bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inheritance of Husk Numbers and Ear Insect Damage in Maize1
Authors: Brewbaker James L. , Kim Soon Kwon 
Published: July 2010

Studies were made to determine the extent and genetic control of husk number variations in maize (Zea mays L.), and to test their association with ear insect resistance and response to environmental influences. Husk numbers were highly uniform within inbreds and single‐cross hybrids, ranging from 6 to 19. Twelve inbreds were chosen to represent this range for diallel and generation‐mean analyses. Analyses were made in Cali, Colombia, and in Waimanalo, Hawaii, of husk numbers from 10‐ and nine‐parent diallels. General combining ability (g.c.a.) mean squares were highly significant at both locations. Specific combining ability mean squares were also significant, but were exceeded by the g.c.a, values by ratios of 5.3 to 1 (Colombia) and 19.9 to 1 (Hawaii). Hybrids showed a significant positive heterotic effect of 11%, and array means correlated well with parental values (r = 0.93). Means and array means for the hybrids grown at both locations were also highly correlated (r = 0.94 and r = 0.86, respectively). F2 and backcross progenies of 10 crosses involving high ✕ low husk numbers were analyzed. Backcross progenies commonly reverted sharply toward parental means, and F2 and F1 means were quite similar. Environmental variability was high and narrow‐sense heritability estimates were low (average 24%). The Cuban Flint‐derived inbred CM111 (India) provided the best genetic source for increasing husk numbers, which is proposed as a practical and efficient alternative to selection for low insect injury for improved ear pest resistance.Damage by the larvae of ear insects was evaluated for earwrm (Heliothis zea Boddie) and fall armyworm [Spodoptera frugiperda (J. E. Smith)] in relation husk numbers in Hawaii and Colombia. Resistance was notably higher in tropical lowland types of maize with high husk numbers. Ear damage in Hawaii (largely earworm) correlated significantly (r = −0.40) with husk numbers that ranged from 6 to 14 in a broad‐based composite. Ear insect damage in Colombia (largely fall armyworm) also correlated significantly (r = −0.68) with husk numbers that ranged from 8.0 to 14.9 in a 45‐entry diallel. Husk numbers were highest for lowland tropical races of maize and lowest for temperate and montane races, correlating significantly (r = −0.71) with elevation at which the race was indigenous. It was concluded that ear pests provided strong selection pressure for higher husk numbers during evolution of maize. Environmental effects on husk numbers appeared solely to relate to temperature during growth, and a reduction of one husk was observed for a corresponding increase of 4 C in growing temperature during early growth.
Cracked Root Mutant in Cotton: Inheritance and Linkage with Fertility Restoration1
Authors: Weaver J. B. , Weaver D. B. 
Published: July 2010

A cracked root condition was observed in a line of upland cotton (Gossypium hirsutum L.) with G. harkenssii Brandegee cytoplasm. F1, F2, and testcross generations were grown to determine the inheritance of the cracked root condition. Observations indicate the character to be controlled by a single gene pair expressing complete dominance in upland stocks. In F1 hybrids between homozygous dominant cracked root upland plants and normal root G. barbadense L. plants, roots appear to be normal to slightly cracked, and inheritance is uncertain. Data indicate linkage of cracked root and fertility restoration with observed recombination values ranging from 6.7 to 14.5%.The symbol Rc is proposed for the gene responsible for the cracked root phenotype and the symbol Rf is proposed for the fertility restoring gene.
Effects of Ploidy Level on the Components of Sucrose Yield and Quality in Sugarbeet1
Authors: Smith G. A. , Hecker R. J. , Martin S. S. 
Published: July 2010

