Identification of Novel Physiological Races of Phytophthora capsici Causing Foliar Blight Using the New Mexico Recombinant Inbred Pepper Lines Set as a Host Differential

Phytophthora foliar blight caused by Phytophthora capsici is a serious limitation to pepper (Capsicum annuum) production worldwide. Knowledge of the physiological race composition of isolates causing phytophthora foliar blight is necessary for success in breeding for disease resistance. The New Mexico recombinant inbred lines (NMRILs) effectively differentiated isolates from different geographical locations (i.e., Turkey, The Netherlands, Argentina, and two states in the United States) into 12 physiological races of P. capsici causing phytophthora foliar blight. This research demonstrates the use of the NMRILs to identify P. capsici foliar blight races and the importance of identifying the physiological races occurring in specific regions where a C. annuum cultivar will be grown. Knowing the physiological race(s) in a region will provide valuable information to formulate breeding strategies to deploy durable foliar blight resistance.

Download Full-text

Physiological Race Characterization of Phytophthora capsici Isolates from Several Host Plant Species in Brazil Using New Mexico Recombinant Inbred Lines of Capsicum annuum at Two Inoculum Levels

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.137.6.421 ◽

2012 ◽

Vol 137 (6) ◽

pp. 421-426 ◽

Cited By ~ 9

Author(s):

Cláudia S. da Costa Ribeiro ◽

Paul W. Bosland

Keyword(s):

New Mexico ◽

Capsicum Annuum ◽

Recombinant Inbred ◽

Recombinant Inbred Lines ◽

Phytophthora Capsici ◽

Screening Method ◽

Inbred Lines ◽

Screening Methods ◽

Resistant Cultivars ◽

Physiological Races

Phytophthora blight, caused by Phytophthora capsici, is one of the most destructive diseases worldwide that affects Capsicum pepper. Attempts to provide universally resistant cultivars has been unsuccessful, which may be the result of the use of different resistance sources, pathotypes, or races of P. capsici isolates and screening techniques. The screening method used at Embrapa Vegetables in Brazil to detect resistance to P. capsici in Capsicum was compared with the screening method used at New Mexico State University. Both screening methods produced similar and consistent results when a range of P. capsici isolates were used. It was concluded that either method can successfully differentiate resistant and susceptible individuals. In addition, 20 P. capsici isolates from Brazil were characterized for virulence using a subset of 26 New Mexico recombinant inbred lines of pepper (Capsicum annuum). Within the P. capsici populations from Brazil, eight new physiological races for the root rot disease syndrome were identified. A total of nine isolates were pathogenic only on the susceptible control, ‘Camelot’. The ability to identify physiological races of P. capsici occurring in Brazil allows for a better understanding about race-specific resistance leading to improved approaches in breeding for durable resistant cultivars.

Download Full-text

Virulence Phenotypes on Chili Pepper for Phytophthora capsici Isolates from Michoacán, Mexico

HortScience ◽

10.21273/hortsci13964-19 ◽

2019 ◽

Vol 54 (9) ◽

pp. 1526-1531

Author(s):

Alfredo Reyes-Tena ◽

Arturo Castro-Rocha ◽

Gerardo Rodríguez-Alvarado ◽

Gerardo Vázquez-Marrufo ◽

Martha Elena Pedraza-Santos ◽

...

Keyword(s):

New Mexico ◽

Disease Severity ◽

Recombinant Inbred ◽

Recombinant Inbred Lines ◽

Phytophthora Capsici ◽

Inbred Lines ◽

Chili Pepper ◽

Economic Losses ◽

Post Inoculation ◽

Resistant Cultivars

Phytophthora blight of vegetables caused by Phytophthora capsici causes significant economic losses in production of Solanaceae and Cucurbitaceae crops in Mexico. The development of universal resistant chili pepper cultivars is challenging due to the diverse virulence phenotypes produced by P. capsici. The objective of the study was to characterize the diversity of phenotypic interactions for P. capsici isolates recovered from production fields in Michoacán, Mexico, to facilitate the development of resistant cultivars. Virulence phenotypes were characterized for 12 isolates of P. capsici using 26 Capsicum annuum New Mexico Recombinant Inbred Lines (NMRILs) in greenhouse conditions. Criollo de Morelos CM-334 and California Wonder were used as resistant and susceptible controls, respectively. Seedlings at the four to eight true leaf stage were inoculated with 10,000 zoospores per seedling and disease severity was evaluated at 20 days post-inoculation. Two of the P. capsici isolates did not infect any pepper host even though the isolate was less than a year old. The 10 virulent isolates were designated in 10 virulence phenotypes. The information generated by this study is of utmost importance for efforts of producing resistant cultivars specific for Michoacán producers.

