Date of this Version
Thesis (M.S.)—University of Nebraska—Lincoln, 1948. Department of Agronomy.
The primary objective of this study was to compare actual performance of double crosses of corn with their predicted performance from single cross data for the same and for different seasons.
Ten single crosses involving all possible combinations of the inbred lines B3, N6, Wf9, O28, and Hy were grown for prediction purposes in 1947. Thirty-six of the higher yielding double crosses which could be predicted from the 1944 U.S.D.A. Uniform Midseason Single Cross tests were also grown.These double crosses included thirteen of the fifteen possible double crosses among the ten single crosses grown for prediction in 1947 and referred to above.A mean of the non-parental single crosses was used to predict double cross performance.Characters measured were grain yield, moisture at harvest, days from planting to silking, plant height and ear height.
A highly significant negative correlation between 1944 predicted and 147 actual yields was obtained.Highly significant r values were obtained when moisture at harvest, days from planting to silking, plant height and ear height were compared for the two years.
In 1944 predicted hybrids of later maturity were highest in yield while early maturity was associated with high yield in 1947.
When 1947 predicated and actual performance were compared, positive but non-significant r values were obtained for all characters.Only 13 double crosses, whose predicted yields were from 72.9 to 76.9 bushels per acre were included in this particular comparison.In such a small sample consisting of hybrids very nearly alike in expected yielding ability, small differences between predicted and actual performance would produce r values which were non-significant.
Advisor: F. D. Keim