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Dry bean (Phaseolus vulgaris L.) is highly susceptible to drought stress, and drought affects 60% of global bean production. We evaluated elite exotic dry bean germplasm derived from the Mesoamerican gene pool for drought tolerance, yield, and adaptation to western Nebraska during 2006 and 2007 at three research sites. Seven tropical lines were evaluated with two great northern cultivars (Matterhorn and BerylR) and one pinto cultivar (Bill-Z) serving as checks. Adjacent nonstressed (NS) and drought-stressed (DS) blocks were evaluated. Within each block, the selected lines were assigned to experimental units using a randomized complete block design with four replications at each location. On average, yield was 60% less, 100-seed weight was 19.2% lower, and maturity occurred 4 d earlier under DS than under NS conditions. Beryl-R, SER 22, and Matterhorn had the greatest average yield under both NS (3564, 3347, and 3440 kg [ha.sup.-1], respectively) and DS (1701, 1773, and 1584 kg [ha.sup.-1], respectively). These genotypes were also the most drought tolerant based on the drought susceptibility index (0.9, 0.8, and 0.9, respectively) and geometric mean (2462, 2436, and 2335, respectively). Based on these results, Matterhorn, Beryl-R, and SER 22 show the most promise for use in breeding for drought tolerance. doi: 10.2135/cropsci2008.12.0694

Iron and zinc are essential micronutrients for human health often found in insufficient quantities in the diet. Biofortification of seed crops has been undertaken to reduce micronutrient malnutrition. The objectives of this study were to identify variability for seed Fe, Zn, P, and phytic acid levels in an [F.sub.5:7] recombinant inbred line (RIL) population developed from a cross between AND696 and G19833, both common beans (Phaseolus vulgaris L.) of Andean origin. Quantitative trait loci (QTL) analysis was conducted with data from 2 yr and 2 P treatments with a previously described linkage map of AND696/ G19833. Significant environmental and genetic variability for Fe, Zn, and P levels was identified, and Fe and Zn levels were correlated (up to r = 0.53). Quantitative trait loci for seed Fe and Zn co-localized on three linkage groups (B1, B6, and B11). On B6, a QTL for Fe ([R.sup.2] = 0.36) was found at the same marker interval as a QTL for seed Zn ([R.sup.2] = 0.39), both derived from AND696. Quantitative trait loci for seed P were identified on six linkage groups and explained 17 to 55% of the total phenotypic variation depending on year and environment.

Grain (pulse) legumes could provide high nitrogen (N), late summer forage for stocker cattle in the southern Great Plains (SGP). This study evaluated the forage yield and nutritive value of tropical annual legumes that were relatively uncommon in the SGP, at a site (35040' N, 98000' W) in central Oklahoma. Included were cultivars of pigeon pea ([Cajanus cajan (L.) Millsp.], cv. GA-2), guar ([Cyamopsis tetragonoloba (L.) Taub.], cv. Kinman), cowpea ([Vigna unguiculata (L). Walp.], cv. Chinese red), and mung bean ([Vigna radiata (L.) Wilcz.], cv. Berkins), and grain soybean ([Glycine max (L.) Merr.] cv. Hutcheson) was used as a control. Seeds were inoculated and planted (60-cm row spacing at 10 seeds [m.sup.-1] row length) annually in mid-June 2003 through 2006. Aboveground samples were collected on six dates, from 45 to 120 d since planting. Soybean, pigeon pea, and guar averaged 3560, 3439, and 3321 kg [ha.sup.-1], while mung bean and cowpea averaged 2918 and 2405 kg [ha.sup.-1], respectively. Mung bean and cowpea accumulated the least N (70 and 65 kg N [ha.sup.-1]), while soybean, guar, and pigeon pea yielded 100, 93, and 77 kg N [ha.sup.-1], respectively. Digestibility of cowpea, mung bean, soybean, and guar were similar (757 to 825 g [kg.sup.-1]), while pigeon pea was least digestible (634 g [kg.sup.-1]). These pulse legumes could provide producers in the SGP with options other than soybean for generating forage or biological N.

