bluuebunny/crossref_metadata_2025 huggingface dataset:
Breeding for Mineral Content in Wheat and Barley1
Authors: Rasmusson D. C. , Hester A. J. , Fick G. N. , Byrne I.
Published: July 2010

Varietal differences in P, K, Ca, and Mg content in wheat, Triticum aestivum L., and barley, Hordeum vulgate L., were investigated in field and greenhouse experiments. Varieties from this survey were used to obtain estimates of heritability of mineral content and information on the relationship between mineral content and grain and dry‐matter production.

Varietal differences in P, K, Ca, and Mg in grain and leaves were large and of similar magnitude in wheat and barley. These differences were relatively consistent in two field environments, but agreement was poor between greenhouse and field. Estimates of heritability of P, K, Ca, and Mg content in grain of wheat and barley were low in the F2 generation. However, estimates ranged from .31 to .80 in grain and .18 to .72 in leaves of wheat for replicated families in the F4 generations. Ca appeared most amenable to selection, followed by P and K.

Large increases in yield and in P and K content occurred with addition of P or K in field experiments. However, differences among varieties in grain and drymatter yields were not associated with varietal differences in P or K content of leaves or grain. Likewise, variety differences in dry‐matter yields obtained in nutrient solution were not associated with variety differences in P content. Varieties of wheat and barley did not appear to differ in efficiency of converting P or K into yield in field or greenhouse experiments.
Surface Area of Chlorophyll‐containing Tissue on the Inflorescence of Triticum aestivum L.1
Authors: Teare I. D. , Peterson C. J.
Published: July 2010

To determine reasons for variability in yield of wheat (Triticum aestivum L.), we measured the chlorophyllcontaining surface area of various components of the wheat inflorenscence and estimated the proportion that contained chlorophyll.

The cultivars were classified according to awn length (long‐awned, medium‐awned, or short‐awned). Makeup of the inflorescence‐area index for the long‐awned cultivars was 46% awn, 30% lemma, 20% glume, and 4% palea; of medium‐awned cultivars, 37% awn, 35% lemma, 24% glume, and 4% palea; and of short‐awned cultivars, 5% awn, 53% lemma, 35% glume, and 7% palea. The inflorescence area was 86%, 80%, and 38% as great as the flag‐leaf area (adaxial + abaxial surface) of the long‐, medium‐, and short‐awned cultivars, respectively.

Correlations of flag‐leaf and awn area with grain yield were 0.488 and 0.719 for flag‐leaf and awn areas, respectively, which supports previous reports of the importance of the awn in filling the ear.
Correlation of Corn (Zea mays L.) Roots Early in Development to Mature Root Development1
Authors: Nass H. G. , Zuber M. S.
Published: July 2010

We grew 40 genotypes of corn (Zea mays L.) in sand culture and evaluated the roots at 28 and 35 days after planting. Total root weight, root volume, and weight of nodal roots were significantly and positively correlated with root‐clump weight and root‐pulling resistance of mature plants under field culture. The percentage of seminal roots was negatively correlated.

Evaluation of corn roots grown in a sand culture provides an efficient method for identifying genotypes with superior root types at an early stage of growth. Our results suggest that corn genotypes with vigorous root systems early in plant development tend to have superior root systems at maturity.
Inheritance of Resistance to Fusarium Wilt in Cotton1
Authors: Kappelman A. J.
Published: July 2010

The inheritance of resistance to Fusarium oxysporum f. vasinfectum (Atk.) Snyd. & Hans. was investigated in seven families of cotton (Gossypium hirsutum L.). Each family contained P1 P2 F1 F2, F3 B1 and B2 generations and each was evaluated in six different greenhouse tests. Plants were grown in fumigated soils and were artificially inoculated with known concentrations of inoculum.

Additive effects were significant in 34 of the 42 tests. Dominance effects were significant in two and epistatic effects were significant in eight tests; however, additive effects also were significant in each of those cases except one. Although estimates of additive effects were of much greater magnitude than were those of dominance or epistasis. it was not possible to draw direct inferences as to the relative importance of those effects, since they were made using the generation‐mean analysis. In the families studied additive gene effects most satisfactorily explained the inheritance of resistance to fusarium wilt in cotton.
Breakup of Linkage Blocks in Cotton, Gossypium hirsutum L.1
Authors: Meredith William R. , Bridge R. R.
Published: July 2010

We conducted this study to determine if the negative genetic associations frequently observed between yield and fiber strength in cotton (Gossypium hirsutum L.) could be reduced by random intermating. We selected for comparison two populations derived from a cross of ‘Stoneville 7A’ ✕ ‘Pee Dee 165’. The “original” population consisted of 96 families, each produced from a random F2 plant. Ninety‐six families comprised the “intermated” population. This intermated population was produced from two generations of random intermating after reaching F3.

Mean comparisons between the two populations showed small but significant differences for some traits, indicating that selection in the intermated population may have taken place or that linked epistasis was involved. Genotypic variances were approximately the same for both populations. The negative genetic correlation between lint yield and fiber strength was decreased by intermating. Genetic correlations between other traits were generally reduced by intermating. These results imply that some modifications of the conventional method of cotton breeding are necessary to improve yield and fiber strength. Modifications discussed are the use of random intermating, diallel selective mating, use of selection indexes, backcrossing, and bulk breeding.
Comparisons of Response to Alternative Selection Procedures Initiated with Two Populations of Maize (Zea mays L.)1
Authors: Moll R. H. , Stuber C. W.
Published: July 2010

Experimental comparisons were made between full‐sib family selection and reciprocal recurrent selection for higher grain yield in populations of Zea mays L. following six selection cycles. The experimental populations involved two open‐pollinated varieties, ‘Jarvis’ and ‘Indian Chief,’ their F1 variety hybrid, and the variety composite formed by random mating the variety hybrid. Comparisons were made in terms of responses of the varieties themselves and the variety hybrid to both kinds of selection, and response of the variety composite to full‐sib selection.

