bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of Semidwarf Barley1
Authors: Ali Mohamed A. M. , Okiror Shadrach O. , Rasmusson Donald C.
Published: July 2010

Five to six cycles of crossing and selection have resulted in well‐adapted semidwarf barleys (Hordeum vulgare L.). The original semidwarf stock was a radiation mutant obtained in the Norwegian cultivar, ‘Jotun.’ This report provides a comparison of the performance of these semidwarf barleys and their normal‐height counterparts. Lines from five populations were compared in field environments for yield and 10 other characters. Inheritance information also was obtained using five populations. The semidwarf lines had higher mean yields than the normal lines in four of the five populations, but the yield difference was modest, amounting to 3% for the average of the five populations. Lodging did not influence yield in these experiments. The semidwarf lines had 7% more tillers, 10% more heads, and a 14% higher harvest index than the normal lines based on the mean of five populations. The semidwarfs also had 10% longer coleoptiles than the normal lines, based on the average of four populations. The normal lines were 5% higher in total dry matter and 8% higher in kernel weight. From the results of this study, it appears that the lengthy breeding program has resulted in semidwarf barleys that have potential for direct use as cultivars and as parental material. If so, the effort illustrates an important principle, i.e., capitalizing on "new germplasm" may require a prolonged breeding effort. Results of this study plus our experience in the semidwarf breeding program indicate that a single gene controls the semidwarf character in this material. The symbol suggested for this gene is sdw.
Genetic Variability for Mineral Elements in Reed Canarygrass1
Authors: Hovin A. W. , Tew T. L. , Stucker R. E.
Published: July 2010

Genetic variability in forage crops for mineral concentration has not been exploited to correct mineral deficiency or imbalance in plants or feeds. The objectives of this study were to determine gene action for concentration of several major and minor elements and to obtain estimates of K/(Ca + Mg) ratio in reed canarygrass (Phalaris arundinacea L.).

Twelve parent clones selected randomly from a broad genetic base and 30 two‐clone crosses of an incomplete diallel were evaluated in small field plots during each of 3 harvest years (one year for N) at two locations to determine genetic variability for mineral concentration. Concentrations of N, P, K, Ca, Mg, Zn, Cu, and Mn were determined in first regrowth forage. Also, the K/(Ca + Mg) ratio was calculated. Most genotypes contained less Ca and Zn than that required to meet the daily needs for a moderately producing dairy cow. The Mn concentration was higher than that usually reported as was the K/(Ca + Mg) ratio.

General combining ability was detected (P < 0.01) for all characters, but specific combining ability only for Mn (P < 0.05). Additive genetic variance was present (P < 0.05) for all elements except N, while non‐additive genetic variance was observed only for Mn concentration. Narrow‐sense heritability estimates were moderately high except those for N concentration and K/(Ca + Mg) ratio.

The estimated potential ranges of mineral concentration that could be reached through a few cycles of selection indicated that Ca and Zn concentrations could be brought up to the desired level. The K concentration could be reduced considerably barring genetic correlation between K and Ca. The phenotypic correlations involving K, Ca, and Mg were all positive. The K/(Ca Mg) ratio could be genetically maintained in a range of 3.0 ± 0.5 units.

Concentrations of maior elements were negatively correlated with forage yield of parent clones and were generally larger than correlations computed for the crosses. Only N and P were significantly negatively correlated with yield in the crosses.
Visual Selection as a Method for Improving Yield of Triticale1
Authors: Salmon D. F. , Larter E. N.
Published: July 2010

In 1973 and 1974, lines from eight F3 populations of hexaploid triticale (X Triticosecale Wittmack) were visually rated for yield by a group of selectors comprised of experienced (plant breeder), novice (graduate student), and inexperienced (summer student) workers. Each selector identified those lines which he predicted would yield as high or higher than the nearest check plot. The experienced selectors and most of the novice selectors identified a high number of the best lines in each population. Comparisons of selector efficiencies indicated that the experienced selectors were more able to identify high yielding lines than were the inexperienced selectors. In addition, the mean yield of the best 20 lines as identified by experienced selectors did not, in general, deviate significantly from the mean yield of those that yielded highest by actual measure. Visual evaluation may be a useful method for identifying high yielding lines of triticale.
Influence of Male Sterile and Normal Cytoplasms on the Expression of Bacterial Blight in Cotton Hybrids1
Authors: Mahill Joel F. , Davis Dick D.
Published: July 2010

Seedlings of 28 F1 hybrids of Gossypium obtained from all single‐cross combinations of seven male and four female parents were evaluated in a greenhouse for bacterial blight (caused by Xanthomonas malvacearum (E. F. Sm.) Dowson) resistance. The four female parents were two lines of male‐sterile (Gossypium harknessii Brandagee ✕ G. hirsutum L.) cytoplasm and their respective ‘B’ lines with normal (G. hirsutum) cytoplasm. Superimposed on each cytoplasm was a line resistant to bacterial blight and a susceptible line. G. Harknessii cytoplasm slightly enhanced bacterial blight resistance in F1 hybrids, accounting for approximately 12% of the total resistance. This is the first reported case in cotton where cytoplasms have been demonstrated to influence the severity of a disease. Both cytoplasms remained stable for blight reaction over four environments. Resistant G. harknessii and G. hirsutum female parents combined well with all male lines to produce relatively high levels of blight resistance. Specific combining ability was probably due to partial dominance effects. Large environmental changes were apparently required to cause noticeable changes in blight reaction.
Breeding Potentials of Noncultivated Cottons. IV. Location and Parental Effects on Agronomic Characters and Fiber Properties in Hybrids1
Authors: Wilson F. D. , Wilson R. L.
Published: July 2010

