scholarly journals GENETIC GAINS AND SELECTION ADVANCES OF THE UENF-14 POPCORN POPULATION

2018 ◽  
Vol 31 (2) ◽  
pp. 271-278 ◽  
Author(s):  
AMANDA GONÇALVES GUIMARÃES ◽  
ANTÔNIO TEIXEIRA DO AMARAL JÚNIOR ◽  
VALTER JÁRIO DE LIMA ◽  
JHEAN TORRES LEITE ◽  
CARLOS ALBERTO SCAPIM ◽  
...  
Keyword(s):  
Grain Yield ◽  
Genetic Gain ◽  
Recurrent Selection ◽  
Selection Index ◽  
Economic Importance ◽  
Average Height ◽  
Breeding Programs ◽  
Genetic Gains ◽  
Full Sibling ◽  
Selection Of

ABSTRACT Recurrent selection can generate successive gains for characters of economic interest without causing genetic narrowing in the population. However, it has rarely been used in breeding programs in popcorn, especially when using full-sibling progenies to generate more expressive gains. The objective of this study was to estimate the genetic gain of the UENF-14 popcorn population through recurrent selection, and verify the evolution of the gains between the selection cycles four and eight. A total of 200 full-sibling progenies were evaluated in randomized blocks arranged in eight sets within three replicates in two environments; each set containing twenty-five progenies and six controls (selection cycles 4, 5, 6 and 7 of the UENF-14, BRS-Angela and IAC-125). The average height, prolificacy, 100-grain weight, ear weight, grain yield, and grain popping expansion of the plants were evaluated. In the selection of the thirty superior progenies for the eighth cycle, the Mulamba and Mock selection index was used, which generated estimated genetic gains of 4.60 for grain yield and 3.61% for popping expansion. The grain yield increased 111.99 kg ha-1 and the popping expansion increased 1.75 mL g-1 per cycle. The evolution of the cycles resulted in an accumulated genetic gain for the main characters of economic importance, allowing the prediction of success in the continuity of the recurrent selection.

scholarly journals GENETIC GAINS IN THE POPCORN POPULATION UENF-14: DEVELOPING THE NINTH GENERATION OF INTRAPOPULATION RECURRENT SELECTION

2019 ◽  
Vol 32 (3) ◽  
pp. 625-633
Author(s):  
AMANDA GONÇALVES GUIMARÃES ◽  
ANTÔNIO TEIXEIRA DO AMARAL JÚNIOR ◽  
GUILHERME FERREIRA PENA ◽  
JANEO EUSTÁQUIO DE ALMEIDA FILHO ◽  
MESSIAS GONZAGA PEREIRA ◽  
...  
Keyword(s):  
Grain Yield ◽  
Indirect Effects ◽  
Recurrent Selection ◽  
Selection Process ◽  
Selection Index ◽  
Average Height ◽  
Direct And Indirect Effects ◽  
Genetic Progress ◽  
Breeding Programs ◽  
Selection Of

ABSTRACT The occurrence of negative correlations between grain yield (GY) and popping expansion (PE) in popcorn complicates the selection process. In an attempt to overcome this inconvenience, we proposed the use of the importance characteristic volume per popcorn per hectare (PV). The objectives of this study were to develop the ninth cycle of the UENF-14 popcorn population, to estimate the direct and indirect effects of PV and to verify the genetic progress among all selective cycles. We obtained and evaluated 200 inbred progenies in randomised blocks arranged in replicates within sets, with nine sets consisting of 25 progenies and one set with all previous eight cycles with three replicates. The average height of the plants, prolificacy, 100-grain weight, grain yield, grain popping expansion and volume per popcorn per hectare were evaluated. Track analysis was performed to determine the direct and indirect effects, and the Mulamba and Mock selection index was calculated for the selection of the 40 superior progenies. There was genetic variability among progenies in all evaluated traits, with a cause-and-effect relationship between PV with GY and PE, allowing simultaneous gains with indirect selection. The selection of the best progenies was more effective when using arbitrarily assigned weights, which provided higher predicted gains for PV (20.73%). The means obtained in all cycles indicated increases, demonstrating the efficiency of using continuous recurrent selection in popcorn breeding programs.

scholarly journals Plant breeders should be determining economic weights for a selection index instead of using independent culling for choosing parents in breeding programs with genomic selection

