Development and Application of Speed Breeding Technologies in a Commercial Peanut Breeding Program

2013 ◽  
Vol 40 (2) ◽  
pp. 107-114 ◽  
Author(s):  
D. J. O'Connor ◽  
G. C. Wright ◽  
M. J. Dieters ◽  
D. L. George ◽  
M. N. Hunter ◽  
...  
Keyword(s):  
Continuous Light ◽  
Breeding Strategy ◽  
Release Time ◽  
Improvement Program ◽  
Breeding Programs ◽  
Breeding Technique ◽  
Release Times ◽  
Two Generations ◽  
Seed Increase ◽  
Winter Breeding

ABSTRACT Reducing the release time of new peanut varieties is a key objective of peanut breeding programs. In the Australian Peanut Genetic Improvement Program release time has traditionally taken 10 to 15 years; however, the relatively recent use of winter breeding and seed increase nurseries has significantly reduced release times. Despite these improvements, full-season maturity cultivars are still limited to two generations in a calendar year, when grown under optimal environmental conditions. This paper describes a new speed breeding technique, which combines controlled environment conditions, continuous light in conjunction with optimal temperature, and a single seed descent breeding strategy in a greenhouse environment. Speed breeding was successful in reducing generation time of full-season maturity cultivars from 145 to 89 days. Speed breeding can rapidly progress the inbreeding of F2, F3 and F4 generations in less than 12 months, and potentially accelerate the development of first cross to commercial release in around six to seven years.

scholarly journals A New Breeding Strategy towards Introgression and Characterization of Stay-Green QTL for Drought Tolerance in Sorghum

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 598
Author(s):  
Nasrein Mohamed Kamal ◽  
Yasir Serag Alnor Gorafi ◽  
Hanan Abdeltwab ◽  
Ishtiag Abdalla ◽  
Hisashi Tsujimoto ◽  
...  
Keyword(s):  
Phenotypic Expression ◽  
Phenotypic Selection ◽  
Breeding Strategy ◽  
Stay Green ◽  
Breeding Programs ◽  
The Public ◽  
Drought Tolerant ◽  
Selection Step ◽  
The Cost

Several marker-assisted selection (MAS) or backcrossing (MAB) approaches exist for polygenic trait improvement. However, the implementation of MAB remains a challenge in many breeding programs, especially in the public sector. In MAB introgression programs, which usually do not include phenotypic selection, undesired donor traits may unexpectedly turn up regardless of how expensive and theoretically powerful a backcross scheme may be. Therefore, combining genotyping and phenotyping during selection will improve understanding of QTL interactions with the environment, especially for minor alleles that maximize the phenotypic expression of the traits. Here, we describe the introgression of stay-green QTL (Stg1–Stg4) from B35 into two sorghum backgrounds through an MAB that combines genotypic and phenotypic (C-MAB) selection during early backcross cycles. The background selection step is excluded. Since it is necessary to decrease further the cost associated with molecular marker assays, the costs of C-MAB were estimated. Lines with stay-green trait and good performance were identified at an early backcross generation, backcross two (BC2). Developed BC2F4 lines were evaluated under irrigated and drought as well as three rainfed environments varied in drought timing and severity. Under drought conditions, the mean grain yield of the most C-MAB-introgression lines was consistently higher than that of the recurrent parents. This study is one of the real applications of the successful use of C-MAB for the development of drought-tolerant sorghum lines for drought-prone areas.

Place of Wood Specific Gravity in the Development of Advanced-Generation Seed Orchards and Breeding Programs

1982 ◽  
Vol 6 (3) ◽  
pp. 177-180
Author(s):  
J. B. Jett ◽  
J. T. Talbert
Keyword(s):  
Specific Gravity ◽  
Loblolly Pine ◽  
Second Generation ◽  
Improvement Program ◽  
Breeding Programs ◽  
The North ◽  
Wood Specific Gravity ◽  
High Heritability ◽  
Pinus Taeda L ◽  
Advanced Generation

Abstract Data from thinnings of 11 genetic tests with an average age of 10 years and from 364 eight-year-old second-generation selections were analyzed to provide an estimate of gain from one cycle of selection for wood specific gravity. Utilizing mid-parent, mature, wood specific gravities and progeny juvenile wood specific gravities, coefficients of genetic prediction, CGP = 0.55 and 0.41, were calculated for the genetic test thinning sample and second-generation selection sample. Expressed as a percentage of the mean, gain from selection was calculated to be 2.6 percent. A strategy was also developed to include wood specific gravity in the North Carolina State Cooperative's second-generation loblolly pine (Pinus taeda L.) improvement program. High heritability figures indicate little need to develop extensive family information for wood specific gravity in advanced-generation breeding programs.

