The reniform nematode (Rotylenchulus reniformis) is among the most economically damaging plant pathogens in the United States. This nematode is mostly known for its damage to cotton but tomato is also well-within its ...The reniform nematode (Rotylenchulus reniformis) is among the most economically damaging plant pathogens in the United States. This nematode is mostly known for its damage to cotton but tomato is also well-within its vast host range that includes 314 plant species across 77 plant families. Nematode-resistant genotypes offer an effective, environmentally safe alternative to agro-chemicals for reniform nematode management. Resistance genes can be introgressed into cultivars through plant improvement efforts. Tomato is a diploid species which is more amenable to identification of resistance genes in contrast to cotton where cultivars are either tetraploid or hexaploid.This greenhouse study examined cultivated and wild Solanum species represented by 40 tomato accessions, to identify resistance and susceptibility responses to R. reniformis. Accessions were evaluated by using single plants in six replicates. Seeds were germinated in sterile soil and inoculated with mixed vermiform R. reniformis. After seven weeks, eggs and vermiform stages were extracted from the root system and counted. A susceptible control S. lycopersicum “Rutgers” (LA1090) was included. Seven putatively resistant tomato genotypes were identified. These genotypes in increasing order of resistance are S. chilense (LA1029), S. lycopersicum (LA1792), S. chilense (LA1932), S. peruvianum var. humifusum (LA0385) S. pimpinellifolium (LA2934), S. peruvianum f. glandulosum (LA1283) and S. pimpinellifolium (LA1579).展开更多
Objective:To investigate the effect of humic acid on nematode infected,resistant and susceptible grapes in relation to lipid peroxidation and antioxidant mechanisms on selected biochemical parameters known as proactiv...Objective:To investigate the effect of humic acid on nematode infected,resistant and susceptible grapes in relation to lipid peroxidation and antioxidant mechanisms on selected biochemical parameters known as proactive substances.Methods:The grape rootstocks,superior,superior/ freedom and freedom were reacted differently to Meloidogyne incognita and Rotylenchulus reniformis according to rootstock progenitor.Two weeks after inoculation,two commercial products of humic acid were applied at the rate of(2,4 mL or grams/plant) as soil drench.After 4 months,nematode soil populations were extracted and counted.A subsample of roots from each plant was stained and gall numbers,embedded stages per root were calculated,final population, nematode build up(Pf/Pi),average of eggs/eggmass were estimated.Subsamples of fresh root of each treatment were chemically analyzed.Results:Freedom reduced significantly the nematode criteria and build up.Humic acid granules appeared to be more suppressive to nematode build up on superior and the higher dose on superior/freedom than liquid treatments.On freedom,all treatments reduced significantly the nematode build up regardless to the material nature.The higher dose was more effective than the lower one.As a result of humic acid applications,the malondialdehyde(MDA) and H_2O_2 contents were significandy reduced after humic acid treatments while the antioxidant compounds glutathione(GSH),ascorbic acid(ASA) and total phenol contents were significandy increased when compared with check.Antioxidant defense enzymes ascorbate peroxidase(AFX),superoxide dismutase(SOD),catalase(CAT) and polyphenol oxidase(PPO) showed significant increase in their specific activities in treated plants compared with nematode treated check.Conclnsions:Humic acid treatments improve we yield of grape by increasing the contents of antioxidant compounds and the specific activities of antioxidant enzymes.展开更多
文摘The reniform nematode (Rotylenchulus reniformis) is among the most economically damaging plant pathogens in the United States. This nematode is mostly known for its damage to cotton but tomato is also well-within its vast host range that includes 314 plant species across 77 plant families. Nematode-resistant genotypes offer an effective, environmentally safe alternative to agro-chemicals for reniform nematode management. Resistance genes can be introgressed into cultivars through plant improvement efforts. Tomato is a diploid species which is more amenable to identification of resistance genes in contrast to cotton where cultivars are either tetraploid or hexaploid.This greenhouse study examined cultivated and wild Solanum species represented by 40 tomato accessions, to identify resistance and susceptibility responses to R. reniformis. Accessions were evaluated by using single plants in six replicates. Seeds were germinated in sterile soil and inoculated with mixed vermiform R. reniformis. After seven weeks, eggs and vermiform stages were extracted from the root system and counted. A susceptible control S. lycopersicum “Rutgers” (LA1090) was included. Seven putatively resistant tomato genotypes were identified. These genotypes in increasing order of resistance are S. chilense (LA1029), S. lycopersicum (LA1792), S. chilense (LA1932), S. peruvianum var. humifusum (LA0385) S. pimpinellifolium (LA2934), S. peruvianum f. glandulosum (LA1283) and S. pimpinellifolium (LA1579).
基金financially supported by Management of the Faculty of Agriculture and Cario Univerisity
文摘Objective:To investigate the effect of humic acid on nematode infected,resistant and susceptible grapes in relation to lipid peroxidation and antioxidant mechanisms on selected biochemical parameters known as proactive substances.Methods:The grape rootstocks,superior,superior/ freedom and freedom were reacted differently to Meloidogyne incognita and Rotylenchulus reniformis according to rootstock progenitor.Two weeks after inoculation,two commercial products of humic acid were applied at the rate of(2,4 mL or grams/plant) as soil drench.After 4 months,nematode soil populations were extracted and counted.A subsample of roots from each plant was stained and gall numbers,embedded stages per root were calculated,final population, nematode build up(Pf/Pi),average of eggs/eggmass were estimated.Subsamples of fresh root of each treatment were chemically analyzed.Results:Freedom reduced significantly the nematode criteria and build up.Humic acid granules appeared to be more suppressive to nematode build up on superior and the higher dose on superior/freedom than liquid treatments.On freedom,all treatments reduced significantly the nematode build up regardless to the material nature.The higher dose was more effective than the lower one.As a result of humic acid applications,the malondialdehyde(MDA) and H_2O_2 contents were significandy reduced after humic acid treatments while the antioxidant compounds glutathione(GSH),ascorbic acid(ASA) and total phenol contents were significandy increased when compared with check.Antioxidant defense enzymes ascorbate peroxidase(AFX),superoxide dismutase(SOD),catalase(CAT) and polyphenol oxidase(PPO) showed significant increase in their specific activities in treated plants compared with nematode treated check.Conclnsions:Humic acid treatments improve we yield of grape by increasing the contents of antioxidant compounds and the specific activities of antioxidant enzymes.
