Selection of commercial and heirloom common bean (Phaseolus vulgaris L.) for organic production in Minnesota

Abstract

The common dry bean (Phaseolus vulgaris L.) is an annual pulse crop produced and consumed around the world. Recent trends in the sales and consumption of organic food within the United States has led to an increase in organic cropland dedicated to the production of organic dry beans. Minnesota, in particular, has seen nearly a four-fold increase in organic dry bean production since 2008. Research dedicated to the evaluation and selection of a) current commercial market class cultivars and b) niche-market heirloom seed types is critical to enhance accessibility of productive seed that complies with organic regulation standards. Between 2012 and 2014, three trials were conducted in southern Minnesota and eastern North Dakota to evaluate commercial and heirloom common bean (Phaseolus vulgaris L.) performance in organic production. Twenty-eight commercial market class cultivars were evaluated at five locations between 2012-2014 using a randomized complete block design. Yield data were subject to stability analysis using linear mixed model methodology, and gross revenue ac-1 was calculated from average yield within a market class. Yield across all seed classes and cultivars ranged from 1181 kg ha-1 to 2839 kg ha-1. Analyses based on small, medium, and large seed size classes indicated increased yield and yield stability in the small and medium seed types. The large environmental effects and lower gross revenues exhibited by larger seed types suggest that growers interested in production of these types should have well-established soil and crop management practices. Yield evaluation of seventeen heirloom cultivars was performed using a randomized complete block design in 2013 and 2014 at four locations around the Twin Cities Metro region. Yields of heirloom cultivars were drastically lower than the commercial market class check included in the trial. Within the heirloom cultivars, yields ranged from 825 kg ha-1 to 2127 kg ha-1 to, with a mean of 1362 kg ha-1. In contrast, commercial check cultivars yielded approximately 44% greater than heirloom cultivars. Stability analyses and economic incentives, however, suggest that production of heirloom cultivars, especially "Jacob's Cattle God", "Lina Sisco's Bird Egg", "Peregion", and "Tiger's Eye", may be a feasible enterprise for local growers. Four heirloom dry bean cultivars, "Jacob's Cattle Gold", "Lina Sisco's Bird Egg", "Peregion", and "Tiger's Eye", were selected for pure line evaluation in 2013-2014 on the basis of market potential, yield, stability across locations in the heirloom dry bean yield trials. Sixty random plants were selected within each cultivar in 2012 and bulked seed from each plant (i.e. "pure line"�) was grown in 2013-2014 as a single plant rows. Sampling plants within each plant row for eight morphological traits provided estimates of genetic variation, including the standard deviation (s) of pure line means, coefficient of variation (CV) among pure lines, and broad-sense heritability (H2) on an entry-mean basis. Selection for improved pure lines within "Jacob's Cattle Gold", "Lina Sisco's Bird Egg", "Peregion", and"Tiger's Eye" was performed after the 2013 season. A gain from selection trial was established during the 2014 season to compare the performance of selected improved pure lines within each cultivar to original heirloom populations. The pure line trial of 2013-2014 and the gain from selection trial in 2014 revealed that genetic variation within heirloom dry bean cultivars was sufficient to allow for selection of traits associated with maturity, yield, and plant architecture within an heirloom population.