February 5, 2007

TO:                  NDSU Research Foundation, Agronomy Chairmen and Corn Breeders, North Central Region, and Hybrid Corn Seed Producers

The Director of the North Dakota Agricultural Experiment Station announces the release of three improved yellow dent populations developed in our corn breeding program.

NDBSK(HI-M)C3 is an earlier version of BSK(HI)C11 developed and improved at Iowa State University (ISU) from the Krug Yellow Dent variety. It is released as an improved early maturing germplasm source for development of inbred parents for early maturing, high quality, and high yielding corn hybrids. This improved population was consistently the best North Dakota improved population for grain yield performance per se even though it was 6.9% less grain moisture at harvest than the original improved version brought to North Dakota.

NDBS11(FR-M)C3 is an earlier version of BS11(FR)C13 developed and improved at ISU. It is released as an improved germplasm source for development of inbred parents for early maturity and high yielding corn hybrids; and as an elite parent for early maturing maize population hybrids. This improved population was consistently the best ND improved population for grain moisture at harvest per se of all newly adapted populations (8.5% less moisture tan the original improved version.

NDBS1011 is a cross between BS10(FR)C13 and BS11(FR)C13, both developed and improved at ISU by reciprocal full-sib recurrent selection. The original cross was made at North Dakota State University and later improved for adaptation to ND.

Hand pollinated germplasm lots of 200 kernels are available from M. J. Carena, Department of Plant Sciences, North Dakota State University, Fargo, North Dakota, 58105. Germplasm lots cost $500 each, but one set of germplasm lots will be supplied at no cost to breeders from public institutions.

Registration of NDSAB(MER-FS)C13 Maize Germplasm

NDSAB(MER-FS)C13 is yellow-dent maize (Zea mays L.) population (Reg. No. GP-399, PI 636493) that was developed at the North Dakota Agricultural Experiment Station, North Dakota State University (NDSU), Fargo, ND as a result of long-term germplasm improvement. NDSAB(MER-FS)C13 was released 13 December 2004 for breeding programs developing elite germplasm for short-growing-season areas. NDSAB(MER-FS)C13 was recommended for release due to its unique performance per se, in hybrid combination, and as source of outstanding inbred lines. It is an improved germplasm source for development of inbred parents for early maturing, high quality, and high yielding corn hybrids.

NDSAB(MER-FS)C13 was developed from NDSAB (GP-125, Cross, 1983) by twelve cycles of modified ear-to-row selection (Carena and Cross, 2003) and one cycle of full-sib recurrent selection (Carena, 2005). For modified ear-to-row selection (Lonnquist, 1964), the proportion of half-sib families selected was 33 % each cycle, and selection within families was approximately 15 % each cycle. Three ND environments were used to evaluate 60 half-sib families. A rank-summation index identified 20 superior families each cycle. The index gave grain yield a 40 % weight, while low grain moisture at harvest, low stalk lodging percentage, and low root lodging percentage were each weighted 20 %. Three ears were selected from a crossing block at Fargo within each of the 20 superior families by selection for stalk lodging resistance and large ear size. Selection was performed at a plant density of 50,000 plants per hectare. For full-sib recurrent selection, the proportion of full-sib families selected was 8 %. Four ND environments were used to evaluate 196 full-sib families in 2001. Sixteen families were recombined based on a heritability index that included grain yield, grain moisture at harvest, root lodging, and stalk lodging. A bulk-entry method of recombination was used to intermate selected families in the winter of 2001-2002. Selection was performed at a plant density of 60,000 plants per hectare. Paired rows were used to obtain population hybrid seed in 2002. Crosses were made using each male parent to pollinate no more than one ear shoot. The ears obtained were harvested, dried and shelled individually, and two balanced bulks were obtained for future experimentation.

NDSAB(MER-FS)C13 was identified after testing the population per se in trials across 15 environments in 2002, 2003, and 2004. Environments included mostly eastern ND environments. Hybrid combinations of NDSAB(MER-FS)C13 were tested across 10 eastern and western ND environments in 2003 and 2004. Commercial-check hybrids were included in these trials (2 to 5). NDSAB(MER-FS)C13 (6.3 t ha^-1, 10.9 %, 661 g kg^-1) was top performer of all populations and significantly (P< 0.05) different from unreleased experimental NDSAB(MER)C12 (5.6 t ha^-1, 17.1 %, 660 g kg^-1) for grain yield, stalk lodging resistance, and starch content, respectively. It also tended to be drier at harvest (17.8 % vs. 19.2 %) with higher grain protein content (98 g kg^-1 vs. 96 g kg^-1), and lower oil content (42 g kg^-1 vs. 44 g kg^-1). Evaluation was performed at a plant density of 75,000 plants per hectare. With respect to NDSABC0, response to half-sib progeny selection increased (P< 0.05) grain yield (5.9 % cycle^-1) and reduced (P< 0.01) stalk lodging in NDSAB(MER) after 12 cycles of modified ear-to-row selection at 50,000 plants ha^-1 (Carena and Cross, 2003).

Population hybrids including NDSAB(MER-FS)C13 were not statistically different from the top commercial check (Pioneer 39D82) for grain yield performance and root and stalk lodging percentages. Therefore, this population hybrid is not only an elite source for inbred line development but also a potential alternative to commercial hybrids for dryland agriculture in North Dakota.

NDSAB(MER-FS)C13 seems to differ from the traditional heterotic groups (BSSS and Lancaster). However, it showed good combining ability with BS21(R)C7, an improved population that behaves as BSSS. The population hybrid NDSAB(MER-FS)C13 x BS21(R)C7 was the top public entry for starch content (665 g kg^-1), value that was not statistically different from Pioneer 39D82 (668 g kg^-1) but was higher than Hyland 2305 (654 g kg^-1).

Early generation testing of NDSAB(MER-FS)C13 derived S₀ and S₁ lines have shown good combining ability with single-cross unrelated tester LH176 x LH177 with higher grain yield performance and test weight, lower grain moisture at harvest, and similar lodging resistance than all checks (Pioneer 39D82, Wensman 5048Bt, and DKC35-51).

NDSAB(MER-FS)C13 is a vigorous improved population with above average emergence percentage in cold soils. NDSAB(MER-FS)C13 typically produces medium-tall plants with medium ears. Each plant develops an average of one ear per plant. Therefore, we suggest the use of inbred progenies for reciprocal recurrent selection programs. NDSAB(MER-FS)C13 is similar in days to flowering to Pioneer 39D82 in Fargo, ND and is earlier than previous NDSAB versions (AES 200 maturity).

Breeder seed will be maintained by the North Dakota Agricultural Experiment Station and distributed in lots of 200 kernels upon request from the corresponding author, Plant Sciences Department, North Dakota State University, Fargo, ND 58105. Signed material transfer agreements will be required by the North Dakota Research Foundation before seed can be shipped. One set of germplasm lot will be supplied at no cost to breeders from public institutions.

M.J. Carena* and D.D. Wanner

References

Carena, M.J. 2005. Maize commercial hybrids compared to improved population hybrids for grain yield and agronomic performance. Accepted in Euphytica.

Carena, M.J. and H.Z. Cross. 2003. Plant density and maize germplasm improvement in the northern Corn Belt. Maydica 48: 105-111.

Cross, H.Z., 1983. Registration of NDSAB and NDSF maize germplasm. Crop Sci. 23: 1227.

Dep. of Plant Sciences, North Dakota State Univ., P.O. Box 5051, Fargo, ND 58105. Registration by CSSA, Accepted      . *Corresponding author (marcelo.carena@ndsu.edu).