CÓRDOBA NATIONAL UNIVERSITY
College of Agriculture, P.O. Box 509, 5000 Córdoba, Argentina.
S.P. Gil, C.S. Perrone, M.M. Cerana, and R.H. Maich.
We are analyzing eight cycles of recurrent selection in bread wheat, C0 (initial) C1, C2, C3, C4, C5, C6, and C7 (intermediate); and C8 (advanced) cycles. Plants were grown in the semiarid conditions of the central region of Argentina, at the Experimental Farm of the College of Agriculture in Córdoba (31°29°S and 64°00°W) during 2005. Five main shoot spikes divided in thirds (lower third: spikelets 4 and 5; middle third: spikelets 9 and 10; and upper third: subterminal) from each of the S-derived families/population were studied. Data were evaluated with ANOVA and Duncan's Multiple Range Test (p < 0.05).
The results did not show significant differences between cycles, although the more advance C8 cycle presented a lot of floral primordia and fertile florets in the lower third.
M. N. Casanova, V. Davidenco, and R. H. Maich.
Changes in agronomic characteristics were measured after eight cycles of a recurrent selection program. Forty-five S1-derived families (five/cycle) were grown during 2006 under the rainfed conditions of the central semiarid region of Argentina. A significant positive linear regression between the grain number/spike and cycles of recurrent selection was observed. Several workers have found positive associations between grain number/spike and grain number/m2, the principal grain yield component. After eight cycles of a recurrent selection program in bread wheat conducted in the central semiarid region of Argentina, genetic progress for grain yield begins to be observed.