2018 ◽  
Author(s):  
Lorena G. Batista ◽  
R. Chris Gaynor ◽  
Gabriel R. A. Margarido ◽  
Tim Byrne ◽  
Peter Amer ◽  
...  
Keyword(s):  
Genomic Selection ◽  
Genetic Gain ◽  
Recurrent Selection ◽  
Selection Index ◽  
Economic Importance ◽  
Index Selection ◽  
Breeding Programs ◽  
Independent Culling ◽  
Economic Selection ◽  
Selection Of

AbstractIn the context of genomic selection, we evaluated and compared recurrent selection breeding programs using either index selection or independent culling for selection of parents. We simulated a clonally propagated crop breeding program for 20 cycles of selection using either independent culling or an economic selection index with two unfavourably correlated traits under selection. Cycle time from crossing to selection of parents was kept the same for both strategies. Our results demonstrate that accurate knowledge of the economic importance of traits is essential even when performing independent culling. This is because independent culling achieved its optimum genetic gain when the culling threshold for each trait varied accordingly to the economic importance of the traits. When gains from independent culling were maximised, the efficiency of converting genetic diversity into genetic gain of both selection methods were equivalent. When the same proportion selected of 10% for each trait was used instead of optimal culling levels, index selection was 10%, 128% and 310% more efficient than independent culling when T2 had a relative economic importance of 1.0, 2.5 and 5.0, respectively. Given the complexity of estimating optimal culling levels and the fact that the gains achieved with independent culling are, at most, equivalent to index selection, the use of an economic selection index is recommended for multi-trait genomic selection.

scholarly journals Genetic Trends Estimation in IRRIs Rice Drought Breeding Program and Identification of High Yielding Drought-Tolerant Lines

2021 ◽  
Author(s):  
Apurva Khanna ◽  
Mahender Anumalla ◽  
Margaret Catolos ◽  
Jérôme Bartholomé ◽  
Roberto Fritsche-Neto ◽  
...  
Keyword(s):  
Grain Yield ◽  
Genetic Gain ◽  
Recurrent Selection ◽  
Historical Data ◽  
Breeding Program ◽  
Positive Trend ◽  
Breeding Values ◽  
Genetic Gains ◽  
Rate Of Increase ◽  
Genetic Trends

Abstract BackgroundEstimation of genetic trends using historical data is an important parameter to check the success of the breeding programs. The estimated genetic trends can act as a guideline to target the appropriate breeding strategies and optimize the breeding program for improved genetic gains. In this study, 17 years of historical data from IRRI’s rice drought breeding program was used to estimate the genetic trends and assess the success of the breeding program. We also identified top-performing lines based on grain yield breeding values as an elite panel for implementing future population improvement-based breeding schemes.ResultsA two-stage approach of pedigree-based mixed model analysis was used to analyze the data and extract the breeding values and estimate the genetic trends for grain yield under non-stress, drought, and in combined data of non-stress and drought. Lower grain yield values were observed in all the drought trials. Heritability for grain yield estimates ranged between 0.20-0.94 under the drought trials, and 0.43-0.83 under non-stress trials. Under non-stress conditions the genetic gain of 0.44% (21.20 kg/ha/year) for genotypes and 0.17 % (7.90 kg/ha/year) for checks was observed. The genetic trend under the drought conditions exhibited a positive trend with the genetic gain of 0.11% (1.98kg/ha/year) for genotypes and 0.55% (9.52kg/ha/year) for checks. For combined analysis showed a genetic gain of 0.39% (12.13 kg/ha/year) for genotypes and 0.60% (13.69 kg/ha/year) for checks was observed. For elite panel selection, 200 promising lines were selected based on higher breeding values for grain yield and prediction accuracy of >0.40. The breeding values of the 200 genotypes formulating the core panel ranged between 2366.17 and 4622.59 (kg/ha).ConclusionsA positive genetic rate was observed under all the three conditions; however, the rate of increase was lower than the required rate of 1.5% genetic gain. We propose a recurrent selection breeding strategy within the elite population with the integration of modern tools and technologies to boost the genetic gains in IRRI’s drought breeding program. The elite breeding panel identified in this study forms an easily available and highly enriched genetic resource for future recurrent selection programs to boost the genetic gains.

