Halo blight is one of the most important bacterial diseases of common beans (Phaseolus vulgaris L.). It is serious under moderate temperature and high humidity conditions. The disease is caused by a seed-borne bacterium, Pseudomonas syringae pv. phaseolicola (Burkh.) Dowson (Psp). The inheritance of leaf reactions to Psp, flower, and stem color was studied using greenhouse-grown 109 F9 recombinant inbred lines (RI) from the P. vulgaris cross BelNeb 1 [resistant (R)] (USDA/NE) × A 55 [susceptible (S)] (CIAT). Two Psp strains, HB16 (NE) and 83-Sc2A (NE), were inoculated using the water-soaking method. A segregation ratio of 1 R:1 S RI lines were observed for disease reactions in leaves for both strains indicating major gene control. The presence of recombinants for SR, RS to the strains indicated that different genes were involved. Stem (SC) and flower (FC) color traits were each determined by two major genes. Linkages were found for reactions to the two Psp strains and also between FC and SC. No linkages were observed from FC and also SC with reactions to Psp strains.
H.M. Ariyarathne and D.P. Coyne
An in vivo system was developed to determine the effects of pH on naturally occurring pigment complexes within cells. The in vivo system was based on a transposable element activator (Ac) inserted into the Ph6 gene. The transposable element activator (Ac) was crossed into two genetically marked Petunia hybrida lines expressing known flavonoid pigments. Plants expressing the transposable element activator (Ac) produced variegated flowers in which the background tissue was lighter in intensity than the sectors. Depending on the genetic background in which the transposable element is expressed, progeny with darker sectors that were also redder in color than the background tissue could also be obtained. The anthocyanin and copigment composition was the same for both of the differently colored sectors and background tissue, while the pH was lower by 0.4 unit in the redder sectors. It was suggested that the Ph6 gene might be a regulatory gene that controls the expression of the pH and anthocyanin concentration.
Bridget Behe, Robert Nelson, Susan Barton, Charles Hall, Steve Turner, and Charles Safley
Consumers in five U.S. markets evaluated photographs of geranium plants with regard to purchase likelihood. Photographic images were colored electronically to produce uniform geranium plants with five flower colors (pink, white, red, lavender, and blue) and three leaf variegation patterns (dark zone, white zone, and no zonal pattern). Photographs were mounted on cards with five selected price points ranging from ($1.39 to $2.79). We randomly generated an orthogonal array, partial-factorial design for consumers to rate a reduced number of choices. Consumers shopping in cooperating garden centers located in Dallas, Texas; Montgomery, Ala.; Athens, Ga.; Charlotte, N.C.; and Wilmington, Dela., rated 25 photographs on the basis of their likelihood to purchase the plants shown. Conjoint analysis revealed that customers in the Georgia garden center placed the highest proportion of their decision to buy on leaf variegation (29%), while customers in the Alabama outlet placed the most emphasis on price (46% of the decision). Shoppers in Texas valued flower color most highly (58% of their decision to buy). Demographic characteristics and past purchase behavior also varied widely, suggesting diverse marketing strategies for geraniums.