Significant increases in yield were observed after six selection cycles in six of the seven populations tested. The exception was the response of the Indian Chief variety to reciprocal recurrent selection, which was not statistically significant. Responses of both varieties to full‐sib family selection were 2.1 times greater than their responses to reciprocal recurrent selection. Response of the variety hybrid to reciprocal recurrent selection was 1.3 times greater than the response to full‐sib family selection. Response of the variety composite to full‐sib family selection was no greater than for Jarvis, which was the most responsive of the two varieties. Heterosis in the variety hybrid increased markedly after reciprocal recurrent selection, but showed little change after full‐sib family selection. An evaluation of five additional traits showed thatincreases in yield were generally accompanied by a change toward shorter plants, with lower ear height, more tillers, and more ears. No change in time of flowering was observed.
Genetic Control of Epidermal Cell and Stomatal Frequency in Maize1
Authors: Heichel G. H.
Published: July 2010

Two inbreds of maize (Zea mays L.) Wf9 and Pa83, that showed a consistent difference in stmnatal frequency (mm‐2) measured by epidermal replication, were used to investigate the genetic control of epidermal cell and stomatal frequency. The consistent difference in stomatal frequency between the inbreds was reproducible on adaxial and abaxial epidermises at three leaf positions on progeny obtained from three successive generations of selfing and grown in different years. The F1 generation showed dominance for low epidermal cell frequency and partial dominance for low stomatal frequency. The segregation ratios of F2 and backcross generations, the patterns of segregation, and the correlation between epidermal cell and stomatal frequency suggest that a simple genetic system controls epidermal cell and stomatal frequency.
Modification of Saponin Content of Alfalfa Through Selection1
Authors: Padersen M. W. , Wang Li‐Chun
Published: July 2010

Progress in selection for both low and high saponin content in alfalfa (Medicago sativa L.) was achieved with chemical and biological assays. Results were characterized by interactions among varieties, crops, and saponin levels. Selections for saponin content significantly affected protein, and forage yield, but not fiber, fat, ash, N‐free extract, or seed yield. There was a tendency for low‐saponin selections to be lower in protein and higher in fiber and forage yield than the high‐saponin selections, but interactions resulting in differences among varieties and crops preclude definite conclusions.
Effect of Seed Source on Soybean Strain Performance for Two Successive Generations1
Authors: Fehr W. R. , Probst A. H.
Published: July 2010

We evaluated the performance of 10 soybean [Glycine max (L.) Merr.] strains by planting seed produced at each of 14 diverse locations in 1967. Significant differences among sources were observed for all characters evaluated. The importance of the range among sources for yield (176 kg/ha), maturity (1.5 days), lodging (0.16 score), height (2.1 cm), seed size (0.59 g/100 seed), field emergence (46.7%), protein percentage (0.50%), and oil percentage (0.23%) will depend on the desired accuracy of strain comparisons. The strains ✕ sources interaction was significant only for maturity and field emergence percentage, indicating that relative performance of strains was consistent across sources.

Significant differences among seed sources were detectable for one crop season only, except for maturity and seed size. The range among sources in the second crop season was 0.3 days for maturity and 0.21 g/100 seeds for seed size.

Geographical distance between sources was not a reliable indication of potential first‐generation differences among sources. Germination percentage and seed size were not useful as direct indices of differences among sources. However, seed lots of a particular genotype that differ appreciably for either character are likely to have differences in progeny performance.

Differences due to seed source may be minimized by growing all test strains, including checks, in the same environment immediately before testing. The persistence test indicated that one common environment immediately before testing is adequate to minimize differences of practical importance.
Regional Maize Diallels with US and Semi‐Exotic Varieties1
Authors: Eberhart S. A.
Published: July 2010

Regional evaluations of US and semi‐exotic maize (Zea mays L.) varieties identified three semi‐exotic Corn Belt varieties [‘BSTL,’ ‘BS2,’ and ‘PHWI(MI)C7’] and two semi‐exotic Southern varieties [‘PHWI(MT)C7’ and ‘(Indian Chief ✕ Diente de Caballo)(S)C2’] that approach exceed the performance of US varieties. Two decades or more breeding were required to develop them as tential breeding populations as sources for the development of hybrids. These semi‐exotic varieties may be potential sources of genetic resistance to insects and diseases including southern leaf blight (Helminthosporium maydis).
Germination and Emergence of selected Forage Species Following Preplanting Seed Treatment1
Authors: Bleak Alvin T. , Keller Wesley
Published: July 2010

