bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Distance from Pollen Plant on Seed Produced by Male‐Sterile Cotton
Authors: Moffett Joseph O. , Stith Lee S. , Shipman Cahrles W. 
Published: July 2010

Because of increasing interest in hybrid cotton, Gossypium hirsutum L. a study was made in southern Arizona in 1973 and 1974 to determine a planting pattern of pollinator and male‐sterile rows that would give satisfactory yields of hybrid seed. In 1973 two rows of pollen plants were alternated with 14 rows of male‐sterile plants. The two male‐sterile rows closest to the pollen plants produced 49% more seeds per flower than were produced in the remaining male‐sterile rows. In 1974 an alternating pattern of 2 rows of pollen parents and 6 rows of male‐sterile parents was planted in 12 replications. There were no significant differences in number of seeds produced per flower among these male‐sterile rows. In both years the seeds were a higher percentage of the total boll weight in bolls from the male sterile plants than in bolls from the pollen plants (68.2 to 60.6 in 1973 and 68.2 to 62.0 in 1974).In both years production of hybrid seed was satisfactory. The male‐sterile plants produced 98% and 79% as many seeds per flower as the pollen plants in 1973 and 1974, respectively. The mean number of bees observed visiting cotton flowers at any given time varied from 0.45 to 10.13 per 100 flowers. Honey bees (Apis mellifera L.) made 38% of the total bee visits in 1973 and 84% in 1974.
Effect of Leaf and Pod Removal on the Distribution of 14C Labeled Assimilate in Soybeans1
Authors: Egli D. B. , Gossett D. R. , Leggett J. E. 
Published: July 2010

The effect of varying source‐sink ratios on the distribution of 14C labeled assimilate in soybeans (Glycine max (L.) Merr.) was investigated in a greenhouse experiment. Varying source‐sink ratios were created by pod (approximately 50%) or leaf removal (two side leaflets from each trifolioliate) at the end of flowering. A single leaf was exposed to 14CO2 17 days after application of the treatments. Pod removal reduced seed yield/plant and increased seed size, whereas leaf removal reduced yield, the number of seed/plant, and seed size. Seven hours after labeling a greater percentage of 14C remained in the leaf in the pod removal treatment (72%) than in either the leaf removal (55%) or the control (59%), and specific leaf weight was higher in the pod removal treatment.The distribution of 14C 24 hours after labeling was not greatly affected by the treatments. The pod removal treatment had a greater percentage of 14C in the labeled leaf, in the stem both above and below the node of the labeled leaf, and less in the seed. Removal of the leaves did not affect the percentage of 14C in the labeled leaf after 24 hours or the distribution of the 14C in the plant, probably because the source‐sink ratio was similar to that of the control. The primary effect of altering the source‐sink ratio was on the movement of 14C labeled assimilate out of the leaf.
Cytological, Morphological, and Agronomic Characteristics of Tall ✕ Giant Fescue Hybrids and Their Amphiploid Progenies1
Authors: Buckner R. C. , Webster G. T. , Burrus P. B. , Bush L. P. 
Published: July 2010

F1 hybrids (2n = 42) of tall fescue (Festuca arundinacea Schreb.) (2n = 42) ✕ giant fescue [Festuca gigantea (L.) Vill.] (2n = 42) were male‐sterile, had poor seed‐set when backcrossed to tall fescue, and generally were intermediate between parental species for most morphological characters. Sterility of the F1 hybrids was attributed to meiotic irregularity resulting from lack of chromosomal association of one genome of each parent. Frequency of mean univalents per cell and in mean micronuclei per quartet of F1s varied from 10.1 to 13.7 and from 2.9 to 6.5, respectively.Four generations of colchicine‐induced amphiploid progenies were male‐fertile, and seed‐set per panicle was equivalent to that of tall fescue. First‐generation progenies varied in chromosome number from 2n = 80 to 84, and in mean micronuclei per quartet from 1.15 to 2.57. Chromosomal pairing of the colchicine‐induced progenies was largely bivalent as evidenced by relatively few micronuclei. Chromosome numbers of fourth‐generation progenies varied from 2n = 53 to a maximum of 84. Ths occurrence of dodecaploids as the most frequent number in fourth‐generation progenies indicates that with rigid selection, rapid progress might be made in securing meiotically stable populations at the 2n = 84 chromosome level.Although hay yields of fourth‐generation progenies compared favorably with ‘Kentucky 31’ tall fescue, both stand and yield declined rapidly after first hay harvest. Poor agronomic performance of the fourth‐generation progenies could have been attributed to their narrow gene base. Because the forage quality of the fourth‐generation progenies was markedly superior to that of tall fescue cultivars, dodecaploid tall fescue ✕ giant fescue populations appear to have promise as a valuable forage crop.
Gaseous Exchange of Simmondsia chinensis (Jojoba) Measured with a Double Isotope Porometer and Related to Water Stress, Salt Stress, and Nitrogen Deficiency1
Authors: Adams J. A. , Johnson H. B. , Bingham F. T. , Yermanos D. M. 
Published: July 2010

