Capsicum baccatum var. pendulum (Willd.) Eshbaugh, commonly referred to as “aji,” is one of the five cultivated species in this genus ( Eshbaugh, 1968 , 1970 ; Pickersgill, 1969 ). Archeological and other evidence suggests that the
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.
John R. Stommel, Mary J. Camp, Judith M. Dumm, Kathleen G. Haynes, Yaguang Luo, and Anne Marie Schoevaars
(Class 2); and accessions of Capsicum baccatum , Capsicum frutescens , and Capsicum chinense with thin-walled “aji”-like and tabasco pod types (Class 3) stored under passive modified atmosphere packaging conditions for 7 to 14 d. An inverse
Ivette Guzman, Krystal Vargas, Francisco Chacon, Calen McKenzie, and Paul W. Bosland
, Solanum melongena , that ripen to a final yellow color: ( A ) ‘NuMex Sunrise’, a Capsicum annuum , ( B ) ‘Aji Puchomucho’, a Capsicum baccatum , ( C ) ‘Thai Yellow Egg’, S. melongena , ( D ) ‘Fatali’, Capsicum chinense , ( E ) ‘Wild Chiltepin’, C
Andrey Vega-Alfaro, Paul C. Bethke, and James Nienhuis
, early maturity, improved fruit size, and red fruit color ( Table 1 ). Both are licensed by PanAmerican Seed (West Chicago, IL). Table 1. Origin, plant and fruit characteristic of cultivars of Capsicum annuum, Capsicum baccatum, and Capsicum
Marisa M. Wall, Cynthia A. Waddell, and Paul W. Bosland
The β-carotene and total carotenoid content of either fresh or dried tissue of fruits of a total of 57 cultivars of six Capsicum species were analyzed using high performance liquid chromatography (HPLC). β-Carotene levels in ripe fruit varied from 0 to 166 μg·g-1 fresh weight, and carotenoid levels were from 1 to 896 μg·g-1 in ripe fruit in 1996. The range of values for β-carotene was similar in 1997, but that for total carotenoids was wider (4 to 1173 μg·g-1 fresh weight). Fresh fruit of the cultivars Greenleaf Tabasco, Pulla, Guajillo, NuMex Conquistador, Ring-O-Fire, and Thai Dragon contained greater amounts of β-carotene per 100 g fresh weight than the recommended dietary allowance (RDA) for vitamin A for the average adult. For dried Capsicum entries, New Mexican, aji, pasilla, and ancho types had the highest levels of β-carotene. In 1996, β-carotene levels among the dried Capsicum germplasm ranged from 2 to 739 μg·g-1 dry weight, and carotenoid levels from 111 to 6226 μg·g-1. Values were higher in 1997, ranging from 24 to 1198 μg·g-1 dry weight for β-carotene and from 187 to 10,121 μg·g-1 for total carotenoids. A pasilla type (C. annuum L.) had the highest total carotenoid content among the dried entries in both years.
Jack E. McCoy and Paul W. Bosland
Powdery mildew [Leveillula taurica (Lév.) Arn] is a fungus causing epidemics on chile peppers (Capsicum sp.) worldwide. It was first observed in New Mexico in the late 1990s and has been a reoccurring issue. During the 2017 growing season, environmental conditions were highly favorable for powdery mildew development and severe infection was observed. This provided a unique opportunity to identify novel sources of resistance in Capsicum to powdery mildew. In the present study, the incidence and severity of powdery mildew was evaluated for 152 chile pepper accessions comprising different cultivars and species. Major differences in disease severity and incidence were observed among the accessions. Of the 152 accessions, 53 were resistant, i.e., received a disease index (DI) score of ≤1. When examining across Capsicum species, 16 Capsicum annuum accessions, all 8 Capsicum baccatum, all 21 Capsicum chinense, 5 of 6 Capsicum frutescens, the Capsicum chacoense accession, and the Capsicum rhomboideum accession were resistant. These results provide several accessions with resistance that can be used in breeding programs. Especially important are the C. annuum resistant accessions, as this resistance can be more quickly incorporated into commercially important C. annuum cultivars as compared with interspecific hybridizations.
Andrey Vega-Alfaro, Carlos Ramírez-Vargas, Germán Chávez, Fernando Lacayo, Paul C. Bethke, and James Nienhuis
The production of sweet peppers (Capsicum annuum) is often constrained in tropical environments by susceptibility to persistent soil-borne diseases, including bacterial wilt (Ralstonia solanacearum). However, the production of sweet peppers in high tunnels using sterile soilless media irrigated with nutrient solution offers the potential to reduce the incidence of bacterial wilt. An additional strategy for disease management is the use of sweet pepper scions grafted onto rootstocks that are resistant to soil-borne pathogens. Two sweet pepper cultivars grown extensively in the tropics, Nathalie and 4212, were used as scions and grafted onto the habanero pepper cultivar Habanero TEC (Capsicum chinense) and the aji pepper cultivar Baccatum TEC (Capsicum baccatum). Two cultivars related to the two rootstocks were prescreened for susceptibility to two virulent strains of bacterial wilt. Graft combinations were grown in two environments, a high tunnel with automatic nutrient solution irrigation of containers filled with sterile coconut fiber and an open field with known high levels of bacterial wilt inoculum. Self-grafted and nongrafted plants of scions were included as checks. The disease susceptibility screening showed that the area under the disease progress curve was consistently low for ‘Habanero TEC’ and ‘Baccatum TEC’ when inoculated with two virulent strains of bacterial wilt, suggesting that habanero pepper cultivars and, to a lesser degree, aji pepper cultivars may be useful as rootstocks in soils with bacterial wilt inoculum. Significant increases in yield, fruit number, and reduced time to flowering were observed in the high tunnel compared with the open-field environment. Individual fruit weight was reduced in the high tunnel compared with the field. Yield, fruit number, fruit weight, and time to flowering were consistent between scions regardless of rootstock. No differences were observed for yield, fruit number, fruit weight, or time to flowering of self-grafted and nongrafted scion checks. In the high tunnel, yield was higher in scions grafted onto ‘Habanero TEC’ compared with self-grafted and nongrafted checks. In the open field, yield and fruit number were highest on scions grafted onto ‘Habanero TEC’. Regardless of graft treatment, high-tunnel production in tropical environments can result in significant increases in yield and fruit number compared with open-field production. No advantage of grafted plants was observed in the high-tunnel production environment. In contrast, in the open-field environment, grafting sweet pepper scions onto pungent habanero rootstocks resulted in a significant increase in yield, fruit number, and fruit size compared with self-grafted and nongrafted checks. The increase was likely attributable to the resistance of habanero pepper cultivars to soil-borne diseases, including bacterial wilt.
Marissa Moses and Pathmanathan Umaharan
, A, B, and C. Capsicum annuum and Capsicum baccatum accessions are indicated within the dotted lines. Accessions from the Upper Amazon, Central America, Lesser Antilles, and Trinidad and Tobago fell solely or predominantly into Cluster B, whereas
Ben A. Bergmann, John M. Dole, and Ingram McCall
bipinnatus ), later and fewer florets in gladiolus, flower deformities in billy buttons ( Craspedia globosa ), decreased fruit production in chili pepper ( Capsicum baccatum ), and reduced spadix width and flower abnormalities in calla lily as reported by