EN
Field experiments were conducted to determine the effects of exclusion ofUV-A/BandUV-Balone on growth parameters, activity of antioxidant enzymes, level of antioxidants and yield, to evaluate the intra-specific variations in sensitivity of these responses in eight soybean (Glycine max) varieties (PK-472, PK-1029, Pusa-24, JS-7105, JS-335, Hardee, NRC-7 and Kalitur). The plants were grown in specially designed UV-exclusion chambers which lined with selective UV filters to exclude either UV-B (\320 nm) or UV-A/B (\400 nm). Plants grown under UV-exclusion filters were compared with those grown under polythene filter which transmitted ambient UV-B and UV-A radiation. The results indicate that the exclusion of solar UV-B and UV-A/B enhanced the vegetative growth (plant height and leaf area), total biomass accumulation and yield (number of seeds and seedweight) of all the varieties as compared with those grown under ambientUV.The activities of SOD,GPX,APXandGR, and levels of ASA were significantly decreased, while atocopherol increased after the exclusion ofUV-BandUV-A/B in all varieties. These results suggest that the ambient level of UV-B and UV-A radiation evoked some active oxygen species to accumulate, which in turn retarded the growth, development and yield of soybean varieties. On the basis of biomass, UV-B (280–315 nm) sensitivity can be arranged in decreasing order as PK-472[Hardee[JS-335[Kalitur[ JS 71-05[Pusa-24[NRC-7[PK-1029 and UV-A/ B sensitivity can be arranged in decreasing order as PK- 472[Kalitur[JS-335[Hardee[Pusa-24[JS 71-05[ NRC-7[PK-1029. The results indicate var. PK-472 is more sensitive than other varieties and PK-1029 is least sensitive to ambient level of UV radiation. This study in the area of UV-B andUV-A/B stress provides an extensive data that can be used as a predictive basis in crop sciences to further investigate some of the tolerant varieties in field studies.