scholarly journals Long-term comparison between index selection and optimal independent culling in plant breeding programs with genomic prediction

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0235554
Author(s):  
Lorena G. Batista ◽  
Robert Chris Gaynor ◽  
Gabriel R. A. Margarido ◽  
Tim Byrne ◽  
Peter Amer ◽  
...  
Keyword(s):  
Recurrent Selection ◽  
Genetic Correlations ◽  
Economic Importance ◽  
Index Selection ◽  
Selection Intensity ◽  
Crop Breeding ◽  
Breeding Programs ◽  
Independent Culling ◽  
Selection Of

In the context of genomic selection, we evaluated and compared breeding programs using either index selection or independent culling for recurrent selection of parents. We simulated a clonally propagated crop breeding program for 20 cycles using either independent culling or an economic index with two unfavourably correlated traits under selection. Cycle time from crossing to selection of parents was kept the same for both strategies. Both methods led to increasingly unfavourable genetic correlations between traits and, compared to independent culling, index selection led to larger changes in the genetic correlation between the two traits. When linkage disequilibrium was not considered, the two methods had similar losses of genetic diversity. Two independent culling approaches were evaluated, one using optimal culling levels and one using the same selection intensity for both traits. Optimal culling levels outperformed the same selection intensity even when traits had the same economic importance. Therefore, accurately estimating optimal culling levels is essential for maximizing gains when independent culling is performed. Once optimal culling levels are achieved, independent culling and index selection lead to comparable genetic gains.

scholarly journals Genetic parameters and estimated genetic gains in young rubber tree progenies

2013 ◽  
Vol 48 (4) ◽  
pp. 411-416 ◽  
Author(s):  
Cecília Khusala Verardi ◽  
Erivaldo José Scaloppi Junior ◽  
Guilherme Augusto Peres Silva ◽  
Lígia Regina Lima Gouvêa ◽  
Paulo de Souza Gonçalves
Keyword(s):  
Genetic Gain ◽  
Genetic Parameters ◽  
Block Design ◽  
Rubber Tree ◽  
First Year ◽  
Genetic Gains ◽  
Selection Gain ◽  
Randomized Block Design ◽  
Using Data ◽  
Selection Of

The objective of this work was to assess the genetic parameters and to estimate genetic gains in young rubber tree progenies. The experiments were carried out during three years, in a randomized block design, with six replicates and ten plants per plot, in three representative Hevea crop regions of the state of São Paulo, Brazil. Twenty-two progenies were evaluated, from three to five years old, for rubber yield and annual girth growth. Genetic gain was estimated with the multi-effect index (MEI). Selection by progenies means provided greater estimated genetic gain than selection based on individuals, since heritability values of progeny means were greater than the ones of individual heritability, for both evaluated variables, in all the assessment years. The selection of the three best progenies for rubber yield provided a selection gain of 1.28 g per plant. The genetic gains estimated with MEI using data from early assessments (from 3 to 5-year-old) were generally high for annual girth growth and rubber yield. The high genetic gains for annual girth growth in the first year of assessment indicate that progenies can be selected at the beginning of the breeding program. Population effective size was consistent with the three progenies selected, showing that they were not related and that the population genetic variability is ensured. Early selection with the genetic gains estimated by MEI can be made on rubber tree progenies.

scholarly journals Estimate of genetic parameters and predicted gains with early selection of physic nut families

2012 ◽  
Vol 36 (2) ◽  
pp. 163-170 ◽  
Author(s):  
Bruno Galvêas Laviola ◽  
Alexandre Alonso Alves ◽  
Fábio de Lima Gurgel ◽  
Tatiana Barbosa Rosado ◽  
Rhayanne Dias Costa ◽  
...  
Keyword(s):  
Grain Yield ◽  
Genetic Parameters ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Biodiesel Production ◽  
Early Selection ◽  
Physic Nut ◽  
Genetic Gains ◽  
Canopy Volume ◽  
Selection Of

