Genetic Manipulation Of Nodulation In Groundnut

There is large variation among cultivars of groundnut in ability to nodulatc and fix nitrogen (N), and in seasonal and diurnal patterns of nitrogenase activity. Total N uptake, or total dry matter production, may be a useful index in ranking cultivan for N2-fixing ability. Certain cultivars of Arachis hypogaea ssp. hypogaea var. bpogaea formed up to 13% of their total nodule number on the hypocotyl, and some cultivars even nodulated on the stem above the crown of the plant. In contrast, cultivars from A. hypogaea ssp. fastigiata var. fasrigiata and var. vulgaris formed few nodules on the. hypocotyl. Non-nodulating plants have been observed in 13 crosses. Genetic analysis indicates that two independent recessive genes are involved. Some progeny of these crosses also form a few big nodules, a trait which seems to be controlled by the host plant