黑龙江省是我国极早熟春玉米主要产区之一,玉米分布遍及全省,其中三分之二以上面积集中在北纬45至48度间的松嫩平原黑土区和炭酸盐黑土区。这里的日照时数长,无霜期短,全年活动积温只有2200～2700℃,年际间常变动于±300℃之间,每三年左右就有一次全省性或局部地区的低温早霜为害,造成玉米产量的大幅度波动。培育早熟高产的玉米杂交种,已成为影响全省粮食产量稳定增长的一个重要因素。我院从1956年就开展了玉米自交系的选育工作。经过五十年代的当地农家良种自 Heilongjiang Province is one of the earliest spring maize producing areas in China. Maize is distributed throughout the province. More than two thirds of the area is concentrated in the black soil area and the carbonate black soil area of ​​the Songnen Plain between 45 and 48 degrees north latitude. The sunshine duration here is long, frost-free period is short, the annual accumulated temperature is only 2200 ~ 2700 ℃, often fluctuating between the year ± 300 ℃, once every three years there is a province-wide or some areas of low temperature early frost damage, Cause substantial fluctuations in corn production. Fostering early and high yielding maize hybrids has become an important factor affecting the steady growth of grain output in the province. Our hospital from 1956 to carry out the breeding of corn inbred lines. After fifty years of local farmers since the seed