Genetic variability and physico-chemical basis of resistance in sorghum to shoot fly, Atherigona soccata

Sorghum shoot fly, Atherigona soccata is one of the important insect pests of sorghum. Information on genetic diversity and mechanisms of resistance is important for developing sorghum cultivars with stable resistance to this pest. We evaluated 30 sorghum lines exhibiting resistance to shoot fly by using 38 SSR markers to measure genetic diversity, and biochemical profiles to identify genotypes with diverse mechanisms of resistance to A. soccata. Phule Yasodha, Mouli, Phule Anuradha, IS 2312, Phule Vasudha, and RVRT 2 showed resistance to shoot fly damage and also exhibited high grain yield potential during the postrainy season. ICSB 433, ICSV 700, ICSV 25019, ICSV 25022, ICSV 25026, ICSV 25039, PS 35805, Akola Kranti, and IS 18551 exhibited antixenosis for oviposition and antibiosis against A. soccata. Shoot fly-resistant lines had high amounts of tannins, polyphenols and proteins as compared to the susceptible check, Swarna. The phenolic compounds kaempferol and salicylic acid were present in the shoot fly-resistant genotypes, but absent in the susceptible check, Swarna. 3, 4-dihydroxy benzoic acid amounts were high in the susceptible check, Swarna, but it was absent in the resistant check, IS 18551. The shoot fly-resistant genotypes ICSB 433, ICSV 700, Pule Yasodha, Mouli, Phule Chitra, Phule Anuradha, ICSV 705, ICSV 93046 and RVRT 2 had similar HPLC fingerprints as the resistant check, IS 18551. Genetic diversity analysis based on SSR markers placed the test genotypes into four groups, suggesting that the sources of resistance to shoot fly are genetically diverse. The genotypes showing resistance to shoot fly with different combination of HPLC fingerprints and genetic diversity based on molecular markers can be used in sorghum improvement program to increase the levels and diversify the basis of resistance to shoot fly for sustainable crop production.