The impacts of maize seed phenology and nutritive traits imparting tolerance to the rice weevil (Sitophilus oryzae L.).

Abstract

Maize is an important food, industrial, and energy crop. In recent years, the maize production has been increasing globally, but also seed losses during storage caused by the stored product pests, particularly the rice weevil (Sitophilus oryzae). This emphasizes the need to minimize postharvest losses, possibly including the development of resistant genotypes. It requires resistance level monitoring across genotypes and nderstanding phenotypic, biochemical (starch, protein, oil, phenolics, antioxidative capacity) and biophysical (kernel hardness, moisture, and weight) traits that influence insect development. This study assessed the susceptibility of 39 maize genotypes to S. oryzae and determined how different seed traits affect the pest development (progeny production - PP) and feeding intensity. Genotypes of the hardest seeds were found among flint (328.93-481.00 N) and popcorn types (324.17-449.20 N). NIR spectroscopy revealed the highest protein content in popcorn (12.07%), starch in dent (65.0%), and oil in white (13.63%) and sweet maize (10.97%) types. Phenolic compounds content varied significantly among genotypes, while antioxidant capacity showed no statistical difference. PP positively correlated with seed moisture (%), content of phenolic ompounds, and antioxidative capacity, but strongly negatively correlated with percentage of oil content. After four generations, the biotest revealed the lowest number of emerged adults on flint, semi-flint, and sweet maize genotypes. The most tolerant/resistant genotypes - 605413 NS (semi-dent), MB 982 (flint), Crveni Kosjerić (semi-flint), and Beli osmak II (flint) - showed reduced seed consumption and progeny production in S. oryzae. Cultivating these genotypes can be recommended to reduce storage losses and support maize production stability.