The impact of differential success of somatic embryogenesis on the outcome of clonal forestry programs. I. Initial comparison under multitrait selection

2006 ◽  
Vol 36 (6) ◽  
pp. 1376-1384 ◽  
Author(s):  
Milan Lstibůrek ◽  
TJ (Tim) Mullin ◽  
Yousry A El-Kassaby
Keyword(s):  
Somatic Embryogenesis ◽  
Recurrent Selection ◽  
Small Variation ◽  
Breeding Population ◽  
Forward Selection ◽  
Selection Scheme ◽  
Initial Comparison ◽  
Multitrait Selection ◽  
The Impact ◽  
Family Variation

A breeding program where clones or clone mixtures are deployed through somatic embryogenesis of superior genotypes produced from elite-parent crosses was evaluated by simulation. A recurrent-selection scheme for general combining ability was considered with a breeding population size of 100 individuals. The population was assortatively pair-crossed with offspring cloned in a progeny test to facilitate forward selection of the next generation. Apart from crosses for the population advancement, "elite" crosses were made among 10 top-ranking individuals in each generation. These crosses differed in their propensity to produce somatic embryos (defined as induction success rate); the impact of this variable propensity on genetic response for two traits in selected 10-clone deployment mixtures was evaluated. The two traits considered in this study can be regarded as "productivity" and "quality". The results revealed that variation in success of clonal propagation does not necessarily lead to a reduction in potential genetic gains from selected clonal mixtures. This can be explained by the relatively small variation that exists among elite crosses, as opposed to large within-family variation. This large within-family variation provides ample potential for selecting superior offspring genotypes, even though they may have not originated from crosses among the very best of the elite parents. This conclusion holds for a range of heritability, correlations between traits, and their relative economic importance.

Relay Selection-aware Non-orthogonal Multiple Access Networks: Direct and Relaying Mode

2020 ◽  
Vol 13 (3) ◽  
pp. 348-354
Author(s):  
Dinh-Thuan Do ◽  
Minh-Sang V. Nguyen
Keyword(s):  
Relay Selection ◽  
Multiple Access ◽  
Decode And Forward ◽  
Selection Scheme ◽  
Fixed Power ◽  
Transmission Quality ◽  
Improved Performance ◽  
Outage Probabilities ◽  
Future Work ◽  
The Impact

Objective: In this paper, Decode-and-Forward (DF) mode is deployed in the Relay Selection (RS) scheme to provide better performance in cooperative downlink Non-orthogonal Multiple Access (NOMA) networks. In particular, evaluation regarding the impact of the number of multiple relays on outage performance is presented. Methods: As main parameter affecting cooperative NOMA performance, we consider the scenario of the fixed power allocations and the varying number of relays. In addition, the expressions of outage probabilities are the main metric to examine separated NOMA users. By matching related results between simulation and analytical methods, the exactness of derived formula can be verified. Results: The intuitive main results show that in such cooperative NOMA networks, the higher the number of relays equipped, the better the system performance can be achieved. Conclusion: DF mode is confirmed as a reasonable selection scheme to improve the transmission quality in NOMA. In future work, we will introduce new relay selections to achieve improved performance.

scholarly journals Chitosan Oligosaccharides Stimulate the Efficacy of Somatic Embryogenesis in Different Genotypes of the Liriodendron Hybrid

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 557
Author(s):  
Asif Ali ◽  
Jiaji Zhang ◽  
Minmin Zhou ◽  
Tingting Chen ◽  
Liaqat Shah ◽  
...  
Keyword(s):  
Somatic Embryogenesis ◽  
Antagonistic Effect ◽  
Growth Speed ◽  
Chitosan Oligosaccharide ◽  
Chitosan Oligosaccharides ◽  
Germination Ability ◽  
Auxin Synthesis ◽  
Branch Development ◽  
The Impact ◽  
Seed Setting Rate