Improved High Resolution Post-Transit Spectroscopy for Determining the Density of States in Amorphous Semiconductors

2000 ◽  
Vol 609 ◽  
Author(s):  
Charlie Main ◽  
Steve Reynolds ◽  
Rashad I. Badran ◽  
Joe M. Marshall
Keyword(s):  
Function Approximation ◽  
Delta Function ◽  
Amorphous Semiconductors ◽  
Rate Equations ◽  
Release Time ◽  
Disordered Materials ◽  
Trapping Rate ◽  
Laplace Inversion ◽  
Crystalline Materials ◽  
Release Times

ABSTRACTWe show that the analysis of post-transit photocurrent i(t) in a multi-trapping context to determine the density of trapping states g(E) is capable of resolving features less than kT in width. A commonly used method uses a Laplace inversion of i(t) data giving the well-known result g(E) ∼ t i(t) but employs a delta function approximation for trap release times, which results in loss of energy resolution. We show that it is possible to retain the exponential distribution function for trap release time and solve the multi-trapping rate equations directly, giving significantly improved resolution. The analysis is performed on computer generated post-transit data for distributed and discrete traps, and compared with the earlier method and other related Fourier transform methods for determining g(E). In addition, the versatility of the new method in handling cases with either distributed traps or with discrete traps means that it can be applied to disordered materials or to crystalline materials with well-defined defect levels.

Potential of SSR markers for plant breeding and variety identification in Australian barley germplasm

2003 ◽  
Vol 54 (12) ◽  
pp. 1197 ◽  
Author(s):  
A. Karakousis ◽  
A. R. Barr ◽  
K. J. Chalmers ◽  
G. A. Ablett ◽  
T. A. Holton ◽  
...  
Keyword(s):  
Ssr Markers ◽  
Polymorphic Information Content ◽  
Strong Association ◽  
Variety Identification ◽  
Improvement Program ◽  
Breeding Programs ◽  
Partial Correlations ◽  
Trait Locus ◽  
Barley Germplasm ◽  
Barley Genotypes

SSR markers closely linked to 18 loci that control 16 important barley traits were assessed for their applicability in Australian barley breeding programs. A panel of 40 genotypes routinely used by the South Australian Barley Improvement Program (SABIP) was used to examine the usefulness of these SSR markers for marker assisted selection (MAS). The success of monitoring a trait locus from donor to recipient lines ranged from 10 to 98%, depending on the marker. SSRs with a high polymorphic information content (PIC) value were found to be the most useful for application in MAS. The assessment also indicated that SSRs derived from genomic sequences were more successful for MAS than those designed from expressed sequence tags. A total of 130 SSR markers were screened among 2 panels of Australian barley genotypes to determine which markers would be the most useful for discriminating Australian germplasm. PIC values generated by this screening were also compared with those generated using a panel of European barley genotypes. Using ordinary correlations (parametric), rank correlations (non-parametric), and partial correlations (multi-variate), a strong association was found between the 2 Australian panels, but no or weak correlation was observed between the 2 Australian panels and the European dataset. It can therefore be concluded that PIC values generated by SSR markers screened with European genotypes cannot be used to predict the usefulness of an SSR marker for discriminating Australian genotypes. From PIC values generated in this study, 36 SSR markers have been selected for the discrimination of Australian genotypes. These markers all show high and/or consistent PIC values among Australian and European barley genotypes.

scholarly journals Using markers in gene introgression breeding programs.

