O'Boyle P.D.,Betaseed Inc. |
Brooks W.S.,Virginia Polytechnic Institute and State University |
Steffenson B.J.,University of Minnesota |
Stromberg E.L.,Physiology and Weed Science |
Griffey C.A.,Virginia Polytechnic Institute and State University
Plant Disease | Year: 2011
Net blotch, caused by Pyrenophora teres f. teres, is one of the most devastating diseases of barley (Hordeum vulgare). Efficient utilization of available resistance sources is dependent upon successful characterization of genes conditioning resistance in diverse sources. Five netblotch-resistant parents and one susceptible parent were intercrossed to identify novel resistance genes and postulate gene number and mode of inheritance. Seedling response to isolate ND89-19 was evaluated in a greenhouse test. Results indicate that the resistant spring barley lines CIho 2291 and CIho 5098 and the winter barley cv. Nomini each have single dominant genes for resistance. Resistance in CIho 5098 is governed by the same dominant gene conferring resistance in Nomini. Resistance in CIho 2291 is controlled by one dominant gene which, putatively, is the same gene conferring resistance in ND B112 but differs from the resistance genes carried by the other parents in this study. The resistance gene in Nomini or CIho 5098 could be pyramided with the resistance gene in CIho 2291 or ND B112 to enhance the durability of resistance against a wide spectrum of P. teres isolates. © 2011 The American Phytopathological Society.
Nilsen E.T.,VA Technology |
Freeman J.,University of North Florida |
Grene R.,Physiology and Weed Science |
Tokuhisa J.,VA Technology
PLoS ONE | Year: 2014
The development of water stress resistant lines of commercial tomato by breeding or genetic engineering is possible, but will take considerable time before commercial varieties are available for production. However, grafting commercial tomato lines on drought resistant rootstock may produce drought tolerant commercial tomato lines much more rapidly. Due to changing climates and the need for commercial production of vegetables in low quality fields there is an urgent need for stress tolerant commercial lines of vegetables such as tomato. In previous observations we identified a scion root stock combination ('BHN 602' scion grafted onto 'Jjak Kkung' rootstock hereafter identified as 602/Jjak) that had a qualitative drought-tolerance phenotype when compared to the non-grafted line. Based on this initial observation, we studied photosynthesis and vegetative above-ground growth during mild-drought for the 602/Jjak compared with another scion-rootstock combination ('BHN 602' scion grafted onto 'Cheong Gang' rootstock hereafter identified as 602/Cheong) and a non-grafted control. Overall above ground vegetative growth was significantly lower for 602/Jjak in comparison to the other plant lines. Moreover, water potential reduction in response to mild drought was significantly less for 602/Jjak, yet stomatal conductance of all plant-lines were equally inhibited by mild-drought. Light saturated photosynthesis of 602/Jjak was less affected by low water potential than the other two lines as was the % reduction in mesophyll conductance. Therefore, the Jjak Kkung rootstock caused aboveground growth reduction, water conservation and increased photosynthetic tolerance of mild drought. These data show that different rootstocks can change the photosynthetic responses to drought of a high yielding, commercial tomato line. Also, this rapid discovery of one scion-rootstock combination that provided milddrought tolerance suggests that screening more scion-rootstock combination for stress tolerance may rapidly yield commercially viable, stress tolerant lines of tomato. ©2014 Nilsen et al.
Schroeder M.W.,Physiology and Weed Science |
Eifert J.D.,Physiology and Weed Science |
Ponder M.A.,Physiology and Weed Science |
Schmale D.G.,Physiology and Weed Science
Poultry Science | Year: 2014
Campylobacter spp. have been isolated from live poultry, production environments, processing facilities, and raw poultry products. Environmental sampling in a poultry grow-out house, combined with carcass rinse sampling from the same flock, may provide a relative relationship between pre- and postharvest Campylobacter contamination. Air samples, fecal/litter samples, and feed/drink line samples were collected from 4 commercial chicken grow-out houses in western Virginia between September 2011 and January 2012. Birds from each sampled house were the first flock slaughtered the following day and were then sampled by postchill carcass rinses. Campylobacter, from postenrichment samples, was detected in 27% (32/120) of house environmental samples and 37.5% (45/120) of carcass rinse samples. All environmental sample types from each house included at least one positive sample except the house 2 air samples. The sponge sample method was found to have a significantly higher (P < 0.05) proportion of Campylobacter-positive samples (45%) than the fecal/litter samples (20%) and air samples (15%) when sample types of all the houses were compared. The proportion positive for the fecal/litter samples postenrichment, for each flock, had the highest correlation (0.85) to the proportion of positive carcass rinse samples for each flock. Environmental samples from house 1 and associated carcass rinses accounted for the largest number of Campylobacter positives (29/60). The fewest number of Campylobacter positives, based on both house environmental (4/30) and carcass rinse samples (8/30), was detected from flock B. The results of this study suggest that environmental sampling in a poultry grow-out house, combined with carcass rinse sampling from the same flock, have the potential to provide an indication of Campylobacter contamination and transmission. Campylobacter qualitative levels from house and processing plant samples may enable the scheduled processing of flocks with lower pathogen incidence or concentrations, as a way to reduce postslaughter pathogen transmission. © 2014 Poultry Science Association Inc.