Heterosis for shoot fly [Atherigona soccata (Rondani)] resistance in sorghum

Abstract

In India, more than 75% of the kharif sorghum growing area is covered by F1 sorghum hybrids, and all of them are highly susceptible to shoot fly [Atherigona soccata (Rondani)] damage. Shoot fly attack is very severe in late-sown kharif and early-sown rabi sorghums. The present study was aimed to test whether exploitable heterosis for shoot fly resistance in F1 hybrids involving CMS (A-lines) and a set of restorers is available. Fourteen F7 recombinant inbred lines derived from the cross 2968 (shoot fly susceptible) x IS 18551 (resistant) were used as testers to develop 28 F1 hybrids with two CMS lines (296A and 27A) in a line x tester mating design. All the 14 restorers, 2 CMS lines, their hybrids (28), and the parents of the restorers (2968 and IS 18551) were planted in a randomized block design with three replications at the National Research Center for Sorghum (NRCS), Hyderabad during the late kharif (first week of August) and early rabi (last week of September) cropping seasons of 2004. The test material was evaluated for shoot fly resistance using standard fish-meal screening technique. Each entry was sown in a two-row plot of 4 m length, with an inter row spacing of 0.60 m. No insecticide was applied in the experimental plots. Observations were recorded on number of eggs seedling-1 (oviposition) at 21 days after seedling emergence (DAE), and deadhearts (DH %) at 28 DAE. Heterosis (H) was calculated following standard procedures.