Registration of the Maize Germplasm CRW3(S1)C6 with Resistance to Western Corn Rootworm

Journal of Plant Registrations, Vol. 1, No. 2, September 2007 151 Maize (Zea mays L.) germplasm CRW3(S1)C6 (Reg. No. GP553, PI 644060) was developed with resistance to western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte) by the USDA-ARS Plant Genetics Research Unit in cooperation with the Missouri Agricultural Experiment Station at the University of Missouri-Columbia, and was released in February 2007. Development of CRW3 began in the 1996–1997 winter nursery when crosses for a diallel of nine parents were made for the purpose of evaluating combining ability for WCR resistance (Hibbard et al., 1999). The parents included a number of inbred lines and populations that showed less root pruning damage by WCR. The diallel crosses and their parents were evaluated for WCR damage in replicated trials in summer 1997. The six most resistant diallel crosses, which included only four of the nine original parents, were crossed as a second diallel in the 1997–1998 winter nursery. Parental materials of the second diallel included NGSDCRW1(S2)C4-15-2S2 × PI340839, TL92A-PAR1779 60-4 × PI340839, TL93A-PAR1774 28-1 × NGSDCRW1(S2)C4-15-2S2, TL92A-PAR1779 60-4 × NGSDCRW1(S2)C4-15-2S2, TL92A-PAR1779 60-4 × TL93APAR1774 28-1, and TL93A-PAR1774 28-1 × PI340839. NGSDCRW resulted from interplanting hybrid R802/R109B with open-pollinated SDCRW1SYN population and subsequent selection for large root size and root-pulling resistance. Lines beginning with TL are from the CIMMYT tropical breeding program. PI340839 is a Supergold popcorn from the J.C. Eldridge popcorn collection at Iowa State University. Other pedigree information for these parental materials can be found in Hibbard et al. (1999). A balanced bulk was created and recombined in the summer of 1998 to form CRW3 C0. For the fi rst cycle of selection, approxiRegistration of the Maize Germplasm CRW3(S1)C6 with Resistance to Western Corn Rootworm