We studied the inheritance of six agronomic characters and five fiber properties in Ft hybrids between two cultivars and eight primitive race stocks of cotton, Gossypium hirsutum L., in 1975 and between the same two cultivars and four other race stocks in 1976. Plants were grown at Phoenix, Ariz., where insecticides were applied as needed for control of pink bollworm, Pectinophora gossypiella (Saunders), and at Tempe, Ariz., where no insecticides were applied. Location effects were significantfor most characters both years. Location ✕ race‐stock interactions were also significant for several characters. Usually, however, hybrid arrays that ranked first at one location also ranked first or second at the other location, thus suggesting that inconsistencies in performance occurred in other arrays. The Tempe location, therefore, was usually as suitable as the Phoenix location, revealing superior hybrid performance in spite of heavy pink bollworm pressure. One exception was bolls/plant in 1976, where the highest ranked array at Phoenix was the lowest ranked array at Tempe. Genetic variability in hybrids was attributed mostly to differences in race stocks, but cultivars contributed variability in a few characters. In 1975, significant race‐stock effects coupled with the absence of cultivar ✕ race‐stock interactions indicated the presence of adequate amounts of additive genetic variability. In 1976, however, five of 11 characters showed significant cultivar ✕ race‐stock interactions, indicating that these race stocks may be more refractory. Individual heterotic combinations also indicated the presence of nonadditive genetic variability. F1 vs. parental cultivar “favorable” heterosis was shown in a number of combinations but did not consistently appear in the same combinations at both locations.
Early Defoliation Affects Corn Grain Yields1
Authors: Crookston R. Kent , Hicks D. R.
Published: July 2010

Field experiments designed to simulate hail damage at various developmental stages revealed an unexpected and potentially important grain yield response from corn (Zea mays L.). Of particular interest were yields following defoliation at the 5‐leaf stage. Two hybrids representing different maturity classes were defoliated. One hybrid was full‐season for southern Minnesota. The other was approximately 80%, of full‐season. Yields of the full‐season hybrid were decreased by 80% (3‐year average, 1973 to 1975). Average yields of the short‐season hybrid were increased by 48% (same 3‐year period). Eleven additional early hybrids at one Southern Minnesota location were defoliated at the 5‐leaf stage in 1975. Yield responses ranged from a 37%, increase to a 14% decrease. Trials conducted in 1976, involving several locations and hybrids, resulted in yield changes varying from a 32% reduction to a 53% increase — suggesting interactions among genotype, environment, and defoliation timing. We propose a physiological explanation for observed yield responses. It appears that early growth alteration or inhibition of leaf function could result in yield enhancement. Effective growth regulation might consist of altering source‐sink relations at the time of reproductive initiation.
A Colorimetric Screening Assay for Lysine in Wheat Using Trinitrobenzesulfonic Acid1
Authors: Felker Peter , Labanauskas C. K. , Waines Giles
Published: July 2010

A colorimetric lysine screening assay in wheat is reported that employs trinitrobenzenesulfonic acid, which reacts only with primary amino proups. When lysine in 26 wheat samples is compared with that determined by traditional amino acid analysis, the assay has a correlation coefficient of 0.938. It is possible to perform 48 lysine determinations per man‐day.
Leaf Angle, Tassel Morphology, and the Performance of Maize Hybrids1
Authors: Lambert R. J. , Johnson R. R.
Published: July 2010

The relative importance of leaf orientation, planting densities, planting patterns, and tassel shading on grain production of certain maize (Zea mays L.) genotypes was investigated. Three experiments were conducted over a 4‐year period to ascertain the effect of leaf angle on grain yield and percentage of unproductive plants in several maize hybrids. A plant‐density experiment using normal, liguleless‐l, and liguleless‐2 leaf types at densities of 60,000, 75,000, and 90,000 plants/ha in 50.8 cm row spacings was conducted over a 3‐year period. The liguleless‐2 hybrids produced 6.7% and 12.9% more grain at 75,000 and 90,000 plants/ha, respectively, than the normal leaf type hybrids. A plant‐spacing experiment using 1,290 cm2 and 645 cm2/plant and the same three leaf types was grown over a 2‐year period. The liguleless‐2 hybrids produced 9.7% and 49.7% more grain at 1,290 cm2 and 645 cm2 (25.4 ✕ 25.4 cm) plant spacings, respectively, than the normal leaf type hybrids. In both experiments an increase in unproductive plants was associated with a reduction is grain yields. An additional 1‐year experiment was conducted to determine if light penetration into the leaf canopy and tassel morphology could account for the increased grain yield of liguleless‐2 hybrids. The normal leaf type hybrids had only 89% as much incident light in the leaf canopy as the liguleless‐ 2 hybrids. In addition, tassel removal increased grain yield of the normal leaf type hybrids but not that of the liguleless‐2 hybrids. Based on results of this study, leaf angle and tassel morphology were two characters associated with increased grain yield of liguleless‐2 hybrids under high plant densities and narrow row spacings. Liguleless‐I hybrids have almost a total vertical leaf orientation and did not respond in the same manner in these experiments as liguleless‐2 hybrids, although the leaf angle and light penetration into the canopy were greater than liguleless‐2 hybrids. Responses of liguleless‐1 hybrids were similar to those of normal hybrids.
Inheritance of Resistance to Races IB‐54 and IG‐1 of Pyricularia oryzae in Rice1
Authors: Eroutor P. G. , Gilmore E. C. , Bollich C. N. , Marchetti M. A.
Published: July 2010

