bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of White Mold Disease Reduction of Yield and Yield Components of Dry Edible Beans
Authors: Kerr Eric D. , Steadman James R. , Nelson Lenis A.
Published: July 2010

Surveys conducted from 1970 through 1973 indicated that dry edible bean (Phaseolus vulgaris L.) plants in western Nebraska irrigated fields averaged 30% infection, and bean fields averaged 13% loss due to the white mold fungus, Sclerotinia sclerotiorum. Plants severely infected by S. sclerotiorum sustained a mean decrease in seed yield of 44% when compared to healthy plants. Total seed yield, and the components of yield, including number of seeds per plant, 100‐seed weight, and number of pods per plant, were significantly reduced by S. sclerotiorum. Reduced number of seeds per plant was the major component of yield loss followed by reduced weight of 100 seeds. Field conditions favoring vigorous foliage growth and high yields of Great Northern and Pinto bean types also favored white mold development. Thus, regression analysis indicated that low to moderate levels of infection by S. sclerotiorum were often associated with higher yields, but with a high percentage of infection yield reduction occurred. A second degree polynomial gave the best correlation of the data (r = 0.56). The assessment of disease losses due to S. sclerotiorum is discussed.
Sterility Induced in Barley by a Synthetic Pyridone1
Authors: Hockett E. A. , Feltner K. C.
Published: July 2010

A chemical gametocide capable of inhibiting pollen production but not affecting female fertility, would be very useful in the production of hybrid barley (Hordeum vulgate L.). In this study, ‘Betzes’ and two ‘Unitan’ two and six row isogenics were sprayed with 0, 1, 2, and 4 kg/ha of sodium 1‐(p‐chlorophenyl)‐l,2‐dihydro‐4,6 dimethyl‐ 2 oxonicotinate (RH‐531) at the five and six‐leaf stages in an attempt to induce male sterility. Seed set was lowest on plants treated at the 4 kg rate and was as follows: Betzes, 18% at five‐leaf stage; Unitan two‐row 33% at six‐leaf stage; and Unitan six‐row 29% at six‐leaf stage. Four kilograms of RH‐531 caused 40% female sterility. Female sterility was greatest when plants were treated at the six‐leaf stage and Unitan six‐row had the most female sterility at that stage.

As rates of RH‐531 were increased, yield, plant height, flowers per spike, lodging, kernel size, and spike length of treated plots decreased. Yield and grain protein were negatively correlated (r = —0.90**), but grain protein/ ha was less in the 4 kg/ha plots because of lower yield. Spraying at the six‐leaf stage reduced yield and plant height more than spraying at the five‐leaf stage. Treatment affected the growth characteristics of Unitan six‐row less than it did the other two cultivars. The number of flowers per spike was reduced less at the six than at the five‐leaf treatment stage in the Unitan isollnes.

RH‐531 did not produce sufficient male sterility to be useful in hybrid barley production, and adverse side effects such as reduced female fertility and stunted plants were drastic.
Genetic Male Sterility in Pigeon Pea1
Authors: Reddy Belum V.S. , Green John M. , Bisen S. S.
Published: July 2010

Six male‐sterile plants, found in two apparently unrelated sources in pigeon pea (Cajantis cajan (L.) Huth) did not produce pollen. Crossing success was normal, indicating that the plants were female‐fertile. White translucent anther color distinguished male‐sterile plants from fertile plants, which had yellowish anthers. A single recessive allele was responsible for the male sterility described here. Study of microsporogenesis revealed that tetrads in male sterile plants did not separate and they completely disintegrated. The tapetum and the intercellular wall of the two adjacent microsporangia persisted in the mature anthers. The potential value of male sterility in breeding programs is indicated.
Evaluation of Cassava Germplasm for Productivity1
Authors: Kawano Kazuo , Daza Pablo , Amaya Alvaro , Rios Mario , Goncalves Wania M. F.
Published: July 2010

A yield evaluation in single‐row plots were made in Colombia of approximately 1,900 accessions of cassava (Manihot esculenta Crantz), collected throughout Latin America and 4,700 hybrid lines from crosses within the same germplasm. Superior genotypes were selected on the basis of harvest index (proportion of root weight to total plant weight) and root yield in single‐row plots and then evaluated in replicated yield trials under diverse environments. With a rainfall of less than 800 mm well distributed throughout the year on a fertile soil, root dry‐matter yield of 21 metric ton/ha/year (average of top 10 genotypes) was obtained without irrigation or fertilization. Yields of 12 metric ton/ha/year dry matter were obtained without irrigation in a climate with a 5 monthd ry season. Yields of 8 metric ton/ha/year dry matter were obtained on acid oxisols of the tropical savanna, with a moderatef ertilizer application. Several genotypes showedc onsistently superior performanceo ver the wide range of environments, and their yields exceeded those of correspondinglo cal strains by 50 to 150%. These results confirm that cassava is an efficient carbohydrate producer adapted to a wide range of environments, is tolerant of drought and acid soils, and offers a great opportunity for genetic improvement. Present farm yields of 3 to 5 metric ton/ha/year (dry matter) could be increased to 10 to 15 ton/ha/year through simple selection and improved cultural practices. Largescale carbohydratep roductioni n tropical savanna o xisols is possible by planting improved cassava genotypes.
Relationship Between Alpha Acids, Beta Acids, and Lupulin Content of Hops1
Authors: Likens S. T. , Nickerson G. B. , Haunold A. , Zimmermann C. E.
Published: July 2010

The sum of (α+β) acids in lupulin glands of 112 female and 24 male genotypes of hop (Humulus lupulus L.) averaged 73 ± 6% by weight. Alpha‐ and beta‐acid content in glands from male or female hops was inversely correlated (r = −0.78 for females; −0.85 for males). A significant change in the a‐acid content of lupulin was associated with a similar change of β‐acid content in the opposite direction.

