Seed coating with micronutrients improves germination, growth, yield and microelement nutrients of maize (Zea mays L.).

Soil and foliar application are the most widely used methods for adding micronutrients to maize. High quality micronutrient fertilizers, however, are difficult to obtain in developing countries; micronutrient seed coatings are an attractive and practical alternative. We applied this approach to maize (Zea mays L.) to demonstrate the effects of boron (B), iron (Fe), manganese (Mn), molybdenum (Mo) and zinc (Zn) sulfates on maize germination, vigor, seedling growth, seed yield and seed quality as well as on seed microelement concentration. Seed coating was tested on three representative Chinese soil types (sandy, purple and lime soils). Compared to untreated controls, coating maize seeds with micronutrients significantly increased the seed emergence rate, seedling height, leaf length, leaf width, leaf area, main root length, root number, above ground fresh biomass, above ground dry biomass, underground fresh biomass, underground dry biomass, ear thickness and yield in sandy, purple and lime soils. Coating maize seeds with micronutrients also significantly increased the yield and quality of maize seed compared to untreated controls including ear barren tip, ear length, ear thickness, grains/row, hundred seed weigh, and rows/ear. Also, B, Zn, Fe, Mn and Mo microelements accumulated in maize seed after coating the seed with micronutrients. Our findings indicate that micronutrient seed coating may improve nutrient uptake and production of maize hybrids.

[Effects of shade-humid environment on the growth characteristics of different maize (Zea mays) hybrids].

The growth traits of 18 maize hybrids were studied in natural and artificial simulation shade-humid environments. Significant differences were observed between the natural and shade-humid environments, and the air relative humidity in the shade-humid environment increased 15.0%-16.4%, the soil moisture increased 27.0%-78.4%, the illumination intensity decreased 72.9%-77.9%, and the quantum decreased 72.8%-79.6%. Shade did not affect the ambient temperature. The 7th leaf width, effective functional leaves, plant total leaves, tassel branch number, stem diameter, plant height, ear height, ear length, ear diameter, rows per ear, kernels per row, 100-grain mass and grain yield per plant under the shade-humid environment showed negative variations (reduction in phenotypic values), with the grain yield per plant and plant height being reduced by 72.3% and 7.1% respectively, and the declining changes of the remaining traits ranging from 14.8%-53.8%. However, the 7th leaf length, 7th leaf length-width ratio, anthesis to silking (ASI) duration, southern leaf blight (SLB) index and sheath blight index showed positive variations (increase in phenotypic values), with increases by 39.8%, 80.5%, 114.3%, 73.0% and 54.8%, respectively. The comprehensive shade-humid-tolerant coefficient calculated from the seven traits of ASI, tassel branches, plant total leaves, plant height, individual grain yield, southern leaf blight and sheath blight index could be easily and reliably used to evaluate the shade-humid-tolerant ability of the maize hybrids. According to this coefficient, the 18 hybrids could be classified into three categories, strongly-resistant, moderately-resistant and weakly-resistant to the shade-humid environment.