Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/1998
Publication Date: N/A
Interpretive Summary: Habanero and Scotch Bonnet peppers, members of a very pungent pepper species (Capsicum chinense) traditionally not grown in the United States, are becoming popular because of the increasing popularity of pungent peppers. The southern root-knot nematode is a major pest of both Habanero and Scotch Bonnet peppers, and the results of a recently completed ARS research project indicate that all available commercial cultivars are susceptible. However, the ARS researchers did identify resistance in several Scotch Bonnet-type accessions that were obtained from heirloom collections. Since the efficient and effective use of any pest resistant germplasm in a plant breeding program is dependent upon an understanding of the inheritance of the resistance trait, this study was initiated to determine the inheritance of southern root-knot nematode resistance in C. chinense. The results of this study demonstrated that resistance to southern root-knot nematodes in C. chinense is controlled by a single dominant gene. This means that the development of southern root-knot nematode resistant Habanero and Scotch Bonnet cultivars is a very feasible objective for a pepper breeding program. The availability of resistant cultivars would eliminate the need to use pesticides to control southern root-knot nematodes in Habanero and Scotch Bonnet plantings.
Technical Abstract: Greenhouse tests were conducted to compare the levels of resistance to the southern root-knot nematode exhibited by recently released Capsicum chinense germplasm lines PA-353, PA-398, and PA-426 to the levels of resistance exhibited by the C. annuum cvs. Carolina Cayenne and Mississippi Nemaheart; to determine the inheritance of the resistance in C. .chinense germplasm line PA-426; and to determine genetic relationship between the resistances exhibited by C. chinense germplasm line PA-426 and C. annuum cv. Carolina Cayenne. The results of a replicated test indicated that the level of resistances exhibited by the C. chinense germplasm lines is equal to the level of resistances exhibited by the resistant C. annuum cultivars. Evaluation of parental, F1, F2, and backcross populations of the cross PA-426 x PA-350 indicated that the resistance in C. chinense is conditioned by a single dominant gene. The results of an allelism test indicated that this dominant gene is allelic to the N gene that conditions southern root-knot nematode resistance in the C. annuum cv. Carolina Cayenne. The availability of a simply inherited source of outstanding resistance makes breeding for southern root-knot nematode resistance a viable objective in C. chinense breeding programs.