Yanjie Wang, Yeqing Chen, Man Yuan, Zeyun Xue, Qijiang Jin, and Yingchun Xu
( Zhang, 2011 ). These cultivars possess several attractive flower colors including red, pink, white, yellow, and versicolor, but compared with other ornamental plants, the lotus flower color is not rich in diversity yet. Flower color has been regarded as
S.O. Park, A. Dursun, and D.P. Coyne
Common bacterial blight (CBB), incited by Xanthomonas campestris pv. phaseoli (Xcp), is an important disease of common bean (Phaseolus vulgaris L.). Tepary bean (P. acutifolius A. Gray) is of interest to bean breeders because of resistance to CBB. The objective was to identify RAPD markers linked to major dominant genes for CBB resistance and purple flower color using bulked segregant analysis in an F2 population from a tepary bean cross Nebr#19 [resistant (R) to CBB and white flower color] × Nebr#4B [susceptible (S) to CBB and purple flower color]. Ten RAPD primers (600 RAPD primers screened) showed polymorphisms between bulked DNA derived from R and S plants. All markers showed coupling linkage with CBB resistance. The RAPD marker of G-14 primer was 5.2 cM distant from the gene for resistance to Xcp strain LB-2. The RAPD marker of L-18 primer was 6.8 cM distant from the gene for resistance to Xcp strain SC-4A. The RAPD marker of G-14 primer was 26.2 cM distant from the gene for resistance to Xcp strain EK-11. Seven RAPD primers showed polymorphisms between bulked DNA derived from purple and white flower plants. All markers showed coupling linkage with the gene for purple flower color. The RAPD marker of Y-6 primer was 3.6 cM distant from the gene for purple flower color.
Mark J. Bassett
Plant Introduction (PI) accession 507984 of common bean (Phaseolus vulgaris L.) has partly colored seed coats and either pure white flowers or light laelia flowers. Crosses were made with white-flowered plants of PI 507984: white-flowered plant #1 × the genetic stock t ers ers2 BC2 5-593 and white-flowered plant #2 × recurrent parent dry bean breeding line 5-593. Inheritance was studied in the F1, F2, and F3 of the former cross and the F1 and F2 of the latter cross. PI 507984 (white flower, plant #1) × t ers ers2 BC2 5-593 gave F1 plants with colored flowers and partly colored seeds. The F2 gave a 9:7 segregation ratio (colored flowers to white flowers), and the genetic model proposed is that flower color is restored in the presence of t/t by two complementary genes, Fcr and Fcr-2. That model was confirmed by F3 progeny tests of 21 F2 parents with colored flowers. The cross PI 507984 (white flower, plant #2) × 5-593 gave an F2 segregation ratio of 9:3:4 (bishops-violet: light laelia: white flowers), indicating that the white-flowered PI 507984 has v lae masked by t. Analysis of all the data suggests that PI 507984 is heterogeneous at Fcr and Fcr-2, having all three possible homozygous genotypes, viz., either light laelia flowers from v lae t Fcr Fcr-2 or white flowers from v lae t Fcr fcr-2 or v lae t fcr Fcr-2. The flower color restoration gene in 5-593 is arbitrarily assigned the symbol Fcr. Great variability occurs in partly colored seeds of PI 507984 due to the environment in which the seed was produced.
Ryan N. Contreras, John M. Ruter, and David A. Knauft
green petioles, and individuals with pink fruit had petioles of intermediate pigmentation. Flower color also corresponded with fruit color. Individuals with pink flowers had purple fruit, whereas individuals with white flowers had white fruit. Flower
Soon O. Park, Dermot P. Coyne, Nedim Mutlu, James R. Steadman, and Geunhwa Jung
Common bacterial blight, incited by Xanthomonas campestris pv. phaseoli (Xcp), is a serious disease of common bean (Phaseolus vulgaris). RAPD markers and flower color (V gene) previously had been reported to be associated with six QTL affecting leaf and pod resistance to Xcp. However, the markers for the QTL were not confirmed in different populations and environments to indicate their merit in breeding. Our objective was to determine if the associations of RAPD markers and the V gene with QTL for leaf and pod resistance to Xcp in a RI backcross population from the cross BC2F6 `PC-50' × XAN-159 and for leaf resistance to Xcp in a F2 population from a different cross Pinto `Chase' × XAN-159 could be confirmed. Among six QTL previously detected, five in the RI backcross population and three in the F2 population were confirmed to be associated with resistance to Xcp. The V gene and RAPD marker BC437.1050 on linkage group 5 were most consistently associated with leaf and pod resistance to two to five XCP strains in the RI backcross population and with leaf resistance to two Xcp strains in the F2 population. The confirmed marker BC437.1050 and V gene on linkage group 5, along with other resistance genes from other germplasm, could be used to pyramid the different genes into a bean cultivar to enhance the resistance to Xcp.
