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Mark J. Bassett

The inheritance of a seedcoat pattern having white micropyle stripe (WMS) on a colored background was studied in two common bean (Phaseolus vulgaris L.) accessions from Centro Internacional de Agricultura Tropical—G12606 and G07262. The WMS character from G12606 was backcrossed into the recurrent parent 5-593, which has black seedcoats. Test crosses of the derived WMS stocks (BC1 and BC2) with genetic tester stocks stp (stippled seedcoat) BC2 5-593 and stp hbw (flowers with half banner petal white) BC3 5-593, respectively, demonstrated in F1 and F2 progenies that WMS is controlled by an allele at the Stp locus. The gene symbol stp mic is proposed for the allele expressing the WMS character. The dominance order at the Stp locus is Stp > stp mic > stp hbw > stp. Although stp and stp hbw each produce a different color pattern on flowers, stp mic does not produce patterned flowers. A selection from accession G07262 with a long, white micropyle stripe was crossed with 5-593 to derive a stock named F3 stp mic long micropyle stripe, which was then crossed to the genetic tester stock t z virgarcus BC2 5-593 to produce F1 and F2. Expression of the long micropyle stripe was controlled by the interaction of t and stp mic in the genotype t Z stp mic. The triple recessive interaction from genotype t z stp mic was also observed.

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Mark J. Bassett

The inheritance of an induced mutant for spindly branch and male sterility (SBMS) was investigated in common bean (Phaseolus vulgaris L.) in F2 and backcross populations. The results support the hypothesis that the mutant is controlled by a single recessive gene. Extensive breeding work with SBMS, involving several thousand F2 progeny, produced no recombinant of the types expected if two closely linked genes controlled the character. Therefore, a single pleiotropic gene apparently controls SBMS. Allelism tests demonstrated that SBMS is allelic with sb but not with sb-2 and sb-3. The gene symbol sb ms is proposed for SBMS because it is a new allele at sb, with the order of dominance being Sb > sb > sb ms. Various ways to exploit the new mutant for marked male sterility are discussed.

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Mark J. Bassett

The inheritance of a new allele, cv, at the C locus for seedcoat color was studied in common bean (Phaseolus vulgaris L.) using plant introduction (PI) accession 527774 as the source of cv. The cross PI 527774 (yellow-brown seed) x v BC25-593 (mineral-brown seed) genetic tester stock was studied in F1 and F2 progeny. An F3 selection from the above cross, designated F3 cv G b v, was crossed to 5-593 (a Florida breeding line with black seeds), and the F1, and F2 progeny were analyzed for color segregation. The second hackcross [S-593 x F1 (F3 cv G b v x 5-593)] was investigated in selfed progenies from 32 random BC2-F1 parents. Two of the BC2-F2 progenies were further tested in BC2,-F3. A third hackcross of cv to 5-593 was made and analyzed, and an allelism test of cv B V BC2-F35-593 with the cartridge huff cu BC3 5-593 genetic tester stock confirmed that cv is an allele at C. The gene symbol, cv, is proposed for the new allele because it is only expressed with V and gives a grayish-brown seedcoat. Genotypes with C/cv do not show heterozygous mottling with G B v or G b v, and there is no difference in seedcoat color between C G B v and cv G B v, or between C G b v and cv G b v.