Germination, seedling emergence, and initial root and shoot elongation were all hastened by preplanting treatments applied to the seeds of seven Agropyrons, Bromus tectorum L., and Elymus junceus Fisch. Preplanting treatments consisted of wetting the seeds at selected temperatures and periods. The best treatment for the Agropyrons and E. junceus was 60 hours at 16 C. The best treatfor B. tectorum was 30 hours at 16 C. Less consistent results were obtained from various preplanting treatments applied to the seeds of four summer growing grasses and one browse species. Five days after planting Eragrostis lehmanniana Nees had 6% emergence from controls and 13 to 31% from pretreated seeds. Sporobolus airoides (Torr.) Torr. emergence from controls was 3% and 35 to 53% from treated seeds. Atriplex canescens (Pursh) Nutt. given pretreatment at 28 C for 10 hours had roots averaging 30 mm longer than the control. We obtained no measurable response to preplanting treatments from Bouteloua curtipendula (Michx.) Torr. or B. eriopoda (Torr.) Torr.
Effect of Leaf Angle on Hybrid Performance in Maize (Zea mays L.)1
Authors: Russell W. A.
Published: July 2010

Two single‐cross diallels of five erect‐leaf (liguled) and five horizontal‐leaf maize (Zea mays L.) inbred lines were compared for yield performance at two row widths and three stand densities at each row width. The inbred lines were known from previous evaluations to have aboveaverage general combining ability. The maximum difference of leaf angle between two hybrids was 30°, and the average difference between the two groups was 11°. The linear yield responses of the two hybrid groups to increased stand densities were different (P<0.01); the linear regression coefficients were 0.35 and 2.70 for the erect‐leaf and horizontal‐leaf groups, respectively. The data from this study suggest that for Corn Belt germplasm presently available the maize breeder should not restrict his selection to plant types that have a distinctly erect‐leaf orientation.
Parameters of the Fibrous Root System of Sugar Beet (Beta vulgaris L.)1
Authors: Fick G. W. , Williams W. A. , Ulrich A.
Published: July 2010

The dry weight of fibrous roots produced by sugar beets (Beta vulgaris L.) grown in vermiculite irrigated with nutrient solution was estimated by measurement of CO2 evolved during wet combustion. This method gave good agreement with data obtained from direct dry weight determination on fibrous roots grown in solution culture. At 69 days postemergence dry weight of fibrous roots was 6.7 g plant‐1 in either system. There was no difference in the frequency distribution of root diameters between the two cultures, and the modal root diameter was 0.12 mm. By assuming that the frequency distribution of lengths in each diameter class was the same as the frequency distribution of diameters, the surface area was estimated to be 6.48 cm2 m‐1 of length in both systems. The length‐to‐weight ratio of fibrous roots was a linear function of the reciprocal of their diameter, and the mean length‐to‐weight ratios were 286 m g‐1 in vermiculite and 275 m g‐1 in solution culture. More than 99% of the total length, but only 72% of the weight, was in roots less than 1 mm in diameter. The maximum weight of fibrous roots observed was 14 g plant‐1.
Inheritance of a Mutation for Dwarfness in Soybeans1
Authors: Fehr W. R.
Published: July 2010

Dwarf soybean plants [Glycine max (L.) Merr.] were found in a row of the ‘Hark’ variety at Ames, Iowa in 1966. All plants in the row were from seeds of a single plant harvested from a foundation seed field of Hark the previous year. The plants had short internodes and petioles. The leaves were similar in shape to normal Hark, but were only one‐fourth normal size. The flowers were approximately three‐fourths the size of normal Hark, but were not abnormally cleistogamous. The inheritance of the Hark dwarf and its relationship to the ‘Lincoln’ dwarf (df2) and the ‘Adams’ dwarf (df3) genes were studied.

The crosses of Hark normal ✕ Hark dwarf, Lincoln dwarf ✕ Hark dwarf, and Adams dwarf ✕ Hark dwarf were studied in F1; F2, and F3. The Hark dwarf was controlled by a single recessive allele, designated df4, that was nonallelic to df2 and df3 and independently inherited. No distinct double recessive phenotype was observed. There was a satisfactory fit to a ratio of 9 normal:3 Hark dwarf:4 Lincoln dwarf in the Lincoln dwarf ✕ Hark dwarf cross and a 9 normal:3 Hark dwarf:4 Adams dwarf in the Adams dwarf ✕ Hark dwarf cross. These data indicated that df2df2df4df4 F2 plants were classified phenotypically as Lincoln dwarfs, and the df3df3df4df4 F2 plants, as Adams dwarfs.

There was a range in height for F2 and F3 individuals of all three dwarf: types, indicating that expression of the df2 df3, and df4 alleles may be influenced by modifying genes.
Relation of the Club Gene with Yield and Yield Components of Near‐Isogenic Wheat Lines1
Authors: Gul Azam , Allan R. E.
Published: July 2010

We studied the effects of the C locus for club and lax spike and the associated linkage blocks on yield, test weight, and yield components (culm number, kernel weight, and kernels per spike) using near‐isogenic wheat (Triticum aestivum L.) lines. The lines were obtained in two backcross‐derived genetic backgrounds. Populations included ‘Suwon 92’/8*‘Omar’ (club background) and ‘Albit’/7*‘Burt’ (lax background). The C locus directly influenced test weight and kernel weight. Culm number showed inconsistency between the two spike types. Added N increased yields of both spike types; in one family club lines responded more than lax lines. The N level ✕ spike type interactions were generally nonsignificant for yield, test weight, and yield components in both backgrounds. Location differences influenced yield for both spike types, but their interaction proved nonsignificant. In the Omar background, kernels per spike were closely linked with the C gene, but this linkage was broken when the C gene of Albit was transferred to Burt. Generally the C locus did not affect yield per se. Observed yield differences apparently reflected linkage blocks closely and oppositely associated with the C locus in the two genetic backgrounds.
Heterosis and Gene Action in Cotton, Gossypium hirsutum L.1
Authors: Meredith William R. , Bridge R. R.
Published: July 2010

Heterosis (F1 — MP), useful heterosis (F1 — ‘Deltapine 16’), and gene action estimates were obtained at four locations from the six groups of populations involving ‘Deltapine 16’ (Gossypium hirsutum L.) crossed with six cultivars (‘Q1,’ ‘Del Cerro 183,’ ‘FTA 263‐20,’ ‘Acala 3080,’ ‘Mo277‐396,’ and ‘Stoneville 603’).

