Parallel response between gametophyte and sporophyte for Fusarium wilt resistance in the recombinant inbred lines of chickpea (Cicer arietinum L.)

摘要

In the present communication, we study the possibility of screening of a large set of chickpea recombinant inbred lines (RILs) for wilt resistance through in vitro pollen tube growth inhibition in the presence of pathotoxin. Further, the number of alleles with resistance differs in their degree of resistance at both gametophytic and sporophytic phase. The RILs of cross JG-62 (highly susceptible) x WR-315 (resistant), segregate for both the loci of wilt resistance and molecular markers linked to the wilt resistance loci. The pollen grains of 43 randomly selected RILs were cultured in cavity slides in the laboratory. The addition of increased concentration of the pathotoxin to the pollen germination medium inhibited pollen tube growth of all the lines. The tube growth inhibition was not uniform across all the lines. It was highest in highly susceptible lines followed by susceptible lines. The degree of pollen resistance depends on the number of alleles/genes for resistance it carries and pollen resistance segregates with alleles for resistance. The study evidenced the parallel response between gametophytic and sporophytic wilt resistance. The toxin concentration required to inhibit 50% pollen tube growth was determined for all the lines. The resistant lines required significantly higher mean toxin concentration for 50% pollen tube growth inhibition, followed by susceptible and highly susceptible lines. The correlation between sporophytic wilt resistance and toxin concentration to inhibit pollen tube growth was highly significant. Higher the sporophytic resistance to wilt, higher was the concentration required to inhibit its pollen tube growth under in vitro conditions. Consequently, pollen response has a potential for rapid and inexpensive screening of a large set of genotypes for biotic stress tolerance.