The present invention relates to a new and distinctive soybean variety designated XB01Z13, which has been the result of years of careful breeding and selection in a comprehensive soybean breeding program.  There are numerous steps in the development of any novel, desirable soybean variety.  Plant breeding begins with the analysis and definition of problems and weaknesses of the current germplasm, the establishment of program goals, and the definition of specific breeding objectives.  The next step is selection of germplasm that possess the traits to meet the program goals.  The breeder's goal is to combine in a single variety an improved combination of desirable traits from the parental germplasm.  These important traits may include, but are not limited to: higher seed yield, resistance to diseases and/or insects, tolerance to drought and/or heat, altered fatty acid profile(s), abiotic stress tolerance, improvements in compositional traits, and better agronomic characteristics. 
These product development processes, which lead to the final step of marketing and distribution, can take from six to twelve years from the time the first cross is made until the finished seed is delivered to the farmer for planting.  Therefore, development of new varieties is a time-consuming process that requires precise planning, efficient use of resources, and a minimum of changes in direction. 
Soybean (Glycine max) is an important and valuable field crop.  Thus, a continuing goal of soybean breeders is to develop stable, high yielding soybean varieties that are agronomically sound.  The reasons for this goal are to maximize the amount of grain produced on the land used and to supply food for both animals and humans.  To accomplish this goal, the soybean breeder must select and develop soybean plants that have the traits that result in superior varieties. 
The soybean is the world's leading source of vegetable oil and protein meal.  The oil extracted from soybeans is used for cooking oil, margarine, and salad dressings.  Soybean oil is composed of saturated, monounsaturated, and polyunsaturated fatty acids.  It has a typical composition of 11% palmitic, 4% stearic, 25% oleic, 50% linoleic, and 9% linolenic fatty acid content (“Economic Implications of Modified Soybean Traits Summary Report”, Iowa Soybean Promotion Board & American Soybean Association Special Report 92S, May 1990).  Changes in fatty acid composition for improved oxidative stability and nutrition are also important traits. 
Industrial uses for processed soybean oil include ingredients for paints, plastics, fibers, detergents, cosmetics, and lubricants.  Soybean oil may be split, inter-esterified, sulfurized, epoxidized, polymerized, ethoxylated, or cleaved.  Designing and producing soybean oil derivatives with improved functionality, oliochemistry, is a rapidly growing field.  The typical mixture of triglycerides is usually split and separated into pure fatty acids, which are then combined with petroleum-derived alcohols or acids, nitrogen, sulfonates, chlorine, or with fatty alcohols derived from fats and oils. 
Soybean is also used as a food source for both animals and humans.  Soybean is widely used as a source of protein for animal feeds for poultry, swine, and cattle.  During processing of whole soybeans, the fibrous hull is removed and the oil is extracted.  The remaining soybean meal is a combination of carbohydrates and approximately 50% protein. 
For human consumption soybean meal is made into soybean flour which is processed to protein concentrates used for meat extenders or specialty pet foods.  Production of edible protein ingredients from soybean offers a healthy, less expensive replacement for animal protein in meats and dairy products.