Gaseous exchange of Simmondsia chinensis [(Link) Schneider] (a desert shrub which may provide a substitute for sperm whale oil) was studied by exposing leaves simultaneously to radioisotopes of water (3HHO) and CO2 (14CO2) to determine conductances to water vapor and total conductances to CO2 assimilation, respectively. Fixation rates of CO2 and mesophyll conductances to CO2 were calculated. Leaf conductance to water vapor and CO2 fixation rates decreased markedly only at very low values of soil‐water and leaf‐xylem pressure potentials and recovered to maximum values after having been subjected to soil water potentials below ‐‐40 bars, indicating the extreme drought tolerance of S. chinensis. The ratios of increased as water stress became more intense, suggesting that transpiration was reduced relatively more than photosynthesis, which could have considerable value under drought stress. Plants under intense water stress generally had little or no reduction in mesophyll conductance to CO2.There was no significant decrease in conductance to water vapor, CO2 fixation rate, or mesophyll conductance to CO2 with increasing salinity down to root medium osmotic potentials as low as —9 bars. This is consistent with the reported high salt tolerance of S. chinensis. Nitrogen‐deficient plants had significant reductions in CO2 fixation rate and mesophyll conductance to CO2 but not in conductance to water vapor.
Selection of Superior Cultivars of Oats by Using Regression Coefficients1
Authors: Eagles H. A. , Hinz P. N. , Frey K. J. 
Published: July 2010

Regression on environmental mean was investigated for measuring production stability of grain and straw yields of 80 lines of oats (Avena sativa L.) tested in 24 field environments. Mean squares for heterogeneity among regressions suggested that the regression parameter was not heritable for grain yield, but may be heritable for straw yield. The regression lines for straw yield tended to converge at an environmental yield level below that normally used for oat production. Therefore, selection with use of mean yields alone would save cultivars that are superior at all yield levels. This situation was attributed to a high correlation between regression coefficients and mean yields.Analyses were conducted on direct and cube‐root scales of measurement. The cube‐root scale was chosen to reduce the heterogeneity of error mean squares obtained from the 24 individual environments, but also was found to reduce the significance of the mean squares for heterogeneity among regressions. The effect of a transformation of the data on heterogeneity and usefulness of regression coefficients is discussed.
Heritability Estimates, Genetic Correlations, and Predicted Gains from S1 Progeny Tests in Three Grain Sorghum Random‐mating Populations1
Authors: Eckebil J. P. , Ross W. M. , Gardner C. O. , Maranville J. W. 
Published: July 2010

Means, variances, heritabilities, genetic correlations, and predicted responses were obtained for grain yield, other agronomicharacters, and grain protein by testing 200 S1 families from each of three random‐mating populations of Sorghum bicolor (L.) Moench. Means of the three populations differed significantly for all characters except kernel weight. The NP3R population, composed of adapted material, was higher yielding than NP5R, which contained exotic germplasm; however, NP5R had twice as much genetic variability for yield and most other characters. NP7BR, a narrow population, yielded the same as NP5R but had the lowest variability for plant height and days to bloom. The grain yield of NP7BR was decreased and its grain protein increased because of poorly pollinated antherless (al al) male‐sterile plants. Variances for yield‐related characters in NP7BR also were biased. Genotype × year interaction variances were low in all populations compared to genetic variances except threshing percentage in NP5R. Broad‐sense heritability estimates for bloom date, plant height, yield, and kernel weight were high in all populations. Heads per plant had the lowest heritability, especially in NP3R and NP7BR.Genetic correlations usually had the highest values in NP5R and the lowest in NP7BR. Grain yield per unit area generally was best correlated with grain yield per head, plant height, and threshing percentage. Days to bloom and grain protein percentage were negatively correlated with yield and had low values, except for NP5R.Predicted gains in yield from selecting the highest 20% of the families in each population were 16.3, 10.2, and 8.7 q/ha per cycle for NP5R, NP3R, and NP7BR, respectively. The smallest predicted gains were for tillers per plant and grain protein percentage. Both NP3R and NP5R appear suitable for recurrent selection studies.
Growth Analysis of Isoline‐Recurrent Parent Grain Yield Differences in Oats1
Authors: Brinkman M. A. , Frey K. J. 
Published: July 2010

