The effect of interplant distance on the effectiveness of honeycomb selection. II. Results of the second selection cycle

Euphytica ◽  
1990 ◽  
Vol 50 (2) ◽  
pp. 147-153
Author(s):  
R. J. Pasini ◽  
I. Bos
Keyword(s):  
Selection Cycle ◽  
Interplant Distance ◽  
Honeycomb Selection

scholarly journals Increasing selection gain and accuracy of harvest prediction models in Jatropha through genome-wide selection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adriano dos Santos ◽  
Erina Vitório Rodrigues ◽  
Bruno Galvêas Laviola ◽  
Larissa Pereira Ribeiro Teodoro ◽  
Paulo Eduardo Teodoro ◽  
...  
Keyword(s):  
Prediction Models ◽  
Block Design ◽  
Phenotypic Selection ◽  
Breeding Population ◽  
Breeding Cycle ◽  
Selection Cycle ◽  
Genome Wide ◽  
Random Block ◽  
Random Block Design ◽  
Number Of Individuals

AbstractGenome-wide selection (GWS) has been becoming an essential tool in the genetic breeding of long-life species, as it increases the gain per time unit. This study had a hypothesis that GWS is a tool that can decrease the breeding cycle in Jatropha. Our objective was to compare GWS with phenotypic selection in terms of accuracy and efficiency over three harvests. Models were developed throughout the harvests to evaluate their applicability in predicting genetic values in later harvests. For this purpose, 386 individuals of the breeding population obtained from crossings between 42 parents were evaluated. The population was evaluated in random block design, with six replicates over three harvests. The genetic effects of markers were predicted in the population using 811 SNP's markers with call rate = 95% and minor allele frequency (MAF) > 4%. GWS enables gains of 108 to 346% over the phenotypic selection, with a 50% reduction in the selection cycle. This technique has potential for the Jatropha breeding since it allows the accurate obtaining of GEBV and higher efficiency compared to the phenotypic selection by reducing the time necessary to complete the selection cycle. In order to apply GWS in the first harvests, a large number of individuals in the breeding population are needed. In the case of few individuals in the population, it is recommended to perform a larger number of harvests.

scholarly journals Recurrent Selection with Glufosinate at Low Rates Reduces the Susceptibility of a Lolium perenne ssp. multiflorum Population to Glufosinate

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1288 ◽  
Author(s):  
Maor Matzrafi ◽  
Sarah Morran ◽  
Marie Jasieniuk
Keyword(s):  
Lolium Perenne ◽  
Recurrent Selection ◽  
Cross Resistance ◽  
Susceptible Population ◽  
Selection Cycle ◽  
Herbicide Resistant ◽  
Repeated Applications ◽  
Resistance To Herbicides ◽  
Rate Selection ◽  
Low Rate

Repeated applications of herbicides at the labelled rates have often resulted in the selection and evolution of herbicide-resistant weeds capable of surviving the labelled and higher rates in subsequent generations. However, the evolutionary outcomes of recurrent herbicide selection at low rates are far less understood. In this study of a herbicide-susceptible population of Lolium perenne ssp. multiflorum, we assessed the potential for low glufosinate rates to select for reduced susceptibility to the herbicide, and cross-resistance to herbicides with other modes of action. Reduced susceptibility to glufosinate was detected in progeny in comparison with the parental population following three rounds of selection at low glufosinate rates. Differences were mainly observed at the 0.5X, 0.75X, and 1X rates. Comparing the parental susceptible population and progeny from the second and third selection cycle, the percentage of surviving plants increased to values of LD50 (1.31 and 1.16, respectively) and LD90 (1.36 and 1.26, respectively). When treated with three alternative herbicides (glyphosate, paraquat, and sethoxydim), no plants of either the parental or successive progeny populations survived treatment with 0.75X or higher rates of these herbicides. The results of this study provide clear evidence that reduced susceptibility to glufosinate can evolve in weed populations following repeated applications of glufosinate at low herbicide rates. However, the magnitude of increases in resistance levels over three generations of recurrent low-rate glufosinate selection observed is relatively low compared with higher levels of resistance observed in response to low-rate selection with other herbicides (three fold and more).

