author(s)
D Sudha Rani, Ch. Chiranjeevi, T Madhumathi, S Krishnam Raju and SK Nafeez Umar

abstract
A total of 215 rice germplasm lines were screened for their relative resistance or susceptibility against rice yellow stem borer, S. incertulas for two successive kharif seasons (kharif 2016 & 2017). The screening trial was executed in augmented block design with 215 rice entries along with local check (BPT 5204) and susceptible check (TN1). The stem borer incidence in terms of per cent dead hearts and per cent white ears at peak infestation were recorded and based of SES scale the status of the rice germplasm screened were determined. The pooled mean of two seasons’ data in terms of per cent DH infestation by YSB inferred that out of 215 germplasm lines screened, none of them registered resistance scale, whereas 87 were moderately resistant, 116 were categorized as moderately susceptible and 22 lines exhibited the status of susceptibility with damage rating of 11-20, 21-30 and 31-40 per cent DH. Similarly, the pooled mean with respect to per cent WE revealed that among 215 germplasm lines, only 14 were found to be resistant, whereas 101, 82, 17 and 1 entries were rated as moderately resistance, moderately susceptible, susceptible and highly susceptible entries, with per cent white ears damage ranged from 6-10, 11-15, 16-20 and 30 percent respectively. The rice entries which had expressed moderate resistance against dead hearts were found susceptible to white ear damage and vice versa confirming both the parameters as independent factors in conferring resistance. Keeping in view the parameters (DH & WE) influence on rice yield, seven germplasm lines (IC No. 381538, 450535, 463380, 464140, 464186, 574807 and 578388) with resistance/ moderately resistant reaction at both vegetative (DH) and reproductive (WE) stages of the rice crop were selected as promising rice genotypes for further breeding programmes.