Growth analysis studies were made on sets of four early and four midseason isolines of oats (Avena sativa L.) that had significant grain‐yield deviations from their recurrent parent in each series. These yield deviations occurred when yield genes, tightly linked to crown rust resistance genes, were transferred from unadapted Avena germplasm into the recurrent parent backgrounds through backcrossing. The higher yielding C.I. 8079‐ and C.I. 7171‐derived isolines had increased growth trait means in each series. Generally, these increases were significant in the early series but not in the midseason series, which also had smaller grain yield increases. C.I. 9170, the early C.I. 8079‐derived isoline, had a significantly higher leaf area duration (LAD), leaf area ratio (), growth rate (), and relative growth rate () than the early recurrent parent. The midseason C.I. 8079‐derived isoline, C.I. 9183, had increases for these traits, but none was significant. Leaf growth increases in the early and midseason C.I. 7171‐derived isolines, C.I. 9178 and C.I. 9188, were very small and presumably did not contribute to the grain yield advantages of these isolines. The low‐yielding C.I. 7232‐derived isolines X550I and C.I. 9192, had significantly lower LAD's, and their 's and 's were reduced, but not significantly.Although isoline‐recurrent parent growth trait differences were not always significant, the trends for these traits in the C.I. 8079‐ and C.I. 7232‐derived isolines, when compared to the recurrent parents, indicated that yield differences within these sets of closely related lines have morpho‐physiological causes that can be explained by growth analysis. LAD, , and were growth traits associated with grain yield differences in these isoline‐recurrent parent comparisons. However, C.I. 7171‐derived isolines had higher grain yields but similar LAD's when compared to their recurrent parents.
Photosynthetic Selection of Zea mays L. I. Plant Age and Leaf Position Effects and a Relationship Between Leaf and Canopy Rates1
Authors: Vietor D. M. , Ariyanayagam R. P. , Musgrave R. B. 
Published: July 2010

Leaf apparent photosynthetic (Pn) rates of inbred, hybrid, and open pollinated plants were studied in association with a continuing program of photosynthetic selection and improvement of Zea mays L. Of major interest was the influence of plant age and leaf position on Pn rates and on results of Pn selection. Apparent photosynthetic rates of multiplant canopies (Pc) of hybrid strain combinations of NY821 and C153 were also measured to determine if variation of Pn rates was indicative of variation of Pc rates.ANOVA revealed highly significant variation of Pn rates among pretassel, silk, and dough stages of inbred and open pollinated plants and among stages ranging from silk to late dent for hybrids. Pn rates generally declined as plants aged, but a small increase from dough to early dent was observed for two maize hybrids.Variation of Pn rates among lower, middle, and upper leaf positions was highly significant for three hybrids, but was rarely significant for the inbred and open pollinated plants. Pn rates of the three hybrids were substantially higher at upper positions from blister through early dent. A significant statistical interaction of age and position effects on the hybrid Pn rates alluded to a more marked age effected decline of Pn at upper positions.A simple comparison of mean Pn rates indicated that Pn response to plant aging and leaf position differed among maize genotypes. The differential response was potentially detrimental to Pn selection efforts.The similarity of trends of mean Pn and Pc rates and a highly significant regression relationship between Pn and Pc rates over time and between two hybrids provided evidence that variation of Pn rates was indicative of variation of Pc rates.
Relation Between Inbred and Hybrid Traits in Maize1
Authors: e Gama Elto E. G. , Hallauer Arnel R. 
Published: July 2010

