Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_21258_1 ( infant_mortality_rate INTEGER, period VARCHAR )

### Question ###
period between 1985 - 1990 have minimum infant mortality rate of what.

### Accurate SQL ###

SELECT MIN(infant_mortality_rate) FROM table_21258_1 WHERE period = "1985 - 1990"