Resistance levels of selected rice genotypes to <i>Sitophilus oryzae</i> L. and <i>Rhyzopertha dominica</i> F. infestations

Abstract

The need to screen new rice genotypes for resistance to stored product insect pests is important to boost production and availability of rice for food security. Therefore, thirteen rice genotypes and varieties included ten interspecific rice genotypes from two crossed parents Oryza sativa (WAB 56-104) and Oryza barthii (IRGC 106107), the two parents and NERICA8 variety were collected from Africa Rice Center, International Institute of Tropical Agriculture (IITA) Ibadan, to examine their resistance level to infestation by Sitophilus oryzae L. and Rhyzopertha dominica F. The resistance of the varieties were assessed by artificial infestation with 12 unsexed adults each in 10 g of the rice varieties in four replicates under laboratory conditions of 26 ± 2oC temperature and 75 ± 5% relative humidity in a completely randomized design. Number of adult insect emergent, per cent grain damage, percent weight loss of infested samples and index of susceptibility were determined. Correlation analysis between nutritional contents of the varieties and infestation variables were also obtained. Results indicate differential responses of the two insects on the rice genotypes/varieties. The O. barthii parent was resistant, while the O. sativa parent was moderately resistant using the susceptibility index. Of the ten rice genotypes, G4, G3, G1, G7, G2, G10 and G9 were resistant in descending order, while G5 and G6 were moderately resistant, whereas only G8 was susceptible. NERICA8 was also found to be susceptible to infestation. In addition, the resistant grains had lower ash content. Modification in genetic variations and nutritional contents of new rice varieties may be a critical factor in insect resistant genotype pro-grammes to reduce post-harvest losses incurred by farmers.&#x0D; Keywords: Rice resistant genotypes; Rhyzopertha dominica; Oryzae sativa; Oryzae barthii; Sitophilus oryzae; susceptibility index

Kerentanan Relatif Jenis Beras Terhadap Sitophilus oryzae L. (Coleoptera: Curculionidae) Pada Keadaan Kadar Air Rendah

“…Hasil penelitian Gowda et al (2019) juga mengungkapkan tentang kerentanan beras terhadap S. oryzae yang ditentukan oleh jumlah F1 yang banyak dan median waktu perkembangan dari S. oryzae yang singkat. Ajao et al (2019) dan Hendrival et al (2019c) mengemukakan bahwa kerentanan beras dan sorgum terhadap S. oryzae ditentukan oleh jumlah F1 yang banyak dan median waktu perkembangan yang singkat. Kerentanan beras juga dipengaruhi oleh kadar airnya selama penyimpanan.…”

“…Jumlah F1 yang banyak dan median waktu perkembangan yang singkat dari S. oryzae dapat meningkatkan kerusakan beras. Hasil penelitian Ajao et al (2019) dan Annisa et al (2021) menunjukkan bahwa jumlah F1 yang banyak dan median waktu perkembangan singkat dapat meningkat kerusakan beras. Kerusakan beras berkaitan dengan aktivitas makan dari larva dan imago dengan gejala kerusakan dimulai dengan terbentuknya beberapa lubang tak beraturan bekas gigitan pada bagian permukaan butiran beras.…”

Varietal Screening of Rice Genotypes for the Rice Weevil, Sitophilus oryzae (Linnaeus) (Curculionidae: Coleoptera) at Laboratory Condition

“…These findings are somewhat in line with Regmi et al (2017). Ajao et al (2019) who observed that small seed size, tightness of it hull, and reddish caryopsis of a particular variety could explain why it was resistant to S. oryzae attacks. However, the infestation in all cases seems to be less because of the hull covering of grains in rough rice as hull comprises 18 to 25% of the rough rice.…”

Genetic Transformation of two Turkish rice (Oryza sativa L.) cutivars through Agrobacterium tumefaciens

“…Previous literature suggests that rice breeding for resistance against rice weevils through traditional rice breeding approaches is not helpful [9,10,11,12,13].…”