bluuebunny/crossref_metadata_2025 huggingface dataset:
Sunflower Performance Relative to Size and Weight of Achenes Planted1
Authors: Robinson R. G.
Published: July 2010

The research was undertaken in response to a common concern of sunflower (Helianthus annus L.) researchers and seedsmen as to whether various achene‐size fractions of a seed lot will produce crops differing in performance.

The objective was to compare crops produced from large, medium, small, heavy, and ungraded achenes in yield and quality. Twelve seed lots of the major types of sunflower were separated into five grades by sieves and wind. An extra large grade representing 3% and a trash grade representing 2% of the original seed lot were additional grades included with one seed lot. Trials were planted at Rosemount, Minn., and thinned to a uniform seedling population of 61,000 plants/ha.

Sunflower achenes ranged from 18 to 52% pericarp. However, large, medium, and small achene grades contained, respectively, large, medium, and small seeds. Correlation between achene size and seed size exceeded + 0.95.

Crops produced from large, medium, small, or heavy achenes did not differ significantly in achene yield, hectoliter weight, or oil percentage. Large achenes produced significantly (5% level for human food varieties, 1% level for birdfeed varieties, and 20% level for oilseed varieties) larger achenes than the small grade, and the medium grade was intermediate.

If size‐graded achenes are used in varietal trials, bias may occur in rating varieties for achene size unless the achenes planted are from similar size‐fractions of the original seed lot.
Interaction of Shrunken‐2 and Sugary‐1 in Dosage Series in Corn Endosperm1
Authors: Holder D. G. , Glover D. V. , Shannon J. C.
Published: July 2010

The interaction of gone dosage on Zea mays L. endosperm carbohydrate composition was studied by quantifying carbohydrates from the 16 genotypes of 21‐day‐old endosperm resulting from all possible sib‐pollinations and reciprocal crosses between lines homozygous for Su1 Sh2 (normal), su1 Sh2 (sugary‐1), Su1 sh2 (shrunken‐2), and su1 sh2 (sugary‐1; shrunken‐2). No dosage effects were produced by either the allele su1 or the allele sh2 for fructose and glucose sugars and starch content of the endosperm. There was a dosage effect of su1 on sucrose content in the homozygous recessive sh2 genotypes. Two and three doses of su1 allele produced a 10 and 26% increase in sucrose content, respectively, over the zero or one dose level of su1. Two doses of su1 produced a very slight increase in water‐soluble polysaccharide (WSP) and three doses produced large amounts of WSP typical of su1. Two doses of sh2 reduced the WSP content of the homozygous recessive su1 genotype and the presence of three doses of sh2 considerably decreased the amount of WSP accumulated at 21 days after pollination. The interaction effects suggested that WSP accumulation in homozygous su1 may be affected by the dosage level of the sh2 mutant. Starch synthesis was markedly decreased in homozygous recessive su1, sh2 and su1 sh2 genotypes.
Evaluation of the Nutritive Quality of Grain Legumes by an Analysis for Total Sulfur1
Authors: Porter W. M. , Maner J. H. , Axtell J. D. , Keim W. F.
Published: July 2010

The protein efficiency ratio (PER) was determined for five varieties of dry beans (Phaseolus vulgaris L.), one variety of mung bean [Vigna radiata (L.) Wilczek], and one variety of cowpea [Vigna unguiculata (L.) Walp.], chosen because they showed variability in total sulfur as percent of crude protein and were available in sufficient quantities for rat feeding trials. The correlation of total sulfur as a percent of crude protein with the sum of methionine and cystine as a percent of protein in the seven varieties was highly significant (r = 0.93). Significant correlations of PER on each of the above two variables were obtained, whereas correlations of PER on methionine or cystine alone were not significant. These data indicate the potential for using analysis of total sulfur as a screening technique for nutritive quality in grain legumes.
Relationships Between Nitrate Reductase, Nitrite Reductase, and Ribulose Diphosphate Carboxylase Activities in Chlorophyll‐Deficient Mutants of Barley1
Authors: Warner R. L. , Kleinhofs A.
Published: July 2010

The relationship between a photosynthetic enzyme localized within the chloroplast and the nitrate‐reducing enzymes was determined by assaying 5‐day‐old chlorophyll‐deficient mutants of ‘Himalaya’ barley (Hordeum vulgare L.) for ribulose diphosphate carboxylase, nitrate reductase, nitrite reductase, and glucose‐6‐phosphate dehydrogenase activities. The mutants varied from albino to nearly normal green and had carboxylase activities ranging from zero to slightly greater than the level in Himalaya seedlings. Carboxylase activity was significantly correlated with both nitrate reductase (r = 0.86) and nitrite reductase (r = 0.78) activities. Nitrite reductase and nitrate reductase activities were also significantly correlated (r = 0.92). Glucose‐6‐phosphate dehydrogenase was not significantly correlated with nitrate reductase (r = −0.11), nitrite reductase (r = −0.11, or carboxylase (r = −0.19). The close relationship between the nitrate‐reducing enzyme and ribulose diphosphate carboxylase may indicate that both nitrate and nitrite reductases are dependent upon chloroplast development or functional chloroplasts for activity in 5‐day‐old barley leaves.
Selection Indexes for Resistance to Corn Earworm Based on Realized Gains in Corn1
Authors: Widstrom Neil W.
Published: July 2010