Rice blast, caused by Pyricularia oryzae Cav., is an internationally important disease of rice (Oryza sativa L.). Information on the mode of inheritance of reaction to races of blast is useful in breeding resistant cultivars. The inheritance of resistance to two specific races of P. oryzae, IB‐54 and IG‐1, was studied in a cross between the resistant cultivar ‘Lebonnet’ and a susceptible selection, CI 9888. Resistance to both races was shown to be conditioned by a single dominant gene by greenhouse inoculation tests performed on the F1, F2, and F3 generations.
Computer Programs for Analyses of Inheritance and Linkage Data1
Authors: Hanna Wayne , Mullinix Ben , Grimes Larry
Published: July 2010

Three computer programs were developed to aid in analyzing genetic inheritance and linkage data. The inheritance programs test goodness‐of‐fit of observed data with 1 to 50 theoretical genetic ratios. One program analyzes two‐to five‐class inheritance data. The second program processes four‐class linkage data (two, two‐class mutants). The third program analyzes four‐class linkage data, prints the chi‐square values for each mutant, calculates a linkage chi‐square value, and determines heterogeneity values. Each of the programs is available on request.
Inheritance of Stippled Leaf in Alfalfa1
Authors: Hartman B. J. , Hunt O. J. , Peaden R. N. , Thyr B. D.
Published: July 2010

Backcross and F2 analysis in alfalfa, MedicagO sativa L., showed that the character stippled leaf was probably controlled by a single recessive gene inherited tetrasomically. The F1, F2 and S1 progeny were evaluated for the degree of stippling and incidence of mutation. The gene appears to be influenced by mutation and/or modifiers, as evidenced by leaf sectors with very little chlorophyll on plants that normally show a slight amount of chlorotic stippling. The stippling character can be detected in the cotyledon stage of the progeny as very small, round, lightly colored areas. The symbol stp is proposed for this gene.
Relationship of Hydroxamate Concentration in Maize and Field Reaction to Helminthosporium turcicum1
Authors: Long B. J. , Dunn G. M. , Routley D. G.
Published: July 2010

In 1959, the cyclic hydroxamate 2,4‐dihydroxy‐7‐methoxy‐l,4‐benzoxazin‐3‐one (DIMOBA) was first reported maize (Zea mays L.) and has since been implicated in resistance to several pathogens. In our study, 14 inbred lines of maize commonly used as parents of many hybrids in the United States, plus the genotypes BxBx and bxbx were utilized to test the relationship of concentrations of hydroxamates and resistance to Helminthosporium turcicum Pass. in the field. One set of the 16 inbreds was analyzed for hydroxamates nondestructively by a rapid procedure using steam tissue from seedlings 36 to 40 cm high. The same set of inbred lines was similarly analyzed at mid‐silking stage by Hamilton's procedure using leaf tissue. A second set of the 16 inbred lines was inoculated in the field with spore suspensions of H. turcicum and evaluated for resistance at mid‐silking stage using a visual rating scale.

A highly significant correlation (r = 0.76, dr. = 43) was obtained between concentrations of hydroxamates in stem tissue from the seedlings and hydroxamate concentrations in leaf tissue at mid‐silking stage. A significant correlation (r = 0.57, dr. = 46) was obtained between concent.rations of hydroxamates in seedling stem tissue and resistance to H. turcicum. Similarly, a highly significant correlation (r = 0.64. df. = 43) was obtained between hydroxamate concentrations in leaf tissue of inbreds at mid‐silking stage and resistance to H. turcicum.
Protein Contents, Grain Weights, and Breeding Potential of Wild and Domesticated Tepary Beans1
Authors: Waines J. Giles
Published: July 2010

Protein contents and 1,000 grain weights of wild and domesticated tepary beans (Phaseolus acutifolius A. Gray) were compared with values for domesticated common beans (P. vulgaris L.). The wild teparies tested had significantly higher mean protein values, but significantly lower grain weights than the domesticated teparies. Domesticated teparies had a larger range of protein values than the wild teparies. Wild and domesticated teparies had significantly lower mean protein contents and much lower mean grain weights than the cultivars of P. vulgaris tested. Only in cultivars of common bean were protein content and grain weight significantly negatively correlated. Teparies may have potential for breeding and for interspecific hybridization to transfer drought tolerance, heat resistance, ozone‐smog tolerance, narrow leaves, and disease resistance from teparies to common beans.
Seedling Growth of Smooth Bromegrass Measured in Five Environments1
Authors: Tan Geok‐Yong , Tan Wai‐Koon , Walton P. D.
Published: July 2010

Nine cultivars of smooth bromegrass (Bromus inermis Leyss.) were grown in four controlled environments in the greenhouse and growth room and one field environment. The four controlled environments were high light and high temperature, high light and low temperature, low light and high temperature, and low light and low temperature. Each environment was planted as complete blocks with nine cultivars assigned at random into each of the four blocks. Four harvests at 1‐week intervals were sampled at random within each cultivar with the first harvest commencing at the two‐leaf stage. The studies were confined to seedlings sampled within 2 months of seeding

Significant differences in tiller number, leaf number and area, seedling dry weight, specific leaf weight (SLW), shoot to root ratio (S/R), relative growth rate (RGR), net assimilation rate (NAR), and leaf area ratio (LAR) were found among bromegrass cultivars and environments. ‘Carlton’ and ‘Manchar’ generally produced the largest number of leaves and tillers, largest leaf area, greatest seedling dry weight, and greatest RGR and NAR among the nine cultivars. ‘Blair’ and ‘Lyon’, in most cases, were the poorest entries.