The α‐acid content of hop cones was related to the quantity and quality of lupulin in the cones. The lupulin quantity was proportional to the sum of (α+β). Lupulin quality was related to the ratio of α‐ and β‐acids (α/β).

Six test crosses were made with parents having high or low α/β values, respectively. The average α/β value for progenies from each cross was nearly identical to the parental midpoint. Data presented in this paper led to formulation of a new working hypothesis for the relationship between hop acids and lupulin content. Lupulin analysis is simple, and a modest laboratory can screen several hundred genotypes each season.
Relationship of the Kernel Sink for N to Maize Productivity1
Authors: Tsai C. Y. , Huber D. M. , Warren H. L.
Published: July 2010

This study was designed to evaluate the relationship of zein content with yield potential of maize (Zea mays L.). Maize cultlvars were grown under different rates of N (0 to 201 kg/ha) with and without nitrapyrin (0.55 kg/ha) added to correlate protein content, kernel weight, and grain yield. Carbon‐14 dioxide was applied to maize hybrid, Pioneer 3369A, to determine the effect of N on sucrose translocation into kernels. The results indicate that zein and glutelins combined may serve as a functional N sink in the kernel to affect starch accumulation, kernel weight, and yield; however, zein may be more effective because its synthesis can be manipulated readily by N fertilization and genetic means. A positive correlation between zein content, kernel weight, and grain yield was consistently observed. The quantities of zein produced vary according to the amounts of N fertilizer applied. The increase in zein with higher rates of N fertilization (up to 201 kg/ha) did not decrease the nutritional quality of seed protein because increases in germ size and a slight increase in non‐zein protein in the endosperm occurred concurrently. Based on this data, the selection of maize hybrids which are capable of producing maximum amounts of zein with additional available N should provide a means of increasing kernel weight and grain yield through the greater N sink potential of these hybrids.
Genetic Variation for Perloline, N, and Digestibility in Tall Fescue1
Authors: Watson C. E. , Frakes R. V. , Chilcote D. O. , Sleper D. A. , Matches A. G.
Published: July 2010

Fifteen single‐crosses of a six‐parent diallel of tall fescue (Festuca arundinacae, Schreb.) were evaluated for perloline concentration, N content, and in vitro digestibility. The crosses were planted at Corvallis, Oregon, and Columbia, Missouri, and harvested on 8 Apr. and 22 Sept. 1975 at Corvallis and on 16 Oct. 1975 at Columbia. The data were analyzed as two experiments. Experiment I consisted of the two harvests at Corvallis and experiment II consisted of the harvests of 22 September at Corvallis and 16 October at Columbia. Both experiments were analyzed for perloline concentration and N content, but only experiment II was analyzed for in vitro digestibility. General (GCA) and specific combining ability (SCA) were significant sources of variation for perloline concentration. SCA indicated some nonadditive gene action for perloline concentration. There were differences between environments as well as genotype ✕ environment interactions in both experiments. GCA was a significant source of variation for nitrogen content in each experiment. However, environmental differences were larger than genetic differences. No differences were found among the crosses for in vitro digestibility, but there was a rather large difference between the two locations. It appeared that digestibility could be improved more by management than by selection in this population.
Diallel Analyses of Grain Yield, Percent Protein, and Protein Yield in Grain Sorghum1
Authors: Wilson N. D. , Weibel D. E. , McNew R. W.
Published: July 2010

A six‐parent diallel cross, including reciprocals, of grain sorghum [Sorghum bicalor (L.) Moench] was analyzed for grain yield, percent protein, and protein yield. Highly significant differences were observed among parents and F1 hybrids for each trait. Reciprocal differences were not significant, but a partial failure of assumptions for the Jinks‐Hayman analysis was noted for all traits.

Differences among the parents indicated an additive component of genetic variation for all traits. The estimates for non‐additive components suggested that dominance was important for all traits. The degree of dominance was estimated to be in the overdominance range, particularly for the yield traits. Dominance was in the direction of higher yields and lower percent protein. The positive and negative alleles were estimated to be equally frequent for yield; or percent protein, the negative alleles were estimated to be more frequent. These results suggest that improvement of percent protein requires selection for recessive alleles that have a low frequency; improvement of yield requires a method to cope with overdominance.

