Genetic response of hybrid maize to downy mildew caused by Peronosclerospora spp. infection
Syahrir Pakki*, Amelia Sebayang, Hishar Mirsam, Nurasiah Djaenuddin, Nurnina Nonci, Amran Muis.

National Research and Innovation Agency, Research Organization for Agriculture and Food

*Correspondent author: andisyahrirpakki111255[at]gmail.com

Abstract

Maize is the second staple food commodity in Indonesia. Apart from being the main source of carbohydrates and protein, the production of maize continues to increase along with the escalation of population growth and animal feed requirements in the last few years. The potential to increase the national production of maize is still feasible because of the yield gap between the potential yields of new superior varieties and the level of yields obtained by farmers. The yield gap caused by biotic stress in maize is mainly caused by pathogens such as downy mildew due to Peronosclerospora spp. Downy mildew distribution is sporadic that can infect a wide area. In Indonesia, it spreads widely and significantly reduces yields in the areas of maize production centres in East Java, Central Java, South Sulawesi, North Sulawesi, Gorontalo, Lampung, and Sumatera. These obstacles can be overcome by integrated pest and disease control technology. One of the strategies is the discovery of downy mildew-resistant varieties that can be combined with other control treatments. The phenomenon of resistance to downy mildew infection of several hybrid maize strains began to be detected in the vegetative growth phase, with symptoms beginning at 14 days after planting (DAP), increasing with plant age, and reaching its peak after 28-35 DAP and then the symptoms will gradually disappear until no infection after 42 HST. This study analyses the resistant maize varieties from 2020 to 2022. The data showed the susceptible comparison variety (Anoman) was infected with 88.94% to 100%. In 2020, BMD73 showed a resistant reaction to Philippinensis species, other strains were classified as susceptible in P. maydis except BMD 76. All strains showed highly susceptible and susceptible reactions. In 2021, in P. philippinensis all strains FCP921.1-FCP921.7 showed a resistant reaction, but line FCP921.1-FCP921-7 had a resistance response that was classified as moderately resistant to P. maydis. The incidence of

Keywords: downy mildew, Perenosclerospora spp, maize

Topic: Integrated pest and disease management