bluuebunny/crossref_metadata_2025 huggingface dataset:
Single Plant Seed Sources for Uniform Soybean Physiology Tests1
Authors: Stutte C. A. , Blem A. R. , Weiland R. T.
Published: July 2010

Soybean [Glycine max (L.) Merr.] plants grown from bulk seed sources and from seed of single parent plants obtained at two edaphically and climatically dissimilar sites in Arkansas were evaluated for uniformity in several physiological and developmental processes. Using the determinate cultivar ‘Davis’, the mean values for the data obtained for most parameters did not differ significantly among the seed sources and production sites. There were, however, large ranges of values within the data. For most parameters, the ratio of variances between the two bulk sources and between the two single parent seed sources differed only randomly; however, large ratios were obtained when the data for plants from bulk seed produced at one site were compared to those for plants grown from single parent seed at the other site. The variance ratio comparisons strongly suggest that the greater portion of the observed variance was due to factors specific for the production sites. To a lesser, though significant degree, this variance also had an intra‐plant genetic component. To obtain maximum uniformity among plants in physiological studies, it would, therefore, be appropriate to use seed all grown at the same location throughout the studies. The use of soybean seed from the same parent plant would offer additional benefit, not only in promoting a high degree of genetic uniformity, but also in minimizing variability due to specific environments at production site.
Kernel Growth Rate and Duration in Maize as Affected by Plant Density and Genotype1
Authors: Poneleit C. G. , Egli D. B.
Published: July 2010

The rate of kernel dry weight accumulation and filling period duration of corn (Zea mays L.) have been suggested as significant factors that influence yield potential. To determine the importance and usefulness of these kernel characteristics, environmental and genetic variations should be investigated. The objectives of this study were to measure the effects of plant density on the kernel growth components and observe the inheritance of these characteristics in the F1 hybrids. Kernel dry weight accumulation rate and effective filling period duration (EFPD) were examined in three corn inbreds and their three F1 hybrids at two plant densities. Kernel dry weight accumulation rate was not affected by plant density; however, EFPD was 2.5 days less at the high plant density. The resultant, smaller kernels along with a reduced number of kernels resulted in a 20% yield reduction per plant at the higher plant density. Yield per plant and per unit area in response to changes in plant density were altered more by kernel number per plant than by kernel size.

A significant increase in kernel size contributed to the greater F1 yields although the major advantage of the hybrids was due to more kernels per plant. In two of the three F1 hybrids, the larger kernel size was due solely to longer EFPD's since the rate of dry weight accumulation of one of the parental inbreds was the same as that of the F1's. In the other F2 hybrid, both rate and EFPD were greater in the F1 genotype than for either parental inbred.

These data show that EFPD but not the rate of kernel growth is influenced to a limited extent by plant density and both are under genetic control. Thus genetic modification of these kernel growth components should be feasible.
Cytology and Breeding of Hexaploid Alfalfa. I. Stability of Chromosome Number1
Authors: Yen Sheng‐Tian , Murphy R. P.
Published: July 2010

Two hexaploid amphiploids (2n=6x=48), a naturally occurring hexaploid, and two hexaploid wild species of alfalfa (Medicago spp.) were used in this study. The parents, F1 hybrids, and a portion of their progenies were analyzed cytologically. Variation in somatic chromosome number was detected in most of the populations studied. Chromosome numbers varied from 2n=36 to 2n=51 with a mean of 46.7 ± 2.51 in the F1 population, and from 2n=33 to 2n=51 (except for one with 2n=72) with a mean of 46.1 ± 2.34 in the selfed and crossed progenies derived from euplold F1 plants (2n=48). The percentage of hexaploids was estimated at 64 in the F1 population and 27 in the selfed and crossed progenies of the euploid F1 plants.

A wide range in plant vigor among individual plants was observed in the field nurseries about 2 months after transplanting. The overall mean vigor score (I lowest to l0 highest) was 5.9 for the progenies of hexaploid F1 plants and 5.6 for the progemes of aneuploid F1 plants. Both values were significantly lower than the mean vigor of the cultivated check cultivars (2n=‐4x=32). The frequency of plants with vigor of 7 (average of the check cultivars) or higher within the progenies of hexaploid and aneuploid F1 plants was 38 and 28%, respectively. No apparent relationship was detected between vigor and the chromosome number of the plants. In the progenies of hexaploid F1 plants, 33% of the plants with vigor of 7 or higher were hexaploids.
Analysis of Genotype‐Environment Interactions of Potato Yield1
Authors: Tai G. C. C.
Published: July 2010

Three methods were used to study genotype‐environment (GE) interactions of potato (Solanum tuberosum L.) yield. They were chosen to represent single (stability variance σ1 of Shukla, 1972), two (genotypic stability parameters α, λ of Tai, 1971), and three (genotypic components v1, v2 and v3 of Tai, 1975) parameters of measurement of genotypic contributions to the GE interactions. Data of marketable yield (W) and three yield components: number of stems/plot (X), number of tubers/stem (Y), and mean tuber weight (Z) of 30 genotypes were collected from nine trials in New Brunswick. Significant differences were found for σ2, α, and λ among the genotypes. The estimates of σ2 were highly correlated to those of λ. Both parameters showed a curvilinear relationship with v1 and v2 suggesting low σ2 and λ values were due to moderate genotypic responses to the environmental components (r1 and r2) supporting X and Y. The linear response parameter α showed close association with v3 which measured the genotypic response to the environmental component (r3) supporting Z. The estimates of v3 showed a moderately positive correlation with the mean marketable yield (W) and were larger than those of v1 and v2 for most genotypes. The estimates of r3 were larger and more variable than those of r1 and r2 over the environments. It is thus concluded that difficulty would be encountered locating high yielding genotypes without sensitive responses to the variation of r3.
Tissue Culture of Annual Ryegrass ✕ Tall Fescue F1 Hybrids: Callus Establishment and Plant Regeneration1
Authors: Kasperbauer M. J. , Buckner R. C. , Bush L. P.
Published: July 2010