Highly significant GCA and SCA effects were observed for all traits. A comparison of their relative magnitudes indicated SCA effects were much more important than GCA. Specified comparisons among the parents were made for GCA and among the parents and hybrids for SCA.
Variability and Inheritance of Sulfate Uptake Efficiency and ATP‐Sulfurylase Activity in Maize1
Authors: Cacco G. , Ferrari G. , Saccomani M.
Published: July 2010

Sulfate uptake efficiency of roots and ATP‐sulfurylase activity in leaves and in roots were evaluated in maize (Zea mays L.) inbreds W75, 65B, 103B, and in the diallel set of F1 hybrids, in order to assay the variability and the inheritance of the two characters. The correlation at the level of genetic regulation between the uptake and the first step of sulfate metabolism was also determined. Wide genetic differences were seen in the uptake efficiency and in enzyme activity. These traits demonstrated a close correlation and a high level of heterosis. The kinetics of sulfate uptake was also affected by crossing; Vmax followed the same pattern as uptake efficiency, while Km, with the exception of the 103B ✕ 65B cross, showed a low level of heterosis.
Evaluation of the Pure‐line Family Method for Cultivar Development1
Authors: Ivers D. R. , Fehr W. R.
Published: July 2010

The pure‐line family method (PLF) has been proposed as a means of developing high yielding cultivars. The method consists of harvesting individual F2 plants from a population and selling the bulk progeny of each plant (family) to a desired level of homozygosity. individual plant (pure line) is harvested from each family, and yield tested in replicated trials. If a line has superior performance, additional plants from the F2 family are evaluated as potential cultivars.

Two soybean [Glycine max (L.) Merr.] populations were used to compare the PLF method with three alternative methods used by soybean breeders, early‐generation testing of bulk progeny from F2 plants (BF), pedigree selection (PS), and single‐seed descent (SSD). derived lines developed by each method were compared for yield during 2 years. The BF method was superior to PLF for identifying the top F2 families, but the number of superior F5 lines selected was similar. The PLF method produced a greater number of superior pure lines than did PS or SSD. Yield of the top line was not different for the four methods.

The choice between PLF and BF would depend on the resources available and the breeding objective. The PLF method generally would be a faster method for cultivar development than BF, but BF would be preferred when recurrent selection by early‐generatlon testing was feasible for improving a character. Cultivar development with PLF would be faster than with PS when winter facilities were available for generation advance. The PLF method may provide a larger number of superior F5 lines than SSD; however, it would sample less genetic variability and require more years, land, labor, and record keeping than SSD.
Photoperiod and Critical Duration for Flower Induction in Soybean1
Authors: Shanmugasundaran S. , Tsou Samson C. S.
Published: July 2010

A photoperiod sensitive (sensitive) soybean [Glycine max (L.) Merr.] line and photoperiod in sensitive (insensitive) line were used to determine the critical seedling stage before possible floral induction and the length of photoinduction required for anthesis. Seedlings of each entry were grown in pots and subjected to either a 10‐ hour or 16‐hour photoperiod. Beginning 3 days after emergence, two pots per entry in the 10‐hour room were exchanged daily with two pots from the 16‐hour photoperiod. No detectable differences between treatments were observed in the flowering time of the insensitive fine. However, the sensitive line exhibited the following: (i) The number of days to first flowering was not affected by the transfer from a 16‐hour to a 10‐hour photoperiod up to 9 days after emergence; (ii) Plants moved from a 10‐hour to a 16‐hour photoperiod before 36 days after emergence did not flower, indicating that induction was completed at 36 days after emergence; (iii) The earliest anthesis occurred 46 days after emergence.

Therefore, we concluded that the induction period was 27 short days (10 hours) and that anthesis occurred 10 days after the completion of induction. The critical time to begin induction was 9 days after emergence for the sensitive line.
Identifying Turgor Responses of Water‐Stressed Cotton to Rapid Changes in Net Radiation Using Spectral Analysis1
Authors: Davis Jerry M. , Huck Morris G.
Published: July 2010

The kinetics of stem shrinkage and swelling in response to changes in the radiation loading of field‐grown cotton (Gossyplum hirsutum L.) plants were examined by time series spectral analysis. This technique involves determination in the frequency domain of the relationship between two time series events. The type and degree of relationship a.re assessed by computing the squared coherency, phase, and gain spectra relating events in the measured net radiation and stem diameter data sets. The squared coherency spectrum shows the statistical strength of the relationship between events in the two time series, while the grain spectrum indicates the amount of response, or the mm of change in stem diam. eter resulting from a unit change in radiation intensity at each frequency. The phase spectra show the relative positions between maximum points in the two time series

Plants growing under conditions of water stress respond to changes in radiation much more rapidly than those growing on well‐watered, deep soils. Although low frequency (slow) shrinkage response may be caused factors affecting both evapotranspiration from the leaves and root water uptake, high frequency (rapid) shrinkage or swelling responses are probably controlled exclusively by alterations in the rate of water loss because of the water storage capacity of the plant itself.
Meiotic Behavior of a Disomic Nematode‐Resistant Sugarbeet1
Authors: Yu M. H.
Published: July 2010

A disomic (2n = 18) sugarbeet (Beta vulgaris L.), selection 51501, resistant to cyst nematode (Heterodera schachtii Schm.), was recovered from the progenies of resistant alien addition lines. Meiosis of this plant was not normal and gave univalents, laggards, fragments, bridges, unequal chromosome distribution, restitution nuclei, and “carry‐over” AI bridges. Two heterozygous paracentric inversions were evident. These aberrations were not necessarily related to the nematode resistance. Nuclear restitution occurred in either the first or second division, or both; consequently, diploid and tetraploid gametophytes were produced. More than 25% of the pollen aborted. The preliminary findings showed that nematode resistance was transmitted to the progenies through the pollen and ovules at an equally low rate (13%). A multiple gene hypothesis of three complementary dominant genes was proposed to interpret the phenomenon of the low frequency transmission of nematode resistance.
Concentrations of Chlorogenic Acid, Oil, and Fatty Acids in Developing Sunflower Seeds1
Authors: Dorrell D. G.
Published: July 2010