We conducted correlation studies between plant and ear traits of inbred lines and single‐cross hybrids of maize (Zea mays L.) developed from Iowa Stiff Stalk Synthetic. We included 160 S7 lines and 320 single‐cross hybrids produced among the lines by use of the cross‐classification mating design. The 160 S7 lines were partitioned into 20 sets of eight lines to produce the 320 single‐cross hybrids (16 hybrids per set). Objectives of our study were to determine the relation between plant and ear traits of the inbred lines and their single‐cross hybrids and to determine the relation of plant and ear traits of the inbred lines with yield of the single‐cross hybrids. Two procedures were used: (1) correlations of inbred lines themselves with means of hybrids that had one inbred line in common and (2) correlations of the means of two inbred lines with their specific hybrids. Simple and multiple correlations were computed for each set of eight inbred lines and 16 single‐cross hybrids and combined across the 20 sets.Simple correlations of plant and ear traits of inbred lines and single‐cross hybrids were small in all instances for both procedures when combined across sets. The coefficient of determination (r2) was less than 0.16 in all instances. Correlations for individual sets for all traits ranged from significantly (P ≤ 0.01) negative to significantly positive. Sampling error was high among individual sets, indicating that small sample sizes can give misleading associations of traits. Multiple correlations of plant and ear traits of inbred lines with yield of singlecross hybrids were only 0.23 (Procedure 1) and 0.21 (Procedure 2). Our results showed that plant and ear traits of inbred lines were not good indicators of their performance in single‐cross hybrids. Correlations of yield of inbred lines with yields of single‐cross hybrids were 0.09 and 0.11. It seems that yield testing of inbred lines in single‐cross hybrids is the only procedure for determining the potential usefulness of an inbred line in single‐cross hybrids. Visual selection of morphological traits in inbred lines will not insure development of higher yielding single‐cross yields.
Seed Setting Efficiency in Eight Cultivars of Upland Cotton1
Authors: Turner John H. , Stewart J. McD. , Hoskinson P. E. , Ramey H. H. 
Published: July 2010

Seed setting efficiency was determined for six cultivars of Upland cotton (Gossypium hirsutum L.) in 1974 and eight cultivars in 1975 at Jackson, Tenn. The number of ovules per ovary was determined by examining blooms at weekly periods. Simultaneously tagged blooms provided identifiable bolls from each bloom period to determine the number of seeds per boll. Seed setting efficiency (S.S.E.) was calculated from: (seeds/boll ÷ ovules/ovary) in percentCultivars differed in ovules/ovary, seeds/boll, and S.S.E. both years. The influence of bloom periods, although significant for ovules/ovary both years, was less than cultivar influence. S.S.E. was also influenced by bloom period in 1974, with lower efficiency at the late bloom period. Cultivar ✕ period interactions were detected for ovules/ovary and seeds/boll in 1974 and for ovules/ovary in 1975.The combined analysis with six of the cultivars show that cultivars influenced ovules/ovary and seeds/boll far more than years or period of bloom. Year ✕ cultivar and year ✕ period interactions obscured the main effects upon seed setting efficiency.
Root and Shoot Development from Sugarcane Callus Tissue1
Authors: Nadar H. M. , Heinz D. J. 
Published: July 2010

Growth of shoots differentiated from sugarcane (Saccharum sp.) callus was enhanced by 5 mg naphthalene acetic acid (NAA)/I in the absence of coconut water, while 0.2 mg 2,4‐dichlorophenoxyacetic acid (2,4‐D)/1 stunted their growth. In the presence of NAA, a crown developed at the base of the shoot on which new shoots and roots developed, grew, and formed a clump of plantlets.Root growth could also be induced by trimming the leaves or by incubation at 15C for 4 to 6 weeks. Leaf trimming resulted in more vigorous root growth than cold treatment, although clonal differences were observed.Results indicate that a medium which stimulates differentiation does not necessarily stimulate shoot growth, and the hormonal requirements for shoot differentiation differ from requirements for root induction in sugarcane callus.
Analysis of Genotypic Similarity in Terms of Mean Yield and Stability of Environmental Response in a Set of Maize Hybrids1
Authors: Johnson G. R. 
Published: July 2010

