GRAIN WEIGHT AND GRAIN QUALITY OF WHEAT IN RESPONSE TO ENHANCED ULTRA-VIOLET (UV-B) RADIATION AT LATTER STAGES OF CROP DEVELOPMENT

摘要

The increase of UV-B radiation may be a challenge for wheat production systems inSouthern Chile. Previous reports had shown that increased UV-B radiation decreasedwheat yield by affecting both grain number and grain weight. The objective of thepresent study was to evaluate the response of grain yield, yield components and grainquality to higher UV-B radiation during key periods for yield component determination. The experiment was carried out at field conditions in the Universidad Austral deChile (40 deg South latitude). Treatments consisted on 2 spring wheat cultivars exposedto 2 periods of supplemented UV-B radiation (280-320 nm): between (f) booting andanthesis and (if) anthesis and physiological maturity. Ultra-violet radiation was enhanced3.5kJ m~(-2) during 5 hours per day by UV-B lamps (Q panel UV-313, Philips). Atharvest, plants were sampled to quantify above-gound biomass, grain yield, grainnumber and thousand grain weight. In addition, protein and gluten concentration ofgrains were measured. Grain yield was not affected (p > 0.05) by UV-B increaseeither at pre- nor at post-anthesis treatments. Similar results were found for each yieldcomponent. In addition, grain protein and gluten concentration showed similar valuesbetween enhanced UV-B and control treatments. Therefore, these results do not supportthat expected increases of UV-B radiation in Southern Chile could compromise wheatproduction systems, at least if increases of UV-B radiation take place at latter stages ofthe crop cycle.