Adzuki bean [Vigna angularis (Willd.) Ohwi & Ohashi] is cultivated in a wide range of agroecological environments from north to south China. An understanding of the genetic variation for crop adaptation facilitates plant breeding. A core germplasm of 231 accessions (selected from a representative collection of 3908 Chinese landraces) was evaluated at diverse locations in China in 1998 to (i) compare differences among sources of landraces for trait expression, (ii) identify underlying patterns of diversity, and (iii) characterize patterns of genetic adaptation across environments. Three-mode pattern analysis of phenology, yield and yield components, and plant height data identified six accession groups with various levels of cohesiveness. The greatest diversity occurred in the germplasm from the provinces of mid-north China, particularly the lower Yellow River basin, with a partial latitudinal separation of the accession origins in different groups. The most contrasting groups came, respectively, from south China (Sichuan-Anhui), characterized by late maturity and small seed size, and from north China (Liaoning--Heilongjiang), characterized by earliness and short habit. Analysis of the multilocation screening provided genotype x environment characterization of the accession groups and a capability to predict the most suitable groups for specific target environments and breeding objectives, thereby enabling plant breeders to make efficient and effective use of germplasm.

Single nucleotide polymorphisms (SNPs) are the most common sequence difference found in plant genomes, yet they have not been widely exploited for producing molecular markers in common bean (Phaseolus vulgaris L.). The objective of this study was to develop a SNP assay based on a type of heteroduplex mismatch cleavage called EcoTILLING for molecular marker development in this important legume, and apply the assay (i) to the conversion of a sequence-characterized amplified region (SCAR) marker useful for selecting virus resistance (SR2) and (ii) to the screening of SNP polymorphisms in newly developed expressed sequence tag (EST)-based markers. The SNP assay involved heteroduplex mismatch cleavage by a single-strand specific nuclease 'CEL I' which was used to uncover two SNPs in the SR2 fragment and 22 SNPs in 37 candidate ESTs, some of which were used in segregation analysis. While developing the SNP techniques we tested several platforms, including LI-COR, nondenaturing polyacrylamide, and agarose gel detection. The agarose gel system was used for SNP genetic mapping in two common bean mapping populations, showing that heteroduplex cleavage is a useful technique for increasing molecular marker number for the crop. Examples are given of mapped SNP markers for the phytic acid pathway gene for myoinositol-1-phosphate synthase and a drought tolerance--related gene, S-adenosylmethionine decarboxylase.

Tolerance to low P soils is a desirable trait in common bean (Phaseolus vulgaris L.) cultivars grown in acid-weathered soils. Genetic variability in response to P-deficient soils exists in the Andean gene pool. G19833, a low P-tolerant indeterminate Andean landrace, has been evaluated for quantitative trait loci (QTL) and tolerance to low P in combination with Mesoamerican parents. Our goal was to expand our understanding of phenotypic traits and QTL from G19833 expressed in an Andean background. An [F.sub.5:7] recombinant inbred line (RIL) population developed from two Andean bean genotypes, G19833 and AND696, a determinate line susceptible to low P soils, was examined under low and high soil P levels in replicated field trials. Phosphorus uptake was reduced by 70% and yield by 60% in low P compared to high P treatments. A linkage map was developed with 11 linkage groups and a total length of 1105 cM. Quantitative trait loci for root growth, seed yield, seed P content, and P use efficiency colocalized near the fin gene on linkage group B1. Quantitative trait loci for root growth traits, seed yield, and P uptake colocalized on B11. Quantitative trait loci for root length density (cm [cm.sup.-3]) and root surface area ([cm.sup.2]) did not colocalize with QTL for P uptake. This study indicates that root traits did not play an important role in tolerance to low P soil in an Andean x Andean cross, contrary to previous results with the same P-efficient Andean parent (G19833) crossed to a Mesoamerican bean genotype.

Identification of forage legumes well adapted to the southeastern United States is complicated by climatic, soil, and biotic factors. Among the pests that impact forage legume persistence are root-knot nematodes (RKNs) (Meloidogyne spp.). We hypothesized that legumes native to the region should have higher levels of resistance to RKN species that are common in this region due to long-term natural selection pressure. The objective of this research was to evaluate the response of 10 southeastern U.S. native legumes to M. arenaria (Neal) Chitwood race 1, M. incognita (Kofoid and White) Chitwood race 3, and M. javanica (Treub) Chitwood. Legumes were grown in Cone-tainers in a greenhouse for 3 wk, inoculated with a given RKN isolate, and after an additional 9 wk were uprooted and evaluated for root galling and nematode egg mass production responses. The level of root galling and egg mass production varied among native legumes, but in general was lower than previously observed on introduced legumes. Desmodium paniculatum (L.) DC., Galactia regularis (L.) Britton et al., and Centrosema virginianum (L.) Benth. varied among the three RKN species in their root galling and egg mass production responses. The accession of D. incanum DC. used was immune to all three RKN isolates, and could be a potential source of RKN resistance genes. The perennial native legumes evaluated all had either a fleshy taproot or a strong rhizome system.