The concentrations of chlorogenic acid, oil, and fatty acids were determined during the development and maturation of sunflower seeds (Helianthus annuus L.). When the cultivars ‘Krasnodarets’ and ‘Peredovik’ were sampled at 4‐day intervals from 5 to 29 days after flowering (DAF), the average chlorogenic acid concentration of hull‐free sunflower meal declined from an initial value of 0.40% to 0.18% at 9 DAF, then steadily increased to 1.96% by 29 DAF. This latter value represented three.quarters of the total chlorogenic acid deposited. The change in oil and chlorogenic acid concentrations followed relatively similar patterns (r = 0.93, at the 0.01 level, 25 dr). However, oil content did not decline during the first week and the period of most rapid increase in oil content occurred about 5 to 7 days before that of chlorogenic acid. The proportion of paimitic acid in the total fatty acids declined from an average of 26% at 5 DAF to 6.5% at 29 DAF, whereas linoleic acid declined from 49.6% at 5 DAF to 38.4% at 13 DAF then steadily increased to 67.0% at 29 DAF. This pattern was partially due to the presence of up to 12% linolenic, arachidic and behenie acids in imma. ture seeds, followed by their virtual disappearance by 17 DAF. Additional sampling between 21 and 49 DAF confirmed that most of the chlorogenic acid in sunflower seeds is synthesized between 13 and 35 DAF with the highest rate occurring between 21 and 28 DAF. Because maximum seed weight, oil content, and chlorogenic acid concentration coincide, it would not be practical to reduce chlorogenic acid levels in seeds by early harvesting.
Nitrate‐Reductase Activity and Grain Yield of Maize Cultivar Hybrids1
Authors: Fakorede M. A. B. , Mock J. J.
Published: July 2010

Nitrate‐reductase activity (NRA) has been suggested as an indirect selection criterion for grain yield in maize (Zea mays L.). This assumes that because of linkage or pleiotropism selection for higher levels of one of these traits would result in a correlated positive response in the other. We tested this hypothesis with maize cultivar hybrids obtained from two recurrent selection programs for improved grain yield.

Five maize cultivar hybrids [BSSS(R)CO ✕ BSCB1 (R)CO, BSSS(R)C5 ✕ BSCB1(R)C5, and BSSS(R)C7 ✕ BSCB1(R)C7 from a reciprocal recurrent selection program involving Iowa Stiff Stalk Synthetic (BSSS) and Iowa Corn Borer Synthetic #1 (BSCB1), and BS12CO ✕ B14A and BS12C6 ✕( B14A from a half‐sib family selection program with the open‐pollinated cultivar ‘Alph’ (BS12)] were grown in 1975 and 1976 at four levels of fertilizer N (0, 90, 180, and 270 kg N/ha) and two plant densities (39,500 and 98,800 plants/ha) in Experiment I. Also, CO )✕ CO and C7 ✕ C7 from the reciprocal recurrent selection program and the hybrids from the half‐sib program were grown in 1975 and 1976 at 59,300 and 98,800 plants/ha with 178 kg N/ha (Experiment II). We assayed NRA by the in vivo technique during the vegetative, anthesis, and grain‐filling stages of development.

Our results showed that average NRA did not change with selection for increased grain yield in the reciprocal recurrent selection program, but selection for improved grain yield in BS12 (half‐sib selection program) was associated with decreased NRA.
Effects of Four Maize Endosperm Mutants on Kernel Vigor1
Authors: Rowe D. E. , Garwood D. L.
Published: July 2010

Kernel vigor of 16 combinations of four recessive endosperm‐altering genes — amylose‐extender (ae), dull (du), sugary (su), and waxy (wx) — was measured to evaluate the potential of these genotypes for sweet‐corn (Zea mays L.) use. Each genotype was studied in near‐isogenic lines, ranging from five to seven backcrosses, of sweetcorn inbreds ‘S3‐61’, Ia5125’, and ‘Ia453’. Replicated 50‐kernel samples were placed in germination toweling, and measurements of (a) germination percentage, (b) average shoot length, and (c) dry weight of roots and shoots were made after growing in cold‐stress test (7 days at 10 ± 0.5 C followed by 5 days at 25 ± 0.5 C). Genotypes with the ae phenotype (ae, ae du, ae su, ae wx, ae du wx, ae su wx) had poor vigor and exhibited some reduced germination and decreased seedling shoot length. In contrast, genotypes with the su phenotype (su, su wx, du su, and du su wx) performed consistently better than genotypes homozygous for ae. Measurement of vigor based on total growth weight (c) gave more consistent results across inbreds than did measurements (a) and (b) averaged over the 50‐kernei sample size. Differences among inbreds were large, indicating that the choice of inbred parents may overcome the deleterious effect of some endosperm gene combinations and permit their use as new sweet corn types.
Protein and Lysine Contents of Endosperm and Bran of the Parents and Progenies of Crosses of Common Wheat1
Authors: Vogel K. P. , Johnson V. A. , Mattern P. J.
Published: July 2010