Corn earworm [Heliothis zea (Boddie)] injury, husk tightness, husk extension, and days to 50% pollen shed were evaluated among 250 selfed progenies from a random‐mated population of Zea mays L. The standard procedure of using relative economic values in conjunction with genotypic and phenotypic variances and covariances was employed to generate a selection index (RS) for identifying progenies with superior resistance to earworm injury. A second index (RI) was generated by substituting direct and correlated realized gains for genotypic variances and covariances, respectively, in the normal equations. A realized selection index (RSI) was derived using weighted earworm‐injury responses from selection for each character as the coefficients (b1) of the index. Comparison of indexes revealed that RSI selections were in closer agreement with RS selections than with selections obtained using the RI index. The RSI index is expected to be fully as effective in providing genetic progress as the RS index, depending on changes that may occur in the interrelationships among characters as selection proceeds.
Male‐Sterile Wheat Seed Production in North Dakota1
Authors: Miller J. F. , Rogers K. J. , Lucken K. A.
Published: July 2010

Normal and male‐sterile lines of an experimental bread wheat, Minn. II‐54‐30 (Triticum aestivum L. em. Thell. and T. aestivum L. em. Thell. with T. timopheevi (Zhuk.) Zhuk. cytoplasm), were planted in a systematic arrangement of alternate drill strips to evaluate seed production of the male‐sterile line. Approximate ratios of 1:1, 2:1, and 3:1 of male‐sterile to normal were tested over seven environments in 1971 and 1972. Drill‐strip widths of the male‐sterile ranged from 3.1 to 11.0 m. Overall mean yields from strips of the male‐sterile were 18.2, 14.6, and 12.8 q/ha (quintals/ha) for the 1:1, 2:1, and 3:1 ratios, respectively. These yields of the male‐sterile represent 64.4, 51.5, and 45.7% of the normal yields, respectively. Seed set distribution within the male‐sterile in the 2:1 and 3:1 ratio drill widths showed a distinct, though not constant, pattern of decrease toward the center of the strips.

A production unit concept was used to compare the efficiencies of the three different ratios from a commercial perspective. Actual yields of male‐sterile from a production hectare were 9.1, 10.1, and 9.9 q for the 1:1, 2:1, and 3:1 ratios, respectively. However, when yield of the normal lines was considered, total yields (normal and male‐sterile) from a production hectare were 23.3, 18.7, and 16.4 q for the three respective ratios.

The data from this study were used to evaluate the relationship between seed production yields and relative profit from growing hybrid wheat. The relative profit decreased as production yields decreased, particularly when yields were below a calculated critical level. Hybrid wheat seed production practices that tend to maintain yields above this critical yield level possibly should have priority over alternative practices that can give maximum yields but are vulnerable to production stresses.
Effect of Frequent Thawing on Viability of Red Clover Seed in Cold Storage1
Authors: Rinker C. M.
Published: July 2010

Freshly harvested ‘Dollard’ red clover (Trifolium pratense L.) seed, testing 96% live seed, was divided into five sublets of 1,360 g each and stored in cotton bags in a freezer in January 1961, to initiate a seed storage experiment. Temperatures in the freezer ranged from ∓5 to ∓15 C. One sublot was continuously frozen; other sublots were allowed to thaw for 24 hours annually, semi‐annually, monthly, or weekly. None of the sublots, including die one thawed more than 670 times (weekly), was reduced in viability from the original lot after 13 years of storage. Percentage of hard seed for all sublots dropped in cold storage from the original 23% to a mean of 5% within 1 year. This seed‐storage experiment will be continued.
Effects of Temperature and Clipping on Growth, Carbohydrate Reserves, and Root Exudation of Western Wheatgrass in Hydroponic Culture1
Authors: Bokhari Unab G. , Singh J. S.
Published: July 2010

The objective was to investigate the influence of three temperature regimes (13/7C, 24/13C, 29.5/18C day/night) and clipping (moderate and severe) treatments on the growth, total nonstructural carbohydrates (TNC), and root exudations of western wheatgrass (Agropyron smithii Rydb.). The mean growth rate of unclipped plants continued to increase with increasing temperature (from 13/7 to 29.5/18C) up to 50 days followed by a decline during subsequent growth at 24/13 and 29.5/18C. The growth rate of clipped plants was higher than the unclipped controls except for the short duration of 10 days following the clippings. Greatest growth rate occurred under moderate clipping and the next greatest under severe clipping compared to the unclipped (control) plants; crown and root growth of clipped and unclipped plants was greater at 24/13 than at 13/7 or 29.5/18C. Shoots of clipped plants continued to grow throughout the 80‐day experimental period, but those of unclipped plants ceased to show any positive dry matter accumulation after 50 days.

The TNC concentrations in the shoots, crowns, and roots of control plants were greater at 24/13 than at 13/7 or 29.5/18C. Concentrations in the three organs of clipped plants declined following clippings, more so in severely than in moderately clipped plants. Severe clipping and high temperature treatments appeared to have a stimulatory effect on root exudations.

This study indicated that decline in the growth rate of this cool season grass following maturity was more marked at higher temperatures (29.5/18C) than at lower temperatures, giving a higher overall growth rate for plants at 13/7C. In general, clipping treatments stimulated shoot growth and also increased the potential growth period of the plant. Evidence suggested that reserves in crowns and roots were not utilized to any marked degree for the regrowth of shoots following clipping.
Evaluation of the World Collection of Safflower, Carthamus tinctorius L. IV. Yield and Yield Components and Their Relationships1
Authors: Ashri A. , Zimmer D. E. , Urie A. L. , Cahaner A. , Marani A.
Published: July 2010

A study of a collection of 903 varieties of safflower (Carthamus tinctorius L.) for the mean yield per plant and the three major yield components, number of heads per plant, number of seeds per head, and seed weight, revealed marked differences in the potential of lines from different origins. Because of the mutual compensation of the yield components, the differences in yield were not as marked as they were for the components. The collection contains an abundance of genetic variability which is available for breeding higher‐yielding safflower varieties. There were regional differences in the components due to human and/or natural selection.

