A major constraint to dry edible and snap bean (Phaseolus vulgaris L.) production worldwide is root rot, one form of which is caused by Fusarium solani f. sp. phaseoli (Burk.) Snyd. & Hans (FSP). Sources of resistance to this pathogen exist in P. vulgaris, and, in the current paper, we studied the inheritance of one such source, FR266, using two recombinant inbred populations, MF and IF, derived from crosses of susceptible cultivars Montcalm (M) and Isles (I) with FR266 (F). Random amplified polymorphic DNA (RAPD) markers, associated with quantitative trait loci (QTL) controlling resistance to Fusarium root rot, also were identified. Genetic resistance to FSP, originally derived from PI 203958, was polygenically controlled and strongly influenced by environmental factors. Heritability estimates (h2) were moderate and ranged from 0.48 to 0.71 for MF population. Several RAPD markers were identified that demonstrated significant associations with resistance to FSP determined from both greenhouse and field evaluations. Markers associated with field ratings tended not to be associated with greenhouse ratings and vice versa, except for the P700 marker which was significantly associated with both greenhouse and field data. Individual markers identified in this study did not explain more than 15% of the phenotypic variation for root rot resistance, whereas a combination of four markers explained 29% of the phenotypic variation for root rot ratings in the field. The two regions of the bean genome associated with root rot resistance corresponded to loci controlling the Pv pathogenesis‐related proteins (PvPR). Mechanisms associated with host defense responses may be involved in resistance to FSP and selection directed towards enhancing these traits may allow for rapid improvement of resistance to Fusarium root rot in bean.

Mineral deficiencies in common bean (Phaseolus vulgaris L.) negatively affect plant growth and development. Genetic differences in seed mineral concentrations have been detected among landraces and genotypes for trace elements such as Zn and Fe, and major elements such as P and Ca, and these differences have been exploited for the genetic improvement of the crop. The objectives of this study were (i) to develop and evaluate a navy bean recombinant inbred population segregating for seed Zn, (ii) to measure other micronutrients in the seeds such as Fe and the major elements P and Ca, and (iii) to identify associations between microsatellite markers and seed mineral content. Transgressive segregants were observed for seed Zn and variation was also found for Fe, P, and Ca. Bean microsatellites associated with Zn, P, and Ca were identified, but there was no association with Fe. Our molecular data identified a locus associated with seed Zn accumulation in bean located on linkage group 9. Further studies would help to find the exact location of the gene. As more information becomes available, breeders will be able to combine techniques of molecular genetics with conventional breeding methods through marker‐assisted selection to develop cultivars with higher seed Zn content.

Pinto beans (Phaseolus vulgaris L.) of cool subtropical and temperate origins are extremely susceptible to white mold disease caused by Sclerotinia sclerotiorum (Lib.) de Bary. Breeding pinto beans with resistance to white mold is difficult because of the paucity of resistant germplasm in a closely related background. White mold resistant ‘ICA Bunsi’, a small white navy bean, is from the same Middle American gene pool, but it is of warm tropical origin and needs to be exploited in pinto bean improvement. Our objectives were to determine inheritance of ICA Bunsi‐derived resistance in a cross with pinto bean, determine association of the resistance with disease avoidance, and identify white mold resistant pinto beans. White mold reactions of 85 F5:8 recombinant inbred lines (RIL) from the cross ‘Aztec’/ND88‐106‐04 were characterized in the field in North Dakota and Washington in 2001 and 2002. Aztec pinto is susceptible to white mold, and ND88‐106‐04 navy bean has partial resistance derived from ICA Bunsi. Disease severity score (1 = no disease to 9 = completely susceptible), yield, and disease avoidance traits were measured. Disease severity for Aztec and ND88‐106‐04 across environments was 6.9 and 2.5, respectively, compared with 4.6 for ICA Bunsi. Reduced lodging and late maturity enhanced disease avoidance. The RILs with stay‐green stem at harvest, similar to ND88‐106‐04, also exhibited less disease. Normal distribution and moderate heritability (Hns = 56 and 36% for WA and ND environments, respectively) for disease score indicated resistance was influenced by environment and likely conditioned by genes with small effects. Nonetheless, white mold resistance was present in a few RILs with high yield potential and pinto seed type.

