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THE UNITED STATES DEPARTMENT OF AGRICULTURE

AGRICULTURAL RESEARCH SERVICE

WASHINGTON, D. C.

NOTICE OF RELEASE OF GEMS-0001 MAIZE GERMPLASM RESISTANT TO LEAF BLADE, LEAF SHEATH AND COLLAR FEEDING BY EUROPEAN CORN BORER

The Agricultural Research Service, United States Department of Agriculture announces the release of European corn borer resistant maize germplasm GEMS-0001. This release culminates several breeding cycles aimed at the introgression of a European corn borer resistance trait from Peruvian maize, PI 503806, into a U.S. Corn Belt adapted inbred line, B94. This germplasm represents a new source of conventional resistance to European corn borer for use by plant breeders but is not intended for use as a cultivar. It was developed by USDA-ARS scientists Drs. Craig A. Abel, Stoneville, MS; Linda M. Pollak, and Richard L. Wilson, Ames, IA.

GEMS-0001 is derived from the cross (PI 503806 x B94) \\\ B94. The recurrent parent, B94, is an AES 800 maturity stiff-stalk synthetic inbred line, selected for its high yield performance in single cross tests. GEMS-0001 flowered 5 days later than B94 at Ames IA in 1998, and 3 days later than B94 at Stoneville MS in 1999. The donor parent, PI 503806, is a tropical maize from Peru selected for its resistance to leaf blade feeding damage caused by first generation European corn borer and leaf sheath and collar feeding damage caused by the second generation of the insect. The resistance for PI 503806 is not based on DIMBOA levels, a cyclic hydroxamic acid that is commonly associated with conventional leaf blade feeding resistance in maize.

Breeding lines from the cross PI 503806 x B94 were advanced by backcrossing to B94 three generations. Throughout the breeding program, donor plants were selected by evaluating their resistance to European corn borer feeding on leaf blades and on leaf sheaths and collars of plants artificially infested with the insect. Only selected resistant plants were carried forward in the breeding effort. Third generation backcross seed were grown in Ames, Iowa in 1999 and plants were full sib-mated to obtain a seed increase for distribution.  

In 1998 Ames Iowa trials, experimental lines were tested for leaf blade resistance by infesting whorls with 250 European corn borer larvae and rating the damage caused to the developing leaves using a 1 - 9 scale where a score of 1 = no damage and 9 = severe damage. Experimental lines were also tested at anthesis by infesting each plant with 250 European corn borer larvae and measuring the length of feeding tunnels eight weeks after artificial infestation. GEMS-0001 and B94 were grown in a randomized complete block design with four replications. GEMS-0001 received a 2.3 leaf blade feeding score compared to 4.3 for the recurrent parent, B94. Stalk tunneling for GEMS-0001 was 19.0 cm compared to 38.1 cm for B94. The percentage of plants with 0 - 7.6, 7.7 - 22.9 and > 23.0 cm of tunneling was 28.6, 46.0, and 25.4, respectively for GEMS-0001 with a range from 0.0 - 71.1 cm, and 0.0, 11.1, and 88.9, respectively for B94 with a range from 20.3 - 68.6 cm. In 1999 Stoneville Mississippi trials, GEMS-0001 and B94 were grown in a randomized complete block design with four replications. The procedures for artificially infesting the plants and evaluating the data were the same as for the Ames, 1998 study. GEMS-0001 received a leaf blade feeding score of 3.3 while the recurrent parent received a 4.8 rating. Stalk tunneling for GEMS-0001 at Stoneville averaged 21.1 cm with a range of scores from 2.5 - 53.3 cm while B94 received an average score of 47.8 cm with a range from 22.9 - 76.2 cm. The percentage of plants with 0 - 7.6, 7.7  - 22.9 and > 23.0 cm of tunneling was 8.1, 38.7, and 53.2, respectively, for GEMS-0001, and 0.0, 4.8, and 95.2, respectively, for B94.

In addition to resistance to European corn borer, GEMS-0001 was also selected for its superior yield compared to other experimental lines in the resistance breeding program. One hundred sixty  second generation backcross parents from the breeding program were tested for yield. Three plants from each parent, including the parent of GEMS-0001, were selfed and crossed to a private non-stiff stalk tester, LH 185, and the hybrid seed was grown in a five location yield trial using U. S. Corn Belt locations. One parent hybrid of GEMS-0001 yielded well at 9756.1 kg per hectare (155.6 bushels per acre) which was 95.3% of the highest yielding commercial check and 105.3% of the commercial check average. The other two parent hybrids of GEMS-0001 yielded 8941.0 kg per hectare and 8727.8 kg per hectare (142.6 and 139.2 bushels per acre).

A limited quantity of GEMS-0001 seed is available for research purposes. Contact Dr. Craig A. Abel, USDA-ARS, P.O. Box 346, Stoneville, MS 38776 (FAX 662-686-5421). Genetic material of this release will be deposited in the National Plant Germplasm System where it will be available for research purposes. When this germplasm contributes to a new cultivar or germplasm, it is requested that appropriate recognition be given its source.   

  Note: Any seed requests should be directed to Mark Millard, USDA-ARS North Central Regional Plant Introduction Station, Iowa State University, State and Mortensen Road, Ames, IA 50011. Phone: (515) 292-6502.

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