目前我国玉米生产上推广的玉米品种和杂交种,大多数是单穗型。这些单穗型玉米已在生产上起了很大的增产作用。但要使玉米在此基础上继续扩大密度、增加光合面积,以获得更高的籽粒产量,经大量试验证明,单纯依靠选育单株大穗是不易达到目的。特别是在夏播玉米产区,生长期短,玉米生长季节气温高,昼夜温差小,后期又逢雨季,光照不足,不易孕育大穗。在这种气候条件下,双穗型玉米是适宜夏播的比较理想的生态型之一。 At present, maize varieties and hybrids popularized in China’s maize production are mostly single-spike type. These single-spike corn has played a large role in increasing production. However, on the basis of this, corn should continue to expand the density and increase the photosynthetic area so as to obtain higher grain yield. It has been proved through numerous experiments that it is not easy to achieve relying solely on breeding large ears per plant. Especially in the summer sowing corn producing areas, the short growing season, the corn growing season, high temperature, small temperature difference between day and night, late rainy season, lack of light, difficult to conceive big spike. Under the climatic conditions, double-tassel corn is one of the ideal ecotypes suitable for summer seeding.