Calluses were established from internode and peduncle explants of field‐grown annual ryegrass (Lolium multiflorum Lam.) ✕ tall fescue (Festuca arundinacea Schreb.) F1 hybrids, and plants were regenerated from the calluses. Modified MS medium with different levels of 2,4‐dichlorophenoxyacetic acid (2,4‐D) was used to initiate (2 to 4 mg of 2,4‐D/liter) and maintain (2 mg/liter) callus and to regenerate (0.25 mg/liter) plants. Plants regenerated after the first two subcultures at 3 to 4‐week intervals appeared to be identical in appearance and chromosome number to the original source plants. The doubled chromosome number was obtained in some plants regenerated after an 8‐week subculture period in which the callus approached senescence. Increasing the number of subcultures before regeneration increased the frequency of phenotypic variants among the regenerants. The techniques described offer an opportunity for forage grass modification via cell and tissue culture.
Some Genetic Implications in the Transfer of High Fiber Strength Genes to Upland Cotton1
Authors: Culp T. W. , Harrell D. C. , Kerr T.
Published: July 2010

After 30 years of breeding, we have had recent success in overcoming the negative association between lint yield and fiber strength in upland cotton (Gossypium hirsutum L.). Lint yield and yarn strength were measured for at least 2 years on F5 and F6 lines derived from a series of crosses involving intermating and selection in the F2, F3, and F4 generations. Correlation coefficients between lint yield and yarn strength were altered from –0.93 to 0.45 by this process. Several breeding lutes recently developed by intermatings and selection have been successfully crossed to commercial cultivars with and without extra fiber strength genes, whereas previous crosses and backcrosses failed to produce segregates with both high yield and extra fiber strength. Moreover, the frequency of superior and rare plants have increased in the later segregating populations. The importance of linkage, rather than pleiotropism, in controlling the association between lint yield and fiber strength and its implications in breeding is discussed.
Cytogenetics of Paspalum urvillei ✕ P. intermedium and P. dilatatum ✕ P. paniculatum Hybrids1
Authors: Burson Byron L.
Published: July 2010

Vaseygrass, Paspalum urvillei Steud., 2n = 4x = 40, was crossed with P. intermedium Munro ex Morong, 2n = 2x = 20, and yellow‐anthered dallisgrass, P. dilatatum Poir, 2n = 4x = 40, was crossed with P. paniculatum L., 2n = 2x = 20. Parents and their hybrids were studied cytologically to determine the genome relationships between these species. Twenty‐five P. urvillei ✕ P. intermedium hybrids were produced; however, the plants were small and only six survived. One reciprocal hybrid was recovered. All hybrids studied cytologically had a chromosome number of 2n = 3x = 30. Meiosis was irregular with a mean chromosome association of 11.13 univalents and 9.45 bivalents per cell for the P. urvillei ✕ P. intermedium hybrids and 10.27 univalents and 9.57 blvalents for the reciprocal hybrid. These findings indicated that P. urvillei and P. intermedium have a common genome with some small structural differences. Since P. intermedium is represented by the II genome formula and the second P. urvillei genome is the J genome, P. urvillei has the basic genome formula of IIJJ, the same as that of yellow‐anthered P. dilatatum, a closely related species. One hybrid was recovered from the yellow‐anthered P. dilatatum ✕ P. paniculatum cross. It had 30 chromosomes with a mean pairing behavior of 10.2 univalents and 9.9 bivalents per cell, which indicated that the two species have a homologous genome. Based on chromosome size, it appears that P. panlculatum has the genome formula of JJ. The relationship of P. paniculatum to other Paspalum species with the JJ genome constitution was discussed. Information obtained concerning genome relations of these species support their taxonomic classifications.
Response of Soybeans to High Temperature During Germination1
Authors: Emerson B. N. , Minor H. C.
Published: July 2010

The variability among soybean [Glycine max (L.) Merr.] genotypes for tolerance to above optimal temperatures during germination was evaluated. In an initial screening, germination of 289 genotypes in maturity groups VIII, IX, and X was tested at 32 and 38 C. Forty‐eight of these genotypes germinated as well at 38 as at 32 C and were selected for further study.

Absolute response of the selected genotypes to temperature in subsequent tests depended on previous history of the seed. Germination of all selected genotypes was significantly reduced at 38 C in tests utilizing seeds stored for 15 to 18 months. Germination of stored seed of 21 genotypes was not significantly affected by temperatures as high as 36 C. When germination of fresh seed harvested at maturity or 3 weeks afterwards was compared at 32 and 38 C, the increase in temperature was found to reduce germination in both harvests, but most markedly among genotypes which were delay‐harvested.