A multiple stepwise regression analysis showed that the most important yield component was the number of heads per plant. The number of seeds per head was of little importance, except for lines from Iran. Seed weight had no effect on yield per plant, except for a minor influence in the Iranian lines. The number of heads per plant had negative but negligible correlations with oil content. Yield per plant was not correlated with season length or oil content. Since the findings were obtained under spaced nursery conditions, they are not necessarily applicable directly to dense field stands.
Genotype ✕ Environment Interactions in Burley Tobacco Variety Tests1
Authors: Gupton C. L. , Legg P. D. , Link L. A. , Ross H. F.
Published: July 2010

The objectives of our study were to estimate the components of variance for burley tobacco (Nicotiana tabacure L.) grown at six locations for 3 years and to determine their implications on testing procedures.

Eleven commercial hurley tobacco cultivars were grown at 6 locations in 4 states for 3 years. For each experiment we recorded the number of days to flowering; number of leaves and plant height after topping; length and width of fifth leaf from the top; internode length; yield of cured leaf; percent total nitrogen; percent α‐amino nitrogen; water‐soluble acids; pH; and percent ash, K2O, nicotine, and secondary amine alkaloids. Estimates of variance components and correlations among years and among locations were computed for each variable.

Estimates of variance components for cultivars were highly significant for all traits. Cultivar ✕ location and cultivar ✕ year interactions were relatively small for all traits. Second‐order interactions were large relative to first‐order interactions for most variables, but in most instances were much smaller than the component for cultivars.

The cultivars source of variation for yield was subdivided to elucidate the variance among F1 hybrids and pure lines and their interactions with environments. The location ✕ hybrid mean square was statistically significant, but the one for location ✕ pure lines was not. These results suggest that some hybrids may not have as much internal buffering capacity as pure lines in burley tobacco.

Our results show that years and locations may be considered random environments and may be used interchangeably. Adding more years costs more in time and money than does adding locations; therefore, using several locations for 2 years seems best for testing burley tobacco.
Physiological Maturity of Seeds in Triticale hexaploid L.1
Authors: Bishnoi U. R.
Published: July 2010

The physiological maturity in seeds of two triticale (Triticale hexaploid L.) cultivars was studied during 1972 and 1973. Maximum germination, dry weight, and seedling vigor were attained 24 to 26 days after anthesis. Some seeds were capable of germination 8 days after anthesis. Moisture content decreased slowly from over 78 to 41% at which time functional maturity was attained. After this stage loss of moisture was accelerated and the seed entered into the ripening phase.
Expected and Actual Gains in Economic Value of Oat Lines from Five Selection Methods1
Authors: Eagles H. A. , Frey K. J.
Published: July 2010

Grain and straw are the two marketable products of the oat (Avena sativa L.) crop in the midwestern United States. Five methods of selection for increasing economic value of the crop and its two component traits, grain and straw yield, were compared in a population of F9, derived lines of oats. The five methods were: (a) selection for increased grain yield; (b) selection for increased straw yield; (c) a selection index calculated to maximize expected genetic gain in economic value; (d) a base selection index, where the traits were weighted by their relative economic values/gram; and (e) a procedure of independent culling levels. Expected gains from selection were computed by use of data from three test sites individually and means of the three sites for 1 year, and actual selection gains were computed with data from the same sites in a second year. Two selection intensities, 10 and 25%, were used and the methods were compared in terms of expected and actual gains.

Selection for one trait only, was superior for improving that trait, but the indexes and method of independent culling levels tended to be superior for improving overall economic value. The superiority of the latter methods was most evident when means across sites were used.

For selecting lines with superior economic values, the base index, (d) above, was preferred because of its simplicity, freedom from need for estimating population parameters, and the equivalency of grains from this method.
Transgressive Segregation for Root‐Knot Nematode Resistance in Cotton1
Authors: Shepherd R. L.
Published: July 2010

F6 families of Gossypium hirsutum L. ✕ ‘Mexico Wild’ (a root‐knot tolerant primitive G. hirsutum from Mexico) were advanced through F10, with selection in greenhouse tests for resistance to root‐knot nematodes [Meloidogyne incognita acrita (Kofoid & White, 1919) Chitwood, 19491. A disinfected larval screening technique effectively classified 85% of the F6 families as intermediate to highly susceptible, even though they had been selected in F2 through F4 in the field for root‐knot resistance in highly infested soil.

Two F10 lines, designated A623 and A61, having the highest resistance known to root‐knot in G. hirsutum, were developed. These lines were transgrassive segregates for resistance. Root‐knot resistance in the F1 generation from resistant A623 ✕ susceptible ‘Stoneville 213,’ ‘Coker 201,’ and ‘Dixie King II’ was incompletely dominant.

