In 2004, 13 field studies were designed to address several aspects of the silage breeding and genetics program.
Advanced lines from cycles WQS C0 and C1 were crossed to four inbreds, and these topcrosses appear in trials named for the tester inbreds (HC33, LH198, LH227, and LH244).
Advanced lines from WQS C2 were crossed with the inbred testers HC33 and LH227, and these appear in trials HC33C2 and LH227C2.
The four recently-released inbred lines W601S-W604S were each crossed to HC33, LH198, LH227, and LH244, and the sixteen hybrids appear together in the trial NEWINB.
As in past years, the Germplasm Enhancement of Maize (GEM) program has provided our program promising breeding populations from Latin America. GEM lines appear in four of our trials, GEM198, GEM244, GEMADV, and GEMNEW.
We also are continuing our research with series of hybrids with different starch and endosperm characteristics that are likely to be related to starch granule packing and ruminal starch degradation. The range of endosperm characteristics extend from the o2 types with very loosely packed starch granules to densely packed flint types. We will evaluate kernel hardness, grain density, vitreousness, and related traits in trial STARCH.
The CIMSEL trial is the second year for a study evaluating two CIMMYT pools, P390 MIRT and P590, selected for borer resistance. We will measure NDF, IVTD, NDFD, and other quality traits in order to determine if selection for insect resistance in these pools has influenced nutritional quality for ruminants.
Most of the trials also included numerous checks and experimental germplasm used by the silage breeding program and the UW Corn Extension Program program directed by J.G. Lauer.
|HC33||Evaluation of 92 advanced (S4+) families from WQS C0 and C1 topcrossed to HC33.|
|LH198||Evaluation of 103 advanced (S4+) families from WQS C0 and C1 topcrossed to LH198.|
|LH227||Evaluation of 98 advanced (S4+) families from WQS C0 and C1 topcrossed to LH227.|
|LH244||Evaluation of 87 advanced (S4+) families from WQS C0 and C1 topcrossed to LH224.|
|Four-Tester C0 and C1 Summary||Mean of HC33, LH198, LH227, and LH244 topcrosses involving WQS C0 and C1 families.|
|HC33C2||Evaluation of 40 S3+ families from WQS C2 topcrossed to HC33.|
|LH227C2||Evaluation of 41 S3+ families from WQS C2 topcrossed to LH227.|
|Two-Tester C2 Summary||Mean of HC33 and LH227 topcrosses involving WQS C2 families.|
|NEWINB||Evaluation of the 16 possible hybrids involving the four recently-released inbred lines W601S-W604S crossed to HC33, LH198, LH227, and LH244.|
|GEM198||Evaluation of 48 promising S3+ GEM lines crossed to LH198.|
|GEM244||Evaluation of 49 promising S3+ GEM lines crossed to LH244.|
|GEMADV||Evaluation of promising advanced (S4+) GEM lines from breeding populations ARZM 17026:N1019, URZM13085:N0204, and SCRO1:N1310. Hybrids involve topcrosses to HC33, LH198, LH227, and LH244.|
|Two-Tester GEM Summary||Mean of LH198 and LH244 topcrosses involving GEM lines.|
|GEMNEW||Evaluation of 17 new GEM lines crossed to LH185, LH198, LH200, LH244, LH283, or LH287.|
|STARCH||Evaluation of 12 hybrids with varying kernel characteristics (formed by crossing GEM lines with varying starch properties, flint inbreds, and several checks). These will be evaluated at multiple harvest periods for several grain characteristics related to ruminal digestion.|
|CIMSEL||Evaluation of two CIMMYT pools, P390 MIRT and P590, selected for borer resistance for five and six cycles, respectively. Evaluation will involve analysis of NDF, IVTD, NDFD, and other quality traits.|