Sed weight was correlated positively with leaf number (0.28 to 0.65), leaf area (0.48 to 0.78), and seedling dry weight (0.38 to 0.79) but was correlated negatively with SLW (—0.15 to —0.67) in all growth stages and environments. The results suggested that increasing seedling vigor at the early growth stage in smooth bromegrass can be achieved by screening breeding material on the basis of seed weight. Furthermore, the correlations between RGR and NAR were highly significant (in most cases, r > 0.90) and persisted throughout the environments studied indicating that cultivar differences in RGR were attributed more to NAR than LAR. Selection for high NAR at the later seedling growth stages (2 months old or more) is suggested as an important parameter in improvement of smooth bromegrass
Effect of Root Temperature on Dry Matter Distribution, Carbohydrate Accumulation, and Acetylene Reduction Activity in Alfalfa and Birdsfoot Trefoil1
Authors: Barta A. L.
Published: July 2010

Although birdsfoot trefoil (Lotus corniculatus L.) is a legume better adapted to poor or marginal soils than is alfalfa (Medicago saliva L.), reduced carbohydrate storage in roots and increased susceptibility of trefoil to roots and crown diseases in warm climates results in poor persistence. The objective of this study was to examine the effect of high root temperature on carbohydrate content and acetylene reduction activity in alfalfa and trefoil during regrowth.

A total of six samplings of each species grown at 16 and 30 C root temperatures were made at flowering and 2 weeks later during regrowth. Dry matter distribution, total nonstuctural carbohydrate (TNC) accumulation, N concentration, and acetylene reduction activity of roots were measured in plants grown in sand with nutrient solution.

High root temperature resulted in significantly reduced total plant or root dry weight only in alfalfa at flowering. However, trefoil root TNC was significantly lower at 30 C at both growth stages and was only 4.3% on a dry weight basis 2 weeks after cutting. It appeared that trefoil root carbohydrate concentration is influenced by root temperature as well as air temperature, thus helping explain why trefoil often fails to persist in warm climates.

Both total plant N and rate of acetylene reduction at flowering were much greater for alfalfa than for trefoil. Rates of acetylene reduction were significantly reduced by high root temperature only in alfalfa. Total plant N was affected much less than was acetylene reduction activity at 30 C in both species.
Seedling Growth of Cicer Milkvetch in Controlled Environments1
Authors: Townsend C. E. , Wilson A. M.
Published: July 2010

Seedling growth of cicer milkvetch (Astragalus cicer L.) is relatively slow and must be improved before the species can become a valuable forage crop. Therefore, our objectives were (a) to determine the effects of temperature on seedling growth of a seed source with a broad genetic base, and (b) to determine the variability among polycross progenies for seedling growth measurements. Seedlings were grown in controlled environmental chambers at 20 C day and 15 C night temperatures (20‐15 C), at 25 C day and 20 C night temperatures (25‐20 C), or in the greenhouse.

In the analysis of growth over a 42‐day period, seedlings at the two temperature treatments in the growth chambers differed significantly for relative growth rate (RGR), leaf area ratio (LAR), and net assimilation rate (NAR). Seedling growth was most rapid at the 25‐20 C treatment. Except for NAR at 25‐20 C, growth periods within both temperature treatments differed significantly for RGR, LAR, and NAR. Simple correlation coefficients between shoot weight, root weight, total weight, shoot height, leaf area, and number of leaves were significant and ranged from 0.91 to 0.99 for each treatment. This suggests that any one of the traits studied would be a reliable indicator of seedling vigor.

Significant differences occurred among environments for height, weight, number of leaves, and multileaflet position for seedlings of 22 polycross progenies. Within most environments there also were significant differences among progenies for these traits. The two growth chamber treatments provided better environments for selection of seedling vigor than did the greenhouse. We believe that environmental growth chambers, along with field testing, can be used effectively to improve the seedling vigor of cicer milkvetch.
An Electronic Weighing and Data Processing System for Field Use in a Small Grain Breeding Program1
Authors: Scott N. H. , Kronstad W. E. , McCuistion W. L.
Published: July 2010

A fast method of weighing grain samples and analyzing yield data immediately in the field was devised. Fewer people are required for the harvest operation, and with instantaneous analysis of the data, decisions can be made as to what material should be advanced for further testing. For off‐station testing, such information is valuable in reducing the number of samples brought back to the main station for further tests. The system provides accurate and timely data acquisition and effects a very significant savings in labor costs.
Leaf Growth, Leaf Aging, and Photosynthetic Rate of Tall Fescue Genotypes1
Authors: Wilhelm W. W. , Nelson C. J.
Published: July 2010