Comparisons of 2χ, 3χ, and 4χ sugarbeet (Beta vulgaris L.) lines and hybrids were made to determine the effects of ploidy level on sucrose yield and quality components in equivalent and non‐equivalent hybrid populations.The relative order of importance for the components of recoverable sucrose was generally the same for all three ploidy levels, with root weight having the greatest path coefficient direct effect and juice purity the least.Purity generally decreased as .ploidy level increased; this decrease was accompanied by increase in the quantity of non‐sucrose chemical components in the extract.Significant differences were found between reciprocal equivalent 3χ hybrids for both yield and quality components. Recoverable sucrose yield of triploids produced from tetraploid female plants. [3χ(4χ ♀ )] averaged 17% greater than that of the reciprocal 3χ(4χ ♂ ) hybrids. The same 3X(4x ♀ ) triploid hybrids also were lower than their reciprocal equivalents in extract concentrations of Na. K, and total N, with decreases of 9, 17, and 12%, rcspectlvely. When components are expressed in rag/100 g sucrose, the corresponding decreases were 13, 20, and 16%, respectively.
Uniform Stage Descriptions in Upland Cotton1
Authors: Elsner J. E. , Smith C. Wayne , Owen D. F. 
Published: July 2010

A systematic method of defining the developmental stages of upland cotton (Gossypium hirsutum L.) is described. The stages of growth are divided into two groups: vegetative and reproductive. The stage of growth of an individual plant is determined by the number of main stem nodes. The uppermost node immediately preceded by a 1.25‐cm internode is considered the latest developed node for staging purposes.Use of these systematic growth stages should lead to more uniform application of agronomic research treatments, cultural practices, and the like.
Effect of Temperature on Rate of Leaf Appearance and Flowering Date in Maize1
Authors: Tollenaar M. , Daynard T. B. , Hunter R. B. 
Published: July 2010

Classification of development in maize (Zea mays L.) based on temperature is important because of the need in agriculture to determine the adaptability of genotypes to particular environments and to predict flowering dates for breeding purposes. An equation predicting the effect of temperature on rate of development of maize was obtained by measuring the rate of leaf appearance of six short‐season maize hybrids. The hybrids were grown in growth cabinets at constant day/night temperatures ranging from 10 to 35 C, in 5 C increments, with a 15‐hour photoperiod. Rate of leaf appearance was also measured on plants grown under 16 regimes of differential day/ night temperature. The predictive value of the temperature vs. rate of leaf appearance curve was compared with calendar days from planting to silking and accumulated heat units from planting to silking, calculated by both the Degree Days and Ontario Corn Heat Unit (OCHU) methods, using date of flowering for 22 hybrids grown during 3 years at four locations.Polynomial regression analysis of data for maize plants grown at constant day/night temperatures produced a cubic equation for rate of leaf appearance (leaves/day) vs. ambient temperature. This equation (Y = 0.0997 − 0.0360T + 0.00362T2 − 0.0000639T3) could be used to predict rate of leaf appearance in fluctuating temperature environments. For field‐collected data, the equation for rate of leaf appearance vs. temperature was superior to calendar days but similar to the Degree Days and OCHU methods in predicting dates of silking. Adjustment of the predicted time to silking by accounting for the effect of mean temperature during the first 30 days after planting on maximum leaf number (increase of 0.2 leaves/C increase in temperature) enhanced the precision of the derived equation in predicting date of silking.
Respiration and Concentration of Water Soluble Carbohydrate in Plant Parts of Contrasting Tall Fescue Genotypes1
Authors: Jones R. J. , Nelson C. J. 
Published: July 2010