Heterosis for lint yield was detected in each cross. F1 yields ranged from 92 to 115% of that of Deltapine 16, while F2 yields ranged from 86 to 107%. Increases in boll size were partially responsible for the increased productivity of the hybrids. Parental lines originating from outside the Delta in general produced hybrid‐by‐location mean squares greater than those from Delta‐derived parents. These interactions were related to the higher relative performance of Deltapine 16 at the locations with higher yield. The potential benefits from utilizing heterosis were especially evident when all traits were considered simultaneous. Four of the six F1's produced yields equal to or greater than Deltapine 16 while also having longer, stronger, and finer fiber.

Heterosis for each of the nine traits studied was determined primarily by dominance gene action. Of the 54 possible tests additive‐by‐additive epistasis was significant in only four instances, and even in those four cases the mean squares for epistasis were much smaller than were those for additive or dominance effects.

Additive effects predominated for lint percentage, seed index, fiber strength, fiber elongation, and fiber fineness. However, dominance was greater for boll size. Both were involved for lint yield and fiber length. In every case there were some crosses that did not fit the general trend.

The interaction of additive effects with locations was usually of greater magnitude than the dotninance‐bylocation interaction. There were 28, 13, and 1 instances of significant additive, dominance, and additive by additive epistatic by location interactions, respectively. Interactions with locations were the greatest practical limitation for lint yield selection and they were less important for the other traits. The interactions with locations were particularly large for the cross involving Acala 3080. Breeding implications are discussed.
Maize with Multilayer Aleurone of High Protein Content1
Authors: Wolf M. J. , Cutler H. C. , Zuber M. S. , Khoo Uheng
Published: July 2010

Coroico corn (Zea mays L.), a South American race of floury maize contained two to six layers of aleurone cells instead of the customary single aleurone cell layer found in ordinary yellow dent corn. In Coroico with an average of 3.7 aleurone cell layers, the aleurone made up 4.3% of the endosperm as against 2.1% in yellow dent corn. Total protein in Coroico aleurone is 35 to 38% compared with 22% in yellow dent corn. Lysine levels in aleurone proteins of all corns examined, both Coroico and yellow dent were comparable ranging from 4.0 to 4.4 g/100 g of protein. Because of the additive effect of the multiple aleurone and the high protein content of the aleurone, lysine in Coroico endosperm was higher than in that of yellow dent corn. Multiple aleurone is transmitted as a partial dominant character over the normal single aleurone condition. Improvement of protein nutritional quality using Coroico germ plasm appears worthwhile.
Grain and Flour Quality Factors of Spring Wheat Treated with Dicamba and RH 5391
Authors: McGuire Charles F. , Lebsock Kenneth L.
Published: July 2010

Quality analyses were made on grain and flour from two hard red spring (Tritirum aestivum L. em Thell.) and two durum (Triticum durum Desf.) wheat cultivars treated in the field with 3,6‐dichloro‐o‐anisic acid (dicamba) and a coordination product of zinc ion and manganese ethylene bisdithiocarbamate‐plus anhydrous nickel sulphate (RH 539). Dicamba treatments caused the following changes. Protein percentage of wheat and flour increased by as much as 17% over the mean of untreated checks. Sulfhydral (—SH) concentration increased up 13.8% over the checks and in proportion to the increased protein content. Diastatic activity of whole wheat increased markedly (28.5% higher than the checks) from treatments, but endosperm tissue represented by flour and semolina was not affected. Mixogram scores of samples from treated wheat were significantly lower than check sample scores. Neither baking quality ratings of the hard red spring wheats nor macaroni performance scores of the durums were changed. Grain from treated plots averaged lower in flour yield than grain from untreated plots. Interactions between varieties and treatments were found for protein percentage, diastatic activity, and mixogram score.

RH 539 did not significantly alter product quality, milling, dough‐mixing properties, or other quality factors evaluated.
Genetic Variability in the Mungbean, Vigna radiata (L.) Wilczek
Authors: Yohe John M. , Poehlman J. M.
Published: July 2010

Three hundred and twenty‐one strains of mungbeans, [Vignu radiata (L.) Wilczek] originating from 18 American, Asian, African, and Middle Eastern countries were grown at Columbia, Mo. and evaluated for yield, days to first ripe pod, plant height, length of first branch, pods per plant, number seeds per pod, 1000 seed weight, virus resistance, mildew resistance, percent protein, percent lysine, and percent methionine. A wide range in genetic variability was identified for each character examined. Performance of the 32 (10%,) highest‐yielding strains is compared with the performance of the total population of 321 strains. Relative to the total population, the high‐yielding strains tended to be moderately early, to have moderately large‐size plants as measured by height and length of the first branch, to have a large number of seeds per pod and moderately high seed weight, and to be resistant to virus. Protein, lysine, and methionine content varied widely among the high‐yielding strains. No single strain excelled in the three yield components — pod number, seeds per pod, and seed weight — or in the three nutritional components — protein, lysine, and methionine.
Environmental Influence on Specific Leaf Weight and Its Heritability in Sainfoin1
Authors: Straley C. S. , Cooper C. S. , Carleton A. E.
Published: July 2010

Specific leaf weight (SLW, mg/cm2) of 24 space‐planted clones of sainfoin (Onobrychis viciaefolia Scop.) and their solid‐seeded progeny was estimated in 1970. Seven of these clones were selected for additional studies. SLW was estimated for these seven clones when grown in the greenhouse during the winter and again in a new space‐planted nursery in the field in 1971. SLW of progeny of these seven clones was also determined when they were grown in space‐planted rows in 1971. Heritability of SLW was determined by the parent‐progeny regression method.

