bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of F1 Hybrids Between Photoperiod Sensitive and Non‐sensitive Pennisetum Millets1
Authors: Bhardwaj Bhup D. , Webster Orrin J. 
Published: July 2010

SummaryThe F1 hybrids between crosses of ‘Tift 23A’ (cytoplasmic male‐sterile line Pennisetum typhoides (Burm.) and five populations of ‘Maiwa’ (P. maiwa Stapf and Hubb) were studied for various characteristics including restoration of male fertility. Tift 23A is day‐length neutral, short, and early maturing whereas Maiwa is day‐length sensitive, tall, and late‐maturing. Results indicate that genes for nonrestoration of cytoplasmic male sterility are present in Nigerian Maiwa populations, and that adapted A and B lines resistant to downy mildew can be produced. It also seems possible to develop high‐yielding, day‐length neutral, and day‐length sensitive strains from the segregating generations of Tift 23A ✕ Maiwa crosses.
A New Factor for Genetic Male Sterility in Sorghum Bicolor (L.) Moench1
Authors: Andrews D. J. , Webster O. J. 
Published: July 2010

Male sterility, controlled at one locus, was discovered in 1963 at Sainaru after seed of a Nigerian sorghum had been irradiated with Co60. Crosses were made and the expression of the sterility remained stable in different genetic backgrounds and in a range of climatic conditions. Crosses with other reported genetic steriles indicate that the sterility found is governed by a new factor. The symbol ms7 is proposed.The male sterility has been used to assist the breeding program by the development of a sorghum composite.
Evaluation of Synthetic Populations Developed from a Maize Variety (BSK) by Two Methods of Recurrent Selection1
Authors: Burton J. W. , Penny L. H. , Hallauer Arnel R. , Eberhart S. A. 
Published: July 2010

The effectiveness of half‐sib selection with a doublecross tester and S1 selection per se was evaluated following four cycles of selection in BSK (the Krug Hi I syn. 3 strain of ‘Krug Yellow Dent’). Five populations, BSK CO, BSK(HT)C2, BSK(S)C2, BSK(HT)C4, and BSK(S)C4, were selfed, sibbed, and crossed in a diallel series. They were also test‐crossed to four single‐cross testersThe average of the four single‐cross testcross yields of the BSK (S) populations increased 10.6% during the four cycles, and the BSK(HT) populations increased 5.7%. The selfing series populations performed better than the testcross series populations when selfed, as indicated by a 38.7% increase for the BSK(S) bulk S1's compared with a 12.0% increase for the BSK(HT) bulk S1s. The populations per se increased 16.3% in the selfing series and 6.3% in the testcross series. The BSK(HT) × BSK(S) crosses exhibited heterosis, which indicated that the two methods developed populations that differed in gene frequency.This study has shown that the mean yield and the general combining ability of BSK were significantly improved by four cycles of selection with both methods of recurrent selection, but S1 selection per se was more effective.
A Quantitative Genetic Study of Verticillium Wilt Resistance Among Selected Lines of Upland Cotton1
Authors: Verhalen Laval M. , Brinkerhoff L. A. , Fun Kwee‐Chong , Morrison Walter C. 
Published: July 2010

A quantitative genetic study of the inheritance of resistance to verticillium wilt (Verticillium albo‐atrum Reinke and Berth.) was conducted among 10 selected lines of upland cotton (Gossypium hirsutum L.) utilizing the Jinks‐Hayman diallel analysis. Parents and F1's were studied in 1968 and 1969 at two locations in Oklahoma with the inclusion of F2 progenies in the second year.General tests of the diallel assumptions revealed a partial noncompliance with those assumptions in this material. Epistasis did not appear to be a complicating factor herein, but significant genotype by environment interactions were found among parents from year to year for their additive and dominance components of variation. A significant portion of the dominance interactions could not be attributed to either years or locations.All estimates of environmental variance and of additive genetic variance were significant, as were most estimates of dominance genetic variance. With one exception, estimates of additive variance were larger than the other parameters estimated in the same test. Wilt resistance displayed partial dominance except in one environment where overdominance was found to occur. Direction of dominance was toward greater susceptibility. The frequency of negative versus positive alleles in the parents was likely unequal and biased towards greater susceptibility. Narrow‐sense heritability estimates suggested that rapid genetic advances through selection could be made in most environments.
Inheritance of Crown Rust Resistance in Avena sterilis L. from Israel1
Authors: Fleischmann George , McKenzie R. I. H. , Shipton W. A. 
Published: July 2010

