Effect of Imbibition/Dehydration Treatments on Germination and Seedling Growth of Maize (Zest mays) Cultivars

Abstract

AbstractCaryopses of maize cultivars of different origin were used for germination experiments. During the phase of germination the moisture supply was changed, so that after an initial soaking the kernels were desiccated. Finally the inbibition/dehydration treatments were followed by soaking the kernels to allow seedling growth. This experimental design mirrors natural conditions (in subtropical/tropical climates) which are characterized by short rain and drought periods during the sowing of maize.The maize cultivars were chosen from German and Thai hybrids and open pollinated varieties. In the treatments, the initial imbibitions were 24, 36, 48 and 60 hours; the dehydration periods were 24 and 48 hours. Percentage of regermination, radicle length, number of mesocotyl roots, root and shoot dry weights, were measured as indicative features for evaluation of the resistance against changing moisture content of the kernels during the germination phase.The results show, that a duration of 36 hours of imbibition describes in general the dehydration‐insensitive phase. Dehydration after imbibition periods of 24 (or 48) hours very often lead to a growth acceleration in the following germination after the kernels are imbibed again. If the germination proceeds for a longer period, as tested for 48 or 60 hours, all maize cultivars will show detrimental effects of dehydration on germination and seedling growth. However, there are distinct differences within the material tested, the Thai cultivars being more resistant than German hybrids. The reactions may be explained by differences in the rate of development during the first phase of germination. Slowly germinating genotypes probably pass later the border line from the insensitive to the sensitive phase against dehydration after an initial imbibition of the kernels.