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  • Author or Editor: J.R. Stavely x
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Abstract

Rust, caused by Uromyces appendiculatus (Pers.) Unger [ = U. phaseoli (Reben) Wint.], is a major disease of bean (Phaseolus vulgaris L.) throughout most of the world (7). Severe epidemics can cause as much as 80% to 100% crop loss. This disease often occurs in severe epidemics on snap beans in the humid Southeastern and Mid-Atlantic United States (1, 5). Fungicides are commonly used to reduce losses. Over 150 pathogenic races of U. appendiculatus have been identified worldwide, including 55 from the contiguous United States (4).

Open Access

Abstract

Belneb Rust Resistant-1 and -2 (Belneb RR-1 and -2), are two medium-large, white-seeded, viney, Great Northern (GN) dry bean (Phaseolus vulgaris L.) germplasm lines and are the first dry bean lines homozygous for resistance to 33 races of the bean rust pathogen [Uromyces appendiculatus (Pers.) Ungar var. appendiculatus] [= U. phaseoli (Reben) Wint.] recently identified (6, 7) from the United States and the Caribbean. These lines were approved for joint release by ARS/USDA, and the Nebraska Agricultural Experiment Station in Apr. 1988. Although nearly 200 races of U. appendiculatus have been identified worldwide (7), the 33 used here (races 38-70) are the only races virulent for several of the most broadly rust-resistant bean germplasm (6, 7).

Open Access

`White Half Runner' is a popular green bean (Phaseolus vulgaris L.) cultivar in the southern Appalachian region of the United States. The cultivar is highly susceptible to rust and virus diseases. Nine breeding lines with `White Half Runner' parentage were compared to `White Half Runner' for rust tolerance, yield, and pod quality in 1998 and 1999 field trials at Crossville, Tenn. The BelTenn selections were developed by USDA plant breeders and the UT selections were developed by University of Tennessee plant breeders. Selections `BelTenn-RR-2', `BelTenn 4-12028', `BelTenn 4-12046', `BelTenn 4-12053', `BelTenn 5-2717' and `UT-96-3' were resistant to rust. Only `UT 96-4' had lower yields than `White Half Runner' in 1999. The BelTenn lines had slightly smaller pods, and the UT selections had larger and rougher pods than `White Half Runner'. `BelTenn-RR-2' wasreleased in 1995 as a breeding line with rust resistance and pod quality similar to `White Half Runner'. Further selection of BelTenn-RR-2 by a private seed company led to the naming of a cultivar named `Volunteer White Half Runner'.

Full access

Common bacterial blight (CBB), rust (RU), and white mold (WM) are serious diseases of great northern (GN) and pinto (P) beans in Nebraska and Colorado. The bacterial diseases halo blight (HB) and brown spot (BS) are sporadic. Severe Fe-induced leaf chlorosis (Fe ILC) occurs on calcareous sites. Separate inoculated disease nurseries are used to screen for resistance to the pathogens causing the above diseases. Yields and seed quality of lines are also determined in non-disease trials. Sources of exotic resistance to the above pathogens and to Fe ILD have been identified and their inheritance determined. A non-structured recurrent selection scheme has mainly been used, occasionally with a backcross program, to combine high levels of the desired traits. Selection for highly heritable traits such as seed size, shape and color, maturity, plant architecture, and RU resistance occurs in early generations while traits of low heritability, such as CBB resistance, WM avoidance, yield, seed coat cracking resistance, and canning quality, are evaluated in separate replicated tests over several years and finally for yield in on-farm-trials. A number of multiple disease resistant, high-yielding, well-adapted GN and P lines are or will be released; P `Chase' (on about 30,000 acres in 1996) and GN WM 3-94-9 (for possible release).

Free access

Understanding the genomic associations among disease resistance loci will facilitate breeding of multiple disease resistant cultivars. We constructed a genetic linkage map in common bean (Phaseolus vulgaris L.) containing six genes and nine quantitative trait loci (QTL) comprising resistance to one bacterial, three fungal, and two viral pathogens of bean. The mapping population consisted of 79 F5:7 recombinant inbred lines (RILs) derived from a `Dorado'/XAN 176 hybridization. There were 147 randomly amplified polymorphic DNA (RAPD) markers, two sequence characterized amplified region (SCAR) markers, one intersimple sequence repeat (ISSR) marker, two seedcoat color genes R and V, the Asp gene conditioning seed brilliance, and two rust [Uromyces appendiculatus var. appendiculatus (Pers.:Pers) Unger] resistance genes: one conditioning resistance to Races 53 and 54 and the other conditioning resistance to Race 108. These markers mapped across eleven linkage groups, one linked triad, and seven linked pairs for an overall map length of 930 cM (Kosambi). Genes conditioning resistance to anthracnose (Co-2) [Colletotrichum lindemuthianum (Sacc. and Magnus) Lams.-Scrib.], bean rust (Ur-5), and bean common mosaic virus (I and bc-3) (BCMV) did not segregate in this population, but were mapped by inference using linked RAPD and SCAR markers identified in other populations. Nine previously reported quantitative trait loci (QTL) conditioning resistance to a variety of pathogens including common bacterial blight [Xanthomonas campestris pv. phaseoli (Smith) Dye], ashy stem blight [Macrophomina phaseolina (Tassi) Goid.], and bean golden mosaic virus (BGMV), were located across four linkage groups. Linkage among QTL for resistance to ashy stem blight, BGMV, and common bacterial blight on linkage group B7 and ashy stem blight, BGMV, and rust resistance loci on B4 will complicate breeding for combined resistance to all four pathogens in this population.

Free access