The inheritance of resistance in four collections of Avian sterilis L. from Israel (D137, F169, F288, and F290) to races 239, 264, 290, 326, 330, and 332 of crown rust, Puccinia coronata Cda. vat. avenae Erikss, was investigated. Three of the collections (D137, F169, and F290) each had a gene conferring rust resistance to all six races, and these genes were independent. The gene in D137 was Pc35 while the genes in F169 and F290 were designated Pc45 and Pc46, respectively. Each of these three collections also contained an additional resistance gene. F169B and F290B were attacked by races 264 and 290, while D137B was attacked by these races as well as race 326.Genetic analysis of F288 indicated that one gene (F288A) confers resistance to races 239, 290, 326, and 330 but not to races 332 and 264, while a second gene (F288B) confers resistance to race 239, but not to the other five races.All the resistance genes from the four collections were dominant.
Heritability and Advance from Selection for Six Soybean Seed‐quality Characters1
Authors: Green D.E. , Luedders V.D. , Moraghan B.J. 
Published: July 2010

Seed harvested from F3, F5, and F6 lines of six soybean [Glycine max (L) Merr.] crosses were evaluated for field emergence percentage and visually rated for defective seedcoat, wrinkled seedcoat, shriveled cotyledons, green cotyledons, and overall appearance. Correlations between field emergence percentage and the visually rated characters were low, although low incidence and severity of the visually rated characters were generally associated with high field‐emergence percentages. The overall rating generally was equal to any other rating as an indicator of relative field emergence.Heritability estimates for field‐emergence percentage were low, due to low genetic variability for the character in the F5 and F6 generations and to the large error associated with estimating the field emergence potential of a seed lot. Estimates of heritability for the visual ratings generally were higher than for field emergence, with heritability of green cotyledons usually being lower than the other visually rated characters.Selecting for high field‐emergence percentage resulted in no significant advance for the character. Advances from selection were somewhat higher for the visually rated characters. The results of this and previous studies suggest that the most efficient means of improving soybean seed quality in a breeding program is to use an overall visual rating and a laboratory germination test in which normal seedlings are counted early in the germinating period, probably at 5 days. An alternative method is to concentrate on improving visually rated characters by selection when environmental conditions cause adequate expressivity.
Heterosis and Combining Ability Estimates in F2 Flax Populations as Influenced by Plant Density1
Authors: Shehata A. H. , Comstock V. E. 
Published: July 2010

Seed yield, its three components (bolls per unit area, seed size, and seeds per boll), oil content, and iodine value were studied in F2 populations of a diallel cross among nine cultivars of flax (Linum usitatissimum L.) at two locations and three plant densities.Average heterosis for yield in F2 was 6% relative to the midparent values. Four F2 populations exceeded in yield the high‐yielding parent by 15 to 19%. One F2 population, ‘Russian’ ✕ C.I. 1664, exceeded by 5.5% the yield of ‘Marine’, the highest yielding cultivar. Varying plant density did not affect the magnitude of heterosis, mean oil percentage, iodine value, nor the estimates of combining ability. Plant density did have a significant effect on mean yields and on the yield components, and showed a significant interaction with genotypes for yield and bolls per unit area. In spite of the latter interaction, seven of the 36 F2 populations were among the highest 25% in yield in all three densities. The interactions of locations with genotypes were significant for most characters, which suggests that more than one test location should be used to evaluate hybrid flax populations. General combining ability effects were significant and much larger for all characters than were specific combining ability effects at all densities.
Selective Modification of Alfalfa toward Acclimatization in a Subarctic Area of Severe Winter Stress1
Authors: Klebesadel L. J. 
Published: July 2010

