2003 Trials – List

WQS | CUBAGEM A | GEM B

WQS (2003)

WQS C2 topcrosses were evaluated at two locations in 2003, Madison and Arlington. The 231 entries consisted of 226 WQS C1 S2 families crossed to HC33 and five check hybrids. There were three replications at each location.

Planting dates were May 16 (Madison) and May 26 (Arlington). The average planting densities were 32,900 plants/acre at Madison, and 32,200 plants/acre at Arlington. Early-season moisture was more than adequate. Dry conditions during pollination and several weeks thereafter reduced yield potential at Madison, and the trial was harvested on September 9. The Arlington trial was also damaged slightly by drought, but the plots were in relatively good condition by harvest, which occurred on September 24.

Ninety-five WQS topcrosses were initially chosen, based on forage yield, for nutritional evaluation. (See WQS – Forage yield evaluation.) Nutritional evaluations included assessment of neutral detergent fiber (NDF), in vitro true digestibility (IVD), in vitro NDF digestibility (IVNDFD), crude protein (CP), and starch concentration. Based on these values, milk/ton of forage and milk/acre were estimated based on MILK2000, which uses forage composition (NDF, IVD, IVNDFD, CP, and starch) to estimate potential milk production per ton of forage. Forage yield is then used to estimate potential milk per acre.

Twenty S2 families from WQS C2 were selected based on superior yield and milk production potential. (See WQS – Nutritional evaluation.) The families were recombined in the 2003/2004 winter nursery in Puerto Rico to form WQS C3 from which a new set of inbreds will be derived. In addition, approximately 80 S5 inbred families related to the 20 S2 selected families were topcrossed to HC33 and LH227 in the 2003/20004 winter nursery for field and quality evaluations, which will occur during the summer of 2004.

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CUBA (2003)

One-hundred-sixty-nine topcrosses to LH279 and 5 check hybrids were evaluated at two locations in 2003, Madison and Arlington. There were three replications at each location. Planting dates were May 16 (Madison) and June 2 (Arlington). The average planting densities were 31,600 plants/acre at Madison, and 32,700 plants/acre at Arlington. Early-season moisture was more than adequate. Dry conditions during pollination and several weeks thereafter reduced yield potential at Madison, but the trial was in moderate-to-good shape by harvest (September 10). The Arlington trial was damaged slightly by drought and also experienced some root lodging. A killing frost occurred prior to harvest (October 9). The combination of drought stress at Madison and killing frost at Arlington led to high average dry matter at harvest (45-47%).

Ninety-five CUBA topcrosses were initially chosen, based on forage yield and root lodging, for nutritional evaluation. (See CUBA – Forage yield evaluation.) Nutritional evaluations included assessment of neutral detergent fiber (NDF), in vitro true digestibility (IVD), in vitro NDF digestibility (IVNDFD), crude protein (CP), and starch concentration. Based on these values, milk/ton of forage and milk/acre were estimated based on MILK2000, which uses forage composition (NDF, IVD, IVNDFD, CP, and starch) to estimate potential milk production per ton of forage. Forage yield is then used to estimate potential milk per acre.

Twenty families were selected based on superior yield and milk production potential. (See CUBA – Nutritional evaluation.) The families will be recombined in the 2004 summer nursery, and the resulting population will be designated as the GEM Quality Composite (GQS) C0.

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GEM A (2003)

The GEM A trial consisted of the ongoing silage evaluation of elite GEM topcrosses that were identified in the past year as having high grain yield and suitable maturity (<120RM) for Wisconsin. There were 36 entries in GEM A involving breeding populations or early-generation GEM inbreds topcrossed to HC33, LH185, LH198, LH247, and LH283.

GEMA was planted at two WI locations, Madison (May 16) and Arlington (June 2), with three replications at each location. The average planting densities were 32,500 plants/acre (Madison) and 31,600 plants/acre (Arlington). Early-season moisture was more than adequate. Dry conditions during pollination and several weeks thereafter reduced yield potential at Madison, but the trial was in moderate-to-good shape by harvest (September 12). The Arlington trial was damaged slightly by drought and also experienced some root lodging. A killing frost occurred prior to harvest (October 5-6). The combination of drought stress at Madison and killing frost at Arlington led to high average dry matter at harvest (40-42%).

Quality evaluation included assessment of neutral detergent fiber (NDF), in vitro true digestibility (IVD), in vitro NDF digestibility (IVNDFD), crude protein (CP), and starch concentration. Based on these values, milk/ton of forage and milk/acre were estimated based on the MILK2000 equations developed by the UW Agronomy and Dairy Science Departments. MILK2000 uses forage composition (NDF, IVD, IVNDFD, CP, and starch) to estimate potential milk production per ton of forage. Forage yield is then used to estimate potential milk per acre.

GEM A Highlights

Two topcrosses had predicted milk yields greater than 34,000 lbs/acre milk/acre (see GEMA Evaluation – Forage yield and quality). Most of this potential was due to high forage yield, e.g., DK212T:N11a12-122-1 X HC33. However, one topcross, BR52051:N04-76-1 X LH198, also had excellent quality (low NDF, high IVD, high NDFD, and high milk/ton). Several of the entries in the GEMA trial were also evaluated in 2002 (2002 GEMA). Inbred bulks from BR52051:N04-76-1 and related lines were selfed and topcrossed in the 2003 summer nursery.

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GEM B (2003)

The GEM B trial consisted of 13 GEM inbreds topcrossed to HC33. The inbreds involved in the GEM B trial were developed by the UW silage breeding program and were chosen based on topcross silage evaluations in previous years.

GEMB was planted at two WI locations, Madison (May 16) and Arlington (June 2), with two replications at each location. The average planting densities were 32,500 plants/acre (Madison) and 31,600 plants/acre (Arlington). Early-season moisture was more than adequate. Dry conditions during pollination and several weeks thereafter reduced yield potential at Madison, but the trial was in moderate-to-good shape by harvest (September 12). The Arlington trial was damaged slightly by drought and also experienced some root lodging. A killing frost occurred prior to harvest (October 5-6). The combination of drought stress at Madison and killing frost at Arlington led to high average dry matter at harvest (45-47%).

Quality evaluation included assessment of neutral detergent fiber (NDF), in vitro true digestibility (IVD), in vitro NDF digestibility (IVNDFD), crude protein (CP), and starch concentration. Based on these values, milk/ton of forage and milk/acre were estimated based on the MILK2000 equations developed by the UW Agronomy and Dairy Science Departments. MILK2000 uses forage composition (NDF, IVD, IVNDFD, CP, and starch) to estimate potential milk production per ton of forage. Forage yield is then used to estimate potential milk per acre.

GEM B Highlights

One topcross, AR17026:N1019-65008-2-3-2-1 X HC33, in the GEM B trial had high silage production potential based on milk/acre (see GEMB Evaluation – Forage yield and quality). This topcross had high forage yield and average milk/ton. The low NDF value indicates that this topcross may have excellent intake potential. This topcross was also entered in the UW corn performance trials conducted by the UW Corn Extension program. In the southern zone (Arlington, Lancaster) late-maturity trial, AR17026:N1019-65008-2-3-2-1 X HC33 was statistically equivalent to the best hybrid in the trial for forage yield and milk/acre. This topcross is designated “JC11” in the report, which can be accessed via http://corn.agronomy.wisc.edu. We will consider formal release of AR17026:N1019-65008-2-3-2-1 in the near future.

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