An initial evaluation of early selection of physic nut genotypes based on phenotypic data is presented. In order to predict the genetic gains with early selection, genetic parameters, e.g. additive genetic variance, were first obtained for grain yield along with other numerous traits. The results demonstrated that additive genetic variance exists not only for grain yield, which is considered to be the most important trait for oil and biodiesel production, but also for numerous other traits. The predicted genetic gains for grain yield, considering the selection of the 30, 20, 10 and 5 best families in the second crop year are respectively, 40.47, 48.43, 61.78 and 70.28%. With the selection of highly yielding physic nut genotypes indirectly genotypes with enhanced volume would be also selected, because yield exhibits moderate to high genetic correlations with height e canopy volume. The results here presented demonstrate the potential of the population gathered in the Brazilian physic nut germplasm bank for genetic breeding purposes and that superior physic nut families can be selected with high accuracy based on the evaluation of its second crop.

scholarly journals Tolerance to preharvest sprouting and yield of wheat genotypes from different breeding programs

2015 ◽  
Vol 50 (8) ◽  
pp. 698-706
Author(s):  
Rafael Nörnberg ◽  
José Antonio Gonzalez da Silva ◽  
Henrique de Souza Luche ◽  
Elisane Weber Tessmann ◽  
Sydney Antonio Frehner Kavalco ◽  
...  
Keyword(s):  
Grain Yield ◽  
Block Design ◽  
Preharvest Sprouting ◽  
Rio Grande Do Sul ◽  
Falling Number ◽  
Breeding Programs ◽  
Wheat Genotypes ◽  
Randomized Complete Block Design ◽  
Superior Genotypes ◽  
Selection Of

Abstract:The objective of this work was to characterize the performance of elite wheat genotypes from different Brazilian breeding programs for traits associated with grain yield and preharvest sprouting. The study was conducted in 2010 and 2011 in the municipality of Capão do Leão, in the state of Rio Grande do Sul, Brazil, in a randomized complete block design with three replicates. Thirty-three wheat genotypes were evaluated for traits related to preharvest sprouting and grain yield. The estimate of genetic distance was used to predict potential combinations for selection of plants with high grain yield and tolerance to preharvest sprouting. The combined analysis of sprouted grains and falling number shows that the TBIO Alvorada, TBIO Mestre, Frontana, Fundacep Raízes, Fundacep Cristalino, and BRS Guamirim genotypes are tolerant to preharvest sprouting. Combinations of TBIO Alvorada and TBIO Mestre with Fundacep Cristalino show high potential for recovering superior genotypes for high grain yield and tolerance to preharvest sprouting.

scholarly journals Wheat Production and Breeding in Israel from 1948 to 2002

2011 ◽  
Vol 40 (No. 1) ◽  
pp. 17-24 ◽  
Author(s):  
Y. Atsmon S ◽  
E. Schwarzbach
Keyword(s):  
Population Growth ◽  
Grain Yield ◽  
Durum Wheat ◽  
Genetic Material ◽  
Wheat Breeding ◽  
Economic Importance ◽  
National Average ◽  
Breeding Programs ◽  
The Sixties ◽  
On Farm

The sown wheat acreage in Israel increased from less than 40 000 ha in 1948 to more than 100 000 ha in the seventies and has declined slightly since that time. About 3/4 of the crop are grown in the central part of the country, mostly rain fed, with precipitation of 250–500 mm. The cultivation of durum wheat, originally dominant, has declined since the sixties to a small percentage of the wheat acreage and durum wheat breeding is thus negligible. Local bread wheat breeding started around 1960 independently at three breeding organisations, one of which extensively used genetic material from international breeding programs in Mexico. Since the fifties about 25 cultivars have been released, but only a few are of economic importance now. Breeding considerably increased the yielding potential of cultivars. The recent top cultivar Galil yields about twice as much as cv. Florence Aurore, the leading cultivar in 1970. The national average grain yield rose from 900 kg/ha in 1948 to recently 2.3 t/ha. The highest on-farm yields under favourable conditions are about 9 t/ha. An increasing proportion of the wheat acreage is used for silage, reaching now more than 25%. Yearly fluctuations of yield are considerable and are closely related to rainfall. Data also show an improvement in water utilisation by the crop during the analysed period. The domestic production covered originally only about 12% of the consumption, reaching 47% in the decade 1970–1979, but declined again due to the population growth from 1.2 to 6.5 millions.  

