Search Results

You are looking at 71 - 80 of 148 items for :

  • "Meloidogyne incognita" x
Clear All
Free access

Richard L. Fery and Philip D. Dukes

Greenhouse experiments were conducted to determine the inheritance of the high level of southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] resistance exhibited by `Carolina Hot' cayenne pepper (Capsicum annuum L.) and to compare the genetic nature of this resistance to that exhibited by `Mississippi Nemaheart.' Evaluation of parental, F1, F2, and backcross generations of the cross `Mississippi Nemaheart' × `California Wonder' confirmed an earlier published report that the `Mississippi Nemaheart' resistance is conditioned by a single dominant gene. Evaluation of parental, F1, F2, and backcross generations of a cross between highly resistant and highly susceptible lines selected from a heterogeneous `Carolina Hot' population indicated that the resistance exhibited by `Carolina Hot' is conditioned by two genes, one dominant and one recessive. Evaluation of the parental and F2 populations of a cross between `Mississippi Nemaheart' and the highly resistant `Carolina Hot' line indicated that the dominant resistance gene in `Mississippi Nemaheart' is allelic to the dominant resistance gene in `Carolina Hot.' Comparison of the data that were collected on the parental lines in the latter cross demonstrated the superior nature of the resistance exhibited by `Carolina Hot.' The presence of the second resistance gene in `Carolina Hot' probably accounted for the higher level of resistance. The ease and reliability of evaluating plants for resistance to root-knot nematodes and the availability of a simply inherited source of resistance makes breeding for southern root-knot nematode resistance a viable objective in pepper breeding programs. This objective should be readily obtainable by the application of conventional plant breeding methodologies.

Free access

Judy A. Thies and Richard L. Fery

Several species of root-knot nematodes [Meloidogyne incognita (Kofoid & White) Chitwood, M. arenaria (Neal) Chitwood, M. javanica (Treub) Chitwood, and M. hapla Chitwood] are major pests of peppers (Capsicum spp.) in the United States and worldwide. Resistance to M. incognita, M. arenaria, and M. javanica has been identified in several Capsicum accessions, but there are few reports of resistance to M. hapla. Therefore, we selected a 10% core (440 accessions) of the 14 available Capsicum spp. in the Capsicum germplasm collection (3,731 accessions) maintained by the U.S. Dept. of Agriculture (USDA), and evaluated this core for resistance to M. hapla in unreplicated greenhouse tests. The 11 best (most resistant) and the 3 worst (most susceptible) accessions identified in these unreplicated tests were re-evaluated in a replicated greenhouse test. Seven of these 11 “best” accessions (PI 357613, PI 357503, PI 439381, PI 297493, PI 430490, PI 267729, and PI 441676) exhibited root gall severity indices <5.0 (1 = no galls; 9 = more than 80% of the root system covered with galls) in the replicated test, and each of these indices was significantly lower than the indices of the “worst” accessions and susceptible controls. Although a gall index <5.0 indicates a moderate level of resistance, more than 3000 M. hapla eggs were extracted per gram of fresh root tissue and the reproductive index was >1.0 for each of these accessions. These observations suggest that the most resistant accessions tested are somewhat susceptible to M. hapla. The results of our evaluation of a core of the USDA Capsicum germplasm collection demonstrates clearly that there is significant genetic variability within the overall collection for M. hapla resistance. Additionally, these results identify portions of the collection where future evaluations for M. hapla resistance should be focused. For example, the origin of the two most promising C. annuum accessions (PI 357613 and PI 357503) in the core was Yugoslavia. Thus, additional accessions from this temperate region of the world should receive priority attention in any effort to identify better sources of resistance in C. annuum to M. hapla.

Free access

Richard L. Fery and Judy A. Thies

conditioning a high level of resistance to the southern root-knot nematode [ Meloidogyne incognita (Chitwood) Kofoid and White], the peanut root-knot nematode [ M. arenaria (Neal) Chitwood], and the tropical root-knot nematode [ M. javanica (Treub) Chitwood

Full access

Cody L. Smith, Joshua H. Freeman, Nancy Kokalis-Burelle and William P. Wechter

watermelon cultivar ‘Royal Sweet’ was estimated with an initial population equal to 122 eggs/100 cm 3 of soil, 1.6 gal on bioassay roots/100 cm 3 of soil, or 3.6 J2/100 cm 3 of soil ( Xing and Westphal, 2012 ). Meloidogyne incognita is a common pest in

Free access

Wenjing Guan, Xin Zhao, Donald W. Dickson, Maria L. Mendes and Judy Thies

the southern United States and in other semitropical and tropical regions of the world. Meloidogyne incognita , M. javanica , and M. arenaria are the most widespread RKN species in the southeastern United States ( Zitter et al., 1996 ), and all of

Free access

Howard F. Harrison Jr., D. Michael Jackson, Judy A. Thies, Richard L. Fery and J. Powell Smith

produce seeds with impermeable seedcoats (hard seeds). The major attributes of lines US-1136, US-1137, and US-1138 have rapid growth, high biomass production, a long vegetative growth period, and southern root knot nematode [ Meloidogyne incognita

Free access

Richard L. Fery and Judy A. Thies

level of resistance to the southern root-knot nematode [ Meloidogyne incognita (Chitwood) Kofoid and White], the peanut root-knot nematode [ M. arenaria (Neal) Chitwood], and the tropical root-knot nematode [ M. javanica (Treub) Chitwood]. Root

Free access

Antonio J. Felipe

) seleccionada por su aptitud al enraizamiento. VI Congr. Nac. SECH, 102. Fernández, C. Pinochet, J. Felipe, A. 1993 Influence of temperature on the expression of resistance in six Prunus rootstocks infected with Meloidogyne incognita Nematropica 24 185 202

Free access

Richard L. Fery and Judy A. Thies

dominant gene conditioning a high level of resistance to the southern root-knot nematode [ Meloidogyne incognita (Chitwood) Kofoid and White], the peanut root-knot nematode [ M. arenaria (Neal) Chitwood], and the tropical root-knot nematode [ M. javanica

Free access

Richard L. Fery and Judy A. Thies

dominant N gene conditions a high level of resistance to the southern root-knot nematode [ Meloidogyne incognita (Chitwood) Kofoid and White], the peanut root-knot nematode [ M. arenaria (Neal) Chitwood], and the tropical root-knot nematode [ M