scholarly journals Recurrent selection with glufosinate at low rates reduces the susceptibility of a Lolium perenne ssp. multiflorum population to glufosinate

2020 ◽  
Author(s):  
Maor Matzrafi ◽  
Sarah Morran ◽  
Marie Jasieniuk
Keyword(s):  
Lolium Perenne ◽  
Recurrent Selection ◽  
Cross Resistance ◽  
Susceptible Population ◽  
Selection Cycle ◽  
Herbicide Resistant ◽  
Repeated Applications ◽  
Resistance To Herbicides ◽  
Rate Selection ◽  
Low Rate

ABSTRACTRepeated applications of herbicides at the labelled rates have often resulted in the selection and evolution of herbicide-resistant weeds capable of surviving the labelled and higher rates in subsequent generations. However, the evolutionary outcomes of recurrent herbicide selection at low rates are far less understood. In this study of an herbicide-susceptible population of Lolium perenne ssp. multiflorum, we assessed the potential for low glufosinate rates to select for reduced susceptibility to the herbicide, and cross-resistance to herbicides with other modes of action. Reduced susceptibility to glufosinate was detected in progeny in comparison with the parental population following three rounds of selection at low glufosinate rates. Differences were mainly observed at the 0.5X, 0.75X, and 1X rates. Comparing the parental susceptible population and progeny from the second and third selection cycle, the percentage of surviving plants increased to values of LD50 (1.31 and 1.16, respectively) and LD90 (1.36 and 1.26, respectively). When treated with three alternative herbicides (glyphosate, paraquat, and sethoxydim), no plants of either the parental or successive progeny populations survived treatment with 0.75X or higher rates of these herbicides. The results of this study provide clear evidence that reduced susceptibility to glufosinate can evolve in weed populations following repeated applications of glufosinate at low herbicide rates. However, the magnitude of increases in resistance levels over three generations of recurrent low-rate glufosinate selection observed is relatively low compared with higher levels of resistance observed in response to low-rate selection with other herbicides (three fold and more).

Honeycomb Selection Designs

2010 ◽  
pp. 87-139 ◽  
Author(s):  
A. C. Fasoulas ◽  
V. A. Fasoula
Keyword(s):  
Honeycomb Selection

scholarly journals Comparing Efficiencies of Two Selection Approaches for Improving Fusarium Basal Rot Resistance in Short-Day Onion after a Single Cycle of Selection

Horticulturae ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 26
Author(s):  
Subhankar Mandal ◽  
Ashish Saxena ◽  
Christopher S. Cramer ◽  
Robert L. Steiner
Keyword(s):  
Environmental Factors ◽  
Random Distribution ◽  
Single Cycle ◽  
Field Screening ◽  
Selection Cycle ◽  
Short Day ◽  
Basal Rot ◽  
Fusarium Basal Rot ◽  
Consistent Method ◽  
Screening Approaches

The development of Fusarium Basal Rot (FBR)-resistant onion cultivars through field and seedling screening approaches faces tremendous challenges due to non-uniform distribution of the disease pathogen and possible multiple mechanisms of host–plant resistance. This study compared the efficiencies of these two methods for increasing FBR resistance of short-day onion after a single selection cycle. Asymptomatic plants or bulbs of seven onion cultivars were selected using a seedling screen performed in a growth chamber or a field screening of mature bulbs. Original and selected populations were evaluated for their responses to FBR stress thereafter employing the same two methods used for screening. The field screening of mature bulbs was found unreliable in both selection and evaluation, likely due to a non-random distribution of the FBR pathogen and variable environmental factors present in the field. The seedling screening successfully increased FBR resistance in the selected cultivar populations revealed by a seedling evaluation. From the results, it is recommended to use a consistent method for both screening and evaluation to make the most selection progress.