Fusarium wilt [Fusarium oxysporum Schlecht. f. vasinfectum (Atk.) Snyd. ✕ Hans.] resistance in the above material was highly associated with root‐knot resistance. Therefore, it may be possible to breed for fusarium wilt resistance by breeding solely for high root‐knot resistance.
Single Dw3 Height‐Gene Effects in 4‐ and 3‐Dwarf Hybrids of Sorghum bicolor (L.) Moench1
Authors: Schertz K. F. , Rosenow D. T. , Johnson J. W. , Gibson P. T.
Published: July 2010

Four‐dwarf, heterozygous 3‐dwarf, and homozygous 3‐dwarf hybrids of grain sorghum [Sorghum bicolor (L.) Moench] differing at the Dw3 locus were compared for height and other characteristics to elucidate this locus. This should not be confused with the Dw2 locus for which commercial hybrids may differ. The two female parents were derived from a 4‐dwarf line and a tall mutant from it and the male parents were derived from a 4‐dwarf doubled haploid and a tall mutant from it.

The homozygous and heterozygous tall 3‐dwarf hybrids exceeded the short 4‐dwarf hybrid in height, grain yield (not statistically significant in 1 of 2 years), and kernel weight. Hybrids from 3‐dwarf males were taller and had heavier kernels than hybrids from 4‐dwarf (short) males. Hybrids from 3‐dwarf females were taller than hybrids from 4dwarf (short) females, but grain yield comparisons were inconsistent. Homozygous and heterozygous 3‐dwarf hybrids did not differ significantly except in height.
Cold Storage of Digitgrass Germplasm1
Authors: Sleper D. A. , Gaskins M. H.
Published: July 2010

An experiment was designed to see if Digitaria decumbens Stent. plant crowns could be stored in a temperature controlled chamber through the winter months in order to protect them from possible winter killing under field conditions in a breeding nursery in North Florida. Plant crowns of four digitgrass cultivars were removed from the field on Sept. 27, Oct. 19, and Nov. 8, 1973, and stored at 0, 5, and 10 C. Best survival occurred with the latest sampling date and at the 10 C temperature. Data show that digitgrass germplasm can be maintained and protected from winter killing by storage under artificial conditions.
Large Incubation Chamber Suited for Use in Selection for Disease Resistance1
Authors: Leath K. T. , Hill R. R.
Published: July 2010

The construction and operation of a large moist incubation chamber and its application in a disease resistance selection program are described. The walk‐in chamber is made of aluminum alloy sheeting bonded to urethane foam insulation. Inside dimensions are 3.36 ✕ 3.36 ✕ 2.05 m high, and it holds about 5,000 seedling alfalfa plants. The disadvantages of other incubation chambers, such as uneven moisture deposits, refrigeration failure, drying of leaf surfaces, small capacity, and high cost are reduced or eliminated by the simple design of this chamber. Temperature is controlled through the flow of thermal‐regulated water across the sloped floor of the chamber. Periodic misting along with the waterflow cooling system maintain the air at loo'% relative humidity. The chamber has been used successfully to produce leafspot and rust diseases of forage legumes and grasses. None of the pathogens required light for infection. In a selection program this chamber facilitates the production of a single disease whenever suitable plants are available, makes possible the sequential infection of regrowth with different pathogens, and reduces the number of escapes.
Hybrid Performance of Selected Maize Lines from Reciprocal Recurrent and Testcross Selection Programs1
Authors: Russell W. A. , Eberhart S. A.
Published: July 2010

We evaluated three maize (Zea mays L.) crosses among BSCBI(R)C5, BSSS(R)C5, and BSSS(HT)C6 populations in six environments. BSCBI(R)C5 and BSSS(R)C5 improved populations from reciprocal recurrent selection, and BSSS(HT)C6 was obtained from testcross selection with a double‐cross tester. Also, we used five selected S3 lines from each of BSCBI(R)C5 and BSSS(R)C5 and five selected S3 or S4 lines from BSSS(HT)C5 in three sets of line ✕ line crosses among the sources. Average yields of the population crosses were essentially equal, which was unexpected for BSSS(R)C5 ✕ BSSS(HT)C6 Most of the variation among crosses in each set was accounted for by average line performance (general combining ability) in all traits.

Average yield of line crosses in a set was significantly higher than the population cross in each set and in the BSCBI(R)C5 ✕ BSSS(R)C5 and BSCBI(R)C5 ✕ BSSS (HT)C6 sets, the best cross yielded 35% more than the population cross. Two BSCBI(R)C5 ✕ BSSS(R)C5 crosses yielded significantly higher than B37 ✕ Oh43, and one of these crosses was equal to B37 ✕ Oh43 for lodging resistance. None of the crosses in the other two sets was equal to B37 ✕ Oh45 for all traits, mainly because of lodging. A modified reciprocal recurrent selection procedure using an inbred tester is proposed as a more efficient method of simultaneously improving breeding populations and developing elite single crosses.
Mitochondrial Efficiency and Growth Rate in Sugarbeet1
Authors: Doney D. L. , Wyse R. E. , Theurer J. C.
Published: July 2010

