Inheritance of resistance to the ‘Kanpur’ race of Phytophthora drechsleri in pigeonpea

Abstract

Phytophthora drechsleri causes stem blight, which is one of the most serious diseases of pigeonpea. Eight races of this fungus have been identified, but the inheritance of resistance to all these races is not clear except for race P2. This study examined the inheritance of resistance to race ÔKanpurÕ (KPR) of P. drechsleri in eight crosses involving four resistant parents, viz. ÔKPBR 80-2-1Õ, ÔKPBR 80-2-2Õ, ÔHy 3CÕ and ÔBDN 1Õ, and two susceptible parents, viz. ÔBaharÕ and ÔPDA 10Õ. The reactions of the parental lines, and their F 1 , F 2 and backcross generations were studied in an infected plot. In the F 1 generation of all crosses, a susceptible reaction was observed that indicated dominance of susceptibility over resistance. The segregation pattern in F 2 indicated that two homozygous recessive genes (pdr 1 pdr 1 pdr 2 pdr 2 ) were responsible for imparting resistance in the parents, ÔKPBR 80-2-1Õ and ÔKPBR 80-2-2Õ, and that a single homozygous recessive gene (pdrpdr) was responsible for resistance in the parents ÔHy 3CÕ and ÔBDN 1Õ. Therefore, ÔKPBR 80-2-1Õ and ÔKPBR 80-2-2Õ with two genes for resistance are better donors because the resistance transferred from them will be more durable compared with ÔHy3CÕ and ÔBDN1Õ with only one gene for resistance.

Influence of rice grain traits to their susceptibility to the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera, Bostrichidae)

“…The selected varieties of rice were obtained from ICAR -National Rice Research Institute, Cuttack; while RNR-15048 was obtained from the Seed Unit at Centurion University. These varieties were kept in the oven for disinfestation at a temperature of 55 o C for 4 hours to eliminate the hidden infestation if any, without affecting the viability of the seeds (Singh, 1989). The grains were kept in a desiccator with KOH solution (51g of KOH per 100 ml of water) for 21 days after disinfection to raise the moisture content near equilibrium (Solomon, 1951).…”