scholarly journals Intracultivar selection for seed quality of soybeans in an ultra-low-density selection model (Honeycomb Selection Designs)

2020 ◽  
Vol 42 ◽  
pp. e44299
Author(s):  
Karla Bianca de Almeida Lopes ◽  
Antônio Eduardo Pípolo ◽  
José Henrique Bizzarri Bazzo ◽  
Claudemir Zucareli
Keyword(s):  
Seed Quality ◽  
Seedling Emergence ◽  
Selection Model ◽  
Accelerated Ageing ◽  
High Productivity ◽  
Significant Difference ◽  
Soybean Genotypes ◽  
Honeycomb Selection ◽  
Standard Cultivar

Selecting genotypes that combine high productivity with high seed quality is a challenge. The exploration of intracultivar genetic variation is an alternative to significantly increase the annual genetic gain and maximize the selection efficiency for both characteristics. The present study aimed to identify intracultivar variation to improve the seed quality of soybean genotypes derived from the commercial cultivar BRS 284, selected using the HSD (Honeycomb Selection Designs) model. Soybean genotypes selected for two years from two environments with contrasting edaphoclimatic characteristics, according to the principles of the HSD selection model, were cultivated under competition by using the experimental model in randomized blocks with four replicates and evaluated regarding the productivity and physiological quality of seeds. The results showed that genotype 284-3 presented a greater mass of 100 seeds, germination, vigour after accelerated ageing test, seedling emergence and emergence speed index than the other genotypes in both environments, with no significant difference in the standard cultivar regarding seed yield. The HSD method was an efficient selection method to identify intracultivar variation to improve cultivar performance.

Early Plant Selection Effects on Crown Traits in Pensacola Bahiagrass with Selection Cycle

Crop Science ◽  
2003 ◽  
Vol 43 (6) ◽  
pp. 1996-1998 ◽  
Author(s):  
A. R. Blount ◽  
R. N. Gates ◽  
P. L. Pfahler ◽  
K. H. Quesenberry
Keyword(s):  
Selection Effects ◽  
Plant Selection ◽  
Selection Cycle ◽  
Crown Traits

scholarly journals Estimación de varianzas genéticas en maíz a partir de líneas S1 y S2

2016 ◽  
Vol 3 ◽  
pp. 9
Author(s):  
Félix V. Navarro ◽  
Wayne C. Youngquis ◽  
William Compton
Keyword(s):  
Genetic Variability ◽  
Inverse Method ◽  
Generalized Inverse ◽  
Selection Effect ◽  
Wide Sense ◽  
Family Selection ◽  
Additive Variance ◽  
Selection Cycle ◽  
The One ◽  
Generalized Inverse Method

The analysis of lines S-l and S-2 and the regression of the measurements of the S-2 on their corresponding S-l were used to estimate the existing genetic variability in a Nebraska Stiff Stalk Synthetic (NSS) corn population at two localities, Mead and Lincoln, Nebraska-USA. A significant genetic variability was found in NSS for grain yield, days to blooming, ear and plant height, grain humidity and lodging percentage. The S-2 lines showed more frequent interaction of genotypes x environment than their S-l. In the wide sense, the heritability for the yield calculated by the analysis of variance of S-2 lines was larger than the one based on the regression of the S-2 on S-l (60 and 42%, respectively). Eight models, originated from Cockerham (1983), were used to identify the existing types of genetic variabilities. The inverse matrix method was used to estimate the parameters of genetic variability when the used co-variances gave a non-singular square matrix. The generalized inverse method o Moore-Penrose was used when the models showed a rectangular matrix. Usually, the best model was the one which estimated the additive variance only. Often times, no consistent covariance estimates were obtained among additive and dominant homocygotic (D-1) effects. For it, we could not infer to what the S-l family selection effect could be on the behavior of the resulting line crosses. The expected genetic gain per selection cycle for yield of S-2 families was 11.4%.

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