
%0 Journal Article
%A Edye, LA 
%A Haydock, KP 
%T Breeding creeping-rooted lucerne for the subtropics
%J Australian Journal of Agricultural Research
%D 1967/12/01
%V 18
%N 6
%P 891-901
%K 
%R https://doi.org/10.1071/AR9670891
%U https://www.publish.csiro.au/paper/AR9670891 
%X A lucerne-breeding programme was undertaken at Lawes, south-eastern Queensland, to transfer the creeping-rooted habit from Heinrichs's Canadian strains to subtropical lucerne varieties. Before intensive selection commenced, the inheritance and association of three characters, summer yield, winter yield, and the number of extra crowns originating as adventitious shoots from roots, were determined in the F2 and F3 generations. The F2 genotypic variances for summer yield, winter yield, and number of extra crowns were predominantly additive and were respectively 81, 53, and 54&#37; of their phenotypic variances. The genotypic correlation coefficient for winter yield and number of extra crowns was negative ( rG = &ndash;0.18), consisting of a negative additive correlation rg = &ndash;0.55 and a positive non-additive correlation rs = 0.50. In the F3 generation the approximate genotypic correlation for these two characters was small and positive and composed of a nearly zero additive correlation and a high positive non-additive correlation. Simultaneous mass selection for summer yield, winter yield. and creeping-rootedness was undertaken in the F3 generation, and the combining ability variances and covariances for these characters were studied in the F4 generation. All three variables were positively associated in their general and specific effects, and the majority of families did not differ significantly from Hunter River in winter and summer yield. The seed production of ten F4 families was studied and it was found that eight families were significantly lower seed producers than Hunter River, their seed yields ranging from 20 to 47&#37; of the mean for Hunter River. Covariance analysis showed seed yield and number of extra crowns to be negatively associated in the F4 generation. The changes in creeping-rootedness in the successive generations F1 to F5 were 2, 9, 34, 19, and 59&#37; compared with a mean of 4&#37; for Heinrichs's Canadian strains at Lawes. Creeping-rooted individuals survived better than non-creeping-rooted plants of similar genotype and better than Hunter River, particularly in the F4 generation, where the respective survival rates were 75, 27, and 23&#37; 19 months after transplanting in the field 