Leaf growth and leaf aging both influence the total amount of CO2 fixed by a particular leaf in the canopy during its photosynthetically productive life. Four genotypes of tall fescue (Festuca arundinacea Schreb.) were selected for all combinations of high and low CO2 exchange rates (CER) and yield. The purpose of this study was to determine CER during aging and leaf growth rates of tall fescue genotypes in growth chambers and in the field on a Mexico silt loam (Udollic Ochraqualfs; fine, montmorillonitic, mesic). Leaf growth of vegetative tillers in controlled environments was continuous throughout the day for all genotypes, regardless of CER or yield performance; however, leaf growth rate during a 24‐hour period changed diurnally in response to altered temperature and plant water status. Average leaf elongation rates were greater in the field during autumn (8.2 mm/ day) than in summer (4.2 mm/day). In both field and growth‐chamber studies, high‐yielding genotypes exhibited approximately 50% greater rates of both leaf elongation and leaf area expansion than did low‐yielding genotypes. During 4 weeks in a growth chamber and 6 weeks in the field, CER of all four genotypes decreased after collar formation at a rate of about 15 to 20% per week. Leaf diffusive resistances were similar for all genotypes and increased during aging from 1.42 sec/cm to 3.56 sec/cm in both studies. Genotypes with faster rates of leaf area development should reach critical leaf area index (LAI) faster than those with slow rates. They also would have relatively younger leaf tissue in the upper canopy, which is more efficient photosynthetically than older leaf tissue.
Emergence Comparisons Between Opaque and Normal Segregates in Two Maize Synthetics1
Authors: Loesch P. J. , Wiser W. J. , Booth G. D.
Published: July 2010

Maize (Zea mays L.) inbred lines and populations with the opaque‐2 gene has several serious agronomic liabilities compared with normal maize counterparts among which are reduced yield, increased ear rot, reduced and slower seedling emergence, and reduced seedling vigor. The objectives of our study were to (1) compare emergence percentages in opaque‐2 and normal segregates from two synthetic populations; (2) determine whether emergence traits were correlated with protein traits; (3) estimate the genetic variances and heritabilities of emergence traits in the two synthetics. In Experiment I, kernels from 118 S1 segregating ears of BSAA+/o2 were germinated in sandbenches in a greenhouse; 93.5% of the normal kernels emerged compared with 82.0% of the opaque kernels. Mean squares for families, endosperm types, and the interaction of families X endosperm type were highly significant for percentage seedling emergence. Emergence percentage was negatively correlated (significant at the 0.01 level of probability) with lysine and protein concentration, and lysine (g/100 g protein). Genetic variances and heritability estimates for seedling emergence were higher in the opaque‐2 class than in the normal. In Experiment II, opaque and normal kernels from 80 segregating 1 ears of BSBB+/o2 were germinated and grown in flats in a growth chamber maintained at 12°C for 13 days and were then transferred to a greenhouse; 88% of the normal and 60.7% of the opaque kernels emerged. The average rate of emergence for normal kernels was slightly faster than for opaque kernels. Mean dry weight of seedlings was higher for normal kernels than for opaque. Genetic variances and heritabilities for these traits usually were larger in the opaque class. The correlations between seedling emergence and protein quality traits were frequently negative or close to zero. We concluded that it should be possible to select for improved seedling emergence in normal and opaque‐2 maize.
Recurrent and Reciprocal Recurrent Selection in Sugarbeet1
Authors: Hecker R. J.
Published: July 2010

Five cycles of recurrent selection (RS) for general combining ability and two cycles of reciprocal recurrent selection (RRS) in sugarbeet (Beta vulgaris L.) were evaluated. The fifth‐cycle RS synthetic produced significantly less sucrose than its source population, but combined equally as well as its source population with a group of four male sterile tester lines. The reduced sucrose yield of this synthetic resulted entirely from reduced root yield, partially accounted for by the estimated 20% inbreeding of this synthetic. Three second‐cycle RRS synthetics were produced from each of two source populations (A and B). These synthetics were generated on the basis of superior progeny performance for recoverable sucrose, root yield, and sucrose content, respectively. Recoverable sucrose increased relative to its source only in the second cycle synthetic for root yield from source A. Root yield improvements were made in two synthetics from the low yield source A. Improvement in sucrose content was made in two synthetics derived from the low sucrose source B. In no synthetic was there a simultaneous increase in root yield and sucrose content. Crosses between the A and B synthetics did not significantly exceed the performance of the superior source parent for recoverable sucrose or any of its components, root yield, sucrose content, or thin juice purity. Reciprocal recurrent selection was successful in improving the general and specific combining abilty of those yield components that were relatively low in the sources. Simultaneous improvement of all components for production and for combining ability was not achieved by either of the two breeding methods.
The Gene Pool Concept as a Basis For Cultivar Selection and Recommendation1
Authors: Pedersen A. R. , Everson E. H. , Grafius J. E.
Published: July 2010

Plant breeders are greatly concerned with the number and location of test sites necessary to assess cultivar performance. Yield trials rarely contain the same entries over sites and years, and this greatly reduces the flexibility needed to compare advanced germplasm with current commercial cultivars over a period of time. In this paper we provide an alternative method to the statistical procedures normally used to compare cultivars. Winter wheat (Triticum aestivum L.) nurseries in Michigan were used to develop the concept of a gene pool base, which allows comparisons over years and sites without regard to particular entries in the sample. It is proposed that as long as entries in the test are a representative sample of the population gene pool, the sample mean can be used as an index of comparison. Yearly additions and subtractions to the gene pool over the relatively short time span of six years did not greatly affect the average reaction to the environment. The regression of cultivar mean yield on nursery mean yield demonstrated that 53 to 95% of the variation in cultivar performance could be explained by site mean performance, with most cultivars falling in the 70 to 85% range. The data points were distributed in a continuum from high to low yielding sites. In graphing the regression of a cultivar on site mean yields, the designation of points by location could be used to suggest which cultivars should be grown in each environment and yield potential range. Locations were identified that had consistently high, low, intermediate, or extremely variable yield ranges over years. Any minimal set of test sites should include the extremes to provide an adequate estimate of the regression line.
Abscission of Flowers and Fruits in Phaseolm vulgaris L. I. Cultivar Differences in Flowering Pattern and Abscission 1
Authors: Subhadrabandhu Suranant , Adams M. W. , Reicosky D. A.
Published: July 2010

