Benefits of Type II Dry Bean Cultivars In Crop Management.

Until recent years, the most common harvest operation for dry bean in the United States consisted of a two-step process. First, mature bean plants were either cut or pulled to form windrows that could be left in the field for several days to ensure uniform dry down. Afterwards, windrows were picked and threshed. The entire operation allows for an efficient harvest in terms of lower seed yield loss, but it requires longer time, multiple pieces of equipment, and additional personnel in some cases. In addition, seed yield and quality may be affected by environmental factors such as rain and/or frost, and harvest schedules of other crops within the same farm. Plant architecture of dry bean cultivars commonly grown had an indeterminate prostrate architecture (type III) and few had an indeterminate upright (type II) habit, with kidney and some cranberry beans being the only group with mostly determinate upright architecture (type I). Plant breeders have devoted efforts to change the bean plant architecture during the last three or four decades, mostly to improve adaptation and seed yield based on an ideotype plant. However, both growers and bean breeders soon realized that having a type II upright architecture would also allow harvesting dry beans in one pass, similar to other crops such as soybeans. Several approaches such as X-ray mutagenesis and recurrent selection were successfully used to develop upright cultivars of navy beans first, followed by black beans, and more recently, pinto and great northern cultivars. Today, most dry bean growers in the northern Great Plains and the Midwest are using direct harvest in at least a portion of their farms because of its easiness in terms of time and equipment. However, in order to avoid significant seed yield losses during direct harvest, several other factors such as row spacing, equipment set up, and field conditions at harvest need to be considered in addition to the cultivar choice.