Anthracnose, caused by the fungus Colletotrichum lindemuthianum, is considered a major constraint in the production of common bean (Phaseolus vulgaris L.). This study aimed to evaluate, in a backcross plant-breeding program, the efficiency of selecting plants resistant to anthracnose using marker-assisted selection (MAS) for two resistance genes, Co-5 and Co-42 derived from the resistance source G2333 based on the linked PCR based markers SAB3 and SAS13. The amplification of both markers was compared using DNAs extracted with two techniques, alkaline extraction, which is a fast, and inexpensive method for high throughput screening; versus a proteinase K based miniprep extraction, which is more time consuming but provides more DNA. To further evaluate the effectiveness of the markers in selecting for resistance, we compared the marker genotypes and observed phenotypes for 266 plants from eight backcross families inoculated with a field isolate of anthracnose. The Co-5 gene and SAB3 proved to be useful and the markers associated with Co-5 and Co-42 could be pyramided to give added levels of anthracnose resistance.

Hedysarum boreale Nutt. is a perennial legume native to western North America, with robust foliage in the late spring season. Due to its wide native range, forage value, and [N.sub.2] fixation, H. boreale is of interest for rangeland revegetation and production. Seed cost is a major obstacle for utilization of H. boreale, primarily due to seed shattering and unreliable seed production, such that a need for improved germplasm exists. This study characterized the genetic relationships of H. boreale accessions, so plant breeders and geneticists will have the information necessary to maintain a broad genetic base within selected germplasm populations. Amplified fragment length polymorphism markers were used on 17 available accessions from Utah, Idaho, Colorado, and Alaska. Seventy percent of the total genetic variation was found within all 17 accessions, yet each accession showed significant isolation by distance. Genetic diversity within accessions was greatest in sites located in eastern Utah. The sole cultivar, Timp, had slightly greater genetic diversity than a collection made from the same site approximately 20 yr later. Two groups of metapopulations were identified in Utah, separated longitudinally approximately along the Wasatch mountain range.

Interseeding nontraditional, cool-season legumes into bermudagrass [Cynodon dactylon (L.) Pers.] paddocks was evaluated as an approach to increasing the quality and duration of forage production and replacing a portion of the N fertilizer required in the southern Great Plains. We compared the effects of interseeding either grass pea (Lathyrus sativa L. 'AC-Greenfix') or lentil (Lens culinaris Med. 'Indianhead') with N fertilizer rates of 0, 45, or 90 kg [ha.sup.-1] N. All plots received 60 kg [P.sub.2][O.sub.5] [ha.sup.-1] in early March. The legume and fertilizer treatments were imposed in mid-March during 2001, 2002, and 2003. Forage samples were clipped from 0.25 [m.sup.-2] quadrats on five sampling dates between I May and 15 July each year. Yield, N concentration, species composition, and in vitro digestible dry matter (IVDDM) were determined. Year, sampling date, and treatment showed significant (P < 0.05) effects, as did the two-way interactions between all three factors. Total end-of-season standing dry matter of bermudagrass and grass pea was 5550 [+ or -] 423 (SEM) kg [ha.sup.-1], which was similar to biomass production with 45 kg [ha.sup.-1] N (5305 [+ or -] 570 kg [ha.sup.-1]) and less than that produced with 90 kg [ha.sup.-1] N (7785 [+ or -] 725 kg [ha.sup.-1]). Forage N and IVDDM concentrations for the grass pea treatment were 34 and 6% higher than for bermudagrass, but N and IVDDM concentrations of the forage mixture were intermediate between the higher N rates. Although additional studies are needed to optimize management for the interseeded legumes, we conclude that this practice can improve the quality and duration of bermudagrass forage production in this region.