Developmental patterns and abscission of flowers and pods were studied in greenhouse and field experiments with three cultivars of dry beans (Phaseolus vulgaris L.). The pattern of flower production, pod retention, number of flowers produced, and percentage of reproductive structures abscised varied with cultivar. The pattern of flower production varied from a concentrated skewed pattern for cultivar ‘Seafarer’ to a longer and more normally distributed pattern for cultivar ‘Black Turtle Soup’. In general, the first‐formed flowers had the highest probability of setting pods and producing mature seed.
Aflatoxin Contamination of Corn Before Harvest: Aspergillus flavus Association with Insects Collected from Developing Ears
Authors: Lillehoj E. B. , Fennell D. I. , Kwolek W. F. , Adams G. L. , Zuber M. S. , Horner E. S. , Widstrom N. W. , Warren H. , Guthrie W. D. , Sauer D. B. , Findley W. R. , Manwiller A. , Josephson L. M. , Bockholt A. J.
Published: July 2010

The study examined the relationship of Aspergillus flavus Link ex Fr. in insects collected from developing ears and aflatoxin contamination of the kernels of corn (Zea mays L.). In 1976 two hybrids adapted for growth in the South and two hybrids adapted to the Corn Belt were grown at 11 diverse locations in the USA. Planting and harvest dates were staggered to examine maturity factors. Of 1621 insect larvae collected, A. flavus was identified on 54 specimens (3.3%). The distribution of A. flavus on the insects was relatively uniform between test locations and across maturity groups and hybrids. However, common occurrence of aflatoxin was restricted to corn grown in the South, particularly in hybrids not adapted to the region. A detailed study of Georgia‐grown corn demonstrated that aflatoxin was not present in kernels 20 days post‐flowering, but the toxin was routinely found in samples collected 40 days after flowering. The results show a broad geographical occurrence of A. flavus on insects feeding on developing corn but a distinct interregional difference in the contamination of the grain by aflatoxin.
Lysine and Protein Characterization of Induced Shrunken Endosperm Mutants of Barley1
Authors: Ullrich S. E. , Eslick R. F.
Published: July 2010

‘Bomi’, Risø mutants 7, 8, 9, 13, and 1508 and ‘Carlsberg II’, Risø mutants 29, 56 and 86, induced high lysine shrunken endosperm and/or low kernel weight mutants of barley (Hordeum vulgare L.), were compared to their respective normal isotypes for kernel weight, protein, and lysine contents in several varied environments in Montana and Arizona. All mutants were lower in kernel weight and higher in lysine content, and six of the mutants were higher in protein content, with a relatively wide range of mutant‐normal differences for each character. Most of the mutants should maintain a positive mutant‐normal difference in lysine percentage if normal kernel weights were achieved through breeding efforts. Both modes of mutagenesis, induced and spontaneous, and two methods of selection, chemical (for high lysine) and visual (for shrunken endosperm), have produced a similar spectrum of high lysine, shrunken endosperm mutants.
Chemical and Morphological Characteristics of Seeds of Some Sunflower Species1
Authors: Dorrell D. G. , Whelan E. D. P.
Published: July 2010

Six species of wild sunflower (Helianthus), including the diploid annuals, H. annuus L. and H. petiolaris Nutt., the diploid perennials, H. giganteus L. and H. maximiliani Schrad., and the hexaploid perennials H. rigidus L. and H. tuberosus L. which are native to southwestern Manitoba and the north central Great Plains, were analyzed. The latter four species were characterized by small seed which averaged 3.4 g/1000, medium‐low oil content, 25.3%, low concentration of palmitic and stearic acids, 4.7 and 1.8%, respectively, and a high concentration of linoleic acid, 81.9%. The remaining species, H. annuus and H. petiolaris, had larger seeds, 7.3 g/1,000 medium oil content, 28.8%, low concentrations of chlorogenic acid, 2.5%, and a high concentration of linoleic acid, 79.6%. This compares with 59.5 g, 44.4, 3.7, and 71.8%, respectively, for the cultivar ‘Saturn’. If wild H. annuus and H. petiolaris are used to transfer desirable agronomic characteristics to cultivated sunflowers, they have the potential of improving oil quality characteristics. Furthermore, they hybridize much more readily with sunflowers than the other species studied.
Genetic Control for Percentage Groat Protein in 424 Advanced Generation Lines From an Oat Cross1
Authors: Iwig M. M. , Ohm H. W.
Published: July 2010

A population of 424 advanced generation lines from an oat (Avena spp.) cross between high and low protein parents was developed in a hierarchy of families and lines with certain genetic relationships. Genotypic variances were estimated and partitioned into components due to additive, dominance, and additive X additive genetic effects for several traits.

