The inheritance of novel flower and seedcoat patterns was studied in three parental materials: PI 390775 and `Springwater Half Runner' (SHR), which have patterned flower and seedcoat colors, and 5-593, a Florida dry bean breeding line with unpatterned purple flowers and seeds. Using crosses between 5-593 and the other two parents, an analysis of F1, F2, backcross F2, and backcross F3 data demonstrated that a single recessive allele in each of the patterned parents controlled flower and seedcoat pattern. Genetic tester stocks were used to demonstrate that the recessive gene for patterning in PI 390775 was nonallelic with C, T, and Mar, the three genes previously known to control seedcoat pattern in common bean. An allelism test between the recessive pattern genes from PI 390775 and SHR demonstrated that they were allelic and that the gene from SHR was dominant. The gene symbols stp (for the gene from PI 390775) and stp hbw (for the dominant gene from SHR) are proposed, where stp stands for stippled seedcoat pattern and the superscript letters hbw stand for half banner white.
Mark J. Bassett
Common bean (Phaseolus vulgaris L.) plant introduction 527829 (formerly Lamprecht M0048) has dark seal-brown (DSB) seedcoats and pink flowers. An investigation was conducted to determine the genotype of DSB seedcoat color. M0048 was crossed with Florida breeding line 5-593, which has genotype P [C r] D J G B V Rk. A series of crosses involving M0048, 5-593, and three genetic tester stocks (v BC2 5-593, c u BC2 5-593, and b v BC2 5-593) led to determination of the genotype. Data analysis indicated that M0048 has the genotype P [? R] J G B v lae, where DSB color is produced by the interaction of R with B. Crosses between [? R] and testers with [C r] always produced seedcoat mottling in F1, except where V masks the effect. The cross [? R] B v (DSB) × c u BC2 5-593 (cartridge buff seedcoat) produced marbled seedcoats (black/cartridge buff) with genotype [? R]/[c u ?] B V. No way was found to determine whether the mottled or marbled seedcoat patterns were controlled at C or R; hence, the allelic ambiguity is indicated with a question mark. Illustrations are provided showing the difference between seedcoat mottling (a highly variable low-contrast patterning) and seedcoat marbling (a less variable high-contrast patterning, usually with cartridge buff as the background color). The development of a new genetic tester stock, [? R] b v BC3 5-593, was described, where [? R] b v gives unpatterned dominant red seedcoat color.
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
The inheritance of flower and seedcoat color was studied using Lamprecht line M0137 (PI 527845) of common bean (Phaseolus vulgaris L.) as the source of a new allele, V wf, at the V locus. The cross M0137 c res V wf × C v BC2 5-593 (a genetic tester stock) was studied in progeny of the F1, F2, F3, and F4 generations. The observed segregation for flower and seed colors was consistent with the hypothesis that M0137 carried a new allele, V wf, that produced (in the presence of P C J G B) white flowers and black seeds rather than the white flowers and mineral-brown seeds produced (in the presence of P C J G B) by v. The V/V wf genotype produced cobalt-violet flowers, the same as V/v. A test cross of F3 V wf × t BC1 5-593 bipunctata demonstrated that V wf is not allelic with t, a gene that can produce white or colored flowers and self-colored or partly colored seeds, depending on background genotype.
Mark J. Bassett
A new gene for flower color pattern, designated white banner (WB), appeared in material derived from the cross `Harvester' snap bean (Phaseolus vulgaris L.) × Plant Introduction (PI) accession 273666 of scarlet runner bean (P. coccineus L.). The WB character has a white banner petal and pale violet wings (veronica-violet 639/2). The inheritance of the mutant was studied in crosses involving dry bean breeding line 5-593, which has bishops-violet (wild-type) flowers, and genetic stocks v BC2 5-593 (white flowers) and blu BC2 5-593 (blue flowers). Segregation in F2 and F3 progenies from the cross v BC2 5-593 × WB supported the hypothesis that WB is controlled by a single recessive gene that is nonallelic with the V locus. An allelism test with blu BC2 5-593 gave evidence that WB is not allelic with the blu locus. The gene symbol wb is proposed for the gene producing WB.
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.
Mark J. Bassett
A mutation for blue (methyl-violet) flower color was induced by gamma irradiation of dry seed in common bean (Phaseolus vulgaris L.). Inheritance and allelism tests demonstrated that the mutation is controlled by a single recessive gene that is not allelic with Sal or V. The gene symbol blu is proposed for this mutant. Linkage was detected between blu and Fin, which controls the change from indeterminate to determinate plant habit. Three linkage estimates ranged from 19 to 35 cM, but the large variability (homogeneity x 2 = 45.32) precludes making a conclusive combined estimate of linkage. The tentative combined estimate of linkage is 27 cM.
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.
Mark J. Bassett and Arie Blom
The white-seeded snap bean `Early Wax' (Phaseolus vulgaris L.) was crossed with a black-seeded breeding line 5-593. The F2 segregation data are consistent with a three-gene model, in which all three genes must be homozygous recessive to give white seed coat. One of the genes is t because of segregation in F2 for plants with white flowers and partial seed coat coloration. We hypothesize that the genes ers and ers2 in the presence of f block all seed color expression in all genes for partial coloration of seed. The hypothesis of three recessive genes was confirmed in a backcross test involving `Early Wax' x F1. The interaction of ers and ers2 was tested in progeny tests of partly colored BC-F1 plants. One of the erasure genes, ers2, blocks color expression in color zones close to the hilum, but only in the presence of ers. The other erasure gene, ers, blocks color expression only in color zones beyond those close to the hilum in a manner similar to the restr locus of Prakken (1972). The old hypothesis that partly colored seed phenotypes require the presence of a second factor e in addition to t, where the function of e is vague and unspecified, should be discarded for lack of supporting evidence, Under the new hypothesis, soldier series phenotypes (e.g., bipunctata, arcus, virgata, and virgarcus) may express in t ers Ers2 by action of ers or in t Ers Ers2 by action of various genes for partly colored seeds other than ers.
Mark J. Bassett and Mathias J. Silbernagel
Dry seed of the common bean (Phaseolus vulgaris L.) breeding line S-593 was treated with 200 Gy of gamma radiation, and M2 seed was produced. The seed was planted at Prosser, Wash., and selection was made for plants with greatly reduced seed set. The inheritance of one of the selections for possible male sterility mutation was studied in F2, F3, and backcross generations. This character is controlled by a single recessive gene, for which the symbol ms-1 is proposed. Plants carrying ms-l/ms-1 produce well-filled pods after manual pollination with pollen from normal plants, but produce no seed when protected from insect pollination in greenhouse and field environments. Uses for this mutant are discussed.