Investigation of nodulation and nitrogen fixation in annual species and varieties of vetchling, genus Lathyrus

The number of root nodules and nitrogen-fixation rate (judged from nitrogenase activity) were studied in nine varieties of five annual vetchling species: Lathyrus sativus, L. tingitanus, L. chloranthus, L. ochrus, and L. odoratus. All vetchling varieties were inferior to pea Pisum sativum in their nitrogen-fixation rate. A variation in nodulation pattern (nodule by number, size, and location) on roots and nitrogen-fixation rate among species and varieties was detected. With regard to nitrogen fixation, the Alisa and Nokturn varieties of sweet pea (L. odoratus) and Anna and Pink Flamingo of Tangier pea (L. tingitanus) deserve special attention.