Genotypes represented within each source (stored, harvested at maturity, and delay‐harvested) were classified for relative tolerance. A confidence interval drawn about the mean germination at 36 (stored seed) or 38 C (seed harvested at maturity and delay‐harvested seed) was used for dividing the genotypes into three classes: those with above, intermediate, and below average tolerance to high temperature. Four genotypes (PI 259538, PI 346304, PI 374166, and PI 374174) were consistently classified as having above average tolerance to high temperature, while four others (PI 174860, PI 203405, ‘Cherokee’, and ‘Hardee’) were consistently classified as having below average tolerance.

Results presented indicate that consistent genotypic differences exist for tolerance to high temperature during germination and that these differences can be most effectively identified among genotypes which have not been subjected to prior stress.
Inheritance and Morphological Traits of a Phytochrome‐controlled Single Gene in Bean1
Authors: Kretchmer Paul J. , Laing D. R. , Wallace D. H.
Published: July 2010

Three bean (Phaseolus vulgaris L.) lines that changed from indeterminate non‐climbing bush to indeterminate climbing, with control by the red/far‐red light ratio, were crossed with a line which remained an indeterminate non‐climbing bush under all red/far‐red ratios. The climbing trait was found to be controlled by one major gene based on segregation data in F2 and backcross progeny from crosses to both parents. Red light stimulated the activity of this dominant allele and far‐red light retarded it. As climbing occurred, internode elongation was greater in climbing than non‐climbing plants. Genetic control of flowering sensitivity to long‐day photoperiod was independent of the gene for climbing vs. non‐climbing growth habits. It was concluded that flowering and climbing are two genetically independent phytochrome‐controlled responses.
Association Between Grain Filling Rate and Duration and Yield Components in Rice1
Authors: Jones D. B. , Peterson M. L. , Geng S.
Published: July 2010

The identification of readily measured traits that are associated with higher yields of field crops is important to plant breeders. The objective of this research was to determine if differences in grain filling rate and duration existed in rice (Oryza sativa L.) and if so, were these grain filling parameters correlated with other yield related components of the rice plant.

Fifteen genotypes of rice were selected to represent a sample having diverse agronomic characteristics. Samples of panicles of the 15 genotypes were taken at weekly intervals for approximately 6 weeks during the grain filling period. The cubic polynomial model was found to closely fit the dry weight data (r2 ≥ 0.95 for all genotypes). Grain filling rate and duration as well as other grain filling parameters were determined from the model. Correlation between the grain filling parameters with yield components indicated that grain firing rate was more important than duration in this study. Grain filling rate, in turn, was positively and highly significantly correlated with actual panicle weight and 100‐grain weight and negatively correlated with panicles m‐2.
Inheritance of Resistance to Bacterial Wilt in Two Alfalfa Gene Pools: Response to Selection and Quantitative Analysis1
Authors: Viands D. R. , Barnes D. K. , Stucker R. E. , Frosheiser F. I.
Published: July 2010

Bacterial wilt (BW) caused by Corynebacterium insidiosum (McCull.) H. L. Jens. is a serious disease of alfalfa (Medicago sativa L.). High levels of resistance to BW in alfalfa are available, but the inheritance of resistance is unclear. Objectives were to study the response to selection for resistance to BW and conduct a quantitative genetic analysis of inheritance of resistance to BW in two unrelated alfalfa gene pools. In the study of response to selection, the original gene pool plus six cycles of selection in the MSA gene pool and the original plus eight cycles of selection in the MSB gene pool were evaluated simultaneously. In the genetic study three sets of six‐parent diallels, including reciprocals and selfs, were produced within each gene pool. Two sets of six‐parent Design II's were produced by crossing parents of one gene pool with parents of the other.

The results from the selection study suggested different modes of inheritance in the two gene pools. The response to selection in the MSA gene pool was quadratic, with a rapid increase in resistance in early cycles of selection; the response in MSB was linear and less rapid. In the genetic study variation due to reciprocals was nonsignificant in both gene pools and specific combining ability was significant only in MSB. Assuming a fixed model, all variances of genetic effects were greater in MSB than in MSA. General combining ability effects also suggested that inheritance was different in the two gene pools. The different types of inheritance suggested why the two gene pools responded differently in the selection study.
Selection for Winterhardiness in Wheat. I. Identification of Genotypic Variability1
Authors: Fowler D. B. , Gusta L. V.
Published: July 2010

Cold hardiness is the primary factor restricting the northward expansion of winter wheat (Tritlcum aestivum L. em. Thell.) in the Great Plains area of North America. Several factors, including the absence of a simple, reproducible method of screening, high experimental error associated with field trials, limited genetic variability, and difficulties in combining a high level of cold hardiness with other desirable characteristics have all been responsible for the lack of progress in breeding for this character. To assess the extent of these limitations 61 field trials were grown in Saskatchewan, Canada, from 1972 to 1977. Included in these trials were 43 winter wheat cultivars of diverse origin.

The Field Survival Index (FSI), based on a modified procedure for determining relative winter hardiness of cultivars in field trials, was developed. This method of estimating cuitivar winterhardiness potential reduces the experimental error associated with field trials, alleviates the difficulties arising from the absence of partial winteridll for a few cultivars in each trial, and allows for the pooling of results from different trials.

