MANGANESE SEED CONTENT AND TAKE-ALL OF CEREALS

Manganese (Mn) is a critical regulator of many physiological defense reactions of plants to disease; and the severity of take-all root, crown, and foot rot of cereals has been correlated with such cultural practices as form of nitrogen (N), pH adjustment, and crop rotation which all influence the availability of Mn. This study was initiated to determine if the content of Mn in seed influences the severity of take-all. Five cultivars of soft red winter wheat (Triticum aestivum L.) were grown under two widely different ecological conditions (alkaline, low Mn soil and Mn sufficient soil) to modify their Mn seed content Four cultivars (Cardinal, Lincoln, Steele, and Twain) differed by 10 to 18 mu g g(-1) in Mn seed content (0.33 to 60 mu g seed(-1)) while the Mn seed content of one cultivar (Caldwell) was similar from both locations. All cultivars were grown at three field locations in Indiana with natural infestations of Gaeumannomyces graminis var. tritici (Ggt). Under these moderately-severe to severe disease conditions, plants from seed with the higher Mn seed content were generally more vigorous, had an average of 11% less take-all (white heads), and yielded an average of 165 kg/ha more grain than plants from seed of the same cultivar with a lower Mn content. No significant differences in vigor, yield, or take-all severity were observed with either source of the cultivar grown from seed produced under widely different environments unless there was a significant difference in Mn seed content