Genetics ◽  
1992 ◽  
Vol 132 (4) ◽  
pp. 1199-1210 ◽  
Author(s):  
F Hospital ◽  
C Chevalet ◽  
P Mulsant
Keyword(s):  
Population Size ◽  
Marker Assisted Selection ◽  
Gene Introgression ◽  
Selection Intensity ◽  
Breeding Programs ◽  
Introgression Breeding ◽  
Size Number ◽  
Theoretical Predictions ◽  
Two Generations ◽  
High Selection

Abstract We investigate the use of markers to hasten the recovery of the recipient genome during an introgression breeding program. The effects of time and intensity of selection, population size, number and position of selected markers are studied for chromosomes either carrying or not carrying the introgressed gene. We show that marker assisted selection may lead to a gain in time of about two generations, an efficiency below previous theoretical predictions. Markers are most useful when their map position is known. In the early generations, it is shown that increasing the number of markers over three per non-carrier chromosome is not efficient, that the segment surrounding the introgressed gene is better controlled by rather distant markers unless high selection intensity can be applied, and that selection on this segment first can reduce the selection intensity available for selection on non-carrier chromosomes. These results are used to propose an optimal strategy for selection on the whole genome, making the most of available material and conditions (e.g., population size and fertility, genetic map).

scholarly journals A Combinatorial 2-Approximation Algorithm for the Parallel-Machine Scheduling with Release Times and Submodular Penalties

Mathematics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 61
Author(s):  
Wencheng Wang ◽  
Xiaofei Liu
Keyword(s):  
Approximation Algorithm ◽  
Single Machine ◽  
Machine Scheduling ◽  
Parallel Machine Scheduling ◽  
Parallel Machine ◽  
Single Machine Scheduling ◽  
Release Time ◽  
Release Dates ◽  
Scheduling Problem ◽  
Release Times

In this paper, we consider parallel-machine scheduling with release times and submodular penalties (P|rj,reject|Cmax+π(R)), in which each job can be accepted and processed on one of m identical parallel machines or rejected, but a penalty must paid if a job is rejected. Each job has a release time and a processing time, and the job can not be processed before its release time. The objective of P|rj,reject|Cmax+π(R) is to minimize the makespan of the accepted jobs plus the penalty of the rejected jobs, where the penalty is determined by a submodular function. This problem generalizes a multiprocessor scheduling problem with rejection, the parallel-machine scheduling with submodular penalties, and the single machine scheduling problem with release dates and submodular rejection penalties. In this paper, inspired by the primal-dual method, we present a combinatorial 2-approximation algorithm to P|rj,reject|Cmax+π(R). This ratio coincides with the best known ratio for the parallel-machine scheduling with submodular penalties and the single machine scheduling problem with release dates and submodular rejection penalties.

scholarly journals Marker-assisted breeding of onion (A. cepa L.) maintainer line resistant to Downy mildew

2021 ◽  
pp. 34-39
Author(s):  
Ya. T. Eidlin ◽  
G. F. Monakhos ◽  
S. G. Monakhos
Keyword(s):  
Downy Mildew ◽  
Inbred Line ◽  
Marker Assisted Selection ◽  
Dna Marker ◽  
F1 Hybrids ◽  
Marker Assisted Breeding ◽  
Maintainer Line ◽  
Breeding Programs ◽  
Maternal Line ◽  
Two Generations

Relevance. F1 hybrids breeding programs of onion are based on the use of nuclear cytoplasmic male sterility (NCMS). Breeding and seed production based on NCMS suggest a development of a female sterile maternal line, a maintainer line and a paternal component. The development of an isogenic pair of sterile line – maintainer line is one of the most labor-, time-consuming and intellectually-intensive stages of a breeding program, the implementation of which becomes more complicated with an increase in the number of traits / genes for which selection is carried out.Methods and results. This paper presents a genetic scheme for the development of a Downy mildewresistant (pathogen P. destructor) maintainer line of onion using marker-assisted selection (MAS). F2 populations were obtained from the cross of the female maintainer inbred line, Bn1- (13) (genotype – cytN msms pdpd) and male inbred line resistant to Downy mildew, No. 136 (genotype – cytT MsMs PdPd). DNA marker DMR1 were used for Downy mildew resistance gene Pd, jnurf13 – for maintainer gene ms and marker system 5`cob: orfA501 – for N, S and T cytoplasms. It was shown that the MAS application allow to develop a stable Downy mildew resistant maintainer line cytN msms PdPd in two generations.