Grain samples from parent and progeny rows of the common wheat (Triticum aestivum L.) crosses, ‘Nap Hal’/ ‘Atlas 66’ and Nap Hal/‘Super X’, were fractionated into their starchy endosperm and bran components to determine the within‐kernel site of their variation in protein and lysine concentration. Nap Hal and Atlas 66 are highprotein wheats. Nap Hal also has elevated grain lysine content. Super X has average protein and lysine content. Transgressive segregation existed both for high and low endosperm protein concentration among the F5 progeny rows of Nap Hal/Atlas 66. Low‐protein progeny rows had endosperm protein percentages that were 3 to 5 percentage points lower than the parental mean (19.5%). High‐protein progeny lines were 2 to 4 percentage points higher than the parental mean. Nap Hal and some of the progeny rows were 5 percentage points higher in bran protein content than Atlas 66. Endosperm and bran protein percentages of Nap Hal/Super X F4 progeny were within the parental range. Some progeny rows had endosperm and bran protein concentrations equal to those of Nap Hal. Variation among the progeny rows for endosperm and bran lysine (% of protein) concentrations was within the range of variability of the replicated parental rows. Variation for grain protein content among the progeny rows of both crosses was due to variation for both endosperm and bran protein content. Variation for grain lysine (% of sample) among the Nap Hal/Atlas 66 progeny rows was due primarily to variation in endosperm and bran protein content with endosperm and bran lysine (% of protein) being of lesser importance.
Effects of Bean Association on Yields and Yield Components of Maize1
Authors: Francis C. A. , Flor C. A. , Prager M.
Published: July 2010

Maize (Zea mays L.) in monoculture and in association with bush and climbing beans (Phaseolus vulgaris L.) was evaluated at CIAT in the Cauca Valley, Colombia (1,000 m elevation, 4° N lat). Since small farmers in the Andean zone plant maize at low densities in association with beans, the objectives were to measure the effects of the associated legume crop on maize yields and net returns.

Maize yields did not differ significantly between monoculture and associated cropping at harvest densities from 3 to 4 ✕ 104 plants/ha, in trials with different bean cultivars, bean plant densities, planting systems, and relative dates of planting of the two crops. There were no significant differences between systems in the following maize components: ear length, ear and cob diameter, row number, shelling percent, weight per 100 seeds, harvest index, prolificacy index, total biological yield, or plant height. Lodging was less severe in an associated culture of maize, wiht an average of 16.4% in association compared to 28.7% in monocrop over six trials. Less fall armyworm (Spodoptera frugiperda Smith) attack was observed in associated crop maize than in monoculture. Efficiency of land use increased with addition of beans to the system, and highest net income was achieved with associated cropping systems. These results may help to explain why small farmers continue to utilize associated cropping systems in the tropics of Latin America.
Response of Prolific and Nonprolific Maize to Growth‐Regulating Chemicals
Authors: Sorrells M. E. , Harris R. E. , Lonnquist J. H.
Published: July 2010

In two different experiments, three prolific and three nonproliflc single‐cross hybrids of maize (Zea mays L.) growth were treated with growing regulating chemicals to determine their effects on ear development. In experiment A, the compounds used were N‐l‐naphthylphthalamic acid (NPA), p‐chlorophenoxyisobutyric acid (PCIB), and 6(γ,γ‐dimethylalllyamino) purine (i6Ade), all at concentration of 10‐4M. Treatments were applied as 0.5‐ml injections to the internode between the first and second ear shoots of nonprolific hybrids and between the second and third ear shoots of prolific hybrids. The auxin translocation inhibitor (NPA) significantly increased total yield of nonprolific hybrids and increased lower ear grain weight and ear number of all hybrids. The antiauxin, PCIB, had no discernible effect, while i6Ade (cytokinin) treatments decreased total yield of nonprolific hybrids and the yield of lower ears of all hybrids. In experiment B, upper ear shoots were excised on the day of silking and treatments of indolebutyric acid (IBA), gibberellic acid (GA3), and cytoklnin (i6Ade) were injected into the remaining ear shank. Gibberellic acid and combinations of IBA and GA3 treatments sgnificantly reduced ear number. The results of these experiments indicate that indoleacetic acid (IAA), GA3, and possibly other hormones interact in a time‐dependent mode to inhibit lower ear development. The close relationship between sink size and total yield demonstrates the importance of an adequate sink for plants grown at low density.
A Visual Indicator of the Physiological Maturity of Soybean Seed1
Authors: Crookston R. Kent , Hill David S.
Published: July 2010

The objective of this study was to identify a visual indicator of the physiological maturity (PM) of soybean (Glycine max [L.] Merrill) seeds. Six soybean cultivars with different seed colors at maturity were grown in the field for 2 years, and the date of maximum seed dry weight accumulation at nodes seven, eight, and nine was determined. Visible seed, pod and leaf charactexistics throughout the maturation process were recorded. Maximum seed dry weight occurred when the seeds had an average of 58% moisture. Of the 11 selected visible criteria, the one that coincided consistently with the determined date of PM was the initiation of seed shrinkage. The complete loss of green color from the pod was also a reliable indicator of PM since it always occurred in the sampling period immediately following observed seed shrinkage. Because the determined date of PM in this study could have been slightly premature, the loss of green color in the pods might be considered the better indicator of seed PM. Loss of green color from the pods would be a convenient and rapid field determination of PM.
Genotypic Variation in Maintenance of Leaf Water Potential in Rice1
Authors: O'Toole J. C. , Moya T. B.
Published: July 2010

