The positioneffects of mark gene and other factors have a little influences on the expect value, but the chromosome length have much influences on it.
标记基因的位置效应和干扰因素对这一期望值的影响是很小的，而染色体的长度对期望方差值影响很大。
2
The positioneffects of grain-filling exist, ie, the grains of upper panicles are better than those in middle, which are furiher better than those of lower parts.
籽粒充实不良的表现具有全穗性，但籽粒充实率在不同粒位间存在一定的差异，上位＞中位＞下位。
3
The utility model has the advantages of simple structure, stable positioneffects, low manufacture cost, volume reduction in due time and convenient transportation.