Breeding for resistance to shoot fly in sorghum during post rainy season.

Abstract

Genetic enhancement for shootfly (Atherigona soccata (Rondani)) resistance was assessed in different segregating generations of sorghum crosses and their parents under different levels of shootfly infestation. The inheritance was studied for oviposition and deadheart formation. Field trials were conducted with F3 , F4 and F5 sorghum progenies for three consecutive years from 2005-08 in post rainy seasons at the farm attached to Directorate of Sorghum Research, Solapur. Five crosses viz., 104 B x IS 2122, RS 585 x IS 18551, R 354 x RSE 97109, RSE 3 x CSV 216 R and R 354 x IS 18551 were taken during three years. F3 s material (172 entries) was subjected to shootfly evaluation. The material was evaluated in F3, F4 and F5 generations during Rabi (2006-08) consisted of 172, 71 and 49 entries, respectively. Shootfly eggs and deadhearts were monitored at 21 days after germination under natural pesticide free condition. Overall improvement of resistance was recorded from F3 to F4 generation in all crosses. A similar consistent increasing trend on oviposition and deadhearts formation was observed with all the crosses in F5 generation. A similar trend in improvement of resistance levels observed in terms of oviposition in F5 progenies ranging from 56.6 % (R 354 x IS 18551) to 92.8 % ( R 354 x CSV 216 R). The consistent levels of shootfly deadheart formation were recorded with the resistant check, IS 2312 (20.95-25.64 %). These crosses will be subjected to evaluation in subsequent generations to obtain stable lines for shootfly resistance. The selection for low level of deadheart percentage would improve the level of resistance in the subsequent generations. The crosses viz., R 354 x IS 18551, 104 B x IS 2122, RS 585 x IS 18551 were conferred with resistance to shootfly.