UV-B IRRADIANCE INDUCED DELETERIOUS EFFECTS ON THE NET PRIMARY PRODUCTIVITY AND COUNTERACTED BY SOME PLANT GROWTH REGULATORS (PGRs), IN BRASSICA COMPESTRIS PT-303 (BROWN SARSON)

The aim of present study to be evaluated the appropriate concentrations of plant growth regulators i.e. (10 -7 ) to (10 -5 M) over UV-B damage on Brassica compestris PT-303. Seeds of Brassica compestris PT- 303 (Brown sarson) were sown in sandy loam soil in field plots (A, B, C, D and E). Plot-A of mustard crop was treated as control and neither sprayed with growth regulators nor exposed to UV-B radiation. Pot-B was treated with UV-B radiation (3-hrs. daily) only. Plot-C was sprayed with IAA solution of (10 -7 M), Plot D was sprayed with Kn solution of (10 -5 M) and plot-E was sprayed with solutions of GA 3 (10 -6 M) concentration daily, along with UV-B radiation in Brassica compestris PT-303. It was observed that IAA was found most effective in (10 -7 M), Kn in (10 -5 M) and GA 3 in (10 -6 M) in crop of Brassica compestris PT- 303 respectively. Therefore, for the field studies, only these concentrations were taken to assess for the studies of net primary productivity of Brassica compestris PT-303 (Brown sarson). Keywords: Brassica compestris PT-303, Total net productivity, IAA, Kn GA 3, and UV-B exposure.