scholarly journals Aerial High-Throughput Phenotyping Enabling Indirect Selection for Grain Yield at the Early-generation Seed-limited Stages in Breeding Programs

2020 ◽  
Author(s):  
Margaret R. Krause ◽  
Suchismita Mondal ◽  
José Crossa ◽  
Ravi P. Singh ◽  
Francisco Pinto ◽  
...  
Keyword(s):  
Grain Yield ◽  
High Throughput ◽  
Vegetation Indices ◽  
Early Generation ◽  
Breeding Programs ◽  
Breeding Lines ◽  
High Throughput Phenotyping ◽  
Seed Increase ◽  
Yield Trials ◽  
Selection Of

ABSTRACTBreeding programs for wheat and many other crops require one or more generations of seed increase before replicated yield trials can be sown. Extensive phenotyping at this stage of the breeding cycle is challenging due to the small plot size and large number of lines under evaluation. Therefore, breeders typically rely on visual selection of small, unreplicated seed increase plots for the promotion of breeding lines to replicated yield trials. With the development of aerial high-throughput phenotyping technologies, breeders now have the ability to rapidly phenotype thousands of breeding lines for traits that may be useful for indirect selection of grain yield. We evaluated early generation material in the irrigated bread wheat (Triticum aestivum L.) breeding program at the International Maize and Wheat Improvement Center to determine if aerial measurements of vegetation indices assessed on small, unreplicated plots were predictive of grain yield. To test this approach, two sets of 1,008 breeding lines were sown both as replicated yield trials and as small, unreplicated plots during two breeding cycles. Vegetation indices collected with an unmanned aerial vehicle in the small plots were observed to be heritable and moderately correlated with grain yield assessed in replicated yield trials. Furthermore, vegetation indices were more predictive of grain yield than univariate genomic selection, while multi-trait genomic selection approaches that combined genomic information with the aerial phenotypes were found to have the highest predictive abilities overall. A related experiment showed that selection approaches for grain yield based on vegetation indices could be more effective than visual selection; however, selection on the vegetation indices alone would have also driven a directional response in phenology due to confounding between those traits. A restricted selection index was proposed for improving grain yield without affecting the distribution of phenology in the breeding population. The results of these experiments provide a promising outlook for the use of aerial high-throughput phenotyping traits to improve selection at the early-generation seed-limited stage of wheat breeding programs.

scholarly journals A multi-part strategy for introgression of exotic germplasm into elite plant breeding programs using genomic selection

2022 ◽  
Author(s):  
Irene S. Breider ◽  
R. Chris Gaynor ◽  
Gregor Gorjanc ◽  
Steve Thorn ◽  
Manish K. Pandey ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Plant Breeding ◽  
Genomic Selection ◽  
Genetic Gain ◽  
Genetic Improvement ◽  
Breeding Strategy ◽  
Breeding Program ◽  
Breeding Programs ◽  
Polygenic Inheritance ◽  
Polygenic Traits

Abstract Some of the most economically important traits in plant breeding show highly polygenic inheritance. Genetic variation is a key determinant of the rates of genetic improvement in selective breeding programs. Rapid progress in genetic improvement comes at the cost of a rapid loss of genetic variation. Germplasm available through expired Plant Variety Protection (exPVP) lines is a potential resource of variation previously lost in elite breeding programs. Introgression for polygenic traits is challenging, as many genes have a small effect on the trait of interest. Here we propose a way to overcome these challenges with a multi-part pre-breeding program that has feedback pathways to optimise recurrent genomic selection. The multi-part breeding program consists of three components, namely a bridging component, population improvement, and product development. Parameters influencing the multi-part program were optimised with the use of a grid search. Haploblock effect and origin were investigated. Results showed that the introgression of exPVP germplasm using an optimised multi-part breeding strategy resulted in 1.53 times higher genetic gain compared to a two-part breeding program. Higher gain was achieved through reducing the performance gap between exPVP and elite germplasm and breaking down linkage drag. Both first and subsequent introgression events showed to be successful. In conclusion, the multi-part breeding strategy has a potential to improve long-term genetic gain for polygenic traits and therefore, potential to contribute to global food security.

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