Future progress in drought tolerance in maize needs new secondary traits and cross combinations

2008 ◽  
Vol 146 (3) ◽  
pp. 287-300 ◽  
Author(s):  
P. MONNEVEUX ◽  
C. SANCHEZ ◽  
A. TIESSEN
Keyword(s):  
Drought Tolerance ◽  
Grain Yield ◽  
Recurrent Selection ◽  
Selection Index ◽  
Gene Pyramiding ◽  
Dry Weight ◽  
Continuous Selection ◽  
Optimal Choice ◽  
Secondary Traits ◽  
The Relationship

SUMMARYThe use of secondary traits such as number of ears per plant, grains per ear, the interval from anthesis to silking, leaf senescence and leaf rolling, together with management of water stress and recurrent selection, have permitted a considerable increase in drought tolerance in the CIMMYT maize source germplasm populations Drought Tolerant Population (DTP) and La Posta Sequía (LPS). Inbred lines were extracted from DTP C9 and LPS C7 cycles and then used for generating single and three-ways hybrids. These were evaluated under normal irrigation and managed drought conditions. A weak, and in some cases no longer significant, correlation was found between grain yield and the traits initially used for selection. Most prominently, the relationship between anthesis-silking interval and grain yield became much weaker in these hybrids. Conversely, significant negative correlations were found between tassel dry weight and grain yield. Three-way hybrids involving two DTP lines yielded more than those involving one only, indicating the feasibility of gene pyramiding for drought tolerance. Overall, the results suggested that the relationship between grain yield and secondary traits has been modified due to continuous selection in the LPS and DTP populations. Some long-established secondary traits have become less important, while others have become more relevant. Mean grain weight, previously not used within a drought selection index, was strongly correlated with yield in the present study. The importance of traits related to the availability in C products for the development of ears and grains are discussed. The results indicate that the traits of source organs contribute marginally to drought tolerance; variation of leaf or root traits seems to be less important than variation in tassel parameters for increasing drought tolerance. For ensuring further progress in drought tolerance in maize, the solution might reside in the manipulation of sink organs. It is therefore suggested that selection for even greater number of ears, bigger grains and smaller tassels may help to increase grain yield under water limited environments in the near future. A short discussion on the optimal choice of parental lines for developing hybrids with maximum expression of drought tolerance concludes the paper.

scholarly journals Population Genomics Along With Quantitative Genetics Provides a More Efficient Valorization of Crop Plant Genetic Diversity in Breeding and Pre-breeding Programs

2021 ◽  
Author(s):  
Peter Civan ◽  
Renaud Rincent ◽  
Alice Danguy-Des-Deserts ◽  
Jean-Michel Elsen ◽  
Sophie Bouchet
Keyword(s):  
Genetic Diversity ◽  
Quantitative Genetics ◽  
Genetic Gain ◽  
Recurrent Selection ◽  
Prediction Models ◽  
Population Genomics ◽  
Breeding Program ◽  
Breeding Programs ◽  
Sequencing Technologies ◽  
Genetic Value

AbstractThe breeding efforts of the twentieth century contributed to large increases in yield but selection may have increased vulnerability to environmental perturbations. In that context, there is a growing demand for methodology to re-introduce useful variation into cultivated germplasm. Such efforts can focus on the introduction of specific traits monitored through diagnostic molecular markers identified by QTL/association mapping or selection signature screening. A combined approach is to increase the global diversity of a crop without targeting any particular trait.A considerable portion of the genetic diversity is conserved in genebanks. However, benefits of genetic resources (GRs) in terms of favorable alleles have to be weighed against unfavorable traits being introduced along. In order to facilitate utilization of GR, core collections are being identified and progressively characterized at the phenotypic and genomic levels. High-throughput genotyping and sequencing technologies allow to build prediction models that can estimate the genetic value of an entire genotyped collection. In a pre-breeding program, predictions can accelerate recurrent selection using rapid cycles in greenhouses by skipping some phenotyping steps. In a breeding program, reduced phenotyping characterization allows to increase the number of tested parents and crosses (and global genetic variance) for a fixed budget. Finally, the whole cross design can be optimized using progeny variance predictions to maximize short-term genetic gain or long-term genetic gain by constraining a minimum level of diversity in the germplasm. There is also a potential to further increase the accuracy of genomic predictions by taking into account genotype by environment interactions, integrating additional layers of omics and environmental information.Here, we aim to review some relevant concepts in population genomics together with recent advances in quantitative genetics in order to discuss how the combination of both disciplines can facilitate the use of genetic diversity in plant (pre) breeding programs.

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