Additive genetic variance was significant for heading date, plant height, percentage groat protein (groat protein), seed yield, and groat weight. Dominance was not significant for any of the traits. Additive ✕ additive genetic variance was significant for groat protein and seed yield. Within several F2‐derived families, large differences in F6 were shown between F3‐derived families and between F4 lines within F2‐derived families for groat protein and seed yield. These large differences may be due to cytological abnormalities occurring when A. sativa L. gennplasm is crossed with A. sterilis L. germplasm causing large intact segments of chromosomes to segregate intead of random recombination.

Small but significant correlations of 0.21, 0.15, −0.27, 0.23, 0.10, and −0.34 were shown between heading date and plant height, heading date and groat protein, heading date and groat weight, plant height and groat protein, plant height and groat weight, and seed yield and groat protein, respectively. Several agronomically desirable lines were identified from the population of 424 lines. These lines demonstrated that the negative correlation between seed yield and groat protein can be broken to some degree. Some genes for high groat protein from A. sterilis appear to have been transferred into good yielding, agronomically acceptable lines.
Screening Soybeans for Drought Resistance. I. Growth Chamber Procedure1
Authors: Sammons D. J. , Peters D. B. , Hymowitz T.
Published: July 2010

The effects of soil moisture stress on root (RWP) and shoot (SWP) water potential, leaf lamina surface area (LSA) and dry weight (LDW), and photosynthesis (PIA) were studied in 21 to 22‐day‐old potted soybean (Glycine max (L.) Merr.) seedlings. Twenty cultivars were studied in an effort to detect differential response patterns to soil moisture stress. Analysis of the pooled data revealed a significant decline for all variables measured with increasing soil moisture stress. However, significant cultivar ✕ soil moisture treatment interaction exists for all variables measured, indicating variation in cultivar response patterns to decreasing soil moisture. Cultivars were classified as drought resistant, intermediate or susceptible for each variable based on individual performance relative to average seedling response to soil moisture stress. An overall estimate of drought performance was made for each cultivar. The results suggest that soybean seedlings differ in drought response. However, cultivars were not consistently classified by the several variables measured. This suggests that assessment of cultivar drought response should be based on observations of a combination of characteristics. Comparison of the results of this procedure to those of an independent field study suggest the desirability of further testing of the material in the field.
Preharvest Desiccation of Rice With Paraquat1
Authors: Eastin E. F.
Published: July 2010

Studies to determine the suitability of paraquat (1,1′dimethyl‐4,4′‐bipyridinium ion) as a preharvest desiccant were conducted on rice (Oryza sativa L.) cultivars ‘Brazos’ and ‘Labelle’. Under hot, clear weather conditions, paraquat rates of 0.14 kg/ha or above desiccated the leaves within 1 day. Under cool, cloudy conditions 2 to 3 days were required for desiccation. Paraquat applied to rice after the grains were fully developed at rates up to 0.56 kg/ha up to 10 days before harvest (DBH) did not reduce grain yields. Grain moisture, however, was reduced when a minimum of 0.14 kg/ha paraquat was applied at least 4 DBH. Percent whole kernels after milling was not lowered, or lowered only slightly, by application of up to 0.56 kg/ha paraquat up to 10 DBH. These results suggest that paraquat could be a valuable preharvest desiccant for rice if toxic residues are not found in the grain.
An Electronic Probe For Estimating Ear Moisture Content of Maize1
Authors: Kang M. S. , Zuber M. S. , Horrocks R. D.
Published: July 2010

A need exists for a reliable and non‐destructive method for identifying genotypes with rapid dry‐down rates in segregating populations of maize (Zea mays L.). We designed an electronic probe for this purpose and report the results of its use. Correlation coefficients between the moisture content estimated with the electronic probe and the percent ear moisture obtained by the conventional oven method were r = 0.90 in 1975 and r = 0.91 in 1976 (r = significant at 1% level). We concluded that the electronic probe method would be useful to maize breeders in identifying genotypes with rapid dry‐down capabilities and could be used by farmers in determining the optimum harvest date.
Temperature Tolerance in Soybeans. I. Evaluation of a Technique for Assessing Cellular Membrane Thermostability1
Authors: Martineau J. R. , Specht J. E. , Williams J. H. , Sullivan C. Y.
Published: July 2010

The effect of temperature on yield of soybeans (Glycine max (L.) Merr.), is often underestimated despite reports of a significant relationship between yield and growing season temperatures. The identification of genotypes having heat tolerance appears to be warranted, but a simple, rapid technique for measuring tolerance to high temperature is needed. A technique previously used for assessing genotypic differences in membrane thermostability (heat tolerance) in sorghum (Sorghum bicolor (L.) Moench) was evaluated for use in soybeans. The technique involves the measurement by electrical conductance of the amount of electrolyte leakage from heat‐damaged leaf tissue cells after exposure to elevated temperatures. The relationship between the degree of injury and the temperature at which that injury was induced was observed to be a sigmoidal response. Genotypic differences in heat tolerance were associated with differences in the relative position of the response curve with respect to the treatment temperature. Greatest sensitivity in detecting genotypic differences occurred at temperatures inducing about 50% injury. Genotypic differences were greatest in newly developed leaf tissue. Consequently, only the most recently developed leaves should be used in the assay. Plant‐to‐plant variation was appreciable and necessitated the use of bulked leaflets from several plants as samples. Genotypic differences were consistent across sampling dates, indicating that the assay can be conducted during any phase of vegetative growth. Results obtained from cultivar trials over several years show significant differences among genotypes and consistent relative ranking of genotypes in different environments. Although requiring replication to achieve a sufficiently small standard error, the technique shows promise as a screening method.
Succulence as a Selection Criterion for Improved Forage Quality in Lolium‐Festuca Hybrids1
Authors: Buckner R. C. , Bush L. P. , Burrus P. B.
Published: July 2010

