Seed degeneration of potato in the tropical highlands of Ecuador

Most strains of the bacterial wilt pathogen Ralstonia solanacearum are tropical, but race 3 biovar 2 (R3bv2) strains can attack plants in temperate zones and tropical highlands. The basis of this distinctive ecological trait is not understood. We compared the survival of tropical, R3bv2, and warm-temperate North American strains of R. solanacearum under different conditions. In water at 4°C, North American strains remained culturable the longest (up to 90 days), whereas tropical strains remained culturable for the shortest time (≈40 days). However, live/dead staining indicated that cells of representative strains remained viable for >160 days. In contrast, inside potato tubers, R3bv2 strain UW551 survived >4 months at 4°C, whereas North American strain K60 and tropical strain GMI1000 were undetectable after <70 days in tubers. GMI1000 and UW551 grew similarly in minimal medium at 20 and 28°C and, although both strains wilted tomato plants rapidly at 28°C, UW551 was much more virulent at 20°C, killing all inoculated plants under conditions where GMI100 killed just over half. Thus, differences among the strains in the absence of a plant host were not predictive of their behavior in planta at cooler temperatures. These data indicate that interaction with plants is required for expression of the temperate epidemiological trait of R3bv2.

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Soft System Methodology in the Management of Agroecosystem Health and Sustainability Concerns of a Tropical Highlands Agroecosystem

Integrated Assessment of Health and Sustainability of Agroecosystems - Advances in Agroecology ◽

10.1201/9781420072785.ch5 ◽

2008 ◽

pp. 127-145

Keyword(s):

Soft System Methodology ◽

Tropical Highlands ◽

System Methodology

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Evaluation of N-P-K-Ca-Mg dynamics in plum (Prunus salicina Lindl.) var. Horvin under nursery conditions

Revista Colombiana de Ciencias Hortícolas ◽

10.17584/rcch.2020v14i3.11941 ◽

2020 ◽

Vol 14 (3) ◽

pp. 334-341

Author(s):

Francisco Orduz-Ríos ◽

Karen Victoria Suárez-Parra ◽

Pablo Antonio Serrano-Cely ◽

Pablo Cesar Serrano-Agudelo ◽

Nicolás Forero-Pineda

Keyword(s):

Fruit Trees ◽

Vegetative Development ◽

Vital Part ◽

Foliar N ◽

Early Stages ◽

Prunus Salicina ◽

Tropical Highlands ◽

Deciduous Fruit ◽

Successful Establishment ◽

Nutritional Balance

Temperate fruit trees are a vital part of the economy of the Cundiboyacense highlands in Colombia. The nursery stage is important because it guarantees development at the final grow site. Little is known about the fertilization processes and nutritional dynamics of deciduous fruit trees in the early stages. This research aimed to evaluate the dynamics of N-P-K-Ca and Mg, along with SPAD units, in grafted plum (Prunus salicina) var. Horvin plants under the conditions of tropical highlands, which were evaluated at different growth points (cm), from grafting to transplant. The foliar N concentrations were the highest, followed by the K, P and Mg concentrations. Macronutrient concentrations in the first-stage of grafted nursery plants require nutritional balance for vegetative development and successful establishment at the definitive grow site.

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Pests and diseases affecting potato landraces and bred varieties grown in Peru under indigenous farming system

Revista Latinoamericana de la Papa ◽

10.37066/ralap.v19i2.232 ◽

2016 ◽

Vol 19 (2) ◽

pp. 29-41

Author(s):

W. Pérez Barrera ◽

M. Valverde Miraval ◽

M. Barreto Bravo ◽

J. Andrade-Piedra ◽

G. A. Forbes

Keyword(s):

Flea Beetle ◽

Farming System ◽

Leaf Beetle ◽

Black Scurf ◽

Potato Seed ◽

Potato Leaf ◽

Pests And Diseases ◽

Andean Potato ◽

Seed Degeneration ◽

Potato Flea Beetle

The major pests and diseases were identified and quantified on thirteen potato landraces and three bred varieties cultivated in Peru. Late blight (Phytophthora infestans) was the primary biotic constraint affecting plants before flowering with an average severity of 24%. No other pathogens caused severe foliar disease, but black scurf (Rhizoctonia solani) was relatively common on tubers of some genotypes with incidence ranging from 4.30 to 33.33%. The viruses most generally considered important in potato seed degeneration, PVY and PLRV, were extremely rare, with 1.11 and 0.12 % incidence, respectively. Other viruses considered mild, such as PVX and PVS, were more common, with incidence of 28.23 and 22.29 %, respectively. Potato flea beetle (Epitrix spp.), potato leaf beetle (Diabrotica spp.) and Andean potato weevil (Premnotrypes spp.) were common, with incidence of 28.14, 18.75 and 13.61%, respectively. Potato landraces known as Ishkupuru, Lengua de vaca, Chaulina, Chaulina Tajacaja and Negro cayash were identified as potentially resistant to P. infestans.

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