Rice (Oryza sativa L.), a semiaquatic species, is best adapted to culture in a submerged soil. Rice grown in rain fed environments may suffer significant yield losses due to drought. At the International Rice Research Institute, Philippines, thousands of genotypes are screened annually for drought resistance in upland fields during the dry season. We monitored the leaf water potential of 17 diverse genotypes to investigate the physiological basis for genotypic differences obtained through visual scoring of plant symptoms. The genotypes were grown in small plots, established by sprinkler irrigation. Twenty‐two ays after emergence, irrigation was stopped and a stress period initiated. Thirty‐nine days later, differentiation of genotypes was considered optimal by visual scoring and intensive diurnal sampling of leaf water potential began. Significant differences were detected among the genotypes for maintenance of relatively high leaf water potential. Two visual scoring techniques, one based on leaf rolling and the other on leaf tip drying, were highly correlated with maintenance of leaf water potential. Visual scoring based on leaf rolling behavior appeared to be influenced by diurnal adjustment of the pressure potential. The integral for the day (—bar.day) was quite effective in separation of cultivars for maintenance of high leaf water potential throughout the day and highly correlated with ranking by visual scoring.
Gaseous Nitrogen Loss and Transpiration of Several Crop and Weed Species1
Authors: Stutte C. A. , Weiland R. T.
Published: July 2010

Evaluations were made of the amounts of water soluble, non‐elemental N that is lost, along with transpiration water vapors, from plant foliage. A pyro‐chemiluminescent analysis of transpirational vapors, condensed in a closed system containing an attached leaf, had revealed that plants do give off non‐elemental N with transpira. tional water. In this study N loss, as well as transpiration rates, was ascertained for several crop and weed species: corn (Zea mays L.), cotton (Gossypium hirsutum L.), sorghum [Sorghum bicolor (L.) Moench], soybeans [Glycine max (L.) Merr.], common cocklebur (Xanthium pensyl‐vanicum Wallr.), entireleaf morningglory (Ipomoea heder‐acea var. integriuscula Gray), ivyleaf morningglory [1. hederacea (L.) Jacq.], jimsonweed (Datura stramonium L.), johnsongrass [Sorghum halepense (L.) Pers.], and palmer amaranth [Amaranthus palmeri (S.) Wats.]. Transpiration and N loss both were measured at 35 C and 2 days later at 28 C in field‐grown plants. With the exception of johnsongrass, all species exhibited significantly higher rates of N loss at 35 than at 28 C. However, only cocklebur and palmer amaranth had significantly higher transpiration rates at the higher temperature. In this evaluation the weed species lost geater quantities of N and water than did the crop plants.
Prevention of Chilling Injury to Seedling Cotton with Anti‐Transpirants1
Authors: Christiansen M. N. , Ashworth E. N.
Published: July 2010

Emerged cotton (Gossypium hirsutum L.) seedlings are severely damaged or killed by temperatures below 10 C. Prolonged chilling induces severe foliar water deficit as a consequence of root water uptake inhibition which causes cotyledonary necrosis, growth retardation or death of seedlings. We tested, under controlled environment, the efficacy of antitranspirant treatments in maintenance of seedling water status, and preventation of chilling injury by high humidity or by antitranspirant treatments. The antitranspirant treatments reduced seedling water loss to approximately 40%. Maintenance of seedling watex status by ambient high humidity or antitranspirant sprays reduced seedling death and cold stress inhibition of subsequent growth. Field experimentation with antitranspirants is suggested to provide means of reducing farm loss of cotton stands.
Multiple Characters and Correlated Response1
Authors: Grafius John E.
Published: July 2010

Selection of a new cultivar usually requires the manipulation of quantitative characters, many of which are correlated. These correlations may be due either to genetic linkages or to physiological and developmental relations. The latter two categories are considered here. The need for an understanding of these relationships is obvious because they impose constraints on the form of a plant and are frequently barriers to improved yield. The approach is based on Sinnott's law which states, “The size of an organ is proportional to the size of the meristem from which it develops.” In an attempt to relate this law to correlation between traits and to predict the tightness of the association, a dichotomy was proposed between: 1) the allometry associated with organs arising from the same meristem and 2) the allometry associated with organs arising from different meristems. It was predicted that generally the correlations in the first category would be expected to be harder to manipulate, but some of the latter category could also be recalcitrant. Examples were given for both categories including one in barley, Hordeum vulgare L., of an increase in yield due to manipulation of correlated traits not arising from the same meristem. Two corollaries to Sinnott's law were proposed. 1) Plasticity is inversely proportional to ontogenetic proximity. Traits arising from the same meristem will tend to be harder to manipulate than those separated in space and time of origin. 2) Numbers and size of organs tend to have an inverse relationship. Examples are given in support of both corollaries.
Selection of a NaCl Tolerant Line of Cultured Alfalfa Cells1
Authors: Croughan T. P. , Stavarek S. J. , Rains D. W.
Published: July 2010