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Mark J. Bassett

An inheritance study was conducted with genetic stocks constructed in the genetic background of the recurrent parent 5-593, a Florida dry bean (Phaseolus vulgaris L.) breeding line with black seeds and purple flowers and genotype P T Z l +. The genetic stocks, t ers ers-2 BC3 5-593 (pure white seeds), t virgarcus BC3 5-593, and t BC2 5-593 self-colored were constructed by backcrossing selected recessive alleles for partly colored seedcoats into 5-593. The cross t ers ers-2 BC3 5-593 × t BC2 5-593 self-colored was studied in F1, F2, and F3. The observed data supported the hypothesis that ers is a synonym for z and that ers-2 is a synonym for a new allele (l ers) at the L locus. The cross t ers ers-2 BC3 5-593 × t virgarcus BC3 5-593 was studied in F1 and F2 progeny, and the results confirmed the hypothesis of allelism between ers and z. `Thuringia' (pure white seedcoats) with genotype P t z L was crossed with t ers ers-2 BC3 5-593, t virgarcus BC3 5-593 and t BC2 5-593 self-colored. The cross `Thuringia' (P t z L) × t ers ers-2 BC3 5-593 was studied in F1 and F2 and supported the hypothesis that l ers is an allele at L. The results of the other two test crosses are discussed. The gene ers-2 is a new recessive allele at L, for which the new symbol l ers is proposed. Thus, the dominance order at the L locus is L > l + > l ers, where l + is the null allele at L found in 5-593. The l + allele does not restrict the colored area of a partly colored seedcoat and is hypothetically the wild-type allele at L.

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Mark J. Bassett

The P locus in common bean (Phaseolus vulgaris L.) can express complete absence of color (white) in seedcoats and flowers with p (with B V) or a pale grayish white seedcoat and nearly white flower with p gri, but P has never been considered a seedcoat pattern locus. Genes controlling seedcoat colors and patterns have been backcrossed into the recurrent parent 5-593 with black seedcoats and violet flowers. The cross, p BC3 5-593 × t stp mic BC3 5-593 (black seeds with a long white micropyle stripe and fibula arcs), failed to show evidence of genetic complementation in either F1 or F2 progeny, leading to the hypothesis that P and Stp are allelic. Five cross combinations between two recessive P alleles (p BC3 5-593 and p gri BC3 5-593) and three recessive alleles at the stippled seedcoat gene Stp (stp BC3 5-593, stp hbw BC3 5-593, and stp mic BC3 5-593) expressed no genetic complementation in seedcoats and flowers of F1 progeny and confirmed the allelism hypothesis. New gene symbols are proposed for the recessive alleles at Stp, viz., p stp for stp, p hbw for stp hbw and p mic for stp mic. The dominance order at P is P > p mic > p hbw > p stp > p gri > p. Crosses were made between t self-colored BC3 5-593 and three other parents—p stp BC3 5-593, p hbw BC3 5-593, and p mic BC3 5-593—to explore interactions between the pattern genes T and P; and segregation for seedcoat patterns in F2 was discussed. The hypothesis was proposed that the T locus regulates expression at P, or the biosynthetic step regulated by P.

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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.

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Mark J. Bassett

The inheritance of corona and hilum ring color of common bean (Phaseolus vulgaris L.) was investigated in the reciprocal cross `Wagenaar' (a Canario market class dry bean) × `Mayocoba' (Mayocoba market class dry bean), where both parents were known to have seedcoat color genotype P [C r] gy J g b v lae Rk. `Wagenaar' has greenish yellow (GY) seedcoat (due to gy) except for purple (dark) corona (due to v lae) and reddish brown hilum ring (due to J), whereas `Mayocoba' has an entirely GY seedcoat. Seeds produced on the F1 progeny plants had GY corona and reddish brown hilum ring. The F2 segregated for three phenotypic classes, the two parental classes and the F1 class, but the segregation did not fit a 1:2:1 segregation ratio due to disturbed segregation. F3 progeny tests of 35 randomly selected F2 parents demonstrated that the two parental classes were true breeding and the F1 class segregated again (as in the F2) for the same three phenotypic classes. In spite of variable expressivity of GY color and disturbed segregation, the data support a single gene hypothesis, for which the tentative symbol Chr is proposed. Chr is dominant for changing purple corona to GY, but recessive for changing reddish brown hilum ring to GY. Thus, only one gene, Chr, controls the difference in seedcoat color between the market classes Canario and Mayocoba. An allelism test between Chr and Z (hilum ring color factor) is needed before a formal proposal for Chr can be made.

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Mark J. Bassett

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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.

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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.