A wide ranges in FSI's was observed for the cultivars considered. These ratings suggest that most successful winter wheat cultivars have only marginally greater winterhardiness than the minimum required for the sea in which they are grown. As in the past, cultivars with USSR genotypes in their pedigrees had the highest winter terhardiness potential.
Effects of Intergenotypic Competition on Plant Height, Days to Heading, and Grain Yield of F2 through F5 Bulks of Spring Wheat1
Authors: Busch R. H. , Luizzi D.
Published: July 2010

The effect of intergenotypic competition in F2 through F5 bulk generations was evaluated in six tall/semidwarf crosses of spring wheat (Triticum aestivum L.). The bulks had been advanced each generation in competitive yield plots at a commercial production seeding rate. Approximately 100 seeds of each generation (F2 to F5) were sampled in each cross, space‐planted, and plant height and days to heading, both found to be monogenic in these crosses, were measured on each plant. The three photoperiod insensitive/sensitive crosses had excess numbers of short plants in the F2 and F3 but two of the three crosses fit monogenic expectations in the and F4 and F5 The sensitive/sensitive crosses fit the expected genetic ratio each generation. A minor shift toward tallness was observed by the F5 when data from the five homogeneous crosses were pooled. Individual insensitive/sensitive crosses fit the expected genetic ratios for days to heading in F5, but when pooled over crosses an excess late‐heading plants was detected.

Grain yield of the F2 through F6 of each of the six crosses across generations did not differ significantly. Correlations of the F2 bulk yields with yields of through F6 bulks remained positive with no appreciable decrease. Apparently, changes in bulk populations grown in North Dakota, heterogeneous for plant height and days to heading, were due primarily to genetic segregation, with intergenotypic competition having only minor, but significant, effects. These relatively minor shifts should not inhibit ease of selection for semidwarfism or early heading from competitively grown bulks in North Dakota.
Root Characteristics of Black Beans. II. Morphological Differences Among Genotypes1
Authors: Stofella P. J. , Sandsted R. F. , Zobel R. W. , Hymes W. L.
Published: July 2010

Total root biomass of two black bean (Phaseolus vulgaris L.) cultivars, ‘Black Turtle Soup’ (BTS) and ‘Strain 39,’ and four black‐seeded lines (70001, 70002, 70003, and 70004) was partitioned into adventitious, basal, and taproot components at several growth stages under both greenhouse and field conditions. Basal root weights were significantly higher for the four lines in the field and for 70001 and 70002 in the greenhouse than for BTS and Strain 39. Genotypes did not differ for adventitious root weights in both environments. Taproot weights were higher for all the lines compared with BTS; and for 70001, 70003, and 70004 compared with Strain 39 in the field. Genotypes did not differ for taproot weights in the greenhouse.

Stem, hypocotyl, and taproot diameters were significantly higher for all the lines than for the two cultivars in the field. Hypocotyl and stem diameters of all lines were higher than for the two cultivars, except for stem diameter of 70002 when compared with BTS in the greenhouse. Taproot diameters of 70001, 70002, and 70004 were significantly higher than for Strain 39 under greenhouse conditions. Basal root diameters (sum of individual basal root diameters) of the four lines were significantly higher than for BTS or Strain 39 in both experiments. Genotypes did^ot differ in the number of basal roots under field conditions.

In the field, most root parameters increased up to the seed initiation stage, followed by a significant decrease or no further increase at the pod fill stage. Significant stage ✕ genotype interactions occurred for basal root diameter and hypocotyl diameter in the field and for taproot weight, stem, hypocotyl, and basal root diameters in the greenhouse. The erect plant type of the lines may be attributable to larger basal roots.
Inheritance of Several Cold Tolerance Traits in Corn1
Authors: McConnell R. L. , Gardner C. O.
Published: July 2010

To learn more about early season growth of corn (Zea mays L.), generation means analyses were used to study inheritance of germination at 7.2 C in the laboratory, and emergence, juvenile growth, and yield in the field. Six inbred parents, their 15 F1 hybrids, their 15 F2, and their 30 backcross populations were used in the analyses. The inbreds were classified into warm (W) and cool (C) season groups based upon their reaction to cold and heat stress in previous experiments.

For the specific group of parents evaluated, generation means analyses indicated that epistatic gene effects as well as additive and dominance gene effects contributed significantly to the variation observed for germination at 7.2 C in the laboratory and for emergence measured in the field. Seedling vigor or growth after emergence in the field appeared to be conditioned predominantly by additive and dominance gene effects. Although some epistatic gene effects were detected, grain yield in the specific group of parents studied was controlled by additive and dominance gene effects.

Contrary to expectations, C ✕ C crosses were no better than W ✕ W or C ✕ W crosses for the cold tolerance traits studied. Percent germination and field emergence data favored W ✕ W crosses, while C ✕ C crosses were slightly better for early season vigor. W ✕ W crosses produced the highest grain yield followed by C ✕ W and C ✕ C crosses.
Yield Losses and Host Selection of Cereal Leaf Beetles in Resistant and Susceptible Spring Barley12
Authors: Webster J. A. , Smith D. H.
Published: July 2010

Yield losses of spring barley, Hordeum vulgare L., caused by feeding of the cereal leaf beetle (CLB), Oulema melanopus (L.), were determined by comparing yields of insecticide‐treated plots with CLB‐infested plots. The CLB caused substantial grain losses in three field tests in Michigan in 1974 and 1975. The average yield loss of seven susceptible barley cultivars in the three tests was 38% due to an estimated peak density of 1.6 larvae/stem. A CLB‐resistarit line from the USDA World Small Grain Collection, CI 6469, and USDA‐SEA No. 70222 with CI 6469 and CI 6671 in its parentage, produced high yields in beetle‐infested plots. In general, fewer CLB eggs and larvae were found on the resistant barleys than on the susceptible cultivars. It appears possible to use plant resistance in spring barley to reduce yield losses caused by the CLB.
Immediate Effect of Male and Female Gametes and N on Five Pearl Millet Grain Characteristics1
Authors: Burton Glenn W. , Rabson Robert , Axmann Helga
Published: July 2010

