Combining ability analyses of stability parameters and forage yield in smooth bromegrass

1980 ◽  
Vol 57 (4) ◽  
pp. 71-74 ◽  
Author(s):  
W. -K. Tan ◽  
G. -Y. Tan
1979 ◽  
Vol 21 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Wai-Koon Tan ◽  
Geok-Yong Tan ◽  
P. D. Walton

The parents and progenies of a 7 × 7 diallel cross of smooth bromegrass (Bromus inermis Leyss.) were evaluated for the genetic variability of some morphological characters and their associations with yield, at four locations in Alberta in 1976 and 1977. Locations, years and their interactions were highly significant for all characters and were subsequently treated as eight environments. The partition of the genotypic variance into general combining ability (GCA) and specific combining ability (SCA) showed that for all morphological characters, GCA was more important than SCA, indicating the importance of additive genetic effects. The genotype × environment (GE) interactions were highly significant. Variation accounted for by GCA was generally higher than the interaction effects of GCA and SCA with environments. Phenotypic and genotypic correlation coefficients revealed that both tiller density and height were significantly correlated with yields. Path coefficient analysis also showed that tiller density, followed by leaf area and tiller dry weight, exerted the greatest direct influence on yield. Selection for large leaf area and more and heavier tillers per unit area would simultaneously increase bromegrass productivity. Furthermore, selection should be based on multi-year and multi-location tests.


2007 ◽  
Vol 58 (11) ◽  
pp. 1100 ◽  
Author(s):  
E. Piano ◽  
P. Annicchiarico ◽  
M. Romani ◽  
L. Pecetti

Finding the optimal parent number for synthetic varieties has a crucial importance in forage breeding. The objective of this work was exploring this number for Mediterranean tall fescue selected for forage yield. The general (GCA) and specific (SCA) combining ability of parents, and their effects on the performance and the inbreeding depression of synthetics, were also assessed. The full-sib families from the diallel cross of 20 genotypes chosen from well performing populations were evaluated for fresh biomass over 13 harvests in Sanluri (Sardinia, Italy). The Syn 1 and Syn 2 of 15 synthetics varying in parent number (4, 8, 12, 16 or 20) and, within same number, in mean GCA of parents were evaluated for dry matter yield over 11 harvests in Lodi (northern Italy) in a greenhouse simulating the temperature pattern of a Mediterranean environment. The yield responses of Syn 2 synthetics with 2 to 20 parents with highest mean GCA were predicted from yield values of S1 and F1 progenies, also evaluated in Lodi. The variance of GCA effects was almost 2-fold larger than that of SCA effects. The observed vigour loss from Syn 1 to Syn 2 of the 4-parent synthetics (−6%) tended to be greater than those of higher parent number groups. The 4-parent synthetics with larger SCA effects tended to greater inbreeding depression. The comparison among synthetics with different parent number and highest GCA of their parents indicated the superiority of the 4-parent synthetic over any other in both generations (P < 0.05). The predicted yield response was maximised by the 3-parent synthetic. The results and other considerations suggest adoption of 4- to 6-parent synthetics.


1999 ◽  
Vol 22 (3) ◽  
pp. 451-456 ◽  
Author(s):  
Cleso Antônio Patto Pacheco ◽  
Cosme Damião Cruz ◽  
Manoel Xavier dos Santos

The objective of the present work was to provide a methodology to study the inheritance of adaptability and stability through the breakdown of Eberhart and Russell regression coefficients and regression deviations in effects due to the mean and additive genetic effects (gi's and gj's) as well as dominance effects (sij's) of Griffing´s methodology, when the diallel is conducted in several environments. It was concluded that the adaptability and stability parameters are determined in the same manner as are genetic effects. So an F1 cross inherits half the general combining ability (GCA) mean effect from each parent, while the effects due to specific combining ability (SCA) are subjected to the same considerations relative to sij's, i.e., they are dependent on specific combinations.


1979 ◽  
Vol 21 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Wai-Koon Tan ◽  
Geok-Yong Tan ◽  
P. D. Walton

Twenty-one progenies and the parents of a 7 × 7 half diallel cross of smooth bromegrass (Bromus inermis Leyss.) were evaluated at four locations in Alberta in each of two years, for genetic variation and genetic by environment interactions in the expression of their yield potentials. Years, locations and their interactions were highly significant in the combined analysis of variance. Combining ability analysis revealed that general combining ability (GCA) and specific combining ability (SCA) were both important in the expression of yield, including spring, fall and annual yield, whereas GCA was more important than SCA for yield per area. Although the genotype × environment interactions were all highly significant, variation accounted for by combining ability effects was generally higher than the interaction effects of GCA and SCA respectively, with environments. High average GCA effects for spring, fall and annual yield were demonstrated for the clones UA5, UA9 and B42. These together with the high average SCA effects suggested that the three clones could be included in a synthetic to develop high yielding cultivars. The results suggested that recurrent selections involving multi-location and multi-year testing seems necessary in breeding for high yielding bromegrass cultivars in Alberta.


2014 ◽  
Vol 16 (1) ◽  
pp. 78
Author(s):  
Mushtaq Ahmad ◽  
Gul Zaffar ◽  
Z.A. Dar ◽  
S.M. Razvi ◽  
Asif Shikari ◽  
...  

Crop Science ◽  
2005 ◽  
Vol 45 (1) ◽  
pp. cropsci2005.0044 ◽  
Author(s):  
M. D. Casler ◽  
M. Diaby ◽  
C. Stendal

Euphytica ◽  
2019 ◽  
Vol 215 (10) ◽  
Author(s):  
Fatemeh Saeidnia ◽  
Mohammad Mahdi Majidi ◽  
Aghafakhr Mirlohi ◽  
Sajed Bahrami

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