Abstract
Nicotinamide adenine dinucleotide (NAD) has been shown to induce plant defense responses to different plant pathogens, including reducing northern root-knot nematode, Meloidogyne hapla, penetration and increasing plant mass in tomato. We wanted to further evaluate NAD that are effective against the more economically important species, M. incognita and whether NAD treatments of tomato seedlings in transplant trays can protect plants in the field. Different NAD concentrations (1 mM, 0.1 mM and 0.01 mM) and three application timings (pre; post; pre and post inoculation) were evaluated in growth room and greenhouse trials. The highest tested NAD concentration (1 mM) suppressed second-stage juveniles (J2) infection for all three application methods. Root gall ratings at 30 days after inoculation (DAI) were also suppressed by 1 mM NAD compared to the other two concentrations, and egg mass number was significantly suppressed for all concentrations and application timings compared to the non-treated control. The rate of 1 mM NAD for all three application timings also improved plant growth at 30 DAI. Long-term effects of 1 mM NAD (pre, pre + post, or post applications) on nematode infection, growth and yield of tomato were evaluated in two additional experiments. All NAD applications suppressed root galls after 60 days, but only the pre + post 1 mM NAD application suppressed gall severity at 105 days, as well as suppressed egg counts by 50% at 60 DAT. No significant difference in plant biomass and fruit yield after 105 days was observed among the treatments. Two field trials were conducted in spring and fall 2020 using tomato seedlings (cv. HM 1823) treated with two different NAD concentrations (1 mM and 5 mM in spring; 5 mM and 10 mM in fall) and transplanting seedlings in fumigated (chloropicrin ± 1,3-dichloropropene) and non-fumigated plastic-mulch beds. No significant impact of NAD in terms of reducing RKN severity or overall tomato growth and production was seen in fumigated beds, but in non-fumigated beds 5 mM NAD slightly increased early fruit yield in spring, and 10 mM NAD reduced root-knot soil populations in fall.
Highlights
Non-chemical approaches to combat various pests and pathogens in agriculture including plant-parasitic nematodes are desirable as they are safer to humans and the environment
Growth room experiments: All application timings of 1mM Nicotinamide adenine dinucleotide (NAD) significantly suppressed J2 root penetration compared to the non-treated control at 2 days after inoculation (DAI) (Table 1)
All NAD concentrations for all application timings suppressed egg masses at 30 DAI compared to the control (Table 1)
Summary
Non-chemical approaches to combat various pests and pathogens in agriculture including plant-parasitic nematodes are desirable as they are safer to humans and the environment. The resistance is governed by a single dominant gene, Mi, which is effective against the most common tropical and sub-tropical species of RKN It is not effective against other RKN spe cies that are common in Florida such as M. hapla, M. enterolobii, M. floridensis or M. haplanaria (Crow and Duncan, 2018). We wanted (i) to evaluate the potential of NAD against a thermophilic RKN species, (ii) evaluate the optimal concentration and application timing of NAD, and (iii) determine the length of protection and (iv) evaluate transplant tray treatments for protection of tomato under natural field conditions
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