a correlation between high phytate diets and limited Zn absorbance in the gastrointestinal tract of humans and Human zinc (Zn) deficiency is a widespread condition prevalent in animals (Saha et al., 1994; House et al., 1982; Turnlund people consuming grain and legume based diets. Dry beans (Phaseolus vulgaris L.) are frequently the major protein source in such diets. et al., 1984;Lonnerdal et al., 1989; Hunt et al., 1998; One way to reduce the incidence of Zn deficiency may be through Zhou et al., 1992). The recommended daily allowance the development of high Zn dry beans. Large variation for dry bean of Zn established for people of the USA is 12 to 15 mg seed Zn concentration exists, which would aid in the development of for adults and 10 mg for children. However, this amount Zn-rich cultivars. The objectives of this study were to determine the of Zn may be too low for people whose diets are vegetarinheritance of seed Zn levels in navy bean and to measure seed ian and phytate rich. Dietary phytate: Zn molar ratios phytic acid (PA) levels in relationship to seed Zn concentration as are a major factor in determining the risk of Zn defian indicator of Zn bioavailability. A high seed Zn cultivar 'Voyager'ciency (Frossard et al., 2000). and a low seed Zn cultivar 'Albion' were used to create the F 2 and One way to alleviate Zn deficiency in humans mainbackcross populations that were field grown in 1999 and 2000. Seed taining legume-rich diets, as seen in countries of Latin Zn was measured in both years and seed phytic acid was measured in 1999. The results of this experiment suggest that a single dominant America, Africa, and to a lesser extent, vegetarians in gene controls the high seed Zn concentration in the Voyager/Albion the USA is to introduce cultivars with increased levels cross. In addition, phytic acid levels between the parent cultivars Navy bean cultivars Albion (Asgrow Seed Company, Kalamazoo, MI, 1987) with low seed Zn and Voyager (Rogers

P1 603038) were released by the USDA-ARS in 1997. A major advantage of these lines is their moderate resistance to white mold [caused by Sclerotinia sclerotiorum (Lib.) de Bary], White mold is a major disease problem of dry edible beans grown worldwide, and cultivars grown throughout the United States are susceptible. These four lines also exhibited high yield potential in both tropical (Puerto Rico) and temperate (Michigan, Nebraska, North Dakota, Washington) environments, resistance to bean common mosaic and necrosis viruses (BCMV and BCMNV), and resistance to rust [caused by Uromyces appendiculatus (Pers.) Unger var. appendiculatus; syn. U. phaseoli]. These four lines were evaluated for physiological reaction to white mold in straw tests (1) conducted at the University of Nebraska (2), Cornell University (M.H. Dickson), North Dakota State University, and the USDA-ARS at Prosser, WA, from 1995 to 1997. Reactions of these four lines to white mold were evaluated in Michigan, Nebraska, and North Dakota in the field from 1995 to 1997 (3). 19365-3 is a small, red dry bean developed from an interspecific Population II (Florida 6-19/Pc-46) using a modified bulk selection of 10 plants for three continuous generations. Population II was cooperatively released in 1985 by the USDA-ARS and the Agricultural Experiment Stations of Puerto Rico and Florida as a heterogeneous Fo bulk possessing different disease resistances, plant habits, and seed sizes, shapes, and colors (4). The common bean parent, Florida 6-19, was an F 4 bulk selection for reclining foliage and short internodes from the cross Guatemala 14-2 (Cambridge collection)/'Remus'. The Phaseolus coccineus L. parent, Pc-46, was developed by recurrent selection for multiple disease resistance by N.G. Vakili in Puerto Rico and released by the USDA-ARS in 1979.19365-3 averaged 98 d to harvest maturity at Othello, WA (1997), and exhibited an upright indeterminate Type Ilb-IIIa growth habit (5). Weight of 100 seeds averaged 24 g. In field and greenhouse tests the reaction of 19365-3 to white mold was comparable to 'Bunsi' (known in Canada as 'Ex Rico 23'). Bunsi navy bean has been widely used as a check cultivar because it has some resistance to white mold (2,3,6). 19365-3 exhibited a top necrosis, black root response to BCMNV strains confirming presence of the / gene for resistance to BCMV and BCMNV. This line is resistant to rust pathotypes in Colorado that overcame the Ur-6 rust resistant gene (7) present in 'Olathe' pinto bean but not the Ur-3 gene (7) present in 'Chase' pinto bean. 19365-5 is a small, pink dry bean developed from an interspecific cross (P. vulgaris/P. coccineus/V233B) using a modified bulk selection of 10 plants, from the F 5 to F 7 generations. The original P.-vulgaris parent was a dry bean derived by recurrent selec