Little information is available concerning genotypic differences in dark respiration (RD) of plant tissues. The objectives of these studies were to determine if a gradient of RD (02 uptake) existed along the leaf blade and to compare maintenance respiration, growth respiration, and concentration of water‐soluble carbohydrate (WSC) leaf blades, terminal meristems areas, and root tips of seven genotypes of tall rescue (Festuca arundinacea Schreb.). Three genotypes had been selected for contrasting yield/tiller, and four genotypes had been selected for contrasting CO2 exchange rate (CER)‐yield relationships.Center portions of mature leaf blades had the highest rate of RD and were used in subsequent leaf studies. Dark respiration of mature leaf blades probably reflected maintenance respiration since it was independent of measured carbohydrate levels and leaf growth had ceased. Rates of RD 3 hours after the photoperiod began were similar to those measured after 48 hours of darkness in elongating leaves and terminal meristems. Concentrations of WSC in these tissues were decreased during the dark period, but probably not enough to stop respiration associated with the growth component. Respiration of root tips was not significantly different among genotypes selected for contrasting yield/tiller, but was decreased to about 44% of the original rate by the 48‐hour dark treatment. That rate may have represented the maintenance component. Rates of RD of mature blades and terminal meristems of low, medium, and high yield/tiller genotypes corresponded to their yield/tiller classification. Conversely, among the four genotypes selected for their differential CER‐yield relationship, the low CER‐Iow yield genotype had the highest RD of mature leaf blades and terminal meristems.In general, concentrations of WSC within tissues did not differ significantly among genotypes. Terminal meristems had a significantly higher concentration of WSC than did other plant tissues studied, and weights of WSC per terminal meristem were significantly different among genotypes. These data showed that genetic variation for RD existed in tall rescue, that RD was different for tissues within a plant, and that 48 hours in darkness was insufficient to decrease WSC enough to clearly separate the growth and maintenance components of RD in tall fescue.
A Temperature Sensitive Miniature Soybean1
Authors: Kilen T. C. 
Published: July 2010

A miniature soybean [Glycine max (L.) Merr.] was grown in field and greenhouse environments in an attempt to find conditions that would favor the development of normal flowers for crossing and for seed production. A growth chamber study was also conducted to examine the effects of night, temperature upon the expression of the miniature trait.When planted in the field in mid‐May, the miniature type grew about 3 cm tall, had cleistogamous flowers, and produced no seed. Planted in a greenhouse in mid‐May, miniature plants grew 21 times as tall as those in the field, had normal flowers and viable pollen, and had relatively good seed production. Average day temperature in the greenhouse was 10 C higher than that in the field, and the average night temperature was 4 C higher. When grown for 3 weeks in a growth chamber at a day temperature of 38 C and night temperatures of either 15, 20, or 24 C, minature plants were 5, 26, and 99% respectively, as tall as the cultivar ‘Hill’. The study showed that the summer greenhouse environment favored seed production in miniature plants, causing their highly cleistogamous flowers to develop, and open normally and permitting their use for crossing.
Capacity for Proline Accumulation During Water Stress in Barley and Its Implications for Breeding for Drought Resistance1
Authors: Hanson A. D. , Nelsen C. E. , Pedersen A. R. , Everson E. H. 
Published: July 2010

During controlled water stress applied at the threeleaf stage, the barley (Hordeum vulgare L.) cultivars ‘Proctor’ and ‘Excelsior’ showed different rates of free proline accumulation and leaf‐firing. Both processes were faster in Proctor (a drought‐susceptible cultivar) than in Excelsior (a drought‐resistant cultivar). The different rates of proline accumulation during stress in Proctor, in Excelsior, and in a wild barley (H. spontaneum C. Koch) could be attributed to differences in the rate of decline of leaf water potential (ψleaf); at the same ψleaf value, all three genotypes contained similar amounts of free proline.After non‐destructive screening of the F2 generation from a Proctor ✕ Excelsior cross for proline‐accumulating capacity under controlled water stress conditions, F3 seed from plants selected for high and low proline accumulation was obtained. When F3 plants were tested for proline accumulation during controlled stress, the selection for proline accumulation was found to have been effective. Reselection among F3 plants and subsequent testing of the F4 generation confirmed this result.Among individual plants of the F3 generation (which was segregating for the prollne accumulation trait) there was a positive association between the amount of free proline accumulated during stress and the severity of leaf‐firing.Massive proline accumulation is a symptom of severe internal water stress in barley and apparently has no survival value during drought. Although there is heritable variation in the amount of proline accumulated during stress, it is not of practical value in breeding for drought resistance.
Inheritance and Association of Six Traits in Safflower1
Authors: Kotecha Ashok 
Published: July 2010