Liriodendron hybrid (L. chinense × L. tulipifera), an essential medium-sized tree generally famous for its timber, is also used as an ornamental and greenery tool in many places around the world. The Liriodendron hybrid (L. hybrid) tree goes through many hurdles to achieve its maximum strength and vigor, such as loss of habitat, vast genetic variation, and low seed setting rate. The establishment of an effective and well-organized somatic embryogenesis (S.E.) system could be used to overcome these obstacles, rather than the old-fashioned seed culture and organogenesis. This study is based on the impact of chitosan oligosaccharide (COS) and its role in the induction of S.E. on the callus of four genotypes of the L. hybrid. The optimal concentration of COS could enhance the momentum and effectiveness in S.E.’s mechanism, which further improves the growth rate of the L. hybrid tree’s plantlets. This study shows that COS has a prominent role in endogenous hormones like indole acetic acid (IAA), zeatin (Z.T.), and gibberellic acid (GA3). Furthermore, COS improves the growth development, growth speed, as well as the development situation of plant germination ability. COS can also regulate branch development and root growth, which could be linked to the antagonistic effect on growth factors to some extent or by affecting auxin synthesis and polar transport.

Simulation of hybrid forest tree breeding strategies

2004 ◽  
Vol 34 (1) ◽  
pp. 195-208 ◽  
Author(s):  
R J Kerr ◽  
M J Dieters ◽  
B Tier ◽  
H S Dungey
Keyword(s):  
Recurrent Selection ◽  
Parental Species ◽  
Tree Breeding ◽  
Forest Tree ◽  
Alternative Methods ◽  
Breeding Strategies ◽  
Reciprocal Recurrent Selection ◽  
Forest Tree Breeding ◽  
Forward Selection ◽  
Pure Species

Computer simulation is the only realistic method of evaluating alternative methods of breeding hybrid forest trees. Empirical tests would be very long term and expensive. This paper describes the development of a simulation program, called XSIM, which generates two different but closely related outcrossing tree species. The genetic correlation between performance in each parental species and performance in the resulting hybrid can be set, in addition to the amounts and types of variances in each parental species. The breeding strategies available for testing include conventional reciprocal recurrent selection, reciprocal recurrent selection with forward selection, recurrent selection within each pure species, and the creation of a synthetic species. XSIM allows the strategies to be compared using the same base populations, equivalent selection intensities, and comparable mating patterns. Innovative best linear unbiased prediction procedures allow all ancestral and current progeny generation data, from both parental species and the hybrid, to be analysed together. The theoretical basis for the simulation is given, and genetic and statistical models are described. In summary, XSIM allows rigorous comparisons of the strategies in terms of genetic gain per time and provides useful insight into hybrid forest tree breeding.

scholarly journals Which Recurrent Selection Scheme To Improve Mixtures of Crop Species? Theoretical Expectations

2019 ◽  
Vol 10 (1) ◽  
pp. 89-107 ◽  
Author(s):  
Jean-Paul Sampoux ◽  
Héloïse Giraud ◽  
Isabelle Litrico
Keyword(s):  
Recurrent Selection ◽  
Genetic Correlations ◽  
Limited Range ◽  
Pure Stand ◽  
Crop Species ◽  
Selection Scheme ◽  
Selection Indices ◽  
Species Mixture ◽  
Set Up ◽  
Two Populations

In a context of increasing environmental challenges, there is an emerging demand for plant cultivars that are adapted to cultivation in species mixture. It is thus pressing to look for the optimization of selection schemes to grow species mixtures, and especially recurrent selection schemes which are at the core of the improvement of many plant species. We considered the case of two populations from different species to be improved by recurrent selection for their performances in mixture. We set up an analytical model of performances in mixture. We expressed the expected responses of the performances in mixture to one cycle of selection in the case of a Reciprocal Mixture Ability selection scheme and of two parallel selection schemes aiming to improve General Mixture Abilities or performances in pure stands. We numerically compared these selection schemes when half-sib or topcross progeny families of selection candidates are tested in mixture. Selection in pure stands appeared efficient within a limited range of genetic correlations between pure stand performance and mixture model effects. The Reciprocal Mixture Ability selection scheme was expected to be less efficient than parallel selections for General Mixture Ability in some situations. The last option enables to control the ratio of expected responses of species contributions to the mixture performance without bias when using selection indices. When more than two species are be improved for their performances in mixture, the advantage of parallel selections for General Mixture Ability is even more marked, providing that compensation trends between species are not too prevalent.

scholarly journals Exergy Analysis of Directional Solvent Extraction Desalination Process

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 321 ◽  
Author(s):  
Sorour Alotaibi ◽  
Osama Ibrahim ◽  
Yu Wang ◽  
Tengfei Luo
Keyword(s):  
Solvent Extraction ◽  
Parametric Study ◽  
Octanoic Acid ◽  
Exergy Analysis ◽  
Small Variation ◽  
Water Yield ◽  
Low Grade ◽  
Design Variables ◽  
Exergy Consumption ◽  
The Impact

