<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Most commercial tobacco cultivars possess the <italic>Rk1</italic> resistance gene to races 1 and 3 of <italic>Meloidogyne incognita</italic> and race 1 of <italic>Meloidogyne arenaria</italic>, which has caused a shift in population prevalence in Virginia tobacco fields toward other species and races. A number of cultivars now also possess the <italic>Rk2</italic> gene for root-knot resistance. Experiments were conducted in 2013 to 2014 to examine whether possessing both <italic>Rk1</italic> and <italic>Rk2</italic> increases resistance to a variant of <italic>M. incognita</italic> race 3 compared to either gene alone. Greenhouse trials were arranged in a completely randomized design with Coker 371-Gold (C371G; susceptible), NC 95 and SC 72 (<italic>Rk1Rk1</italic>), T-15-1-1 (<italic>Rk2Rk2</italic>), and STNCB-2-28 and NOD 8 (<italic>Rk1Rk1</italic> and <italic>Rk2Rk2</italic>). Each plant was inoculated with 5,000 root-knot nematode eggs; data were collected 60 d postinoculation. Percent galling and numbers of egg masses and eggs were counted, the latter being used to calculate the reproductive index on each host. Despite variability, entries with both <italic>Rk1</italic> and <italic>Rk2</italic> conferred greater resistance to a variant of <italic>M. incognita</italic> race 3 than plants with <italic>Rk1</italic> or <italic>Rk2</italic> alone. Entries with <italic>Rk1</italic> alone were successful in reducing root galling and nematode reproduction compared to the susceptible control. Entry T-15-1-1 did not reduce galling compared to the susceptible control but often suppressed reproduction.</p></abstract>

Most commercial tobacco cultivars possess the Rk1 resistance gene to races 1 and 3 of Meloidogyne incognita and race 1 of Meloidogyne arenaria, which has caused a shift in population prevalence in Virginia tobacco fields toward other species and races. A number of cultivars now also possess the Rk2 gene for root-knot resistance. Experiments were conducted in 2013 to 2014 to examine whether possessing both Rk1 and Rk2 increases resistance to a variant of M. incognita race 3 compared to either gene alone. Greenhouse trials were arranged in a completely randomized design with Coker 371-Gold (C371G; susceptible), NC 95 and SC 72 (Rk1Rk1), T-15-1-1 (Rk2Rk2), and STNCB-2-28 and NOD 8 (Rk1Rk1 and Rk2Rk2). Each plant was inoculated with 5,000 root-knot nematode eggs; data were collected 60 d postinoculation. Percent galling and numbers of egg masses and eggs were counted, the latter being used to calculate the reproductive index on each host. Despite variability, entries with both Rk1 and Rk2 conferred greater resistance to a variant of M. incognita race 3 than plants with Rk1 or Rk2 alone. Entries with Rk1 alone were successful in reducing root galling and nematode reproduction compared to the susceptible control. Entry T-15-1-1 did not reduce galling compared to the susceptible control but often suppressed reproduction.

Reproduction of <italic>Meloidogyne incognita</italic> Race 3 on Flue-cured Tobacco Homozygous for <italic>Rk1</italic> and/or <italic>Rk2</italic> Resistance Genes

Virginia Polytechnic Institute and State University

Journal of Nematology

This work is licensed under the Creative Commons Attribution 4.0 International License.

Reproduction of  Race 3 on Flue-cured Tobacco Homozygous for  and/or  Resistance Genes

Most commercial tobacco cultivars possess the Rk1 resistance gene to races 1 and 3 of Meloidogyne incognita and race 1 of Meloidogyne arenaria, which has...

Reproduction of Meloidogyne incognita Race 3 on Flue-cured Tobacco Homozygous for Rk1 and/or Rk2 Resistance Genes

Pubblicato online: 21 lug 2017

Pagine: 79 - 86

Ricevuto: 24 nov 2015

Accettato: 08 ott 2021

DOI: https://doi.org/10.21307/jofnem-2017-012

© 2016 Jill R. Pollok et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.