The parents, F1 and F2 from four crosses of safflower (Carthamus tinctorius L. and C. palaestinus Eig.) were studied in field experiments. Data were taken on individual plants to estimate heritability, gene action, and mode of inheritance of plant height, time of flowering (TF), time to maturity (TM), time from flowering to maturity (TFM), leaf length, and stem diameter. In all crosses, F2 variability was largely genetic for all traits. Gene action was additive for plant height and leaf length, but nonadditive for TF, TM, and TFM. Gene action for stem diameter was additive in Cross 3 but nonadditive in Cross 4. The broad‐sense heritability estimates were high for all traits studied. Maternal effects were absent, except for TM and leaf length. In all F2's, continuous distributions were observed, suggesting multiple‐factor inheritance for plant height, TF, TM, TFM, leaf length, and stem diameter. Heritability estimates in the narrow sense for TF and plant height, calculated from the cross N4051 ✕ 830293, were 11 and 79%, respectively. In the same cross, the values for expected genetic advance for TF and plant height were 0.70 and 17.0%, respectively. On the basis of apparent gene action, heritability estimates and expected genetic advance, direct selection to improve plant height should be effective.Plant height was not associated with striped hull or flower color; however, plant height was associated with anthocyanin pigmentation. Also, TF was not associated with striped hull, anthocyanin pigmentation, or flower color. Correlation coefficients of TF with TM and TM with TFM were high.
Selection Indices for Corn Grain Yield, Percent Protein, and Kernel Weight1
Authors: Kauffmann K. D. , Dudley J. W. 
Published: July 2010

The objectives of this study were (i) to compare the effectiveness of a desired gain index, direct selection, and an estimated index for improvement of corn (Zea mays L.) grain yield and percent protein and (ii) to compare the effectiveness of mass selection and half‐sib family selection for increasing percent protein. Seven selection method‐index combinations were applied to two corn populations (RSSSC, a composite of four stiff‐stalk selections and RSL, a ‘Lancaster’ population) in each of 2 years. For half‐sib family selection, 200 families from each population were evaluated in three replications each year. For mass selection, 500 ears, 25 ears from each of 20 blocks, were analyzed for protein and kernel weight.Selected progenies were evaluated in 20 replications in 1977. Indices compared were: (i) desired gain indices to (a) increase yield 20% and jprotein to 13% (HSPY) and (b) increase percent protean while holding kernel weight constant using half‐sib family means (HSPK) mass selection (MSPK); (ii) direct selection for grain yield (HSBY) or percent protein (HSBP); (iii) estimated indices to maximize gain in protein (HSEP) or grain yield (HSEY) using information on both traits.Mass selection was as effective as half‐slb family selection for increasing percent protein; simultaneous improvement of grain yield and percent protein using a desired gain index was feasible; agreement with prediction of gains from an estimated index or a desired gain index was as good as for single‐trait selection; genetic variance and covariance estimates from 200 half‐sib families were sufficiently accurate to be useful in index development.
Seedling Selection for Morphological Characters Associated with Yield of Tall Fescue1
Authors: Jones R. J , Nelson C. J. , Sleper D. A. 
Published: July 2010

Selection for herbage yield characters of forage grasses at an early stage of plant development would be desirable. Therefore, growth chamber and field experiments were conducted to determine if seedings selected for divergence in morphological characters associated with herbage yield remained consistent when plants were grown under field conditions. We also sought to determine the distribution of welght/tiller in field canopies.Genotypes of tall fescue (Festuca arundinacea Schreb.), selected for a range in yield/tiller as seedlings, generally maintained similar rankings when grown under low competition conditions in a replicated pot experiment in a growth chamber and under sward conditions in the field. In all studiest he high yleld/tiller genotype had a higher proportion of large tillers and a lower proportion of small tillers than did the low yield/tiller genotype. Weight/tiller within a genotype was distributed neither normally nor log normally. Predominant morphological characters associated with high yield/tiller and high forage yield in these genotypes were low rate of tiller production and high rate of leaf elongation
Distribution of Total Non‐Structural Carbohydrates in Soybean Plants Having Increased Reproductive Load1
Authors: Streeter J. G. , Jeffers D. L. 
Published: July 2010

