Combining Ability of S1 and Derived S3 Lines of Corn¹

Effect of Visual Selection During Inbreeding Upon Combining Ability in Corn1

“…I N THE corn breeding literature presently available there is considerable difference of opinion regarding the value of visual selection during successive generations of inbreeding for modifying combining ability in subsequent hybrid combinations. Unpublished data from the Mexican Agricultural Program of The Rockefeller Foundation 3 indicated that selfing of sl lines accompanied by visual selection during each generation was of little or no practical value towards modifying combining abi.lity in specific hybrid combinations when the lines involved were from local varieties specifically well adapted to the conditions under which the inbreeding and testing were done. However, since there were only a few crosses in the Local X Local classification, two additional experiments were designed, from which data were obtained in 1952 and 1955.…”

Estimation of mass selection parameters from a heterogeneous oat population

“…Visual selection for re sistance to stalk breakage was effective in one experiment. Gains in com bining ability from visual selection practiced by Wellhausen and Wortman (1954) were present only when the maize lines were tested in hybrid com bination in the selection environment. When Russell and Teich (1967) tested visually-selected n#i^e lines at high planting rates, those selected from populations grown at high plant densities were superior in yield to lines selected from populations grown at low plant densities.…”

Characterization of maize inbreds in testcrosses for plant and ear characters and yield at varying plant densities and effectiveness of selection in successive generations of inbred progenies for improvement of hybrid yields

“…Because very little change in combining ability was observed across gener ations, they concluded that visual selection during inbreeding had no effect on general combining ability. Wellhausen and Wortman (1954) Field data were obtained on ear and plant appearance and yield. The single crosses x generations interaction was highly significant in 1951 and 1955, indicating that in these two years at least some of the single crosses differed in performance as the lines involved varied in degree of inbreeding.…”