Pearl millet, Pennisetum americanum (L.) Leeke, inbreds ‘Tift 12,’ ‘Tift 13’, ‘Tift 18DB’, ‘Tift 23DB’, ‘Tift 239DB’, and ‘Bil 3B’ were grown in the field in plots fertilized with 15, 80, or 150 kg/ha of N with P and K adequate to study the immediate effect of male and female gametes and N on five pearl millet grain characteristics. Plants were replicated four times. Within each N‐treatment plot selfed, sibbed, open‐pollinated, and intermated seed was produced so that each genotype supplied both female and male gametes. Grain characteristics determined were thousand‐kernel weight (TKW), total amino N and proline (Pro) N of grain acid hydrolysates, N/Pro ratio, and dye‐binding capacity (DBC). Nitrogen treatments affected all grain characteristics except the N/Pro ratio, female gametes affected all grain characteristics, and male gametes affected TKW, proline and the N/ Pro ratio significantly. The female effect was greater than the male effect. Open‐pollinated seed was significantly higher than self‐pollinated seed in all characteristics measured. The data show that pollen source has an immediate effect on three of the pearl millet grain characteristics measured. They also indicate that selfpollinated seed of pearl millet and perhaps other cross‐pollinated crops should be used for the most accurate assessment of grain characteristics of any genotype. A minimum seed population and a standard pollen source could serve as an alternate but less desirable substitute for selfed seed for crops with a high degree of self‐incompatibility.
Inheritance of Seed Protein in Crosses Involving ‘Hand’: A Hard Red Winter Wheat1
Authors: Cowley Craig R. , Wells Darrell G.
Published: July 2010

‘Hand’ wheat (Triticum aestivum L.) is high in protein, has excellent baking and dough handling properties, and is resistant to leaf rust (Puccinia recondita Rob. ex. Desm. f. sp. tritici) and stem rust (P. graminis f. sp. tritici Eriks. and Henn.). The pedigree of Hand is uncertain. However, it possesses a single gene, SrTt1, for resistance to stem rust as determined by an F2 analysis of crosses with stem rust tester lines. A study was conducted of Hand to determine the inheritance of high seed protein.

Crosses were studied of Hand with ‘Centurk’ and an experimental line, TX62A2522‐8‐2, both low in protein, and of Hand with ‘WS1809’, a spring habit cultivar, and an experimental line, NE68513, both high in protein. Single plants of progeny rows of artificially vernalized seedlings of parents, F1, F2, F3 BCF1, and BCF2 were studied in the field. Hand differed from Centurk and TX62A2522‐8‐2 for protein level by one dominant gene for high protein which we have named PrHand. In NE68513*2/Hand, 21% of the BCF2 lines were higher in protein than NE68513 which derived recessive high protein from Atlas 66. Based upon dominance relations and transgressive segregation, we concluded that Hand and NE68513 have unlike genes for high percent seed protein.

Transgressive segregation was not detected in the reciprocal backcrosses involving WS1809 and Hand. However, three selected progeny rows from WS1809/2*Hand averaged 2.1 and 0.8 percentage points higher than the means of the respective parents. Although not significantly different, that may suggest a difference in genes or alleles for high protein. Selections higher in protein than Hand were most prevalent in crosses involving only high protein parents, providing additional evidence that different genes were involved.
The Effect of Carbohydrate Concentration on the Respiration Rate of Soybean1
Authors: Coggeshall B. M. , Hodges H. F.
Published: July 2010

Two experiments were conducted to determine the relationship between respiration rate and carbohydrate concentration in source and sink tissue in soybean (Glycine max (L.) Merrill). Experiment I was conducted during V8/R1, R2, and R4 stages of maturity. Defoliation, 92% shading, and control treatments established a range in sugar and starch concentrations for source leaves and the corresponding above.ground sinks at each stage. This range was primarily due to a reduction in source size by defoliation, or a reduction in photosynthate source by shading, thereby reducing the carbohydrate supply to the sinks. This range was primarily due to a reduction in source size by defoliation, or a reduction in photosynthate source by shading, thereby reducing the carbohydrate supply to the sinks. Respiration was positively correlated with carbohydrate content in V8/R1 and R2 tissues in which growth respiration predominates. However, where maintenance respiration likely predominated (R‐4 leaves and pods) the respiration‐carbohydrate content correlations were poor.