Growth rate and root mltochondrial oxidative phosphorylation measurements were made on sugarbeet (Beta vulgaris L.) to examine the relationships between these important factors. Measurements were made on eight hybrids and their inbred parents on four dates in 1971 and on two hybrids and their inbred parents at bi‐weekly intervals in 1972. Hybrids had faster growth rates (root and total weight) and more efficient mitochondria (larger ADP:0 ratios) than their inbred parents. Root mitochondrial measurements [RC (respiratory control) ratio, ADP:0 ratio, and state‐3 (ADP stimulated respiration) oxidation rate] made in 1971 were largest when plants were growing most rapidly (Aug. I to 7) and smallest in stored roots (Nov. 15). In 1972, mitochondrial efficiency (ADP:0 ratio) measurements departed from growth‐rate measurements in the early and latter part of the growing season but were highly correlated (r ≥ 0.87) with root fresh weight and total dry weight from early July to mid‐October. A close relationship was obtained between root mitochondrial efficiency (ADP:0 ratio) and growth rate throughout the major part of the growing season.
14C‐Photosynthate Translocation in C3 and C4 Plants as Related to Leaf Anatomy1
Authors: Gallaher R. N. , Ashley D. A. , Brown R. H.
Published: July 2010

This study was performed to investigate the relationship between 14C photosynthate translocation and phloem cross‐sectional area in C3 and C4 plants. Spots 5 mm in diameter were labeled by 14CO2 exposure on fully expanded leaves of two monocots (Panicum maximum Jacq., a C4 species and Panicum milioides Nees ex. Trin., a C3 species) and two dicots (Amaranthus retroflexus L., a C4 species and Glycine max Merrill, a C3 species). The spots were removed after 3 hours of translocation and equally divided. Half of the spots were used for 14C analysis and half for anatomical study of cross sectional areas of phloem and other tissues.

In all cases percent translocation from and cross‐sectional area of phloem tissue in labeled spots were higher in C4 than in C3 plants. P. maximum had 100% greater translocation out of and 96% more phloem tissue in the labeled spots than P. milioides. A. retroflexus translocated 48, 91, and 45% more 14C out of spots over the midvein, secondary, and tertiary veins, respectively, than G. max. A. retrollexus had 5, 92, and 66% more phloem tissue in the above respective spots than G. max. Photosynthesis rates were higher in C4 than in C3 plants, but differences were not as great as those in translocation.

Data from this study indicate that C4 plants have both a greater translocation capacity and larger cross‐sectional area of phloem than C3 plants.
Translocation Patterns in Soybeans Exposed to 14CO2 at Four Different Time Periods of the Day1
Authors: Russell W. J. , Johnson D. R.
Published: July 2010

Field grown soybeans [Glydne max (L.) Merr.] were exposed at the mid.bloom stage to 14CO2 for 1 hour beginning at either 9 AM, 11 AM, 1 PM, or 3 PM CDT to evaluate the effects of time of day when exposed to 14CO2 on the translocation and distribution of labeled assimilates. Plants were harvested 0, 1, 3, 6, and 24 hours after labeling. By the end of the labeling period, 16.9% of the total recovered 14C had been exported from the leaves and 36.9% had been exported by the end of 24 hours (averaged over the four exposure times).

Leaves labeled during the time periods associated with the highest net C fixation rates (11 to 12 AM and 3 to 4 PM) assimilated more 14C, translocated more to the stems and roots, and exhibited a higher rate of export from the leaves. Percent 14C recovered in each component (except nodules) was significantly different between the 9 to 10 AM and 3 to 4 PM exposure periods. Differences between the two midday exposures were relatively small, averaged over all harvest times and increased only when compared immediately and 24 hours after labeling.

Carbon‐14 labeling and translocation experiments should be conducted during relatively constant time periods to allow nonconfounded intercomparisons between data when experimental technique dictates multiple times of exposure to 14C, especially between the early morning and late afternoon exposure periods.
Response of Soybeans to a Morphactin1
Authors: Clapp J. G.
Published: July 2010

Morphactins (a group of plant growth regulating chemicals) were observed to inhibit apical growth on soybeans [Glycine max (L.) Merr.] in North Carolina during 1971. One material, EMD‐7301 (containing 12.5% of methyl‐2‐ chloro‐9‐hydroxyfluorene‐(9)‐carboxylate) was evaluated under field conditions to determine the effects on plant height, lodging, seed weight, pods/plant, seed/pod, maturity, and grain yields.

Foliar applications of EMD‐7301 at rates of 12.4, 24.7, 49.4, 98.8, 197.7, and 790.7 ml/ha at flower initiation failed to increase soybean yields over a 2‐year period. A 10.5% yield increase occurred during the first year of study with the 49.4 ml/ha rate. Plant height was reduced by all application rates. Lodging was reduced by the 98.8 ml/ha rate. The highest rate of application (790.7 ml/ha) delayed maturity by 10.5 days, reduced the number of pods/plant by 54.5% and seed/pod by 19.4%, and had no effect on seed weights.
Evaluation of Selection Potential for Earworm Resistance in Two Corn Populations and Their Cross1
Authors: Widstrom N. W. , Wiseman B. R. , McMillian W. W.
Published: July 2010

Variances and expected selection progress for reduced injury by the corn earworm [Heliothis zea (Boddie)] and for husk tightness were estimated in two corn (Zea mays L.) populations and their F1 and F3 generations. A half‐sib mating design was used to test all populations during each of two successive years. Heterosis estimates for earworm injury and husk tightness were less than 5%, except for an estimate of 13.9% for husk tightness in the F3. Estimates of genetic variance showed that dominance for corn earworm resistance was of less significance than that for husk tightness.

