Soybean, however, is very sensitive to photoperiod, or day length, and does not move from vegetative to reproductive growth until a critical day length is met. This requirement restricts a variety's adaptability to a band about 150 miles north and south of its origin. Since Pennsylvania falls within the same latitudes as the major growing areas of the midwest, our growers have access to the same varieties. Figure 6-2 shows suggested maturity groups for each county in Pennsylvania. Selecting a variety for proper maturity, disease tolerance, standability, and yield performance is essential for successful soybean production.
Maturity is identified by maturity groups, as described above.
In addition, there is a trend in the seed industry to include information about a variety's relative maturity within the group as part of its name. Soybean varieties are developed by state agricultural experiment stations and private industry. Performance data for many of these varieties are reported in the annual publication, Soybean Performance Report, available from county offices of Penn State Cooperative Extension. Poor-quality seed may limit yield and crop performance because of low germination, excessive foreign material, weed seed, and seed of other varieties or crops. Soybean seed is sensitive to rough handling and storage conditions.