A‐syn.B, a strain of variegated alfalfa (Medicago media Persoon) possessing exceptional adaptation to subarctic conditions, has been developed during the past two decades at the College Research Center in subarctic, interior Alaska (63.8° N. lat.). This strain was synthesized from persistent plants remaining after winters had eliminated the less hardy bulk of populations from numerous alfalfa cultivars in experimental field plantings.A‐syn.B displayed significantly better winter survival in the field than 33 other strains from Canada, northern Europe, and the conterminous USA. Etiolated growth in autumn, an estimate of stored reserves, was expressed in greater amount and over a longer period by A‐syn.B than by ‘Rhizoma,’ ‘Rambler,’ or ‘Vernal,’ varieties that are considered extremely winter‐hardy elsewhere. A‐syn.B sustained less injury to artificial freeze stress than Vernal. This new strain is considered to represent selection for genotypes better adapted for reserve storage and coldhardiness development than midtemperate alfalfa varieties under the brief term of short photoperiods in the Subarctic prior to onset of winter.Another Alaskan synthetic, A‐syn.A, derived from artificial crosses of M. media X M. falcata backcrossed to M. falcata, was superior to A‐syn.B in two of five tests and inferior to pure M. falcata in winter survival only in one test that was exposed to greatest winter stress. A‐syn.B was superior in winter survival to varieties of alsike, red, and strawberry clovers (Trifolium spp.), birdsfoot trefoil (Lotus corniculatus L.), crownvetch (Coronilla varia L.), and sainfoin (Onobrychis viciaefolia Scop.), and less hardy than two native Alaskan legumes.
Performance of Stocks within Long‐Time Inbred Lines of Maize in Testcrosses1
Authors: Fleming A. A. 
Published: July 2010

The objective of these experiments was to determine the effect of seed stocks (sources) within long‐time inbreds of maize (Zea mays L.) on their performance in hybrids. Prior to increase, the inbreds were maintained by different breeders in several states. Seed stocks within the six long‐time inbred lines were compared in three‐way testcrosses.Significant differences in the hybrids, depending on geographical source of the inbreds, were observed in 9 out of 10 agronomic characters: yield, ear height, plant height, time of silking, stalk lodging, erect plants, ears per plot, dropped ears per plot, and leaf position. No significant differences occurred in grain quality. Ear height had the most significant differences. Thus, genetic changes and shifts in gene frequency may be occurring constantly within an inbred. These changes may not only affect the performance of the inbred, but also of the hybrid in which it is used.
Estimating Genetic Variance in Maize by Use of Single and Three‐way Crosses among Unselected Inbred Lines1
Authors: Wright J. A. , Hallauer Arnel R. , Penny L. H. , Eberhart S. A. 
Published: July 2010

Unweighted least squares and maximum likelihood procedures were used and compared for the estimation of genetic variance for eight quantitative traits in maize (Zea mays L.). The genetic material was developed from unselected inbred lines isolated from a strain of Krug Yellow Dent maize. All possible single and 3‐way crosses were produced from 60 inbred lines, which traced back to 51 S0 plants. The mean squares from the diallel and triallel analyses were used in estimating the genetic components of variance.Fitting the error and a six‐parameter genetic model showed that: 1) it was not possible to obtain realistic estimates of the epistatic components, although significant effects were detected in the analyses of variance; 2) the estimates of additive geuetic variance were significant for all traits for both estimation procedures; 3) the nonadditive components accounted for only a small proportion of the total genetic variance; 4) three iterations of the maximum likelihood procedure were sufficient to stabilize the estimates; and 5) the maximum likelihood procedure generally reduced the errors of the estimates.For the two‐parameter genetic model the largest proportion of the total genetic variance was additive for all traits. The estimates of deviations due to dominance were larger than twice their standard errors for all traits in the two‐parameter model for the combined single and three‐way cross data. The frequency of significant interactions with environments was higher for the additive than for the dominance effects.
Influence of Unfilled Cotton Seed upon Emergence and Vigor1
Authors: Ferguson David , Turner John H. 
Published: July 2010

The influence of cottonseed fullness upon emergence and seedling growth was studied under a minimal temperature of 17 C ± 1. Seeds of Acala SJ‐1 (Gossypium hirsutum L.) were sorted by X‐ray photography into four classes, or degrees of seed filling (50, 75, 90, and 100%).Completely filled seeds were superior to partially filled seeds for total emergence, seedling survival, and early growth. Emergence and seedling survival were related more to seed fullness than to seed weight in this study. These data indicate that grading of planting seed based upon weight or size is not adequate to remove many inferior seeds.
Evaluation of Cross‐fertilization in Forage Crops1
Authors: Gorz H. J. , Haskins F. A. 
Published: July 2010

