at least ten-fold as soil moisture increased. The greatest increases in P diffusion occurred as soil moisture increased beyond one-third bar.Using a P fertilized soil or P treated powdered cellulose as the P source and a minus P nutrient solution to nourish a split root system with water and nutrients, data were obtained which suggested that P uptake and rice-shoot growth (indicators of P availability) increased with increasing moisture level. Phosphorus uptake and rice-shoot growth were greatst when the soil or P treated cellulose were water-saturated. These data indicate that increased soil P availability upon flooding can be attributed to an increase in the diffusivity factor.Paper Number 4532 of the Journal Series of the North Carolina Agricultural Experiment Station.Paper Number 4532 of the Journal Series of the North Carolina Agricultural Experiment Station.     

An approximate method for optimum independent culling level selection for n stages of selection with explicit solutions

Summary An approximate method with explicit solutions to apply independent culling levels for multiple traits in n-stages of selection was developed. An approximate solution was found for sequentially selected traits. Two assumptions were necessary. The first was to assume that subsequent selection would not appreciably change the mean of traits already selected, and the second was to approximate the variance of a correlated trait in a selected population with an upward biased projection. The procedure was shown to give near optimal results regardless of selection intensity or genetic correlations if phenotypic correlations among traits were low. The procedure gave poor results only for certain sequences of selection when phenotypic correlations were high. However, in those cases good results were obtained using a different sequence of selection. With high correlations, the procedure is recommended only after comparing solutions and expected genetic gain for all sequences of selection. If the expected aggregate gain for the sequence of selection desired is less than that of another order, culling points associated with the optimal ordering must be determined. Genetic gain from use of culling points is independent of order of selection. The procedure is recommended for use with computer programs that attempt to find optimal culling points to reduce computational time and to check results.Journal Paper No. 12448 of the Purdue University Agricultural Experiment Station     

Relative growth and nutrient accumulation rates for tobacco

Summary Tobacco plants (Nicotiana tabacum L.) were grown from transplanting until floral expression in the phytotron units of Southeastern Plant Environment Laboratories to evaluate the relationship between relative growth rate (RGR) and relative accumulation rates (RAR) of N, P, K, Ca, and Mg. RAR is calculated to be analogous to RGR. Plants were grown in both controlled-environment rooms with artificial light and air-conditioned greenhouses with natural light at three temperature conditions and three application rates of N-P-K. RGR and RAR were calculated only for the period of grand growth which occurred within the interval from 7 to 32 days after transplanting. In general, neither RGR nor RAR were affected by temperature or nutrient level. However, both temperature and nutrient level affected dry matter accumulation of the plants apparently by an influence on the rapidity with which plants adjusted to their new environment during the initial 7-day interval after transplanting. RAR for P and K were coequal with RGR of the whole plant; thus, the concentrations of P and K within the plant tended to remain constant during growth. RAR for N, Ca, and Mg were less than RGR for the whole plant; thus, internal concentrations of these nutrients declined during growth. RAR of N, Ca, and Mg for the whole plant were equivalent to RGR of the roots. As a rationale for the association of RGR of roots and RAR of N, it is proposed that the soluble carbohydrate pool in the roots concurrently influences both N absorption, as NO₃ ^-, and growth of new roots of immature plants. Research reported in this paper was supported in part by National Science Foundation (RANN) Grants GI-39229 and GI-39230. Operation of the Phytotron Units of Southeastern Plant Environmental Laboratories at Duke and North Carolina State Universities was supported by National Science Foundation Grants GB-28950-1A and GI-28951. Approved as Paper Number 4773 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, NC. Research reported in this paper was supported in part by National Science Foundation (RANN) Grants GI-39229 and GI-39230. Operation of the Phytotron Units of Southeastern Plant Environmental Laboratories at Duke and North Carolina State Universities was supported by National Science Foundation Grants GB-28950-1A and GI-28951. Approved as Paper Number 4773 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, NC.