The SLW of the 24 space‐planted clones ranged from 5.4 to 12.5. The range in SLW of solid‐seeded progenies was 4.9 to 7.7 and the heritability estimate for SLW was very low (.O8). SLW of the seven selected clones was much lower in the greenhouse than in the field. The heritability estimate of SLW measured on space‐planted clones and progenies was .54. However, the heritability estimate of SLW measured on solid‐seeded progenies and space‐planted clones was zero. This study indicated that SLW in sainfoin is greatly influenced by the environment. Large differences in SLW occurred in space‐planted clones and progeny but not in solid seedings of progeny.
Pollination by Honey Bees of Male‐sterile Cotton in Cages1
Authors: Moffett Joseph O. , Stith Lee S.
Published: July 2010

In 1969 and 1970, honey bees (Apis mellifera L.) successfully pollinated the caged A‐line flowers of a three‐species cross between Gossypium arboreum L., G. thurberi Todaro, and G. hirsutum L., which exhibits cytoplasmic male sterility at lnoderately high temperatures. The pollen source was an isogenic B‐line. The supply of seeds was increased from a few to more than 80 kg. The A‐line plants produced 84% as much seed cotton as the B‐line plants. Some 2% of the seeds produced on A‐line plants were from self‐fertile flowers; 98% were the result of crossing. A reduction in sunlight of 47% lowered yields of seed cotton 50%, compared with plants subjected to a 27% reduction.
Influence of Maturity Genes on Plant Growth in Sorghum1
Authors: Quinby J. R.
Published: July 2010

Eight sorghum [Sorghum bicolor (L.) Moench] maturity genotypes were grown under favorable conditions at Plainview, Texas from a planting on June 6, 1969. Under the 10‐hour nights of the summer the genotypes flowered at different times and differed in leaf number and plant size. The maturity genes are known to control time of floral initiation but, in addition, appear to influence rate of growth as measured by leaf size and panicle weight.
Nucleoside Diphosphate Glucose Pyrophosphorylase Isoenzymes of Developing Normal, Brittle‐2, and Shrunken‐2 Endosperms of Zea mays L.1
Authors: Weaver S. H. , Glover D. V. , Tsai C. Y.
Published: July 2010

Maize (Zea mays L.) endosperms from normal, brittle‐2, and shrunken‐2 near‐isogenic sublines of the Oh43 inbred were assayed for nucleoside diphosphate glucose pyrophosphorylase activity at 10, 20, and 30 days post‐pollination. Polyethaleneamine‐cellulose thin layer chromatography and polyacrylamide gel electrophoresis were used for product assay and identification of isoenzyme patterns from crude enzyme preparations, respectively.

Evidence is presented for the existence in corn endosperm of pyrophosphorylose activity with guanosine triphosphate and thymidine triphosphate in addition to adenosine triphosphate, cytidine triphosphate, and uridine triphosphate. Two adenosine diphosphate glucosepyrophosphorylase isoenzyme bands from normal and shrunken‐2 endosperms were detected with the same pattern, suggesting that the shrunken‐2 gene may be regulatory in nature. Brittle‐2 showed an altered mobility of the adenosine diphosphate glucose pyrophosphorylase banding pattern, which indicates that brittle‐2 may be a structural gene. Three isoenzymes for uridine diphosphate glucose pyrophosphorylase were found in normal and mutant endosperms. Evidence indicated that guanosine triphosphate may be utilized by adenosine diphosphate glucose pyrophosphorylase. Thymidine triphosphate and possibly cytidine triphosphate may be utilized by uridine diphosphate glucose pyrophosphorylase.

There were no differential appearances of the pyrophosphorylase isoenzymes during corn endosperm development. However, quantitative differences in the isoenzyme bands were observed.
Mass Selection versus Maternal‐Line Selection in Russian Wildrye1
Authors: Marshall S. W. , Slinkard A. E.
Published: July 2010

A paired comparison of maternal‐line selection versus mass selection for seedset rating and seed weight concurrently was made in Russian wildrye (Elymus junceus Fisch.). Maternal‐line selection (essentially mass selection with pollination among selected plants) was superior to mass selection in increasing seedset rating and seed weight. The net result was greatly increased seed yield.
Effect of Time and Plant K Status on 14C‐labeled Photosynthate Movement in Cotton1
Authors: Ashley D. A. , Goodson R. D.
Published: July 2010

