Abstract

                                A field experiment was conducted to determine the effect of spacing and nitrogen on heat unit requirement, growth and yield of horsegram (Macrotyloma uniflorum L.). Regarding the crop phenology, observation indicated that the crop had maturity period ranging from 95 to 100 days and 98 to 106 days for CO, and Paiyur, respectively. Analysis of phenophase wise heat units showed the highest value at late reproductive phase (pod initiation to pod maturity) followed by vegetative phase (emergence to branching) in both the cultivars. It has been observed that application of nitrogen @ 10 kg ha¹ had advanced the days to flower initiation by 4 days in CO, and 3.5 days in Paiyur,. The treatment with nitrogen @ 10 kg ha¹ and spacing 30 x 10 cm recorded the greater values of crop growth characters. However, the treatment with nitrogen @ 10 kg ha' and spacing 30 x 5 cm recorded the greater values of yield characters in both the cultivars

Key words : Horsegram, Photo Thermal Unit, Hello Thermal Unit, Phenology.