This paper presents an exergy analysis to evaluate the performance of a continuous directional solvent extraction (DSE) desalination process using octanoic acid. The flow of exergy was calculated for each thermodynamic state and balanced for different components of the system to quantify the inefficiencies in the process. A parametric study was performed to evaluate the impact of three critical design variables on exergy consumption. The parametric study reveals that the total exergy input decreases significantly with an increase in heat exchanger effectiveness. The results also indicate that the heat exchangers account for the highest exergy destruction. The total exergy consumption, however, has a slightly declining trend as the recovery-ratio increases. There is a small variation in the total exergy consumption, within the uncertainty of the calculation, as the highest process temperature increases. When compared to conventional desalination processes, the exergy consumption of the DSE, with heat recovery of 90%, is comparable to those of multi-stage flashing (MSF), but much higher than reverse osmosis (RO). Octanoic acid, which has low product water yield, is identified as the primary factor negatively impacting the exergy consumptions. To exploit the low-grade and low-temperature heat source feature of the DSE process, directional solvents with higher yield should be identified or designed to enable its full implementation.

Comparison of International Source-Term Codes

1993 ◽  
Vol 333 ◽  
Author(s):  
W. Zhou ◽  
M. J. Apted ◽  
P. Robinson
Keyword(s):  
Nuclear Waste ◽  
Preliminary Analysis ◽  
Source Term ◽  
Near Field ◽  
Different Types ◽  
Solution Methods ◽  
Initial Comparison ◽  
Models Comparison ◽  
The Impact ◽  
Transport Factors

ABSTRACTSource-term codes to predict the release of radionuclides from nuclear waste packages have been developed and implemented worldwide. A survey and initial comparison of the attributes and capabilities of 13 international source-term codes was recently completed. This preliminary analysis focused on comparison of transport factors/processes and solution methods. This initial comparison is a necessary first step in a properly-conceived, systematic benchmarking of source-term codes. Advantages of such a comparison include assurance of the mathematical correctness of implemented models, comparison and quantification of variances introduced by different types of simplifications, and identification and quantification of the impact of near-field processes.

Colony relocation of Greater Crested Terns Thalasseus bergii in Bass Strait, south-eastern Australia

2020 ◽  
Vol 37 ◽  
pp. 166-171
Author(s):  
Aymeric Fromant ◽  
◽  
Yonina Eizenberg ◽  
Rosalind Jessop ◽  
Arnaud Lec’hvien ◽  
...  
Keyword(s):  
Prey Availability ◽  
South Australia ◽  
Barrier Islands ◽  
Breeding Population ◽  
Storm Events ◽  
Jack Mackerel ◽  
Seabird Species ◽  
Eastern Australia ◽  
Environmental Variations ◽  
The Impact

A newly established Greater Crested Tern Thalasseus bergii colony was observed on Kanowna Island, northern Bass Strait, in December 2019 and was monitored through January 2020. A maximum of 532 ± 28 nests was counted,representing ~15–20% of the known northern Bass Strait breeding population. Resightings of 69 leg-banded individuals (from 3 to 24 years of age) demonstrated that founding individuals originated from colonies in Victoria [The Nobbies on Phillip Island (54%), Corner Inlet Barrier Islands (39%), Mud Islands in Port Phillip Bay (6%)] and one individual from South Australia. Breeding began 2 months later than usual for northern Bass Strait, perhaps because the birds only moved to Kanowna Island after failed nesting attempts elsewhere (Corner Inlet and Phillip Island). Individuals were observed to mainly feed their chicks with Barracouta Thyrsites atun and Jack Mackerel Trachurus declivis, contrasting with the usual predominance of Australian Anchovy Engraulis australis in the diet of this species in the Bass Strait region. This relocation may result from local changes in prey availability and/or a combination of potential human disturbance, predation and storm events. The recent 50% decrease in the number of breeding Greater Crested Terns in Victoria suggests substantial changes in the regional environmental conditions, highlighting the importance of understanding the impact of environmental variations on seabird species.

