Passionfruit woodiness virus (PWV) can infect bean (Phaseolus vulgaris L.), causing a light and dark green foliar mosaic, veinbanding, downward curling, and plant stunting. The intensity of these symptoms can vary with the strain of the virus and cultivar, but they resemble those caused by bean common mosaic virus. In genetic populations derived from crosses and backcrosses involving cultivars that are resistant (`Black Turtle 1', `Clipper', and `RedKote') or susceptible (`Black Turtle 2', `California Light Red Kidney', and `Pioneer'), a single dominant gene conferred resistance to an Australian strain PWV-K. To this gene, the symbol Pwv (Passionfruit woodiness virus) is tentatively assigned. In plants derived from rooted cuttings of backcross populations, the same factor also conditioned resistance to three other Australian strains, PWV-Mild, PWV-51, and PWV-Tip Blight.
Karl J. Sauter, David W. Davis, Paul H. Li, and I.S. Wallerstein
Yield in common bean, Phaseolus vulgaris L., can be significantly reduced by high temperature (I-IT) during bloom. Ethylene production from plant tissue increases as a consequence of various stresses, including heat stress. The inheritance of leaf ethylene evolution rate (EER) of HT-stressed (35/30C day/night) progenies from crosses among bean genotypes previously categorized as HT sensitive or tolerant, based on cell electrolyte leakage, was investigated. Evidence from generation means analysis of Fl, F2, and backcross progenies shows EER to be genetically controlled, with additive, dominance, and epistatic effects indicated for low EER. The range (0.62 to 2.52 μg-1·hr-1) of EER from field-grown lines and cultivars suggests the existence of considerable genetic variability. EER was associated (r = –0.70) with heat tolerance, as estimated by cell electrolyte; leakage.
Mark J. Bassett
Linkage relationships between the locus for shiny pods (ace) and the loci for reclining foliage (rf) and pink (v lae) or white (v) flower color were studied in several crosses among common bean (Phaseolus vulgaris L.) parents. Florida dry bean breeding line 5-593 (Ace Rf V.) was crossed with F3 ace/ace Rf/rf V/v lae, and data were taken in F2. Selections from the previously mentioned F2, viz., F3 ace Rf V, F3 ace rf v lae plant no. 1 and F3 ace rf v lae plant no. 2, were backcrossed to 5-593. Data were taken in F2 on segregation for pod, foliage, and flower characters. Linkage between Ace and V was 37 map units (cM), and linkage between Ace and Rf was 31 cM. A revised estimate for the linkage between Rf and V was 11 cM. The map orientation for linkage group VII is ace -31-rf-11-V.
Mark J. Bassett
Dry seeds of common bean (Phaseolus vulgaris L.) were treated with 20 krad (1 rad = 0.01 Gy) of gamma rays to induce plant mutations to be used as genetic markers in mapping studies. Four leaf mutants are described and illustrated. Inheritance studies demonstrated that each is controlled by a single recessive gene. The proposed gene symbols are: cml for chlorotic moderately lanceolate leaf, lbd for leaf-bleaching dwarf, glb for glossy bronzing leaf, and 01 for overlapping leaflets. Linkage tests involving cml and nine previously reported marker mutants failed to detect any linkages.
Mohamed F. Mohamed, Paul E. Read, and Dermot P. Coyne
Few studies on embryogenesis in common bean (Phaseolus vulgaris L.) have been reported and only the early stages of somatic embryogenesis were observed. Dry seeds from two common bean lines were germinated in darkness on L-6 medium containing 4% sucrose, 0.2 g casein hydrolysate /liter and 2.0 g phytagel /liter. The medium for seed germination was supplemented with 0, 2, 4 or 6μM forchlorfenuron (CPPU). Explants from cotyledonary leaves, petioles, hypocotyls and shoot apices were prepared from 14 day-old seedlings. Callus was derived from explant cultures incubated in darkness at 26C on the medium containing 4 μM 2,4-D and 1 μM Kinetin. The callus was transferred after 4 weeks into 125 ml Erlenmeyer flasks containing 50 ml liquid medium and placed on a gyrotary shaker (120 rpm) under cool-white light (12 μmol.m-2.s-1). The liquid medium was used with 2, 4 or 6 μM of 2,4-D alone or with zeatin supplements at relative concentrations of 0.25 and 0.5. Up to 200 somatic embryos from 40 to 50 mg callus inoculations were induced after 4 to 5 weeks. Callus derived from seedlings grown on CPPU-containing medium gave more repetitive somatic embryos. Cotyledonary stage embryos with clear bipolar structure were observed only from callus derived from seedlings grown on CPPU when transferred to suspension cultures containing 2,4-D and zeatin. All somatic embryos differentiated strong roots and some developed leaf-like structures on conversion medium.
Mark J. Bassett
Crosses were made with two common bean (Phaseolus vulgaris L.) parents that have pink flowers (v lae/-) and mineral-brown seedcoats with dark corona, viz., v lae BC3 5-593 (derived from Lamprecht V0491) and F3 v lae dark corona (derived from Lamprecht M0048). The third parent v BC2 5-593 had white flowers (v/v) and mineral-brown seedcoats without dark corona (derived from Lamprecht M0056). The F2 progenies of the crosses v BC2 5-593 × v lae BC3 5-593 and F3vlae dark corona × v BC2 5-593 segregated for only two phenotypic classes: either pink flowers and seeds with dark corona or white flowers and seeds without dark corona. Thus, it was demonstrated that the dark corona character (Cor) is either tightly linked to vlae (<4 map units) or is a pleiotropic effect of vlae. Pleiotropy is more probable, but tight linkage cannot be ruled out. A linkage of 15 map units between Cor and R (currently, R is known to be tightly linked with C) reported by Lamprecht was not found by subsequent authors, and the linkage map of common bean should be revised accordingly, i.e., no linkage exists between V (Cor) and C.
Phillip D. Griffiths
selection and evaluation in multistate greenhouse and field comparisons through the w-1150 regional project. White mold is a serious disease of common bean worldwide reducing both yield and quality ( Kerr et al., 1978 ). Host plant resistance can be
Wei-Ling Chen and Hsueh-Shih Lin
The common bean ( Phaseolus vulgaris L.; 2 n = 2 x = 22), one of the most important legume crops that originated in southern Mexico to Central America, is cultivated in tropical, subtropical, and temperate regions. It is produced mainly for dry
Soon O. Park, Dermot P. Coyne, Geunhwa Jung, Paul W. Skroch, E. Arnaud-Santana, James R. Steadman, H.M. Ariyarathne, and James Nienhuis
Published as Nebraska Agricultural Research Division journal series paper 12166. Research was conducted under Projects 20-036 and 20-042. We acknowledge financial support from the Title XII Bean/Cowpea CRSP (AID Contract No. DNA-1310-G-SS-6008
Mark J. Bassett
The inheritance of two new induced mutations for spindly branch was investigated in common bean (Phaseolus vulgaris L.). Each mutant was found to be controlled by a recessive gene. Allelism tests were performed beween a previously reported spindly branch mutant (sb) and the two new spindly branch mutants; the new mutants were found to be nonallelic to sb and to each other. The gene symbols sb-2 and sb-3 are proposed for the new mutants. Repulsion phase F2 linkage tests were made for all nine combinations of reclining foliage (rf) and sb among the two mimic mutant series rf, rf-2, rf-3 and sb, sb-2, sb-3. No linkages were detected.