Screening of Soybean Varieties for Delayed Planting in Kebai Area,Heilongjiang Province

Kebai Area, located in the west part of Heilongjiang Province, is an important soybean producing region in the northeast China. Natural disasters especially drought stress and chilling in spring occurred frequently and usually caused late-or even re-planting in Kebai Area. Therefore, to select varieties with suitable maturity groups and yield is important for soybean production under delayed planting environments in this area. In the current study, 14 soybean varieties belonged to MG 000, MG 00 and MG 0 were evaluated based on the performances in growth periods, agronomic traits and yield components in the date-of-planting experiments（May 11, May 21, June 2, June 11 and June 22）, in order to select soybean varieties for different sowing dates in this area. The results showed that, along with the delay of sowing dates, the number of days from sowing to emergence（VE）, days from VE to beginning bloom（R1）, days from R1 to full maturity（R8） and days from VE to R8 were all shortened. The plant height and the number of nodes on main stem of the tested varieties were increased along with the delay of sowing dates except the normal planting date（May 11）. However, the 100-seed weight of all tested varieties decreased with the delay of sowing dates. Among the tested varieties, Heihe 35 was more sensitive than others in 100-seed weight, i.e., 0.15 g decrease for each day delay when late-planted. The relationship between yield and planting dates were complicated. Seven out of 14 varieties yielded highest in the normal planting date, but another 7 including the local widely-planted variety of Keshan 1 yielded higher in late-planting（early to mid-June） than in early-planting. Huajiang 4（MG 0.2） and Keshan 1（MG 0.3） were high and stable in yield in different sowing dates, so they were recommended as the ideal varieties for late-planting in this region. Huajiang 2（MG 0.5） and Heihe 51（MG 0.5） can be used as alternative varieties for late-planting because they performed also stably in yield. Heihe 35（MG-1.1） and Heihe 49（MG-1.2）, two super-early maturing varieties can be planted as late as in late-June. Rainfall distribution is the major environmental factor affecting soybean yield in Kebai Area. To efficiently use the natural precipitation in soybean production, it is imperative to make the rainy season overlap with the flowering period of soybean.