Additive variance for earworm injury in the F3 was higher than the mean variance of the parents. This difference may be caused by factors such as multiple alleles, coupling linkages, and segregation of genes in the F3 for which alleles are fixed in one or both of the parents. On the basis of expected selection progress for the characters measured and a highly significant positive correlation between resistance to earworm injury and husk tightness, the authors suggest improvement of these populations by selecting primarily for low earworm injury, while requiring the selections to meet prescribed standards for husk tightness and yield.
Role of Awns in Photosynthesis, Respiration, and Transpiration of Barley Spikes1
Authors: Johnson Richard R. , Willmer Colin M. , Moss Dale N.
Published: July 2010

To assess the role of awns in photosynthesis, respiration, and transpiration, the water vapor and Co2‐exchange rates were measured on spikes of barley (Hordeum vulgare L.) genotypes ranging from awnless to those having several meters of awn/spike. The plants were grown in large pots in the field and brought into the laboratory for measurement. An increased amount of awn tissue resulted in greater rates of net photosynthesis, dark respiration, and transpiration per spike. The awns of all genotypes remained photosynthetically active throughout grain filling, although some reached maximal activity soon after emerging from the flag leaf sheath, while others had peak rates only a few days before maturity.

The total length of awn tissue of each spike remained constant throughout the grain‐filling period, but the awn dry weight of the full‐awned genotypes increased during that period. Awn dry weight, rather than awn number or awn length, best described the amount of photosynthetic tissue present. The genotype which had the dense spike character had a lower photosynthetic efficiency (mg CO2 fixed per g awn dry weight) than did the other genotypes. Removing the top two leaves on each culm to reduce the assimilate supply to the grain increased synthetic rates of the spikes slightly, but not sufficiently to compensate for the leaf area removed.
Identification of Rye Chromosomes in Wheat‐rye Addition Lines and Triticale by Heterochromatin Bands1
Authors: Darvey N. L. , Gustafson J. P.
Published: July 2010

The rye (Secale cereale L.) chromosomes of four series of wheat (Triticum aestivum L.) ‐ rye addition line were identified according to their heterochromatic banding patterns using Leishman staining. The characteristics of chromosomes 1R, 3R, 4R/7R, 5R, and 6R were relatively consistent from series to series, while 2R and 7R/4R varied considerably and were therefore difficult to classify. In some of the six triticales (✕ Triticosecale Wittmack) analyzed, certain rye chromosomes easily identified as 2R and 4R/7R, were absent.
Correlated Responses and Responses to Index Selection Involving Yield and Ear Height of Maize1
Authors: Moll R. H. , Stuber C. W. , Hanson W. D.
Published: July 2010

Replicated selection studies were undertaken to evaluate the predictability and repeatability of correlated responses and responses to selection indexes. In each of six samples of the variety ‘Jarvis’ (Zea mays L.), first generation families were selected for five criteria; yield, ear height, and three indexes based on both yield and ear height. In three additional samples, families were selected for yield alone. Each sample was composed of 300 full‐sib families evaluated in a different location‐year environment.

Evaluation of responses to divergent selection showed that responses of both traits were generally symmetrical. Large average deviations from predictions were observed for correlated responses and responses to index selection. Variation among replicates for correlated responses was no greater on the average, than variation for direct responses. Responses of component traits to index selection were more variable in general, than responses to singletrait selection. Therefore, index selection responses tended to be less repeatable than responses to single trait selection. Although correlated responses to single trait selection deviated considerably from expectation, they appeared to be as repeatable as the direct responses, which agreed satisfactorily with expectation. Further investigation of the relationship between the two traits suggested a nonlinear association. Failure to account for this nonlinearity in predictions and indexes may have contributed to the discrepancies between observed and expected results.
A Comparison of Pea Aphid‐resistant and Susceptible Alfalfas, for Field Performance, Saponin Concentration, Digestibility, and Insect Resistance1
Authors: Pedersen M. W. , Sorensen E. L. , Anderson M. J.
Published: July 2010

Six pea aphid [Acyrthosiphon pisum (Harris)]‐resistant (PAR) and five pea aphid‐susceptible (PAS) alfalfa (Medicago sativa L.) varieties were compared for foliage and root saponin concentration, forage yield, lodging, foliage color, pea aphid resistance, in.vitro digestibility, and clover root curculio [Sitona hispidula (F.)] resistance.

The PAR varieties were characterized by higher yields, but lower digestibility than the PAS varieties under noneconomic levels of pea aphid infestation. When yields of hay were corrected for digestibility, the PAR varieties had an advantage of 0.9 metric ton/ha over five cuttings. Lodging was not affected by level of pea aphid resistance, but was much higher in some varieties than others. Foliage and root saponin contents were not significantly correlated. Pea aphid resistance had a significant negative correlation with root saponin level; clover root curculio damage had a significant positive correlation with foliage saponin level. There was no evidence that breeding for pea aphid resistance had changed the foliage saponin concentration. However, it may have reduced the saponin in the roots. ‘Lahontan’ had high resistance to clover root curculio feeding (a feature that undoubtedly contributes to its longevity in infested areas).
Significance of Parts Other Than Blades and Stems in Leaf‐stem Separations of Alfalfa Herbage1
Authors: Fick Gary W. , Holthausen Richard S.
Published: July 2010

Leaf‐stem separations of alfalfa (Medicago sativa L.) herbage have been widely used, but designation of petioles, stipules, stem tips, and reproductive structures as leaves or stems has been inconsistent. The objective of this study was to characterize this material and thus establish a basis for including it with either the leaf blades or stems.