SummaryIn the improvement of forage crop varieties knowledge of the extent of cross‐fertilization is of value for (1) determining the extent and randomness of crossing in breeding procedures, (2) estimating varietal changes due to contamination and mechanical mixtures, and (3) evaluating effects of cross‐fertilization in the development and production of synthetic and hybrid combinations. Genetic markers can aid greatly in the evaluation of cross‐fertilization, and thus in the development and production of new varieties. Ideally, markers should be distinctive and readily detected in the seedling stage, conditioned by a single dominant gene with complete penetrance, and have no adverse effects on plant growth, zygote viability, or randomness of cross‐pollination.
Genetic Control of Root Fluorescence in Soybeans1
Authors: Fehr W. R. , Giese J. H. 
Published: July 2010

We studied the genetic control of root fluorescence in soybeans [Glycine max (L.) Merr.]. Fluorescent roots emit a soft blue glow when exposed to ultraviolet light, while nonfluorescent roots exhibit the dark violet color of the light source. Two soybean varieties with fluorescent roots, 'Blackhawk' and 'Hawkeye,' and one variety with nonfluorescent roots, 'Minsoy,' were used.Evaluation of F1 plants, F2 populations, and F3 families from the crosses Blackhawk ✕ Hawkeye, Blackhawk ✕ Minsoy, and Hawkeye ✕ Minsoy indicated that root fluorescence was controlled by a single gene. Fluorescence is completely dominant to nonfluorescence. The same allele for fluorescence is present in Blackhawk and Hawkeye. The symbol Fr will be used to designate the fluorescent gene.
Meiosis of Trisomics of Diploid Alfalfa1
Authors: Buss G. R. , Cleveland R. W. 
Published: July 2010

Several single primary trisomic plants (2n = 17) were produced by crossing a triploid (2n = 24) with several diploid plants (2n = 16). The diploid parents were Medicago saliva L., M. falcata L., and derivatives of hybrids of the two. The triploid was also a hybrid. The proportion of trisomic plants varied among families, averaging 13 and 34% when the triploid was used as the male and. fenmle parent, respectively. Double trisemics (2n = 13) occurred in 3X by 2X progenies only.Chromosome pairing relationships at meiosis in microsporocytes were observed for 10 single primary trisomics. Mean numbers of trivalents per cell at MI differed significantly among plants, ranging from 0 to 0.47. Metaphase pairing behavior might be used in conjunction with other attributes to identify trisemics.The trisomic condition did not impart distinguishing plant morphological characteristics.
Yields of S1 Lines from Original and Advanced Synthetic Varieties of Maize1
Authors: Genter C. F. 
Published: July 2010

Four maize (Zea mays L.) synthetic varieties were selfed and approximately 200 S1 lines of each were grown in separate replicated yield trials with the parental populations to compare inbreeding depressions and yield distributions among the S1 lines. The four parental populations were (i) ‘iowa Stiff Stalk Synthetic,’ SSS, (ii) an advanced synthetic derived from SSS by seven cycles of recurrent selection based on half‐sib yield, SSS(HT)C7, (iii) ‘Virginia Corn Belt‐Southern Synthetic,’ CBS, and (iv) an advance synthetic derived from CBS by four cycles of recurrent selection for S1 yield, CBS(S)C4.Inbreeding depression was lower for S1 lines from each of the advanced synthetics than for those of the corresponding original and was lowest for the S1 lines from SSS(HT)C7. Inbreeding depressions were 39.1 and 27.8%, respectively, for S1 lines from SSS and SSS(HT)C7, and 38.3 and 32.5%, respectively, for S1 lines from CBS and CBS(S)C4. S1 lines from SSS(HT)C7 averaged 9.3% higher in yield than those from SSS, although the range of yields was less at both extremes for lines from the advanced population. S1 lines from CBS(S)C4 averaged 27.2% higher than those from CBS with a comparable range of yields.SSS(HT)C7 yielded slightly less than SSS. CBS(S)C4 yielded approximately 19% more than CBS. In all populations the maximum S1 yield approximated that of the parental source. Two S1 lines from CBS(S)C4 were comparable in yield to that of a double‐cross hybrid check variety. One effective means of increasing inbred line yields appears to be increasing the yields of parental source populations.
Effects of Temperature and Photoperiod on Spring Wheat Pollen Viability1
Authors: Welsh J. R. , Klatt A. R. 
Published: July 2010