A salt‐tolerant line of alfalfa (Medicago sativa L.) cells was selected for use in a comparative study examining the cellular traits associated with the capacity to tolerate salt. Suspension cultures of alfalfa cells were plated onto agarsolidified media containing 1% (w/v) NaCl. Within 2 months of exposure, more than 99% of these plated cells exhibited arrested growth and discoloration. A small number of cells exposed to salt, however, continued to grow and maintain a healthy appearance. These variants were subcultured onto media containing 1% NaCl every 3 to 4 weeks for 8 months. Several differences were observed between a salt‐selected cell line and a nonselected cell line from the original population in response to a gradient of NaCl concentrations in the nutrient media. Callus growth rates and ionic uptake by the cell lines differed. The selected line grew better than the unselected culture at high levels of NaCl, suggesting an increased NaCl tolerance. This selected line performed poorly in the absence of NaCl and the data suggest that it required a substantial amount of NaCl for optimal growth. A general shift towards a halophytic mode of salt tolerance within the salt‐selected cell line is suggested.
Influence of Sclerotinia Wilt on Seed Yield and Quality of Sunflower Wilted at Different Stages of Development1
Authors: Dorrell D. G. , Huang H. C.
Published: July 2010

Wilt caused by Sclerotinia sclerotiorum (Lib.) de Bary reduced yield and quality of sunflower seeds (Helianthus annuus L.) produced in field plots. The amount of reduction depended upon the stage of plant development when wilt occurred. Less than 0.5% of the plants were wilted at the bud stage and 7.2% by the start of anthesis. Thereafter approximately 6% of the plants wilted each week until 8 weeks after flowering when 60% of the plants had been killed. Seed yields were reduced more than 70% when wilting occurred within 4 weeks of flowering. This reduction was primarily due to lower seed weight. Oil content increased from 32.7% for plants wilted in the first 2 weeks, to 46.4% when wilting was delayed until 8 weeks after flowering. Protein content of oil‐free meal was fairly stable and averaged 53.1% during the first 5 weeks, but increased to 57.7% thereafter. Fatty acid composition was relatively unaffected by wilting as linoleic acid content varied from 74.4 to 76.8%. Thus, the oil was considered to be of excellent quality regardless of when wilting occurred.
Longevity of Alfalfa Seed1
Authors: Wilton A. C. , Townsend C. E. , Lorenz R. J. , Rogler G. A.
Published: July 2010

Two hundred twenty‐eight lots of alfalfa (Medicago spp.) seed, ranging in age from 23 to 70 years (stored between 1906 and 1953) were tested for germination. A seed lot represented a plant introduction or open‐pollinated seed from a single plant. The seed had been stored in unheated and uninsulated buildings at Belle Fourche, S. D., and Mandan. N. D. One M. falcata L. seed lot germinated 27% awter 68 years and a second lot germinated 48% after 66 years of storage. For M. sativa L., one seed lot germinated 7% after 70 years and a second lot germinated 30% after 62 years of storage. Medicago falcata, in most instances, retained seed viability longer than did M. sativa. Significant variation between seed lots of the same species harvested the same year suggests that seed longevity may be genetically controlled. This hypothesis is supported by wide differences in seed longevity of M. sativa and M. falcata. When germination percentage was regressed on years of storage, a correlation coefficient of —0.95 and a linear regression coefficient of —2.23 were found for M. sativa and some of its hybrids. Coefficients were significant at a >0.0001 probability level. Every year of storage between 30 to 70 years presupposed a 2.23% decline in seed germination.
Fruiting Pattern in Narrow‐Row Cotton1
Authors: Buxton D. R. , Patterson L. L. , Briggs R. E.
Published: July 2010

Previous research with narrow‐row cotton (Gossypium hirsutum L.) has concentrated on end‐of‐season effects on yield and fiber characteristics with little attention given to seasonal fruiting patterns. Our objective was to monitor the seasonal fruiting pattern of cotton planted at various combinations of row spacings and plant densities. ‘Deltapine 16’ was grown 3 years on one or two rows per beds that were either 76 or 102 cm from center to center with densities of 7.4, 14.8, and 22.2 plants/m2. The plots were divided into flower tagged (tagged plots) and yield portions (yield plots). In the tagged plots, flowers were tagged daily with the date of anthesis. Open bolls were harvested weekly and assigned to weekly flowering intervals before being analyzed for boll and fiber properties. Before harvesting the yield plots, we also took open boll samples to be analyzed for boll and fiber properties. At equivalent plant densities in the yield plots, two rows per bed resulted in up to 11% more seedcotton than one row per bed. Plant density had no significant effect on yield. In the tagged plots, seasonal flower and boll production was higher from two rows per bed than one row per bed with differences ranging from 8 to 22% more flowers and 2 to 12% more bolls, depending upon bed size and plant density. The seedcotton yield advantage of two rows per bed was near maximal from bolls that were set (flowered) by late July; thereafter the production rate on one and two rows per bed was similar. Boll period (time from flowering to open boll) was increased slightly by high plant density. Boll size, lint index, seed index, fiber strength, and fiber fineness from the yield plots were all significantly reduced by increases in plant density, although the average effects were less than 5%. While fruiting pattern and yield were primarily influenced by row spacing, plant density had the greatest influence on boll and fiber properties.
Temperature Tolerance in Soybeans. II. Evaluation of Segregating Populations for Membrane Thermostability1
Authors: Martineau J. R. , Williams J. H. , Specht J. E.
Published: July 2010