Download Full-text

Using Recombinant Inbred Lines to Monitor Changes in the Race Structure of Phytophthora capsici in Chile Pepper in New Mexico

Plant Health Progress ◽

10.1094/php-rs-15-0034 ◽

2015 ◽

Vol 16 (4) ◽

pp. 235-240 ◽

Cited By ~ 4

Author(s):

Li Jiang ◽

Soum Sanogo ◽

Paul W. Bosland

Keyword(s):

New Mexico ◽

Recombinant Inbred ◽

Recombinant Inbred Lines ◽

Phytophthora Capsici ◽

Resistance Index ◽

Inbred Lines ◽

Resistance Testing ◽

Chile Pepper ◽

New Races ◽

Pepper Breeding

Since 2008, 11 races of Phytophthora capsici have been identified in New Mexico based on their reactions to a set of host differentials, the New Mexico Recombinant Inbred Lines (NMRILs) developed by the Chile Pepper Breeding Program at New Mexico State University. The objective of this study was to appraise the current race structure of 13 isolates of P. capsici newly collected from chile pepper fields in New Mexico. Of the 13 isolates, 12 were identified as new races. Race 25 (isolate PWB175) was the most virulent isolate, and showed virulence that was higher than that of race 1 (PWB24), which is widely used as a highly virulent race for resistance testing of chile peppers in the United States, and was considered as a potential risk for chile pepper production in New Mexico. Of the 17 NMRILs tested, only 7 were needed for the identification of the 12 new races. The NMRILs are genetically stable including their disease reactions, and hence, are invaluable as P. capsici race differentials. A resistance index that ranges from 0 to 1 with 1 being resistant to all isolates was developed in this study. Among all the NMRILs evaluated, one NMRIL (NMRIL-R) had a low resistance index of 0.17, demonstrating its susceptibility to most of the isolates, while other NMRILs (A, B, F, O, and Z) showed medium to high levels of resistance to the P. capsici evaluated with the range of resistance index from 0.75 to 0.89. The NMRILs with a high resistance index can be a good source of resistance for chile pepper breeding programs. The results of this study prove that multiple races of P. capsici can exist in a single production field and plant breeders must be cognizant to breed for more than one race in a given production location. Accepted for publication 3 December 2015. Published 17 December 2015.

Download Full-text

A Rapid Technique for Multiple-race Disease Screening of Phytophthora Foliar Blight on Single Capsicum annuum L. Plants

HortScience ◽

10.21273/hortsci.45.10.1563 ◽

2010 ◽

Vol 45 (10) ◽

pp. 1563-1566 ◽

Cited By ~ 10

Author(s):

Ariadna Monroy-Barbosa ◽

Paul W. Bosland

Keyword(s):

Capsicum Annuum ◽

Root Rot ◽

Recombinant Inbred Lines ◽

Phytophthora Capsici ◽

Pepper Plant ◽

Phytophthora Blight ◽

Chile Pepper ◽

Physiological Races ◽

Foliar Blight

Phytophthora blight, caused by the oomycete Phytophthora capsici Leon., is a major disease that threatens production and long-term viability of the chile pepper (Capsicum annuum L.) industry. For each phytophthora disease syndrome such as root rot, foliar blight, and stem blight separate and independent resistant systems have evolved in the host. In addition, several physiological races of the pathogen have been identified. A novel, effective, and accurate screening technique is described that allows for multiple races to be evaluated on a single plant of C. annuum. The P. capsici resistant line Criollo de Morelos-334, a susceptible cultivar, Camelot, and three New Mexico Recombinant Inbred Lines, -F, -I, -S, were used to evaluate the new technique for phytophthora foliar blight multiple-race screening. Using three P. capsici physiological races, no interaction among the physiological races was observed with this technique. This novel technique provided a rapid disease screen evaluating multiple physiological races for phytophthora foliar blight resistance in a single chile pepper plant and can assist plant breeders in selecting for disease-resistant plants.