Alfalfa herbage from the vegetative to the seedpod stages of development was separated into three fractions (blades, stems minus 3 cm of tip, and “other parts”) and analyzed to determine the total herbage represented by each part and the percentage in vitro true digestibility (IVTD) and crude protein (CP). From the bud through the seedpod stages the other parts represented a nearly constant 11% of the total herbage dry matter and contributed about 9 g of IVTD dry matter and 2 g of CP for every 100 g of herbage. The IVTD of the other parts was generally zero to five percentage units lower than that of the blades, but as much as 25 percentage units higher than the stems minus tips. The CP content of the other parts ranged from four to eight percentage units below the blades and from four to eight percentage units above the stems without tips. For the narrow range of cultivars and environments represented in this study, a two‐way separation which removes stems minus the tip from the rest of the alfalfa herbage both combines morphological parts of similar digestibilities and facilitates a simple estimation of blade content.
Performance of Pure Lines Obtained from Superior‐yielding Heterogeneous Lines in Soybeans1
Authors: Boerma H. R. , Cooper R. L.
Published: July 2010

F2−derived heterogeneous parental‐fines (HPL) were selected for high seed yield, based on F3, F3−F4, and F3−F4−F5 combined generation means in four soybean [Glycine max (L) Merr.] crosses. In the F5 generation, 30 pure lines (PL) were isolated from each of the nine selected HPL.

A comparison of seed yields of HPL and their unselected PL indicated that either an overcompensation, undercompensation, or additive effect was responsible for seed yield of the nine selected HPL A nonadditive effect was responsible for the lodging score of one HPL.

A comparison of seed yields and maturities of selected HPL and their selected PL indicated that in one HPL, PL could be isolated that were significantly higher in seed yield and earlier in maturity. In the other HPL, PL were isolated that were earlier in maturity while being equal in yield to the HPL. These results are discussed in relation to the bulk and early‐generation yield testing selection procedures.
Export of 14C‐Assimilates in Cotton Leaves1
Authors: Benedict C. R. , Kohel R. J.
Published: July 2010

A study was made of the export of 14C‐assimilate in mature leaves of ‘Stoneville 213’ cotton (Gossypium hirsutum L.). Fruiting branches and subtending leaves of field grown plants were pulse‐labeled with 14CO2 for 5 min at about mid‐day. The amount of 14C‐assimilate transported to the cotton boll from the subtending leaves, bracts or boll wall, as well as the amount of 14C‐assimilate remaining in the leaves and bracts, were determined over a 22‐hour period. During this translocation period, leaves and bracts export 14C‐assimilate to the boll wall, ovules and lint; whereas the boll wall does not export 14C. assimilate. The leaves are the dominant source of assimilate for cotton bolls throughout the season.

There is a differential rate of export and retention of H2O soluble and insoluble (starch) assimilate from the leaves and bracts. There is an initial rapid phase of transport of H2O soluble compounds from both leaf and bract sources. About 80% of these compounds disappear 6 hours after exposin the sources to 14CO2. After 22 hours, over 90% of this pool is depleted. In contrast, there is a retention of 14C in the starch fraction up to 6 hours after pulse‐labeling the sources with 14CO2. After 6 hours, there is a slow export of 14C‐assimilate from the starch fraction stored in the sources. Cotton leaves export assimilate stored as starch slowly. At the end of 22 hours, 90 to 95% of the 14C‐assimilate disappears from mature leaves and bracts.
Parental Inbreeding and Performance of Alfalfa Single‐crosses1
Authors: Hill R. R.
Published: July 2010

S2 and S4 progenies were obtained from 10 S0 parents each from ‘MSA‐W4’ and ‘MSB‐W4’ alfalfa (Medicago sativa L.). Two five‐parent diallel sets were attempted within S0, S2, and S4 parental generations in each cultivar. All but one of the sets with S2 and S4 parents gave incomplete diallels. First harvest dry matter yields were measured in small row plots during each of two growing seasons.

Average yields of the S2−crosses were less than those of the S0−crosses in all sets. Individual exceptions to the average trend occurred in both populations, but more frequently in MSA‐W4 than in MSB‐W4. The number of S4−crosses was small, and the results with them were variable. Yields of all S4crosses in one set, which had one parent common to all crosses, were greater than yields of the corresponding S0 or S2−crosses. Other S4 crosses generally yielded less than the corresponding S0 or S2−crosses.

Mean squares for both general (GCA) and specific combinnig ability (SCA) pooled over sets in MSA‐W4 increased from the S0 to the S2 parental generation. This increase was greater for SCA than for GCA. GCA was significant in the S2−crosses from MSB‐W4, but no combining ability mean square was significant in the S2 or S4−crosses from MSB‐W4.
Genetic Analysis of Leaf Differentiation Mutants in Upland Cotton1
Authors: Dilday R. H. , Kohel R. J. , Richmond T. R.
Published: July 2010

A series of leaf mutants in Gossypium hirsutum L. was tested for allelism and linkage, and three closely linked loci were established on chromosome 15. One locus is represented by a single mutant allele, crinkled leaf (crcr), and the other two loci are represented by a multiple allelic series. The two loci with the multiple allelic series were designated as strap leaf and veins‐fused. Alleles of the strap leaf locus are rugose (srsr), Lubbock‐1 (slsl), strap leaf (ss), norma(SS), and Heritable Abnormality‐3 (ShSh). Alleles of the veins‐fused locus are veins‐fused (vfvf), normal (VfVf), and Heritable Abnormality‐1 (VfhVfh).From independent two and three‐point linkage data, we generated a calculated four‐locus linkage map as follows: cr‐O.20.s‐l.20‐vf‐4.90‐Lg [Lg = Green lint] The seven mutants tested all affect leaf development. Each of the three distinct loci appeared to function differently in leaf development and differentiation in cotton.
Effect of Flat‐square in Cotton on Selected Agronomic Characters1
Authors: Khalifa H. , Stith L. S. , Fisher W. D.
Published: July 2010

