Stability of resistance to sorghum shoot fly, Atherigona soccata

Sorghum shoot fly, Atherigona soccata is one of the most important pests of dual-purpose sorghums during the postrainy season in India. Therefore, it is important to identify stable sources of resistance to develop cultivars with shoot fly resistance and adaptation to postrainy season. We evaluated 190 lines adapted to the postrainy season across five locations, of which 30 lines were identified with resistance to A. soccata. These lines were further evaluated for three seasons across five locations to identify lines with stable resistance to this pest across seasons and locations. Data were recorded on oviposition non-preference, deadheart incidence, recovery resistance, morphological traits (leaf glossiness, seedling vigor, plant height and days to 50% flowering), and grain yield. The sorghum genotypes CSV 22, ICSB 422, ICSB 425, ICSB 428, ICSB 432, ICSB 458, ICSB 463, IS 2312, IS 5480, IS 18662, Phule Chitra, RSV 1093, IS 18551, and RSV 1235 exhibited resistance to shoot fly damage across seasons, of which ICSB 425, ICSB 428, ICSB 432, IS 2312, IS 5480, and IS 18551 showed non-preference for oviposition. Six genotypes (ICSB 425, IS 2312, IS 18662, RSV 1090, RSV 1093, and IS 18551) also showed good recovery resistance following shoot fly damage. Principal coordinate analysis placed the maintainer lines (B-lines) with shoot fly resistance in two clusters with ICSB 422, ICSB 432, ICSB 435, ICSB 456 and ICSB 458 in one cluster and ICSB 425, ICSB 428 and ICSB 463 in the other; the open pollinated varieties/germplasm lines (restorers) were placed in a different group (CSV 22, IS 5480, IS 2312 and RSV 1093), suggesting the possibilities for developing hybrids with adaptation to the postrainy season. Based on regression coefficient and deadheart incidence, the genotypes IS 2312, ICSB 425, RSV 1090 and ICSB 428 were stable in expression of resistance to shoot fly across seasons and locations. The genotypes CSV 22 and RSV 1093 exhibited high grain yield potential and resistance to shoot fly damage, while Phule Yashoda, IS 2312, RSV 1235, and ICSV 574 were moderately resistant to shoot fly damage, but had high grain yield potential. These genotypes can be used in sorghum improvement for developing cultivars with shoot fly resistance, high grain yield and adaptation to postrainy season.