A RECURRENT SELECTION SCHEME FOR FABA BEAN

1987 ◽  
Vol 67 (1) ◽  
pp. 79-85 ◽  
Author(s):  
G. G. ROWLAND
Keyword(s):  
Protein Content ◽  
Vicia Faba ◽  
Seed Yield ◽  
Faba Bean ◽  
Recurrent Selection ◽  
Seed Protein ◽  
Random Mating ◽  
Seed Protein Content ◽  
Selection Scheme ◽  
Seed Protein Concentration

A recurrent selection method for use in faba bean (Vicia faba) was evaluated over a 10-yr period. The method consists of growing superior lines in open-pollinated random mating nurseries (RMN), selecting heavily podded plants from these lines, evaluating the offspring for yield and seed protein concentration, and replacing inferior lines in the RMN with selections deemed superior. Two types of RMN were established, one for yield (RMY) and the other for both yield and seed protein content (RMP). The criterion for entry of a line into the RMY was a seed yield in the top 3 % of a yield trial while entry into the RMP required a line to be in the top 5% for seed yield and 3% for protein content. A positive increase in seed yield of the selected lines from both RMNs was found over time, but no increase in seed protein content was noted.Key words: Vicia faba, recurrent selection, breeding method, faba bean

scholarly journals Breeding pattern of Oreochromis niloticus (Linnaeus, 1758) (Pisces: Cichlidae) versus native congeneric species, Oreochromis macrochir (Boulinger, 1912) in the upper Kabompo River, northwest of Zambia

2021 ◽  
Author(s):  
Arthertone Jere ◽  
Wilson Jere ◽  
Austin Mtethiwa ◽  
Daud Kassam
Keyword(s):  
Sex Ratio ◽  
Oreochromis Niloticus ◽  
Breeding Population ◽  
Cold Season ◽  
Biological Research ◽  
Congeneric Species ◽  
Wet Season ◽  
Males And Females ◽  
The Impact ◽  
Somatic Index

Investigating the determinants of reproductive biology of fishes is an essential component of biological research. Breeding pattern was investigated to determine the impact of exotic Oreochromis niloticus on the native congeneric Oreochromis macrochir in the upper Kabompo River. Gonado-somatic index and sex ratio was used to investigate the breeding pattern in both invaded (where O. niloticus is present) and uninvaded (where O. niloticus is absent) sections of the river. Oreochromis macrochir was the only native congeneric species found in both sections. Results showed that the overall gonado-somatic index means for both sexes of O. macrochir in both sections were similar. For O. niloticus in invaded section indicated all year reproduction though reduced spawning in cold season (May-June), but with increased spawning activity in wet season (February-March). In O. macrochir, males and females were found breeding in both dry and wet seasons only, as for cold season no reproduction was recorded. Sex ratio (females: males) was 1:1.3 and 1:1.7 for O. niloticus and O. macrochir respectively, and both significantly deviated from the sex ratio of 1:1 (ꭓ2=8.42 and 9.37; p<0.05). Oreochromis niloticus formed the most abundant fish caught 221(63.5%) than O. macrochir 127(36.5%). Our study has revealed that O. niloticus was able to spawn in all seasons with 23% higher breeding population than O. macrochir, which explains the suppression in the abundance. We expect O. niloticus to invade further downstream of the Kabompo River due to natural dispersion.

scholarly journals Selection for Tuber Characters Can Maintain High Specific Gravity in a Diploid Potato Breeding Population

HortScience ◽  
1990 ◽  
Vol 25 (2) ◽  
pp. 227-228 ◽  
Author(s):  
K.G. Haynes ◽  
F.L. Haynes
Keyword(s):  
Specific Gravity ◽  
Recurrent Selection ◽  
Breeding Population ◽  
High Specific Gravity ◽  
Solarium Tuberosum ◽  
Hybrid Population ◽  
Base Population ◽  
Diploid Potato Breeding ◽  
Growing Conditions ◽  
Tuber Specific Gravity

A base population of high specific gravity clones was established from a diploid hybrid population of Solarium tuberosum Group Phureja and Solarium tuberosum Group Stenotomum previously adapted to the long-day growing conditions in North Carolina. This base population was subjected to two 2-year cycles of recurrent selection. During each cycle, selections in the field were made on the basis of tuber smoothness, shape, and size. Tubers from unselected clones were bulked by plots. Tuber specific gravity was determined for the selected and unselected (bulk) clones. Tuber specific gravity was significantly greater in the selected than in the unselected clones in each cycle of selection.

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