Biochemical basis of resistance in different varieties of maize for their relative susceptibility to Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae)

Abstract

Study on the susceptibility of 20 maize varieties against Angoumois grain moth, Sitotroga cerealella (Olivier) was carried out under No-choice test method. The susceptibility was assessed on the basis of moth emergence, developmental period, insect weight, weight of flour, grain weight loss, grain damage and nutritional indices. Besides, biochemical characters of the grains were analyzed. Results showed that Pratap makka-5 was the most resistant variety with longest developmental time of 38.36 days, least adult emergence of 3.5, lowest susceptibility index of 2.88, minimum grain damage of 7.21% and grain weight loss of 1.45% followed by EH-2253 and EH-2101. The most susceptible varieties were PMH-1, Navjot, KH-101 and HQPM-1 with shortest developmental time, highest adult emergence, highest susceptibility index, highest grain damage and highest weight loss percentage. Correlation coefficients between susceptibility parameters and biochemical characteristics were calculated, yielding a clear relationship amongst different chemical/nutraceutical parameters, and susceptibility traits. Ash content positively correlated with the progeny emerged (r=0.476) and the susceptibility index (r=0.559). Furthermore, ash content negatively correlated with the median developmental time (r=-538). Amylose and susceptibility index (r=0.734) and phenolic and median development time (r=680) had strong positive relationship. The varieties with low ash content, increased phenolic and reduced amylose concentration had more resistance to S. cerealella. This research showed that it is important to breed maize variety considered on the low ash, low amylose and high phenolic content besides other morphological and physical characteristics in order to get maize variety which is resistant to S. cerealella. Key words: Sitotroga cerealella, biochemical properties, susceptibility index, maize post-harvest research.