An analysis providing full information on hybrid similarity and stability of response to environments is developed and applied to a study of 49 maize (Zea mays L.) hybrids grown at 18 locations. The model provides weighted estimates of hybrid means, coefficients of the regression of each hybrid on an environmental index, and coefficients of the regression of each hybrid on a set of orthogonal residual vectors that are the characteristic vectors of R̂R̂‵ where R̂ is the m ✕ n matrix of estimated deviations from the weighted regressions on the environmental index of n hybrids grown in m environments.Genotypic similarity was defined as euclidian distance between genotypes in the space whose coordinate axes were the 18 locations. In the analysis, the original data were orthogonally transformed into a space whose coordinate axes were the mean vector, environmental index vector, and the characteristic vectors of R̂R̂‵. By means of the transformation, genotypic similarity, mean differences, relative stability, and comparative stability could all be expressed in terms of a model of the regression of genotypic performance on linear comparisons among environments.A cluster analysis arranged the hybrids into groups that were differentiable in terms of means and stability. Differences among means was the greatest source of variation among clusters. Variation in stability was due primarily to response to the environmental index and the first characteristic vector of R̂R̂'.
Spontaneous and Induced Interspecific Gene Transfer For Crown Rust Resistance in Avena1
Authors: Sharma D. C. , Forsberg R. A. 
Published: July 2010

Crown rust resistance from Avena tetraploid CI 7232 was transferred to Avena sativa L. utilizing irradiation with thermal neutrons. The relationship between an alien chromosome from CI 7232 and its homologue in hexaploids was also studied.CI 7232, derived from a cross between A. abyssinica Hochst. (2n=28) and A. strigosa Schreb. (2n=14), possesses resistance (Pc‐15) to crown rust (Puccinia coronata Cda. f. sp. avenae Fraser and Led.) from A. strigosa. Earlier, CI 7232 was crossed with the susceptible hexaploid ‘Clarion’, and dark kernel color (D) and resistance (R) from the tetraploid parent were linked in nearly all F8 F10 lines. Only one of 1,355 F7 plants was found to have light kernel color (L) and resistance. We previously reported that all D‐R and L‐R plants were unstable for rust resistance, and that this instability was caused by the failure of a substituted alien chromosome (1′A) to transmitted through the pollen.In this study, seeds from two L‐R plants with 20″ 1′+1′A were irradiated with thermal neutrons (Total dose: Flux ✕ time of 8.8 ✕ 1012 / Nth / cm2). Irradiated seeds were space planted in a field nursery, inoculated with crown rust in early tillering stages, and classified prior to heading. Resistant plants were then crossed as pollen parents to Clarion as a screen for functional male gametes carrying resistance. Two of the resulting I‐Fl's were resistant, and ratios in their respective I‐F2 and I‐F3 populations confirmed monofactorial inheritance. Thus, Pc‐15 had been transferred from the alien chromosome to one in the hexaploid complement which had normal male and female transmission. Metaphase I and tetrad observations in two homozygous and two heterozygous I‐F3 plants revealed completely normal meiosis.In the original, nonirradiated, monosomic alien substitution plants (20″+l′+l′A), L‐R or D‐R alien chromosomes were loosely associated with their hexaploid mate in about 85% of the cells, but recombination between the two marker loci occurred only rarely. The L‐R recombinant chromosomes evidently still carry a large, non. homologous segment of the alien chromosome (including Pc‐15) which completely blocks its pollen transmission.
Heterosis in Full‐sibs Within and Between Half‐sib Families in Open‐Pollinated Varieties of Maize1
Authors: de León Jóse Luis , Lonnquist J. H. 
Published: July 2010

When the full‐sib reciprocal recurrent selection RRS(F) scheme is applied in a single open‐poliinated maize (Zea mays L.) population each random fuli‐sib (FS) family the result of a cross of plants from (a) within previous half‐sib (HS) family or (b) plants from different previous HS families. The effects of resulting differences in inbreeding on the heterosis in the two kinds of families were studied. Samples of each type were developed and evaluated in each of two maize populations. Grain yield, ear height, and moisture at harvest were considered. Results showed that FS between HS outyielded FS within HS families by 8.5 and 11.7% in the ‘Northwestern Dent’ variety and in ‘Early Flint’ composite, respectively. Assuming a 1% loss in yield for each 1% increase in inbreeding, both figures approach the 12.5% inbreeding coefficient calculated for FS within HS families.Full‐sibs made at random in a maize population are most likely to be FS between plants from different HS families. Some will not be. In the initiation of RRS(F) within a population, advantages exist where HS families are identified so as to assure that all FS arise from parents of different HS. Lower yielding FS formed from within HS family crosses will be avoided and not included in performance trials. This would enhance selection of superior FS crosses and increase genetic progress when a RRS(F) program is applied in maize breeding.