Succulence or water content was used as an index for selection to improve forage quality of Lolium‐Festuca hybrid derivatives. Leaf‐roll, moisture content, and in vitro dry matter digestibility, determined during drought stress, were used as selection criteria to isolate succulent parents of ‘Kenhy’ and an experimental strain, G1‐307. Kenhy and G1‐307 had significantly less leaf‐roll; higher moisture content, palatability, and digestibility; lower acid‐detergent‐fiber content than ‘Kentucky 31’ and ‘Fawn’ tall fescue (Festuca arundinacea Schreb.) when all were compared in field plots. Stomata in Kenhy had a smaller pore size and a lower frequency per unit area than those in Kentucky 31, which may account for differences between the two cultivars in leaf‐roll and succulence characteristics. A positive relation was observed among moisture content, digestibility, and palatability. Moisture content was negatively correlated with acid detergent fiber. An analysis of variance for moisture content of parents and progenies of G1‐307 indicated that this characteristic was sufficiently heritable to permit improvement of forage quality of tall fescue through breeding.
Inheritance of the Absence of the Kunitz Trypsin Inhibitor in Seed Protein of Soybeans1
Authors: Orf J. H. , Hymowitz T.
Published: July 2010

Soybean [Glycine max (L.) Merrill] seds from reciprocal crosses of ‘Amsoy 71’ and P.I. 157440, reciprocal crosses of P.I. 196172 and P.I. 157440, and the cross P.I. 157440 ✕ ‘Jefferson’ were analyzed using polyacrylamide gel electrophoresis to study the inheritance of the absence of the Kunitz trypsin inhibitor (SBTI‐A2). Amsoy 71 has the SBTI‐A2, at Rf 0.79 (Tia), Jefferson at Rf 0.75 (Tib), P.I. 196172 at Rf 0.83 (Tic), and P.I. 157440 lacks the SBTI‐A2, band. The F2 and F3 data establish that the absence of the SBTI‐A2, band is inherited as a recessive to the codominant alleles Tia, Tib, and Tic. The allele for absence of the SBTI‐A2 band is designated ti. The homozygous recessive condition (ti ti) results in the lack of SBTI‐A2. The lack of the SBTI‐A2, protein was confirmed using spectrophometric assay procedures.
Synthesis of Commercial F1 Hybrids in Cotton. II. Long, Strong‐fibered G. hirsutum L. ✕ G. barbadense L. Hybrids with Superior Agronomic Properties1
Authors: Davis Dick D.
Published: July 2010

I investigated for 2 years at Las Cruces, New Mex., lint yield and fiber properties of two interspecific hybrids between Gossypium hirsutum L. and G. barbadense L. Both hybrids exhibited significant overall heterosis for yield of seedcotton. The hybrids produced 48 and 42% more seedcotton and 33 and 26% more lint cotton, respectively, than an ‘Acala 1517‐70’ check. The hybrids in general were no taller than the commercial check. Both hybrids have fiber that is slightly longer, finer, and about equal in strength to their G. barbadense parents. Some evidence in this study suggests that extra fine fiber of the hybrids is due to reduced fiber diameter.
Genetic Control of Hypocotyl Pigmentation among White‐Flowered Soybeans Grown in Continuous Light1
Authors: Palmer R. G. , Payne R. C.
Published: July 2010

Seedlings of 64 white‐flowered soybean (Glycine max L. Merr.) plant introductions, cultivars, and genetic lines were grown in continuous light of 505 μEm−3S−1. Tawny (T _ Td _) pubescent genotypes (22 samples) and light‐tawny (T _ td td) pubescent genotypes (20 samples) had bronze pigmentation on the hypocotyl shortly after emergence. Gray (t t Td _ or t t td td) pubescent genotypes (22 samples) had no detectable bronze pigmentation.

Reciprocal F1 hybrids of tawny pubescent plants and gray pubescent plants had bronze hypocotyl color and tawny pubescence. In the F2 generation, plants with bronze hypocotyl color invariably had tawny pubescence, while all plants with green hypocotyls had gray pubescence. The T locus has a pleiotropic effect on hypocotyl color and on pubescence color which was detected in white‐flowered soybeans. This relationship was constant in all tested populations and suggests a simple, rapid, and inexpensive method of detecting certain off‐types in whiteflowered soybean populations at the seedling stage.
Role of Roots and Shoots of Soybeans in Tolerance to Excess Soil Zinc1
Authors: White M. C. , Chaney R. L. , Decker A. M.
Published: July 2010

Reciprocal grafts were used to determine the relative importance of the roots and shoots of soybean (Glycine max L.) in tolerance to excess soil Zn. Grafts, in all combinations, were made between ‘Wye’ (Zn‐tolerant) and ‘York’ (Zn‐intolerant) soybean cultivars. For plants grown at soil pH 6.2 and soil Zn additions of 1.31, 131, and 393 ppm, the results showed that the scion genotype controlled relative Zn tolerance, while the rootstock genotype controlled Zn absorption and translocation. Differences in foliar Zn concentrations were not responsible for differential Zn tolerance of these two soybean cultivars.