Author: Roger Alan Weyhrich
Publisher:
ISBN:
Category :
Languages : en
Pages : 272
Book Description
This was in agreement with theory but not with several previous studies of this nature. Effective population size comparisons showed that intermating less than ten individuals resulted in significant inbreeding depression in the populations per se. Intermating 10-30 individuals resulted in the same responses to selection. The effects of genetic drift were apparent in the responses for all selection methods. In general, the estimates of genetic drift were opposite in sign to that of the direction of selection.
Analysis of Responses to Recurrent Selection in the BS11 Maize Population
Author: Roger Alan Weyhrich
Publisher:
ISBN:
Category :
Languages : en
Pages : 272
Book Description
This was in agreement with theory but not with several previous studies of this nature. Effective population size comparisons showed that intermating less than ten individuals resulted in significant inbreeding depression in the populations per se. Intermating 10-30 individuals resulted in the same responses to selection. The effects of genetic drift were apparent in the responses for all selection methods. In general, the estimates of genetic drift were opposite in sign to that of the direction of selection.
Publisher:
ISBN:
Category :
Languages : en
Pages : 272
Book Description
This was in agreement with theory but not with several previous studies of this nature. Effective population size comparisons showed that intermating less than ten individuals resulted in significant inbreeding depression in the populations per se. Intermating 10-30 individuals resulted in the same responses to selection. The effects of genetic drift were apparent in the responses for all selection methods. In general, the estimates of genetic drift were opposite in sign to that of the direction of selection.
Response to S1 Recurrent Selection and Estimation of Genetic Parameters in Effective Population Sizes of the BS11 Maize Population
Author: Kebede Mulatu Ponta
Publisher:
ISBN:
Category :
Languages : en
Pages : 408
Book Description
The S1 selection increased yield in 10-S1, 20-S1, and 30-S1 due to favorable additive effects. In BS11C0 population both additive and dominance genetic effects were responsible for grain yield; however, the additive effect was greater than the dominance effect. Larger effective sizes (20-S1, 30-S1) had loci with more favorable additive effects and showed better response to selection than the smaller effective sizes (5-S1, 10-S1). The inbreeding depression effects were significant in all the populations as the result of genetic drift. Grain moisture, root lodging, stalk lodging, and all other correlated agronomic traits were improved in the desired direction. Direct and indirect responses were more favorable in the larger effective population sizes than in the smaller. The results suggest that effective size of 30 is preferable for recurrent selection programs planned for at least ten or more years.
Publisher:
ISBN:
Category :
Languages : en
Pages : 408
Book Description
The S1 selection increased yield in 10-S1, 20-S1, and 30-S1 due to favorable additive effects. In BS11C0 population both additive and dominance genetic effects were responsible for grain yield; however, the additive effect was greater than the dominance effect. Larger effective sizes (20-S1, 30-S1) had loci with more favorable additive effects and showed better response to selection than the smaller effective sizes (5-S1, 10-S1). The inbreeding depression effects were significant in all the populations as the result of genetic drift. Grain moisture, root lodging, stalk lodging, and all other correlated agronomic traits were improved in the desired direction. Direct and indirect responses were more favorable in the larger effective population sizes than in the smaller. The results suggest that effective size of 30 is preferable for recurrent selection programs planned for at least ten or more years.
Response to Thirteen Cycles of Reciprocal Full Sib Recurrent Selection in the BS10 and BS11 Maize (Zea Mays L.) Populations
Author: Benjamin Aaron Ford
Publisher:
ISBN:
Category :
Languages : en
Pages : 374
Book Description
Increases in grain yield, the primary trait for selection, include a direct response of 2.2 percent per cycle in the population cross, and indirect responses of 3.3 and 1.2 percent per cycle in BS10 and BS11, respectively, but only the response for BS11 fits a linear model. Linear trends through the first nine selection cycles, however, indicate a 4.6 percent per cycle increase for the population cross, as well as increases of 1.6 percent in BS10 and 1.6 percent in BS11 parent populations. Evaluations of random S1 line performance for BS10CO, BS10C13, BS11CO, and BS11C13 indicate decreasing trends in genetic variability over 13 cycles of FR. Exceptions are grain yield in BS10 and BS11 and plant height in BS11. While genetic variance estimates for grain yield are nearly equal for BS11CO and BS11C13, a nearly significant increase in variability is evident from BS10CO to BS10C13. Variability estimates suggest FR for grain yield in BS10 and BS11 will be effective in future selection cycles.
Publisher:
ISBN:
Category :
Languages : en
Pages : 374
Book Description
Increases in grain yield, the primary trait for selection, include a direct response of 2.2 percent per cycle in the population cross, and indirect responses of 3.3 and 1.2 percent per cycle in BS10 and BS11, respectively, but only the response for BS11 fits a linear model. Linear trends through the first nine selection cycles, however, indicate a 4.6 percent per cycle increase for the population cross, as well as increases of 1.6 percent in BS10 and 1.6 percent in BS11 parent populations. Evaluations of random S1 line performance for BS10CO, BS10C13, BS11CO, and BS11C13 indicate decreasing trends in genetic variability over 13 cycles of FR. Exceptions are grain yield in BS10 and BS11 and plant height in BS11. While genetic variance estimates for grain yield are nearly equal for BS11CO and BS11C13, a nearly significant increase in variability is evident from BS10CO to BS10C13. Variability estimates suggest FR for grain yield in BS10 and BS11 will be effective in future selection cycles.
