Varietal response of sunnhemp, Crotalaria juncea L. to Rhizobium japonicum (cowpea type) with reference to dynamics of nodulation

Varietal response of sunnhemp to Rhizobium japonicum was studied in terms of nodule number and nodule size for five varieties at six different crop stages.There was no significant difference amongst the varities in nodulation. However, there was, significant difference between crop ages in nodulation. The interaction behveen varieties and crop age was not significant in nodulation. The peak nodulation in sunnhemp occurs well before flowering stage (24–28 days after sowing) unlike other legumes where maximum nodulation was noticed at flowering stage. Dynamics of nodulation based on nodule number reveals that three varieties namely K-12 yellow, SS-11 and Chindwara were best fitted to Couchey model whereas two varieties, K-12 black and SJ-67-42 were best fitted to reciprocal straight line and hyperbola respectively. Similarly, the nodule dynamics based on nodule size (diameter) revealed that K-12 black and Chindwara were best fitted to couchey model whereas K-12 yellow, SJ 67–42 and SS-l1 were best fitted to modified hoerl. Thus, varieties responded differently in nodule dynamics based on both nodule number and nodule size.