National Research Centre for Sorghum, AICSIP, IARI, Regional Station, Hyderabad, 500 030, India
Four experiments were conducted to determine the stability of varietal resistance and dominance of rust reaction in F1 hybrids under different genetic (plant pigment) and cytoplasmic backgrounds. All the tan pigmented varieties and hybrids were not resistant to rust. GSV-4 and SPV-312 were tan (T) parents highly resistant and stable in rust reaction over environments. Male sterile and B-lines were moderately susceptible.
Purple (P) pigmented parents transmitted susceptibility as dominant character. Incomplete dominance of resistance was observed in some of the T x T crosses where one of the parent was highly resistant. The T X T hybrids were relatively more resistant than T X P or P X P crosses. Partial dominance mechanism of resistance observed in some T X T crosses cculd be useful to develop commercial hybrids.
