The objective of the present study was to determine “do correlation and regression models able to describe relationship between laboratory seed vigour tests and field seed emergence of crops”. So some Iran important crop included corn, wheat, barley, sorghum, alfalfa, Iranian clover, safflower, rapeseed, dry pea, mungbean, white bean, broad bean, suger beet, sunflower and cotton stored one year and then several vigor test take on them and simultaneous they sowing in farm and germination percentage in labetorary and emergence percentage in farm recorded then means of seed germination and seed emergence were comparsion by analys variance and simultaneous correlation coefficient and simple and multiple regression relations were determine. Base on my finding, correlation coefficient and regression relations can not describe relationship between seed laberatiry results and seed emergence in farm, because correlation coefficient and regression relations only to find isotropy of several variables but in seed studies we want to find quantitative relations these variables, so we will report that we must not recommend use of correlation coefficient and regression relations in study of relationships between seed performance and vigour tests.