大量的研究表明,两个不同的玉米杂交种混种具有一定的增产优势,然而在我们品种普查中发现有些农民将稀密不同的两个杂交种混种在一起,试图达到增产增收的目的,这是很不科学的。其原因是: 1.由于耐密的紧凑型品种和稀植的平展型品种前期生长势不同(至少绝大多数稀密品种不会达成一致),这样稀密混种过程会导致弱势品种中“三类苗”增多,这样势必引起产量下降;同时由于稀密混种导致幼苗不能迅速建成群体,抵抗不利环境条件和病虫侵害的能力减弱,也会导致产量的下降, 2.由于稀密品种生长过程中的竞争关系及其受多变自然环境条件 Numerous studies have shown that two different hybrids of maize hybrids have some yield advantages. However, in our census, some peasants were found to mix two hybrids with different densities in an attempt to achieve the goal of increasing yield and income. This is very unscientific. The reasons are: 1. Due to the difference in prophase growth potential between compact and thinly planted varieties (at least the vast majority of the varieties will not agree), such a dense mixing process will result in weaker varieties “Three types of seedlings” increase, which is bound to lead to decline in production; the same time due to rare and mixed seedlings can not be quickly formed into groups, to resist the adverse environmental conditions and the ability of pests weakened, will lead to decline in production, 2. Due to thin The competitive relationship between varieties and their growth and their changing conditions of natural environment