Submitted to: Bean Improvement Cooperative Annual Report
Publication Type: Germplasm Release
Publication Acceptance Date: 2/9/1995
Publication Date: N/A
Interpretive Summary: This is a germplasm release, no interpretive summary is required.
Technical Abstract: Eight germplasm lines, numbered ARS-R93001 to ARS-R93008, are the first released Red Mexican beans (Phaseolus vulgaris L.)with an erect Type II growth habit as compared with the prostrate indeterminate vine Type III habit of commercial cultivars. The new germplasm was developed cooperatively by USDA-ARS and the Michigan Agricultural Experiment Station and released in 1994 as lines that combine upright and narrow profile and short vine architecture with the desirable seed size, shape and red seed color of the Red Mexican market class. The germplasm as a whole yielded 81.2% of 'Rufus' but were equivalent in yield to'Garnet'. One hundred seed weight of the new germplasm ranged from 33.0 g to 39.9 g. Seeds were larger and heavier than commercial Red Mexican varieties. The new germplasm ranged from 39 to 55 cm in height and averaged 81.2 days to maturity with a range of 76.0 to 84.7 days. The new germplasm had excellent resistance to lodging gcompared to 'Rufus' and 'Garnet'. Resistance of the new germplasm to bean rust and bean common mosaic (BCMV) diseases is variable. ARS-R93002 is segregating for the Ur-3 rust resistance gene which conditions resistance to race 53 and all indigenous rust races prevalent in Michigan. Germplasm lines -R93006, -R93007 and -R93008 carry the single dominant hypersensitive I-gene resistance to BCMV combined with the recessive bc-12 gene. Based on the use of trained judges, instruments, and gravimetric procedures, the culinary quality of the eight new germplasm lines is equivalent to 'Rufus' and 'Garnet'. The new germplasm lines with their upright plant structure represent a significant improvement in the adaptation of Red Mexican beans for the humid Great Lakes region of the American Midwest.