Genetic variability for heat tolerance has been alluded to in several crop species but few reports of inheritance or heritabilities of the trait are reported. Some screening for heat tolerance, employing controlled environmental chambers, has been reported but only limited numbers of plants can be evaluated in such facilities. A technique measuring membrane thermostability (heat tolerance) was used to screen segregating soybean (Glycine max (L.) Merr.) populations derived from crosses of heat tolerant and intolerant parents grown in 1076 and 1977. Significant genetic variance for heat tolerance was observed in all populations in both years. The mean of the progeny in tolerant ✕ intolerant cross was intermediate although closer to the tolerant parent. No definitive conclusions could be reached as to the number of genes involved due to the relatively small number of progeny examined. Heritability estimates obtained from 1976 data were relatively high indicating that selection for heat tolerance would be effective. Calculated expected gains from selection ranged from 16 to 18%. Phenotypic and genotypic correlations of heat tolerance with other traits were near zero and nonsignificant except for the genotypic correlation of heat tolerance and maturity. It appears that substantial genetic variability for membrane thermostability exists in soybeans and selection for heat tolerance types is feasible.
Aliphatic Nitro Compounds in Crownvetch: A Review1
Authors: Gustine David L.
Published: July 2010

Aliphatic nitro compounds found in crownvetch (Coronilla varia L.) can adversely affect animals. They are glucose esters of 3‐nitropropanoic acid (NPA) and are found primarily in the Coronilla, Astragalus, and Indigofera genera of Leguminosae family, as well as in other families. Methods have been established for isolation, identification, and analysis of these compounds. The toxicology of NPA in nonruminant animals has been studied, and symptoms produced by NPA, including methemoglobinemia, have been described. Recent data support the hypothesis that NPA exerts its toxic effect by irreversibly inhibiting the mitochondrial enzyme, succinate dehydrogenase. During this event, nitrite ion is released, which results in methemoglobinemia. In contrast to nonruminants, ruminants rarely exhibit toxic symptoms, because NPA is metabolized to nontoxic products by rumen microorganisms. Growth and storage conditions influence the levels of NPA in crownvetch. Information concerning the inheritance and function of NPA in crownveteh is inadequate. Crownvetch may be safely fed to ruminants but, if fed to nonrnminants, its concentration should not exceed 5% of the diet.
Virus Symptom‐Free Plants of Red Clover Using Meristem Culture1
Authors: Phillips Gregory C. , Collins G. B.
Published: July 2010

Recently developed techniques for in vitro red clover (Trifolium pratense L.) culture were adapted for the culture of shoot meristem tips. Symptomless plants were obtained from meristem cultures of the virus‐infected clones of ‘Kenstar’ red clover. A basal culture medium designated ‘ML2’ which included 4.0 /µg/liter picloram (4‐amino‐3,5,6‐trichloropicolinic acid) as the auxin and 1.0 mg/liter 6‐benzylaminopurine as the cytokinin yielded single plants from excised shoot meristem tips. Higher auxin levels in the medium resulted in callus formation and multiple shoot initiation. Crown‐derived meristems yielded normal appearing plants from culture while axilderived meristems produced abnormal plants. About 65% of the shoot meristem explants including the meristematic dome and first foliar primordium survived culture, and 80% of the larger meristem explants, including the second foliar primordium, survived culture. The smaller explants yielded a greater proportion of symptomless plants compared with the larger explants. About 90% of the meristem‐derived shoots rooted on a medium designated R(PC). Tests using Chenopodium amaranticolor Coste & Reyn. as a virus bioassay plant suggested that twothirds of the meristem‐derived plants were virus‐free. Plants obtained in this manner will enable red clover breeders to maintain synthetic cultivars more efficiently, since seed set is greatly increased in virus‐free plants.
A Model for Evaluating Progress from Recurrent Selection1
Authors: Smith O. S.
Published: July 2010

A model was developed to study the relationship between the change in the mean and changes of allelic frequencies in improved populations arising from recurrent selection. The change in the mean in the improved populations is a function of Δp, the weighted average change in allelic frequency, α, the average effect of a gene substitution in the base population, and R, the change in inbreeding depression in the improved populatious.

The model is illustrated by use of data from two studies designed to evaluate recurrent selection methods in corn (Zea mays L.). The analysis indicated significant changes in the weighted average change in allelic frequency and in the amount of inbreeding depression in these populations. Direct and indirect effects of selection were not significantly different in most of the populations studied.
The Ideal Cassava Plant for Maximum Yield1
Authors: Cock J. H. , Franklin D. , Sandoval G. , Juri P.
Published: July 2010

A series of trials were carried out using cassava (Manihot esculenta Crantz). Crop growth rate increased with leaf area (LAI) up to LAI 4; root growth rate increased up to LAI 3 to 3.5, then declined. Leaf area index is determined by leaf size, leaf formation rate, and individual leaf life. Leaf size reached a maximum 4 months after planting and then decreased; the maximumw as a varietal character. Leaf life was reduced by shading but in full daylight was determined by a variety. Leaf formation rate per shoot apex showed little genetic variation and declined with time; large differences in leaf formation rate per plant were determined by differences in branching pattern. Top growth had preference over root growth, and root sink was not limiting when root number per plant was nine or more.

A computer program was written to implement a dynamic growth model which suggests that high‐yielding plants will branch late in life and possess large leaves and long leaf life. Potential yields of more than 25 metric tons/ha per year of dry roots are obtainable at 400 to 450 g cal cm−2 day radiation.