The common bean (Phaseolus vulgaris L.) was introduced from the Americas into the Iberian Peninsula approximately 500 yr ago. Considerable genetic variation for morphological traits, allozymes, phaseolin protein, and reaction to bacterial, fungal, and viral diseases exist in the germplasm. Our objective was to identify novel genetic variation in an collection from the Iberian Peninsula. Three hundred forty-seven accessions were characterized for seven morphological traits, phaseulin protein, and eight allozymes at the Mision Biologica de Galicia, Pontevedra, Spain, between 1998 and 2005. All 347 accessions were cultivated common bean of which 102 were typical Andean and 52 were Middle American, corresponding to the two major gene pools. Nine groups could be identified among the remaining 193 accessions. Twentyeight accessions with the Middle American phaseolin formed four groups: 13 large (41-55 g 100 seed [weight.sup.-1]), five very large (56-70 g 100 seed [weight.sup.-1]), two extra-large (>70 g 100 seed [weight.sup.-1]), and eight inter-gene pool recombinants. The latter had one or more morphological and allozyme traits of the Andean gene pool. Similarly, 165 accessions with the Andean phaseolin formed five groups: 19 extra-large, 30 very large, 80 medium (25-40 g 100 seed [weight.sup.-1]), 10 small (

Cultivated soils often are either deficient or possess toxic concentrations of one or more mineral elements that adversely affect emergence, growth, maturity, production potential, and/or nutritional quality of common bean (Phaseolus vulgaris L.). Our objective was to study the inheritance of resistance to soil Zn deficiency. The resistant `Matterhorn' was crossed with the susceptible `T-39'. The [F.sub.1] was backcrossed to Matterhorn (B[C.sub.1]) and T-39 (B[C.sub.2]), and advanced to the [F.sub.2]. The two parents, [F.sub.1], [F.sub.2], B[C.sub.1], and B[C.sub.2] were evaluated in a Zn deficient field trial at Kimberly, Idaho in 2001. Plants were classified as tall-healthy or stunted with chlorotic leaves. Leaves were sampled from the two types of plants at flowering and analyzed for Zn concentration. The tall plants had an average leaf Zn concentration of 22.5 mg [kg.sup.-1]. In contrast, stunted plants had a Zn concentration of 15.0 mg [kg.sup.-1] All [F.sub.1] plants were tall resembling Matterhorn, except that unlike Matterhorn (white flowers and seeds) they had purple flowers and black shiny seeds. Thus, the resistance to Zn deficiency was dominant. A segregation of 45 resistant (R) to 20 susceptible (S) plants was observed in the [F.sub.2], giving a good fit to 3 R:1 S ([chi square] = 1.1538, P = 0.28). All plants in B[C.sub.1]were resistant. In B[C.sub.2], 142 R and 139 S plants were observed, giving a ratio of 1 R to 1 S ([chi square] = 0.032, P = 0.86). This supports a single dominant gene controlling soil Zn deficiency resistance. The symbol Znd is proposed for the dominant allele controlling resistance to soil Zn deficiency, and znd for its susceptible counterpart., AS MUCH AS 60% of the soils in the common bean production regions around the world suffer from mineral deficiencies or toxicities (CIAT, 1992; Thung and Rao, 1999; Wortmann et [...]

Five genes control the expression of partly colored seed coat patterns in common bean (Phaseolus vulgaris L.), viz., T, Z, L, Bip, and J. Because these genes have complex interactions, giving various seed coat patterns, it is often difficult to assign specific effects to a particular gene. The problem is compounded by multiple alleles at T, Z, and L. Molecular markers linked to those pattern genes have the potential to assist in identifying the genes involved in specific interactions. We have begun a series of experiments to identify useful molecular markers linked to these genes. A group of three parental genotypes and five backcross lines were screened by random amplified polymorphic DNA (RAPD) techniques to identify putative markers. Potential markers were then mapped in appropriate [BC.sub.3]-[F.sub.2] populations. To date, recombination has not been detected between RAPD markers [OAM13.sub.1350], and [OM19.sub.400] and the T gene. A single recombinant was detected between RAPD marker [OAM10.sub.560] and the Z gene, and the marker mapped at a distance of 1.4 centimorgans (cM)., Partly colored seed coat patterns in common bean are characterized by a colored pattern contrasted with a white background pattern. The gene, T, for totally colored, prevents the expression of [...]

TARS-PT03-1 (Reg. no. GP-238, PI 636363) was developed cooperatively by the USDA-ARS Tropical Agriculture Research Station (TARS), Vegetable and Forage Crops Production Research Unit, Agriculture and Agri-Food Canada, and the [...]