Relationships Among Carbohydrate Content of Kernels, Condition of Silks After Pollination, and the Response of Sweet Corn Inbred Lines to Infection of Kernels byFusarium moniliforme

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Abstract
Twenty-two inbred lines were selected for carbohydrate analyses on the basis of a range of resistance to infection of kernels by Fusarium moniliforme. Relationships among the incidence of symptomatic and asymptomatic infection of kernels by F. moniliforme and the kernel content of individual sugars, total sugar, phytoglycogen, starch, and total carbohydrate were examined by linear-regression analysis. Quantity and concentration of kernel carbohydrates were not related to infection of kernels by F. monliforme. Asymptomatic infection of kernels by F. moniliforme was less for inbreds with silks that were green and actively growing at inoculation than for inbreds with green-brown or brown silks. Thus, browning and senescence of silks appeared to be important in initiating infection. Relationships among emergence of seedlings, carbohydrate variables, and infection of kernels by F. moniliforme were also examined by regression analyses, including principal factor regression. Infection of kernels by F. moniliforme and carbohydrate content of kernels were related to emergence of sweet corn inbred seedlings, yet much of the variation in emergence was not explained by these variables. Infection of kernels by F. moniliforme was the variable that was most highly related to emergence; however, symptomatic and asymptomatic infection accounted for only 39 and 30% of the variation in emergence, respectively. Many of the kernal carbohydrate variables were significantly related to emergence when the variation in emergence due to kernel infection was accounted for in multiple regression modes. Based on these results, we do no expect the genetic improvement in the performance of sweet corn seedlings would be rapid if selection were based solely on the individual variables measured in this study.