Effects Of Density On Plant Traits And Yield Of Maize

Rational close planting is an effective measure to icrease unit yieald. To study the rational planting density for different hybrids and the effects of different density on maize yield and related traits, three spring maize hybrids, i.e., Liaodan539, Liaodan565, and Liaodan527 were planted in 4 density settings in this research.Our results showed that, the plant height increased as the density advanced. For the compact type hybrid, the coefficient of plant height and density was not significant. For the semi-compact type hybrid, the coefficient of plant height and density was positively significant. The density effects on plant height were more obvious at jointing and big trumpet stage than the other stages. The ear height presented an increasing trend as of the density increasing. The compact types had an extremely significant positive correlation of ear height and planting density, and the semi-compact types had a significant positive correlation of that. Different hybrid had different density-reaction curve for yield, and every hybrid had its optimal density under which it gained the highest yield. The yields of the compact types increased as the density improved, and the declined slowly after reached an optimal density. Various hybrids had different reactions for Different density in. Density had a smaller effect in ear grain number and 100-grain weight for Liaodan565, while had a greater effect for Liaodan539 and Liaodan527. The ear grain number and 100-grain weight decreased as the density increased. The unit yield affected by comprehensive effects of different related factors instead of individual one. As the increase of density, a shorter and thinner ear with more severe barren ear tip was observed, and then the single plant yield decreased. However, The population yield increased. So a reasonable increase of density had positive effects on unit yield. An over-large population will decrease unit yield. The leaf area per plant, the population leaf area index, and the photosynthetic potential had a similar trend as the density increasing, which increased slowly from seedling to jointing stage, and suddenly increased from jointing to big trumpet stage, reached the highest from big trumpet to silking stage, then decrease slowly, and decreased rapidly 30-day after silking. For the same hybrid, the leaf area per plant of middle- and higher- density was smaller and decreased more rapidly than that of lower-density. In this study, the chlorophyll content was not a determinant factor to yield. The dry matter accumulated slowly from seedling to jointing stage. Individual and population dry matter accumulation presented increasing trends from heading and silking to maturing stage, and increased rapidly at heading stage.The data set collected in this research included plant agronomic traits, yield and yield contributed factors, ear traits, photosynthetic characteristics, and dry matter accumulation etc. Our results showed that density has great effects on plant height, ear height, ear length, ear width, leaf area index, and dry matter accumulation. So these traits can be used to evaluate the density-tolerance of hybrids and to screen rational planting density. Our results provide hybrid matching cultivation techniques with reference value.