Data were collected from flat and nonflat‐square cotton (Gossypium hirsutum L.) plants in replicated experiments to evaluate their relative performances for yield components and fiber characteristics. Results indicate that the flat‐square trait has an adverse effect on seed cotton yield, boll weight, lint percentage, lint index, fiber fineness, and strength. Flat‐square plants produced more flowers than nonflat‐square plants at Tucson, Marana, and Phoenix, Ariz.; but flat‐square plants had a higher rate of shedding of deformed and incomplete flowers as well as reduced boll weight, lint percentage, and lint index. Thus, nonflat‐square plants produced more seed cotton at harvest time, but they had similar crop maturity. Pedigree selection is suggested as one breeding procedure to effectively eliminate or minimize this abnormality.
Inheritance of a Completely Branched Mutant in Safflower1
Authors: Abel G. H.
Published: July 2010

Inheritance of a completely branched (branches arise from 100% of the axial nodes) mutant was studied in safflower (Carthamus tinctorit L.). Data from F2 and F3 progeny of a cross between a mutant and a tall‐branching cultivar (branches arise from 5 to 25% of the nodes) support the hypothesis that one completely dominant gene determines the incompletely branched habit; this gene is designated Cb. The double recessive cbcb determines the completely branched mutant. For the incompletely branched progeny, results suggest the presence of additional genetic variation for distribution of percentage of branching.
Effect of Selection for Self‐fertility and Self‐sterility in Alfalfa and Related Characters1
Authors: Busbice Thad H. , Gurgis Ramzy Y. , Collins Harry B.
Published: July 2010

Two cycles of selection for self‐fertillty in alfalfa (Medicago sativa L.) doubled self‐fertility, as measured by the percentage of ovules developing into seed after selling, and they increased cross‐fertility slightly, as measured by the percentage of ovules developing into seed after crossing to unrelated tester plants. Selection for self‐sterility reduced self‐fertility by more than threefourths and cross‐fertility by one‐third to one‐half. Based on 40 plants representing a wide range of self‐fertility, correlations between self‐ and cross‐fertility were 0.5 or 0.6, depending on the tester used in crossing. Selection for self‐fertility increased the abundance of pollen, whereas selection for self‐sterility decreased it. Both self and cross‐fertillty were highly correlated with abundance of pollen. Number of ovules per flower and the size of ovules before pollination changed only slightly in response to selection and neither was correlated with self or cross‐fertility.

By 96 hours after pollination, the ovules had become separated by size into two distinct groups. The smaller ovules, representing one group, either were not fertilized after pollination or aborted very soon after fertilization. The larger ovules, representing the other group, most probably were fertilized, but some aborted before producing seed. The most pronounced difference in the distribution after selling and crossing was the proportion of ovules in the two groups. Ovule growth occurred mostly at random within the ovary, but after selling, there was evidence that basal ovules were fertilized slightly less often than ovules nearer the style, suggesting a weak self‐incompatibility system.
Relationship of Leaf Photosynthesis to Forage Yield of Tall Fescue1
Authors: Nelson C. J. , Asay K. H. , Horst G. L.
Published: July 2010

Genetic variation exists for leaf photosynthesis in tall rescue (Festuca arundinacea, Schreb.), but little information exists on its relationship to forage yield. Therefore, net carbon exchange (NCE) of leaves of tall rescue genotypes was measured in the field during regrowth stages and compared to forage yield of the swards in the subsequeut harvest. Genetic variation existed for both yield and NCE on a leaf area basis, but no consistent relationship between these characters was found. Both NCE and forage yield were increased by irrigation during drought. Correlations between NCE and yield also tended to change from positive to negative with irrigation. Although NCE on a single leaf basis is a primary component of forage yield, other factors such as a environmental stress, canopy shape, and dry matter distribution will need to be considered if NCE is to be included in an effective selection index for improvement of forage yield.
Nitrogen Effects on Growth, Seed Yield, and Protein of Seven Pea Cultivars1
Authors: Trevino I. C. , Murray G. A.
Published: July 2010

Nitrogen fertilization effects on vegetative growth, seed yield, and seed protein of seven pea (Pisum sativum subsp, arvense L.) cultivars were studied under greenhouse conditions. Nitrogen was applied as ammonium nitrate at seven equally spaced intervals at rates of 0, 50, and 100 ppm N. Nitrogen fertilization with 50 ppm N increased total seed protein of five cultivars 47 to 109% due to an increase in protein/seed and higher seed yield. Protein/seed progressively increased in all cultivars as rate of N application increased. Maximum increase in protein/seed was from 26.6 to 51.9% in a semi‐dwarf (SD) winter‐type pea. Seed yield decreased when plants received 100 ppm N. The number of days from planting to the first flower and number of nodes to the first flower was not influenced by N fertilization except in the SD pea. Nitrogen increased the number of days to flowering and increased the number of nodes before the first flower in the SD pea. Maturity was delayed by N application in all winter cultivars except ‘Inc 16.’ The spring‐type peas — ‘Alaska,’ ‘Perfection,’ and ‘P3’ (tall, spring‐type) showed no maturity differences from N application. Data from these experiments should be of practical value to plant breeders working toward improvement of protein content of peas.