Effective Population Size, Genetic Variability, and Gains from Recurrent Selection in the BS11 Maize Population
Author: Peter S. Guzman
Publisher:
ISBN:
Category :
Languages : en
Pages : 230
Book Description
Although the predicted gain cycle-' for a trait in a recurrent selection method increased with increasing effective population size, differences among the predicted values were agronomically insignificant. The comparison between the predicted gains and the realized gains obtained in a related study revealed that intermating greater number of individuals would not result in a significant response over a few cycles of selection. Based on the results of the study, I conclude that there is no distinct advantage of using larger effective population size to maintain genetic variability and to realize gain in a short-term maize recurrent selection program.
Publisher:
ISBN:
Category :
Languages : en
Pages : 230
Book Description
Although the predicted gain cycle-' for a trait in a recurrent selection method increased with increasing effective population size, differences among the predicted values were agronomically insignificant. The comparison between the predicted gains and the realized gains obtained in a related study revealed that intermating greater number of individuals would not result in a significant response over a few cycles of selection. Based on the results of the study, I conclude that there is no distinct advantage of using larger effective population size to maintain genetic variability and to realize gain in a short-term maize recurrent selection program.
Evaluation of Recurrent Selection for Combining Ability Between Two Partitioned Populations in Maize
Author: Gregory John Holland
Publisher:
ISBN:
Category :
Languages : en
Pages : 238
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 238
Book Description
Response to Eight Cycles of Full-sib Reciprocal Recurrent Selection for Grain Yield and Standability in BS10 and BS11 Maize Populations
Author: Guillermo Hugo Eyherabide
Publisher:
ISBN:
Category :
Languages : en
Pages : 290
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 290
Book Description
Direct and Correlated Responses to Recurrent Selection for Grain Yield in Maize Breeding Populations
Author: Morakinyo Abiodun Bamidele Fakorede
Publisher:
ISBN:
Category :
Languages : en
Pages : 678
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 678
Book Description
Response to Full-sib Reciprocal Recurrent Selection in a Double-cross Maize Population
Author: Eduardo J. Graterol M.
Publisher:
ISBN:
Category :
Languages : en
Pages : 128
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 128
Book Description
Direct and Correlated Response to Recurrent Selection for Grain Yield in Maize Breeding Populations
Author: M.A.B. Fakorede
Publisher:
ISBN:
Category :
Languages : en
Pages : 326
Book Description
Dr. G. F. Sprague initiated recurrent selection programs during the 1940' and 1950' to improve the grain-yield performance of several maize (Zea mays L.) population at the Iowa Agriculture and Home Economics Experiments Station. Seven cycles of reciprocal recurrent selections (RRS) in Iowa Stiff Stalk Synthetic (BSSS) and Iowa Corn Borer Synthetic #1 (BSCB1), and six cycles of recurrent half-sib selection (HS) in the open-pollinated variety 'Alph'(i.e., BS12) have been completed. Inbred B14 was the tester in the HS program. My objectives were to (1) evaluate progress that resulted from the RRS and HS programs and (2) evaluate changes in several other traits associated with recurrent selection for grain yield. I evaluated the CO x CO, C5, and C7 x C7 of the RRS program, and CO and C6 of the HS program, each testcrossed to B14A. Estimated gain from seven cycles of RRS was 2.06 q/ha (or 5.21%) per cycle and observed difference in mean yield between CO and C6 of the program was 2.25 q/ha (or 6.00%) per cycle. Improved hybrids outyield their unimproved counterparts at all levels of nitrogen (0, 90, 180, and 270 kg N/ha) and plant density (39,000; 59,300; 79,000; and 98,800 plants/ha) investigated. Each hybrid displayed a positive, curvilinear response to nitrogen and a negative, linear response to plant density. Stability and adaptation-reaction analysis revealed that improved hybrids consistently demonstrated greater adaptation to high-nitrogen environments, but their unimproved counterparts did not take (...).
Publisher:
ISBN:
Category :
Languages : en
Pages : 326
Book Description
Dr. G. F. Sprague initiated recurrent selection programs during the 1940' and 1950' to improve the grain-yield performance of several maize (Zea mays L.) population at the Iowa Agriculture and Home Economics Experiments Station. Seven cycles of reciprocal recurrent selections (RRS) in Iowa Stiff Stalk Synthetic (BSSS) and Iowa Corn Borer Synthetic #1 (BSCB1), and six cycles of recurrent half-sib selection (HS) in the open-pollinated variety 'Alph'(i.e., BS12) have been completed. Inbred B14 was the tester in the HS program. My objectives were to (1) evaluate progress that resulted from the RRS and HS programs and (2) evaluate changes in several other traits associated with recurrent selection for grain yield. I evaluated the CO x CO, C5, and C7 x C7 of the RRS program, and CO and C6 of the HS program, each testcrossed to B14A. Estimated gain from seven cycles of RRS was 2.06 q/ha (or 5.21%) per cycle and observed difference in mean yield between CO and C6 of the program was 2.25 q/ha (or 6.00%) per cycle. Improved hybrids outyield their unimproved counterparts at all levels of nitrogen (0, 90, 180, and 270 kg N/ha) and plant density (39,000; 59,300; 79,000; and 98,800 plants/ha) investigated. Each hybrid displayed a positive, curvilinear response to nitrogen and a negative, linear response to plant density. Stability and adaptation-reaction analysis revealed that improved hybrids consistently demonstrated greater adaptation to high-nitrogen environments, but their unimproved counterparts did not take (...).
Evaluation of Visual S1 Recurrent Selection for Early Vigor in Maize
Author: Daryl Keith Hexum
Publisher:
ISBN:
Category :
Languages : en
Pages : 132
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 132
Book Description