Experiment II was conducted during the R5 stage of maturity. Control, 92% shading, defoliation, and depodding treatments resulted in a range in sugar and/or starch concentrations in source leaves and pod tissues. Defoliation and shading reduced the carbohydrate supply from the source to the sink as in Experiment I. The two‐thirds depodding treatment was not severe enough to affect the carbohydrate concentration in the pods. However, starch accumulated in the leaves 7 days after the treatment was initiated. A significant positive relationship was found in the R5 leaves among respiration and sugar or starch concentrations. Conversely, an insignificant relationship was found in pods which contained predominately storage tissue undergoing maintenance respiration.
Relationship of “Bloomless” (bm bm) Sorghum to Greenbug Resistance1
Authors: Peiretti R. A. , Amini Iraj , Weibel D. E. , Starks K. J. , McNew R. W.
Published: July 2010

Parental, F1 and F2 sorghum [Sorghum bicolor (L.) Moench] populations involving the bloomless trait were studied for their reaction to greenbugs (Schizaphis graminum Rondani). Plants were grown in pots in the greenhouse, classified into bloom or bloomless (presence or absence of white wax on leaf sheath) categories, rated for greenbug damage, and studied for tolerance, anti. biosis, and non preference. The objective of the researchwas to learn more about the nature of the resistance of bloomless sorghum to greenbugs since bloomless may be useful in commercial sorghums.

Bloomless was inherited as a simple recessive with complete dominance of bloom. The tolerance to damage of ‘Shalin Grain’ and ‘IS 809’ by greenbugs was inherited independently of the bloomless trait. The bloomless plants did not exhibit greenbug tolerance as did Shallu Grain and IS 809, except where the two traits were combined in an F2 individual plant. Bloomless plants showed only slightly more of an antibiotic effect on greenbugs than the susceptible check and significantly less than the resistance check. In this study, bloomless plants 50 to 70 days old exhibited a significant nonpreference to greenbugs compared to the susceptible check.
Comparison of Achene Characteristics and Combining Ability of Branching and Non‐Branching Near‐Isogenic Sunflower Restorer Lines1
Authors: Dedio Walter
Published: July 2010

The achene characteristics and combining ability of branching and non‐branching near‐isogenic restorer lines were compared. Branching lines were considerably higher in oil content but had smaller achenes than the non‐branching forms. There was no difference in achene yield, oil content, and achene size between hybrids using branching and non‐branching restorer lines as male parents.
Leaf CER from Post‐Flowering to Senescence of Field‐grown Soybean Cultivars1
Authors: Sinclair T. R.
Published: July 2010

Data were collected continuously on the leaf CO2 exchange rates (CER) of field‐grown soybean cultivars. These data were recorded during two seasons from post‐flowering through leaf senescence. The soybean leaves were remarkably insensitive to most environmental conditions. Light saturation at 90 to 100 nE cm−2 sec−1 was readily achieved on most days and then, CER essentially plateaued for most of the midday hours. Only cool night temperatures significantly altered CER. When leaf senescence was uninterrupted by a cool night, CER decreased slowly and gradually over a 10 to 14‐day period. Substantial differences among cultivars were observed both in the maximum CER achieved and in the persistence of high CER throughout the season. Cultivars that showed superior CER did so consistently between the 2 years.
Effects of Potassium Fertilization on Nitrogen Fixation and Nodule Enzymes of Nitrogen Metabolism in Alfalfa1
Authors: Duke Stanley H. , Collins Michael , Soberalske Ronald M.
Published: July 2010

Studies with four‐year‐old ‘Vernal’ alfalfa (Medicago saliva L.) fertilized yearly from planting with 673 kg/ha K as K2SO4 or KC1 and 448 kg/ha K as K2SO4 were made to determine the effects of K on nodulation, acetylene reduction, and nodule enzyme activities. The high rates of K fertilization increased nodule number and acetylene reduction rates over control plants, although the greatest increase in nodule mass and acetylene reduction rates was with the 673 kg/ha K as K2SO4 treatment. This indicates that Cl and/or S may alter or mask the effects of K fertilization. Increases in acetylene reduction rates on a plant basis with K fertilization were due to increases in nodule mass and not increases in activity per unit weight of nodule tissue. With all treatments a positive linear correlation (P <0.01, r = 0.854) was found between nodule number and acetylene reduction rate. The greatest increase in shoot weight per plant over control plants was with the 673 kg/ha K as KC1 treatment. Positive linear correlations were found between rates of acetylene reduction and the activities of enzymes involved in ammonia assimilation (NAD‐glutamate dehydrogenase, glutamine synthetase, NADP‐glutamate dehydrogenase), amino acid interconversions (glutamate oxaloacetate transaminase), C supply (NADP‐isocitrate dehydrogenase) and energy transduction (glucose‐6‐phosphate dehydrogenase, malate dehydrogenase). Due to lower nodule protein concentrations and higher nodule masses in the K treatments, specific activities and, in general, activities on a per plant basis of enzymes assayed from K treatments were much higher than those of the control treatment. Malate dehydrogenase and NADP‐glutamate dehydrogenase specific activities were significantly higher than control plants for both 673 kg/ha K treatments. There were few differences between treatments for enzyme data calculated on a gram fresh‐weight basis. Yields of the two 673 kg/ha K treatments were nearly equal at third cut and were significantly higher than those of control plants. These data suggest that K fertilization increases alfalfa yields by increasing nodulation and N2‐fixation.
Partitioning within the Taproot Sink of Sugarbeet: Effect of Photosynthate Supply1
Authors: Wyse Roger
Published: July 2010

