Selection of Rhizobium isolates able to improve productivity of lentil (Lens culinaris Medik)

Nitrogen-fixing efficiency is influenced by genetic combination of rhizobia strain/legume genotype. In this research, 48 rhizobia isolates from lentil (Lens culinaris Medik) were characterized for DNA polymorphism and assayed for their ability to improve, in open field, grain yield of lentil. By DNA polymorphism analysis, only four haplotypes were observed for Rhizobium isolates from lentil seeds, whereas a higher genetic variability was observed for Rhizobium isolates obtained from root-tubercles. The performance of the 11 rhizobia haplotypes was analysed in the field after inoculation on two Italian lentil ecotypes. Two isolates of rhizobia induced a significant improvement of grain yield (plus from 37% to 40% with respect to non-inoculated plants) on the Colfiorito ecotype, whereas no significant improvement of yield was obtained on Colliano.