The effect of time and plant K status on the rate and pattern of photosynthate translocation in 5‐week‐old cotton (Gossypium hirsutum L.) plants was investigated using 14CO2 labeling techniques. The cumulative total of 14C‐photosynthate translocated from the source leaf increased in a hyperbolic manner with distance during a 2‐hour translocation time. The maximum velocity of photosynthate translocation was approximately 50 cm per hour. Decreasing the K content of plants markedly reduced both the quantity and the distance that photosynthate moved from the source leaves. The reduction in photosynthate translocation resulting from reduced K content was obtained before visible K deficiency symptoms appeared on the plant.
Rj4 — A Gene Conditioning Ineffective Nodulation in Soybean1
Authors: Vest Grant , Caldwell B. E.
Published: July 2010

Ineffective nodulation in the soybean [Glycine max (L.) Merrill] inoculated with Rhizobium japonicum strain 61 was shown to be controlled by a single dominant gene which we have designated Rj4.
Production of Alfalfa Plants from Callus Tissue1
Authors: Saunders J. W. , Bingham E. T.
Published: July 2010

Alfalfa (Medicago sativa L.) plants were produced from callus tissue cultured on a variety of semisolid media. Plants could be obtained from callus placed on a basal medium, but addition of naphthalene acetic acid, tyrosine, or a cytokinin either alone or in certain combinations increased efficiency. The most efficient production was accomplished on a medium composed of Blaydes' inorganic and vitamin constituents with 100 mg/liter inositol and 2.0 g/liter yeast extract. Ability of fresh callus to differentiate into plantlets depended on the hormone levels of the initial callus‐inducing medium, as well as on the genotype of the donor plant. Daylength appeared not to be critical for shoot differentiation. Plants differentiated out of callus derived from immature anthers, internode sections, seedling hypocotyls, and immature ovaries. Callus was obtained from anthers which were in premeiotic to nearly mature stages. Histological studies indicated that in most cases anther callus arose from somatic cells in interlocular connective tissue. Most of the 200 plants recovered from callus were tetraploid, as was the donor plant, although at least nine octaploids and several off‐type plants, including albinos, were obtained.
Genetic Variance for Reaction to Five Foliar Pathogens in Alfalfa1
Authors: Hill R. R. , Leath K. T.
Published: July 2010

Plants randomly sampled from ‘Saranac,’ ‘MSA‐C4,’ and ‘MSB‐C4’ alfalfa (Medicago sativa L.) were used to construct a series of eight five‐parent diallel crosses within each cultivar. Reactions of crosses and parents to Uromyces striatus Schroet. var. medicaginis (Pass.) Arth., Stemphylium botryosum Wallr., Pseudopeziza medicaginis (Lib.) Sacc., Phoma herbarum West f. medicaginis West ex. Rab., and Leptosphaerulina briosiana (Poll.) Graham and Luttrell were observed in greenhouse and inoculation chamber experiments.

Additive genetic variance was significant for reaction to U. striatus and P. medicaginis in each of the cultivars, and for reaction to S. botryosum and L. briosiana in MSA‐C4 and MSB‐C4. Significant nonadditive genetic variance was observed for reaction to U. striatus in MSAC4 and MSB‐C4. Additive genetic variance for reaction to P. herbarum was not observed in any of the cultivars, but significant nonadditive genetic variance was observed in MSA‐C4 and MSB‐C4. The standard errors of the nonadditive components were so large that interpretation was difficult, but digenic variance appeared to be important for reaction to P. herbarum and L. briosiana in MSA‐C4, and for reaction to P. herbarum in MSB‐CA. Genetic variances were usually larger in MSA‐C4 and MSB‐CA than in Saranac.
Apomixis and Sexuality in Eragrostis curvula1
Authors: Voigt P. W. , Bashaw E. C.
Published: July 2010

Weeping lovegrass, Eragrostis curvula (Schrad.) Nees, reproduces by obligate apomixis (diplospory). Eventual success in the breeding of this important forage and conservation species depends on the identification of sexual types and their successful manipulation. The objective of this study was to examine megasporogenesis and embryo sac development in plants producing variable progenies (presumed sexuals) compared with development apomictic plants. Offspring of the presumed sexual plants were also examined cytologically.

The study indicated that the plants producing variable progenies were indeed sexual. The best indicator of sexuality was evidence of meiosis and the presence of a tetrad of megaspores. The number of nuclei in mature embryo sacs was not always a good indicator of mode of reproduction.

It was apparent that diplospory is genetically controlled. Based on the cytological results from the offspring of the sexual plants, we propose, as a working hypothesis, that mode of reproduction in Eragrostis curvula is controlled by only a few genes and that sexuality is either dominant or epistatic to apomixis.

Because apomixis is apparently obligate in this species, we believe that, through hybridization of sexual and apomictic strains, diplospory can be effectively manipulated in a lovegrass breeding program.
Ecology of Exotic Races of Maize. I. Leaf Number and Tillering of 16 Races Under Four Temperatures and Two Photoperiods1
Authors: Stevenson J. C. , Goodman M. M.
Published: July 2010

Use of photosensitive types of maize (Zea mays L.), such as the approximately 250 Latin American races, is severely limited by late flowering and excessive growth under field conditions encountered in latitudes exceeding 30°%. It is known that both shorter day lengths and lower temperatures tend to reduce excessive growth by initiating flowering at an earlier stage of development. The joint effects and possible interactions of such treatments apparently have not been previously studied. Sixteen races of maize, adapted to varying altitudes, growing conditions, and latitudes, were grown in the North Carolina State University Phytotron at day/night temperatures ranging from 10/6 to 34/30 C under short (9‐hr) days. The same races were grown under long days at temperatures ranging from 18/14 to 34/30 C. The photoperiod difference was much more effective than temperature in decreasing leaf numbers, and while the interaction of photoperiods and temperatures was significant, it was relatively small. Lowest leaf numbers were generally obtained under the 18/14 C 9‐hour day regime. Since these numbers ranged as high as 20 leaves per plant, additional reduction, perhaps by using shorter days with temperatures in the range of 14 to 22 C, would be desirable.

