Tamil Nadu Agricultural University, Coimbatore
The possible mechanism of resistance to yellow vein mosaic disease of okra was assessed by estimating the chemical constituents in the resistant and susceptible types of okra. The role of nitrogenous compounds in resistance mechanism was reported. The total nitrogen was low in the resistant donors and F1 hybrids derived therefrom. In the nitrogen fractions, amide nitrogen and nitrate nitrogen were higher in the resistant wild parents while protein nitrogen, ammoniacal nitrogen and nitrate nitrogen were higher in the susceptible cultivar parents. The total crude protein was higher in the susceptible cultivars. Thus the amide and nitrate fractions of nitrogen were responsible for resistance while higher total nitrogen made up from other fractions of nitrogen rendered the host susceptible to yellow vein mosaic disease.