Genotypes of sugarbeet (Beta vulgaris L.) differ widely in partitioning of photosynthate between sucrose and nonsucrose dry matter in the taproot sink. Differences in root (sink) morphology between various genotypes and agronomic practices (cell size and distance between vascular rings) have been found to be related to photosynthate partitioning. The objective of this research was to determine the effect of photosynthate supply on partitioning within the root sink. It was hypothesized that altering the photosynthate supply would not affect partitioning, but would rather affect the growth rate of the root with no change in relative root morphology. Photosynthetic rates of field‐grown sugarbeets were increased by CO2 enrichment and reduced by shading. Carbon dioxide levels within the canopy were increased to 600 to 850 ppm using a propane‐fired CO2 generator with dry ice. In the shading treatments, light levels were reduced by 50% with a nylon mesh screen suspended above the canopy. Shading reduced total dry matter production by 29%, but had no effect on either the root:shoot ratio or the sucrose content of the taproot on a dry weight basis. Although the size of root was altered in the two treatments, the differences were compensated by increased or decreased frequency of vascular rings, resulting in no change in vascular density or in cell size. These results are consistent with previously proposed models for photosynthate partitioning within the taproot of sugarbeet and indicate that the partitioning mechanism maintains a constant partitioning ratio between sucrose and nonsucrose dry matter independent of photosynthate supply.
Inheritance of Cool‐Temperature Seedling Vigor in Rice and Its Relationship with other Agronomic Characters1
Authors: Li Cheng Chang , Rutger J. N.
Published: July 2010

Nature of gene action and inheritance of seedling vigor as measured by height of rice (Oryza sativa L.) seedlings grown for 14 days at 18 C was determined in the F1 and F2 generations of a nine‐parent diallel cross. Additive and dominance effects were highly significant, with additive effects being consistent over both the F1 and F2 generations, while dominance effects were somewhat inconsistent over generations. In the F1 and F2 hybrids, varying degrees of dominance or overdominance were observed for high seedling vigor. The minimum number of dominant alleles controlling the overall parental differences was estimated to be five in the F1 and four in the F2. A moderately high heritability for seedling vigor (57% and 70% for F1 and F2, respectively) indicated that a major portidn of the phenotypic variability is controlled by genes with additive and/or additive × additive effects. High general combining ability for seedling vigor was found in high seedling vigor parents. Seedling vigor was highly correlated with earliness and larger seed size, but relatively low correlations were observed with mature plant height.
Agronomic, Genetic, and Cytologic Evaluation of a Vigorous New Semidwarf Oat1
Authors: Brown P. D. , McKenzie R. I. H. , Mikaelsen K.
Published: July 2010

A vigorous new semidwarf line of oats (Avena saliva L.), designated as OT 207, was selected from OT 184 following irradiation of seed with 1,150 rads of fast neutrons. Because of the potential of a semidwarf oat, the genetics, cytology, and productivity of this new semidwarf were studied. The stature of OT 207 is controlled by a single dominant gene for which the symbol Dw‐6 has been assigned. Cytological observations showed that OT 207 contains 42 chromosomes and that meiosis and mitosis are normal. OT 207 is 34% shorter than its mother‐line. The height reduction is due to shorter internodes, particularly the peduncle. There is no change in the number of internodes. Lodging resistance and shattering resistance are superior to that of the check cultivars ‘Rodney’ and ‘Hudson.’

Yield of this semidwarf relative to the check cultivars has been variable. Usually differences in yield were insignificant or OT 207 yielded significantly less. In 19/75, OT 207 yielded significantly more at a 15 cm than at a 30 cm row spacing, while the yield of Harmon’ was not significantly different at the two spacings. Genotype by row spacing interaction was significant. In 1976, both varieties gave significantly higher yields at a 114 kg/ha seeding rate than at a 57 kg/ha, while neither genotype, row spacing (15 cm vs. 30 cm) or interactions were significant.
Dynamics of Osmotic Adjustment in Rice1
Authors: Cutler J. M. , Shahan K. W. , Steponkus P. L.
Published: July 2010

The dynamics of osmotic adjustment in response to the development of plant water deficits were studied in the leaves of several upland rice cultivars. As deficits developed, the osmotic potential of leaves of plants not previously stressed decreased more rapidly than expected if due only to dehydration, with the result that the loss of turgor was delayed. Under rapid soil drying conditions (4 to 6 days), osmotic potential declined nearly linearly with water potential as water potential declined to about −12 bars, but the rate was not sufficient to totally maintain turgor. Under slow soil drying conditions (20 to 22 days), the reduction of osmotic potential, after an initially more rapid decline which was sufficient to totally maintain turgor, was similar to that found under the rapid drying conditions. The final extent of active reduction of osmotic potential was identical under both rapid and slow drying conditions and resulted in minimum “fully hydrated” osmotic potentials of approximately −18 bars. Plants exposed to more than one cycle of stress and 2 days of recovery showed no active osmotic adjustment beyond this minimum during subsequent stress. Thus there was a limit to the extent of osmotic adjustment which was independent of the rate of stress development and stress duration. The actual extent of adjustment depended on stress history and stress intensity.
Root Volumes of Avena Species1
Authors: Carrigan Lori , Frey K. J.
Published: July 2010

Volumes of root systems were measured at regular intervals during the growth cycle of one oat cultivar and one (Avena saliva L.) line and four weedy oat (A. sterilis L.) lines. The oat plants were grown hydroponically by using modified Hoagland nutrient solution to provide the nutrient source. The experimental design was a randomized block with three replicates, and a plot consisted of two plants imbedded in a 6.3‐cm cork. Root volume was measured on each plot at weekly intervals by water displacement. When mature, the plants in a plot were harvested, separated into roots, straw, and panicles, and dried. Subsequently, dry weights were taken on the three portions

