Comparison of mass selection and S1-testing recurrent selection methods in sorghum

The application to autotetraploids of the concepts of varietal value and of test value allows the derivation of expressions of genetic advance for the different types of varietal values (per se value, line value, single-cross or double-cross values, synthesizing ability) according to the testing system used to select the intercrossed plants. Formulae are given for series of intrapopulation schemes and for reciprocal recurrent selection. With autotetraploids, if non-inbred plants are intercrossed and when epistasis is not involved, there is a contribution of additive effects and of dominance effects for the considered testing systems. However, it is shown that, except for mass selection or S1 selection devoted to improve the per se value of the population, the contribution of dominance is very low. The formulae are exactly the same as for diploids if the contribution of dominance variance is neglected.Key words: autopolyploid, quantitative genetics, varietal ability, test value, recurrent selection.

Download Full-text

Gamete and recurrent selection for improving physiological resistance to white mold in common bean

Canadian Journal of Plant Science ◽

10.4141/cjps09128 ◽

2010 ◽

Vol 90 (2) ◽

pp. 153-162 ◽

Cited By ~ 11

Author(s):

H. Terán ◽

S P Singh

Keyword(s):

Common Bean ◽

Recurrent Selection ◽

Severe Disease ◽

White Mold ◽

Progeny Testing ◽

Selection Methods ◽

Evolutionary Origins ◽

Physiological Resistance ◽

Selection For ◽

Interspecific Breeding

White mold (WM) is a widely distributed and severe disease of common bean in North America. The objective of this study was to determine the effectiveness of gamete (GS) and recurrent (RS) selection methods for improving WM resistance. Two double-crosses, namely USPT-WM-1/CORNELL 601//USPT-CBB-1/92BG-7 and ‘Chas’/I 9365-25//ABL 15/A 195 were made. Equal numbers of progenies from both crosses were subjected to GS and RS. The GS was practiced from F1 to F4 by selecting WM resistant single plants followed by progeny testing in the subsequent generation. Two cycles of RS were practiced by intermating selected WM resistant plants in each cycle. Thirteen selected families in each method and parents were evaluated at 16, 23, and 33 days post first inoculation in replicated trials in two greenhouse environments. Higher frequencies of families with lower WM scores were obtained from GS than RS. The average genetic gains due to GS and RS were 19.6 and 7.9%, respectively. Employing multiple-parent-crosses involving parents of diverse evolutionary origins delayed WM evaluation, and application of GS are recommended for improving physiological WM resistance in common bean.Key words: Interspecific breeding line, introgressing resistance, multiple-parent crosses, Phaseolus vulgaris, pyramiding resistance, Sclerotinia sclerotiorum

Download Full-text

Theoretical Comparison of Recurrent Selection Methods for the Improvement of Self‐Pollinated Crops

Crop Science ◽

10.2135/cropsci1996.0011183x003600050018x ◽

1996 ◽

Vol 36 (5) ◽

pp. 1171-1180 ◽

Cited By ~ 5

Author(s):

I. Goldringer ◽

P. Brabant ◽

A. Gallais

Keyword(s):

Recurrent Selection ◽

Selection Methods ◽

Theoretical Comparison

Download Full-text

THE EFFICIENCY OF USING DOUBLED HAPLOIDS IN A RECURRENT SELECTION PROGRAM IN A DIPLOID, CROSS-FERTILIZED SPECIES

Canadian Journal of Genetics and Cytology ◽

10.1139/g78-059 ◽

1978 ◽

Vol 20 (4) ◽

pp. 505-511 ◽

Cited By ~ 13

Author(s):

T. M. Choo ◽

L. W. Kannenberg

Keyword(s):

Doubled Haploid ◽

Recurrent Selection ◽

Doubled Haploids ◽

Additive Genetic Variance ◽

Significant Loss ◽

Doubled Haploid Population ◽

Mass Selection ◽

Complete Dominance ◽

Haploid Population ◽

Selection Intensities

Mass selection in both doubled haploid and diploid populations was simulated for a 30-year period under additive and complete dominance models. The response to S1 selection was also included for the purpose of comparison. All selection programs were conducted at two selection intensities, 5% and 25%, under 0.2 heritability with a constant population size of 400. S1 lines were evaluated in 10-plant plots with four replications; use of a winter nursery was assumed. The character under selection was controlled by 20 major (A = 2) genes and 20 minor (A = 1) genes. The initial frequency of ten of the major genes and ten of the minor genes was 0.5; that of the remaining ten of each type was 0.1. The response to mass selection with doubled haploids was about 1.4 times faster than diploid mass selection and equal to S1 selection in terms of gain per year. If replicated trials were used to evaluate the doubled haploids, the rate of gain was faster than in S1 selection. The greater efficiency of using doubled haploids was due to doubling of the additive genetic variance and the elimination of dominance variance. However, significant loss of desirable genes occurred in the mass selected doubled haploid population under both the 5% and 25% selection intensities in the additive and complete dominance models.

Download Full-text