A New Gene that Controls Root Nodulation in Chickpea
- Onkar Singh and
- O. P. Rupela
Nonnodulating (Nod−) genotypes are an important genetic resource for studies of the legume-rhizobium symbiosis. Investigations were carried out to determine the host genetic control of nodulation in two newly identified Nod− chickpea (Cicer arietinum L.) genotypes, Annigeri NN and Rabat NN, and the genetic relationship between these and other known Nod− genotypes. Annigeri NN and Rabat NN were crossed with each other, with their respective wild-type parents ‘Annigeri’ (Desi) and ‘Rabat’ (Kabuli), and with already known Nod− mutants P319-1 NN and PM 233. The parents, F1, F2, and backcross progenies of the crosses were tested for nodulation by mean of a mixture of rhizobial strains in the greenhouse. Chi-square tests were conducted on the crosses to examine genetic hypotheses of monogenic and digenic inheritance. Genetic analyses of Nod− × Nod+ crosses showed a monogenic recessive gene action for nonnodulation in both Annigeri NN and Rabat NN. The studies of Nod− × Nod− crosses indicated that the same gene controls root nodulation in Annigeri NN and P319-1 NN, and that this gene is different from the ones controlling the Nod− trait in Rabat NN and PM 233. These results implied that the recessive gene controlling nonnodulation of roots in Rabat NN is different from the ones earlier identified in PM 233, P319-1 NN, and Annigeri NN. A new gene symbol, rn8, is proposed to be assigned to the locus producing the Nod− phenotype in Kabuli chickpea genotype Rabat NN. This is the first report of a nonnodulating gene in Kabuli chickpea.
Copyright © . .