In contrast, temperature rather than photoperiod length is more effective in altering the numbers of tillers per plant. With a single exception, the races that tillered did so more profusely at the lower temperatures.
Effects of Genetic Diversity on Heterosis in Tall Fescue1
Authors: Moutray J. B. , Frakes R. V.
Published: July 2010

The object of this study was to determine the extent of heterosis for plant height, anthesis date, panicle number, seed yield, and fall vigor rating in a tall rescue (Festuca arundinacea Schreb.) group selected for diverse morphology, origin, and anthesis date. Nine parents, nine single‐cross progeny, and eight S1 progeny were included.

Single‐cross progeny were superior to their parents in all characteristics except seed yield, while the parents exceeded their respective Sl's except in plant height.

Single crosses average 15, 28, and 5% above the midparent for plant height, panicle number, and seed yield, respectively, had a 3% earlier anthesis date, and were 23% lower in fall vigor rating (more vigorous). Single crosses averaged 6% above the high parent for panicle number and 10% below the low parent for fall vigor rating.

Crosses between maturity groups resulted in the greatest heterosis above the midparent for all characteristics. Crosses within the early maturity group were tallest (106% of high parent) and had the most vegetative vigor (115% of high parent).

Indications are that crosses between clones of diverse morphology, origin, and anthesis date can result in greater heterosis than has been observed in crosses between clones selected on similarities.
Evidence of Heritable Resistance to Fusarium solani f. sp. pisi and Pythium ultimum in Peas1
Authors: Muehlbauer F. J. , Kraft J. M.
Published: July 2010

Ninety pea (Pisum sativum L.) populations were produced by crossing, in all possible combinations, five lines reported to be resistant to pea root and five commercial lines. Results from pathological tests conducted in soil artificially infested with F. solani (Mart.) Appel & Wr. sp. pisi (F. R. Jones) Snyd & Hans or P. ultimum Trow. did not agree with test results from soil naturally inrested with these pathogens and indicated that other pathogens or factors may be important in field soil. General combining ability effects were important in naturally and artifically infested soil, indicating a fixable amount of genetic variance for resistance to these pathogens. A highly significant correlation (r = .60, df = 53) between disease indices in soil artificially infested with F. solani and P. ultimum indicated that resistance to the two pathogens may be conditioned by the same factors.
Inbreeding Cultivated Alfalfa in One Tetraploid‐Haploid‐Tetraploid Cycle: Effects on Morphology, Fertility, and Cytology1
Authors: Obajimi A. O. , Bingham E. T.
Published: July 2010

Nine haploids (2n=2x=16) from three cultivated alfalfa (Medicago saliva L.) clones (2n=4x=32) were retetraploidized using colchicine. The level of homozygosity in such retetraploidized plants is reportedly equivalent to about 3.8 generations of selfing, although they have not gone through a sexual generation. Also, they have only monoallelic and duplex diallelic loci. Tetraploid leaflet shape and serrations were restored in all cases. All other size and vigor (fresh weight) relationships and fertility were influenced by inbreeding depression, individual genes, or an interaction of these and ploidy. In general, vigor was restored to a greater degree than fertility; perhaps a reflection of selection pressure for vigor, but none for fertility, imposed on developing haploids. Factors causing low fertility were operative postmeiotically since chromosomes paired mainly as bivalents (multivalents only 0 to 0.7 per cell) and meiosis was normal in induced tetraploids. Evidence for inbreeding depression being manifested at both gametophytic and zygotic levels was discussed.
Nitrate Reductase Activity and its Relationship to Accumulation of Vegetative and Grain Nitrogen in Wheat (Triticum aestivum L.)1
Authors: Eilrich G. L. , Hageman R. H.
Published: July 2010

Nitrate, nitrate reductase activity, soluble protein of total leaf tissue, fresh and dry weight, and reduced nitrogen of total shoot tissue of ‘Arthur’ wheat (Triticum aestivum L.) were measured at intervals throughout the spring growing season in response to three rates of nitrogen [as CA(NO3)2] applied on each of five dates. Yield of straw and grain and their respective concentration of reduced nitrogen at maturity were also obtained.

A positive relationship observed between nitrate content and nitrate reductase activity of the leaf tissue substantiated the dependency of the enzyme activity upon availability of substrate. The increase in nitrate reductase activity in response to added nitrogen was paralleled by an increase in vegetative reduced nitrogen, indicating a casual relationship between enzyme activity and accumulation of reduced nitrogen in the plant. Since translocation of vegetative nitrogen to the grain was uniform across treatments, a significant positive correlation was found between nitrate reductase activity (expressed as moles N ha‐1 per season) and grain nitrogen (kg N ha‐1) at maturity. Seasonal nitrate reductase also correlated significantly and positively with grain yields (kg ha‐l). Similar results were obtained in the preceding season with ‘Ottawa’ and ‘Gage’ wheats, except that the application of nitrogen to Gage caused excessive lodging and thus eliminated the signifiraut correlations between enzyme activity and grain yield and grain nitrogen.