Seven cultivars of spring wheat (Triticum aestivum L. em Thell.) including the cultivars ‘Chris,’ ‘Crim,’ their male‐sterile counter‐parts, the restorer ‘Dirk’ and the Fl′s of the male‐steriles ✕ Dirk were subjected to the nine combinations of 12‐, 14‐, and 16‐hour photoperiods and 24 C ‐ 7 C, 30‐13, .and 35‐18 day‐night temperature regimes. Pollen viability was based on stainable grains and seeds per spike were counted. The r value between pollen stainability and seed counts was 0.87.Temperature had the greatest effect on pollen viability iu the experiment. In general, high temperatures reduced pollen viability. Photoperiod had minor effects with longer periods slightly reducing viability. Chris and Crim had the highest viabilities. The pollen viability of Dirk tended to drop sharply with high temperatures. The Fl′s were intermediate. Male‐sterile Chris had consistently low pollen viability. Male‐sterile Crim had quite viable pollen at low temperatures and short to medium daylengths, but low viabilities at other environments. Genotype ✕ environment interactions occurred only at the 14‐hour photoperiod where viabilities of Chris, Crim, and male‐sterile Crim were not reduced at high temperatures.
Twenty Years of Reciprocal Recurrent Selection with Two Synthetic Varieties of Maize (Zea mays L.)1
Authors: Penny L. H. , Eberhart S. A. 
Published: July 2010

Five cycles of reciprocal recurrent selection in two synthetic varieties of maize (Zea mays L.) were summarized. Yields of the varietal cross and one parental variety were increased significantly, but the yield of the other variety de, creased slightly. Expected gain in the varietal cross yield, calculated from pooled heritabilities and selection differential, was 7.2% per cycle, but observed gain was only 1.7% per cycle.In the sixth cycle, selection among S1 plants was substituted for selection among S0 plants. Selection within the randomly mated varietal cross was initiated for comparison with selection within the two parental varieties individually. Estimates of genetic variance within the parental populations in the sixth cycle were higher than for the three previous cycles, and genetic variance was higher within the randomly mated varietal cross than within the parental varieties.
A Geometrical Approach to Yield Models in Upland Cotton (Gossypium hirsutum L.)1
Authors: Maner B. A. , Worley S. , Harrell D. C. , Culp T. W. 
Published: July 2010

Yield models were developed for selected Upland cotton (Gossyplum hirsutum L.) genotypes. Yield was equated with the volume of a rectangular parallellepiped having the following dimensions: bolls per square meter (X), seeds per boll (Y), and seed cotton per seed (Z). Axis (Z) was divided into its two fractions: lint per seed (L) and weight per seed (S). Yield components of selected genotylpes were expressed as a percentage of ‘Coker 201,’ when the variance was set at zero.BolIs per square meter (X axis) had the gxeatest influence on yield. We expect that the greatest gain in yield improvement should come from exerting selection pressure on this character. Concurrent selection pressure should also be placed on seeds per boll (Y) and seed cotton per seed (Z) to maintain these components at levels similai to those of leading commercial varieties grown in the ecological area.
Studies of Nonrandom and Barren‐Type Sterility in Sorghum bicolor1
Authors: Jaisani B. G. , Drolsom P. N. 
Published: July 2010

The frequency of nonrandom‐type sterile Sorghum bicolor (L.) Moench plants among the progenies of random‐type sterile plants in the S1, S2, and S3 generations decreased with advancing generations. The progenies of non‐random‐type sterile plants became more uniform, suggesting genetic control of such sterility.Barren‐type sterility was observed in S1 S2, and S3 generation sorghum plants. The breeding behaviors of the segregating progenies suggested that this character was controlled by two gene pairs and that the double homozygous condition resulted in the expression of recessive barren‐type sterility. Fourteen progenies segregated for 15 nonbarren to 1 barren‐type sterile plants as expected. Eight progenies showed good agreement to a 3:1 ratio, and five progenies had an excess of barren‐type sterile plants. These findings further suggested that the genes governing barrenness are expressed only under certain environmental conditions.