The oat lines and cultivars differed significantly in final root volume and weight and in panicle and straw weight. The relationship among genotypes for root volume varied with measurement period. The root volume per plot was quite similar for all genotypes until the 6th week. After 6 weeks the root volumes for five genotypes, CI 9170 and ‘Dal’ (A. saliva) and PI 324774, PI 324776, and PI 324780 (A. sterilis), did not change much (volumes of 2.5 ml/plot for CI 9170 to 6.5 to 8.0 ml/plot for the other four). But the volume of the A. sterilis line, PI 324748, increased from 10.0 ml/plot at week 6 to 28.0 ml/plot at week 16. PI 324748 also had significantly greater root, straw, and panicle weights at harvest.
Effectiveness of Selection in Upland Cotton in Stress Environments1
Authors: Quisenberry J. E. , Roark Bruce , Fryrear D. W. , Kohel R. J.
Published: July 2010

Much of the Upland cotton (Gossypium hirsutum L.) acreage growni n the UnitedS tates is producedin environments where lack of moisture and low temperatures frequently limit production. The purpose of the current research was to test the effectiveness of selecting for lint yield in such stress environments as compared with an optimal environment. Random F3 plants from a composite cross population were advanced two generations by self‐pollination. The F4 and F5 progenies were grown at Lubbock, Big Spring, and College Station, Tex. in 1976, and the F5 progenies were grown at the same locations in 1977. In both years, all locations were classified as deficient or adequate in temperature and moisture based on input heat units and available water. Genotype × environmenitn teractions, within‐location herltabifities, and genetic advance for lint yield were estimated.

In 1976, Lubbockw as deficient in heat units and adequate in precipitation, Big Spring was adequate in heat units and deficient in precipitation, and College Station was adequate in both heat units and moisture. Entries were not significantly different for lint yield at either Lubbock or Big Spring, although the genotype × environment interaction was significant for these locations. At College Station, entries were significantly different, whereas the genotypes × environment interaction was not significant. We concluded that selection within the stress environments was largely based upon genotype × environment interactions. A significant genetic advance for lint yield was realized at all locations when the selection was made at College Station in an environment considered optimal for the growth of Upland cotton.
Growth of Sugarbeet Seedling in Various Atmospheres of Oxygen and Carbon Dioxide1
Authors: Wyse Roger
Published: July 2010

The allocation of photosynthates is the result of complex competitive interactions between sinks for available photosynthate. The objective of this research was to determine if altered photosynthate supplies would change the normal partitioning patterns in young sugarbeet plants. Photosynthetic rates were enhanced by CO2 enrichment and photorespiration was reduced by a combination of high CO2 and low O2. The plants were grown in growth chambers having day‐night temperatures of 28/22 C with a photoperiod of 16 hours. When the first true leaves appeared, the seedlings were placed in treatment chambers within the larger growth chambers, and the following combinations of oxygen and carbon dioxide were established (% O2 — ppm CO2): 21‐300; 21‐1,000; 5‐300; 5‐1,000. Photon Flux Density within the treatment chambers was 320 /μE/m2/sec. The plants were maintained within the chambers for 10 days.

Elevated CO2 enhanced total dry matter accumulation by 180% but low O2 had no significant effect. The final dry matter accumulation expressed on a final leaf area basis was increased 56 and 19% by 1,000 ppm CO2 and 5% O2 respectively. The additional photosynthate resulting from enhanced photosynthesis was allocated preferentially to the root sink. The primary effect of low O2 was to enhance root diameter and leaf number, but low O2 had little effect on other growth characteristics. Results indicate that the young sugarbeet root is the preferred sink for additional photosynthate.
Recent Advances in Guayule Seed Germination Procedures1
Authors: Naqvi Himayat H. , Hanson George P.
Published: July 2010

Guayule (Parthenium argentatum Gray), a xerophytic shrub native to northeastern Mexico and southern Texas, is receiving renewed attention as a potential source of natural rubber in the semiarid regions of the world. A major problem in propagating guayule is seed dormancy. The objectives of this investigation were to evaluate and modify old seed treatment methods and to develop an improved standard procedure for quick and complete germination of guayule seeds to enhance breeding and improvement of the crop. The optimum concentration of sodium hypochlorite (NaOCl) needed for breaking seed dormancy was higher for younger than older seeds. Seeds should be washed and soaked in distilled water for 8 hours followed by a 2‐hour treatment with a solution of equal parts of gibberellic acid (200 ppm) and NaOCl (1.0% for fresh seeds, and 0.25% for 1‐year‐old seeds). With this procedure freshly harvested seeds germinated 100% under light and over 70% in complete darkness. Emergence of seedlings from soil depended primarily upon seed size. Large guayule seeds emerged better at all depths to 18 mm after standard treatment than did medium or small seeds.
Monosomics of Cotton1
Authors: Edwards G. Allan , Brown Meta S. , Niles G. A. , Naqi Safia A.
Published: July 2010

From 1946 to 1975, 166 monosomic plants of Gossypium hirsutum L. were placed in the monosome testing program at Beasley Laboratory. The 85 that have been identified have been deficient in one of the following chromosomes: 1, 2, 4, and 6 from the A subgenome; 16, 17, and 18 from the D subgenome. These monosomes came from irradiation treatments, translocations, tertiary monosomes, duplication‐deficiencies, cytological combinations, trisomics, other aneuploids desynaptics, other Gossypium species, cultivars, and breeding stocks.