Maintenance of nitrate reductase activity during the reproductive phase in varieties resistant to lodging can increase the yield of grain protein aud prevent the depression of percent grain protein frequently observed when grain yields are high.
Alfalfa Seed Size as an Indicator of Hybridity1
Authors: Pedersen M. W. , Barnes D. K.
Published: July 2010

The size of hybrid and selfed alfalfa (Medicago saliva L.) seed were studied with a view to utilizing size differences in breeding procedures. Pollen parents and seed parents both had a measurable effect on alfalfa seed size. On the average, selfed seeds on a given seed parent were about 10% smaller than F1 hybrid seed. Some pollen parents produced larger hybrid seeds than other pollen parents. Maternal parent ✕ pollen parent interactions also influenced seed size. The reduction in selfed‐seed size was attributed to inbreeding depression. The hybrid‐seed size response was considered to be an expression of heterosis.

Seed size was used as a basis to separate hybrid seeds by sieving open‐pollinated seed of white‐flowered alfalfa grown in plots adjacent to colored‐flowered alfalfa. A seedling hypocotyl‐color test was used to identify hybrid seedlings. Seed size and percent crossing were closely correlated in a positive manner.

Applications of these results that deserve further study include: (i) the relationship between combining ability for seed size and combining ability for forage yield; (ii) sieving to improve quality of seed stocks; and (iii) increasing the proportion of hybrid seed in hybrid seed cultivars.
Effects of Fruit Load, Temperature, and Relative Humidity on Boll Retention of Cotton1
Authors: Ehlig C. F. , LeMert R. D.
Published: July 2010

Climatological factors and the boll load from the first fruiting cycle were evaluated as primary causes for low boll retention by cotton (Gossypium hirsutum L.) during midseason. Boll retention was permitted from incipient flowering, or after June 26, July 15, July 30, or August 14, by the daily removal of flowers. Boll retention was greater than 75% initially, but decreased to less than 50% after bolls equivalent to 500 to 1,200 kg lint/ha (1 to 2 bales/acre) were retained and less than 20% after bolls equivalent to 700 to 1,300 kg lint/ha (1.25 to 2.25 bales/ acre) were retained. The fruit load was the primary cause for low boll retention and cessation of flowering during midseason. No direct relationship between low boll retention and high maximum or minimum temperatures or high relative humidity was observed.
Probable Genotype of Some Triticum aestivum ‘Agent’ Derivatives for Reaction to Puccinia recondita f. sp. tritici1
Authors: Browder L. E.
Published: July 2010

Analysis of infection‐type data from ‘Agent’ wheat (Triticum aestivum L. em Thell.) derivatives and their parent cultivars inoculated with selected cultures of Puccinia recondita Rob. ex Desm. f. sp. tritici indicated that ‘Blueboy’ and ‘Blueboy II’ probably have the genes for low reaction Lr1 and Lr10; in addition, Blueboy II has a gene for low reaction from Agent ‘Fox’ wheat probably carries Lr10 in addition to the Agent gene for low reaction; Lr10 in Fox was probably derived from its parent cultivar, ‘Tascosa.’ Cultures of P. recondita virulent to Agent, Fox, and Tascosa, but avirulent to a nearisogenic line having Lr1, have been discovered. These cultures do not attack Blueboy or Blueboy II, apparently due to the effect of PLr1/Lr1. These results suggest a potentially useful approach to breeding for rust resistance in wheat, the use of known combinations of genes for low reaction in cultivars, developed by backcrossing a recurrent parent having several genes with a donor parent with a single widely effective gene, coupled with deployment of different gene combinations into different geographic areas.
Influence of Temperature and Photoperiod on Floral Initiation and Leaf Number in Sorghum1
Authors: Quinby J. R. , Hesketh J. D. , Voigt R. L.
Published: July 2010

Twelve sorghum [Sorghum bicolor (L.) Moench] cultivars were grown in the field at two elevations in Arizona and in two day lengths and five temperature regimes in phytotron greenhouses in an effort to obtain a better understanding of the influence of photoperiod and temperature on time of floral initiation and leaf number in sorghum.

Maturity genotypes were known for seven of the cultivars tested. Alleles at all four maturity loci responded differently to temperature. All cultivars responded to differences in temperature differently in the two photoperiods, indicating interaction between temperature and photoperiod.

Regardless of length of photoperiod, most cultivars produced more leaves in the warmer night temperature regime of 32/29 C than in the 32/23 C regime, but leaf numbers also tended to be high in the cold 17/11 C regime. Plastochrons varied among cultivars.
Temperature Control of Time Intervals Between Vegetative and Reproductive Events in Soybeans1
Authors: Hesketh J. D. , Myhre D. L. , Willey C. R.
Published: July 2010

An attempt was made to develop general relationships quantitatively describing the effect of temperature on growth and development of a soybean [Glycine max (L.) Merrill] shoot. The time required for emergence and expansion of cotyledons and the appearance of the first pair of unifoliolates and of subsequent successive trifoliolate leaves on the main shoot was measured in controlled environments in a phytotron. For plants in greenhouses in midsummer, degree‐days per trifoliolate on the main shoot was fairly constant between 12 and 30 C. In the 30 C greenhouse the rate of trifoliolate emergence was much less in late fall than in early spring, suggesting that photosynthate supply was limiting in late fall. Increasing photosynthate supply by enriching the CO2 level around the plants in growth cabinets did not greatly affect the rate of trifoliolate emergence. This kind of data may permit the logical development of programs that simulate soybean growth.