Download Full-text

Differentiation of Race Specific Resistance to Phytophthora Root Rot and Foliar Blight in Capsicum annuum

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.128.2.0213 ◽

2003 ◽

Vol 128 (2) ◽

pp. 213-218 ◽

Cited By ~ 57

Author(s):

Lisa M. Oelke ◽

Paul W. Bosland ◽

Robert Steiner

Keyword(s):

New Mexico ◽

Capsicum Annuum ◽

Root Rot ◽

Specific Resistance ◽

Phytophthora Capsici ◽

Significant Implication ◽

Phytophthora Root Rot ◽

Physiological Races ◽

Foliar Blight ◽

Extensive Breeding

Despite extensive breeding efforts, no pepper (Capsicum annuum L. var. annuum) cultivars with universal resistance to phytophthora root rot and foliar blight (Phytophthora capsici Leon) have been commercially released. A reason for this limitation may be that physiological races exist within P. capsici, the causal agent of phytophthora root rot and phytophthora foliar blight. Physiological races are classified by the pathogen's reactions to a set of cultivars (host differential). In this study, 18 varieties of peppers were inoculated with 10 isolates of P. capsici for phytophthora root rot, and four isolates of P. capsici for phytophthora foliar blight. The isolates originated from pepper plants growing in New Mexico, New Jersey, Italy, Korea, and Turkey. For phytophthora root rot, nine of the 10 isolates were identified as different physiological races. The four isolates used in the phytophthora foliar blight study were all determined to be different races. The identification of physiological races within P. capsici has significant implication in breeding for phytophthora root rot and phytophthora foliar blight resistance.

Download Full-text

Diverse sources of resistance to Spodoptera litura (F.) in groundnut

Indian Journal of Genetics and Plant Breeding (The) ◽

10.31742/ijgpb.79s.1.8 ◽

2019 ◽

Vol 79 (01S) ◽

Author(s):

M. A. Saleem ◽

G. K. Naidu ◽

H. L. Nadaf ◽

P. S. Tippannavar

Keyword(s):

Recombinant Inbred ◽

Spodoptera Litura ◽

Hot Spot ◽

Recombinant Inbred Lines ◽

Insect Pest ◽

Inbred Lines ◽

Leaf Damage ◽

Botanical Variety ◽

Resistant Genotypes ◽

Botanical Varieties

Spodoptera litura an important insect pest of groundnut causes yield loss up to 71% in India. Though many effective chemicals are available to control Spodoptera, host plant resistance is the most desirable, economic and eco-friendly strategy. In the present study, groundnut mini core (184), recombinant inbred lines (318) and elite genotypes (44) were studied for their reaction to Spodoptera litura under hot spot location at Dharwad. Heritable component of variation existed for resistance to Spodoptera in groundnut mini core, recombinant inbred lines and elite genotypes indicating scope for selection of Spodoptera resistant genotypes. Only 29 (15%) genotypes belonging to hypogaea, fastigiata and hirsuta botanical varieties under mini core set, 15 transgressive segregants belonging to fastigiata botanical variety among 318 recombinant inbred lines and three genotypes belonging to hypogaea and fastigiata botanical varieties under elite genotypes showed resistance to Spodoptera litura with less than 10% leaf damage. Negative correlation existed between resistance to Spodoptera and days to 50 per cent flowering indicating late maturing nature of resistant genotypes. Eight resistant genotypes (ICG 862, ICG 928, ICG 76, ICG 2777, ICG 5016, ICG 12276, ICG 4412 and ICG 9905) under hypogaea botanical variety also had significantly higher pod yield. These diverse genotypes could serve as potential donors for incorporation of Spodoptera resistance in groundnut.

Download Full-text