Thumbiko Mkandawire, PLANT SCIENCE, SDSU, Brookings, SD, Karl Glover, Plant Sciece, SDSU, Brookings, SD and William A. Berzonsky, BayerCrop Science, Lincoln, NE
Plant genotypes with lesion mimic genes constitutively produce hypersensitive reaction-like flecks, chlorotic and necrotic symptoms in the absence of pathogen infection. On the other hand, they are potential sources of resistance genes against different diseases in different plant species. However, some studies have reported that they are less productive since they prioritize the energy resources for defense at the expense of reproductive development. Therefore, we conducted an experiment to evaluate the effectiveness of Allopurinol compound in suppressing formation of hypersensitive reaction-like symptoms on Ning7840 and Alsen genotypes that possess and lack the lesion mimic genes respectively under different levels of Allopurinol treatment in a greenhouse environment. Furthermore, we also wanted to evaluate the effects of Allopurinol treatment on grain yield, grain number and chlorophyll content. There were significant genotype X Allopurinol treatment interaction effects on mean grain yield, mean grain number and amount of chlorophyll in the leaves. There was a positive increase in grain yield and grain number with increase application of Allopurinol treatment up to 50µM, beyond this level there was negative response in grain yield and grain number. Allopurinol treatment reduced hypersensitive reaction-like symptoms in the lesion mimic line, with highest level (75µM) having the least chlorotic area. There was a decline in mean chlorophyll content, with Allopurinol levels above 25µM in lesion mimics line; on the contrary, there was an increase in chlorophyll content with higher levels of Allopurinol in a non-lesion mimic line (Alsen). Allopurinol level of 50µM gave the highest genotypic mean grain yield while 75µM gave the lowest chlorotic leaf area in Ning7840. In general, the results suggest that higher levels of Allopurinol treatment were effective in suppressing hypersensitive reaction-like symptoms in Ning7840 but at the expense of grain yield and grain number, which was higher at 50µM.