Soon O. Park, Dermot P. Coyne, Nedim Mutlu, Geunhwa Jung, and James R. Steadman
Common bacterial blight, incited by Xanthomonas campestris pv. phaseoli (Xcp) is a serious disease of common bean (Phaseolus vulgaris L.). Randomly amplified polymorphic DNA (RAPD) markers and flower color (V gene) previously were reported to be associated with six quantitative trait loci (QTL) affecting leaf and pod resistance to Xcp. However, the markers for the QTL were not confirmed in different populations and environments to indicate their merit in breeding. The objective was to determine if the associations of RAPD markers and the V gene with QTL for leaf and pod resistance to Xcp in a recombinant inbred (RI) backcross population from the cross BC2F6 `PC-50' × XAN-159 and for leaf resistance to Xcp in an F2 population from a different cross pinto `Chase' × XAN-159 could be confirmed. One or two genes from XAN-159 controlled leaf and pod resistance to Xcp. Among six QTL previously detected, five in the RI backcross population and three in the F2 population were confirmed to be associated with resistance to Xcp. The V gene and RAPD marker BC437.1050 on linkage group 5 were most consistently associated with leaf and pod resistance to two to five Xcp strains in the RI backcross population and with leaf resistance to two Xcp strains in the F2 population. One to three QTL affecting leaf and pod resistance to Xcp accounted for 22% to 61% of the phenotypic variation. Gene number (one to two) estimations and number of QTL (one to three) detected for leaf and pod resistance to Xcp in the RI backcross population were generally in agreement. The marker BC437.1050 and V gene, along with other resistance genes from other germplasm, could be utilized to pyramid the different genes into a susceptible or partially resistant bean line or cultivar to enhance the level of resistance to Xcp.
Mark J. Bassett
The genetics of the vermilion flower color (more orange than scarlet or salmon red) of Phaseolus coccineus L. is largely unknown, but the gene Sal for salmon red is the gene essential for its expression. Lamprecht line M0169 (PI 527868) expresses salmon red flowers with vein pattern on the wing petals and black seedcoats. M0169 (Sal Am and an unknown gene that inhibits the scarlet flower color expression of Am) was crossed with v BC3 5-593 (sal am and no inhibitor gene, expressing white flowers and mineral brown seedcoats). Line 5-593 is a Florida dry bean (Phaseolus vulgaris L.) line used as the recurrent parent for development of genetic stocks. The F2 from Sal Am V wf BC1 5-593 (scarlet flowers, black seedcoats) × v BC3 5-593 (white flowers, mineral brown seedcoats) supported the hypothesis that a partly dominant gene Am changes salmon red to scarlet flower color and that Am has no expression with sal. The F3 progeny test of 27 random F2 parents from the above cross supported the hypothesis of a single partly dominant factor (Am) with no expression without Sal, where only Sal/Sal Am/Am completely eliminates the flower vein pattern (VP) of Sal. F4 progeny tests of 29 random F3 parents derived from a F2 selection with Sal/Sal Am/am V wf/v supported the hypothesis that Am is linked to V (cM = 9.4 ± 1.93) and the hypothesis that Am is linked with a dominant gene (tentative symbol Oxb) that (with Sal v) changes seedcoat color from mineral brown with red haze to oxblood red. Another F4 progeny test of seven selected F3 parents with Sal/Sal Am/am v/v and oxblood seedcoat color supported the hypothesis that the Oxb gene (linked with Am and derived from M0169) with Sal v expresses oxblood seedcoat color. The gene symbol Am is proposed for the gene from M0169 that with Sal v expresses two pleiotropic effects: changes salmon red to scarlet flower color and eliminates the VP of salmon red. The interaction of Sal with Am for flower color and VP expression is discussed for all gene combinations.