Improving Tropical Beef Cattle by Simultaneous Selection for Weight and Heat Tolerance. Heritabilities and Correlations of the Traits1

1973 ◽  
Vol 37 (3) ◽  
pp. 637-642 ◽  
Author(s):  
Roberta Gomes da Silva
Genome ◽  
1998 ◽  
Vol 41 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Ahmet Yildirim ◽  
Stephen S Jones ◽  
Timothy D Murray

The objectives of this study were to map and tag the previously undescribed eyespot resistance gene PchDv on chromosome 4V of Dasypyrum villosum in a wheat background. The 82 F2 plants used for mapping were produced from a cross between a susceptible\i wheat 'Yangmai-5' (4V(4D)) substitution line and a resistant wheat 'Chinese Spring' disomic addition line of chromosome 4V of D. villosum. Segregation for resistance and susceptibility among F2 plants was 3:1, indicating that resistance was controlled by a single dominant gene. PchDv mapped to the distal part of chromosome 4V and was bracketed by two RFLP markers, Xcdo949 and Xbcd588, in a 33-cM interval. This distance could not be reduced, owing to a lack of polymorphic loci in this region. Theoretically, double recombination in this region occurs in 3.3% of the individuals; therefore, 96.7% of the selected genotypes would have PchDv, with simultaneous selection for both flanking markers. Double recombination between the flanking markers was observed in 2 out of 82 (2.4%) F2 individuals.


2002 ◽  
Vol 138 (3) ◽  
pp. 249-253 ◽  
Author(s):  
F. MEKBIB

Phenotypic yield stability is a trait of special interest for plant breeders and farmers. This value can be quantified if genotypes are evaluated in different environments. Common bean is the main cash crop and protein source of farmers in many lowland and mid-altitude areas of Ethiopia. An experiment was undertaken to evaluate common bean genotypes for yield performance at Alemaya, Bako and Nazreth in Ethiopia for 3 years. The yield performance of genotypes was subjected to stability analysis and yield-stability statistics were generated to aid the selection of genotypes that were high yielding and very stable. The significant genotype by environment interaction indicated that the relative performance of the varieties altered in the different environments. Genotype yield performance varied ranging from 1511–2216 kg/ha. Simultaneous selection for yield and yield-stability statistics using YS(i) statistics indicated that A 410, GLP x92, Mx-2500-19, G 2816, A-195, 997-CH-1173, Diacol calima, ICA 15541 and AND 635 were both high yielding and stable. Following this study, using farmers’ evaluation and other criteria, GLP x92 and G-2816 were identified as preferred genotypes and were released for further production.


Heredity ◽  
1965 ◽  
Vol 20 (1) ◽  
pp. 142-144 ◽  
Author(s):  
J W James

2009 ◽  
Vol 54 (6) ◽  
pp. 617-627 ◽  
Author(s):  
J. B. Gaughan ◽  
T. L. Mader ◽  
S. M. Holt ◽  
M. L. Sullivan ◽  
G. L. Hahn
Keyword(s):  

2009 ◽  
Vol 87 (10) ◽  
pp. 3089-3096 ◽  
Author(s):  
L. M. Melucci ◽  
A. N. Birchmeier ◽  
E. P. Cappa ◽  
R. J. C. Cantet

1969 ◽  
Vol 20 (6) ◽  
pp. 1177 ◽  
Author(s):  
T Nay ◽  
RH Hayman

Phenotypic correlations between body weight, follicle characters, and fleece characters have been investigated in a flock of 95 fine-wool non-Peppin Merino wethers, reared in the same locality under the same conditions. The results indicated that three follicle characters, follicle chord, follicle depth, and the index of follicle bending, were independent of body weight. It was found, in agreement with the results of other workers, that body weight was highly correlated with both greasy and clean wool weights (r = 0.53 and 0.51 respectively). It was also found that follicle characters were significantly correlated with most of the fleece characters which contribute to the clean fleece weight per unit area of skin. The correlation coefficient of wool weight per unit area of skin with follicle chord was 0.33, with follicle depth 0.28, and with follicle bending index –0.35. The follicle characters were also correlated with greasy and clean fleece weights. Crimp number per inch was predicted for individual animals by using as criterion the length of the follicle chord. A highly significant correlation coefficient of 0.67 was obtained between predicted and observed crimp number. The close relationship between crimp chord and follicle chord reported in previous work was confirmed. It is suggested that simultaneous selection for body weight and certain follicle characters may have an additive effect on the production of clean wool. It is also suggested that the genetic antagonism between clean wool weight and number of crimps per inch can be explained in anatomical terms.


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