The purpose of these experiments was to compare the distribution of total non‐structural carbohydrate (TNC) in soybean (Glycine max (L.) Merr.) plants with “normal” and with an increased reproductive load. This study included a comparison of methods for extraction and analysis of carbohydrates in soybean plant organs. Extraction with commercially available hydrolytic enzymes (“Clarase”) and analysis of extracts with ferricyanide method were chosen based on superior precision, accuracy, and recovery of standard added to samples.Number of fruits and seed weight/plant were increased 30% or more by placing aluminum foil reflectors in plots for 2 weeks near the end of flowering. Beginning with the 2nd week of the reflector treatment period, plants were sampled twice weekly for analysis of TNC. Height, number of nodes, leaf blade dry weight, and stem + petiole dry weight of control and reflector‐treated plants were similar.The initial effect of reflectors was to increase TNC concentration in all vegetative tissues. After reflectors had been removed for several weeks and throughout the period of rapid seed development, TNC concentration in pods and stems + petioles was almost always lower for reflector‐treated than control plants. There was a four‐fold decline in TNC concentration of pods and stems + petioles during seed development. However, leaf blades showed relatively little decline in TNC concentration during seed development, and senescent Ieaf blades contained 9% or more TNC. Also, increasing reproductive load by 30% appeared to have little effect on leaf blade TNC.Based on this and other recent work, it is concluded that pods, stems, and petioles serve as major sources of stored carbohydrate for developing seeds while stored carbohydrate in leaf blades is relatively unavailable for supporting seed development. From the standpoint of TNC content, the soybean plant appears capable of maintaining higher reproductive loads.
A Comparison of Replicated S1 per se vs. Reciprocal Full‐Sib Index Selection in Corn. I. Indirect Response to Population Densities1
Authors: West D. R. , Compton W. A. , Thomas M. A. 
Published: July 2010

Two cycles of S1 per se selection have been completed in each of three corn (Zea mays L.) populations: Nebraska B Synthetic (NBS), Nebraska Stiff Stalk Synthetic (NSS), and improved Nebraska Krug variety (NKS). In addition, two cycles of reciprocal full‐sib recurrent selection (RFS) have been completed between NBS and NSS and between NBS and NKS. Each selection scheme was replicated three times. Selection was based on an index (resulting in a calculated value of yield on standing plants) and on yield trials generally grown at 51,666 plants/ha. Response at 68,888 and 17,222 plants/ha (called here indirect density response) is reported in this study. Each replicate of each selection procedure was grown as an S1, random mating (RM), or variety cross population. Index values of cycle 2 (C2.) were increased 20% or more over C0 in tests of bulked S1 populations selected by S1 per se performance while response to RFS selection varied from an increase of 9% in C2 of NKS to a negative response of −10% in NBS. Significant selection ✕ plant populaion density effects were found only in the random mating test of the NKS population. Response to S1 per se selection was significantly greater than response to RFS selection in the NBS random mating population, but response to the two methods did not differ in NSS or NKS grown as random mating populations.Index means of variety crosses of C2 were approximately 12% above C0 variety crosses and there were no differences between selection methods. The evaluation of selection response indicated that in the early cycles of selection, response to selection at one plant density will be unchanged when selection products are grown at other plant densities. Response to S1 per se selection was greater than RFS selection response in bulk S1 and RM evaluations, but the RFS and S1 per se methods resulted in equal improvement of variety cross performance.