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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 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

Linkage between the Fin locus controlling plant habit and the Z locus controlling partly colored seedcoats in common bean (Phaseolus vulgaris L.) was studied in the F2 and F3 progenies from the cross `t virgarcus BC3 5-593' (determinate habit, virgarcus pattern of partly colored seeds, fin tz) × `Steuben Yellow Eye' (indeterminate habit, sellatus pattern of partly colored seeds, Fin t z sel). The heterozygous genotype z sel/z produces the piebald pattern of partly colored seeds, whereas Fin is completely dominate to fin. Selection was made in the F2 for crossover phenotypes: indeterminate habit with virgarcus seeds or determinate habit with piebald seeds. Linkage calculations were based on crossover genotypes confirmed by F3 progeny tests grown in the greenhouse. The recombination percentage between Fin and Z was 1.032±0.33 map units. The gene symbol z sel is proposed, where t Z gives the expansa partly colored seedcoat pattern, t z sel gives sellatus, and t z gives virgarcus.

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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 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

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.

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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

The inheritance of hilum ring color in common bean (Phaseolus vulgaris L.) was investigated using various genetic tester stocks developed by backcrossing recessive alleles into a recurrent parent stock 5-593 with seedcoat genotype P [C r] D J G B V Rk, viz., mar BC2 5-593, mar BC3 5-593, mar v BC2 5-593, mar d BC2 5-593, and mar d BC3 5-593. The current hypothesis is that the margo character is controlled by mar and hilum ring color is controlled by d but expresses only with mar. The V locus controls flower and seedcoat color. The allelism test crosses `Citroen' (P C d j g b v lae) × mar BC3 5-593 and `Citroen' × mar d BC3 5-593 demonstrated that mar is allelic with j and that the putative d in mar d BC3 5-593 is allelic with the d in `Citroen'. Thus, the former genetic tester stocks mar BC3 5-593 and mar d BC3 5-593 are reclassified as j BC3 5-593 and d j BC3 5-593, respectively, because mar is a synonym for j. Similarly, the former genetic tester stock mar v BC2 5-593 is reclassified as j v BC2 5-593. The interaction of j with d expresses as loss of color in the hilum ring. The development of the white-seeded genetic tester stock P c u d j BC3 5-593 was described in detail, where the all-recessive tester `Prakken 75' was used as the source of the recessive alleles. The previously reported work showing that the partly colored seedcoat gene t interacts with mar to control seedcoat pattern is now interpreted to mean that the joker (J) locus interacts with t to produce partly colored seedcoat patterns. The genetic loci D and V were found to segregate independently. The common gene for dull seedcoats (asper, asp) is discussed and contrasted with j.

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Mark J. Bassett

The development of genetic tester stocks in common bean (Phaseolus vulgaris L.) for the partly colored seedcoat patterns `bipunctata BC3 5-593' (t z bip) and `virgarcus BC3 5-593' (t z) was described. The inheritance of the bipunctata pattern was studied in the F2 from the crosses `bipunctata BC1 5-593' × 5-593 and `bipunctata BC2 5-593' × 5-593. The data supported the hypothesis that a single recessive gene (bip) converts virgarcus (t z Bip) to bipunctata (t z bip). The inheritance of bipunctata was also studied in the F2 from the cross `bipunctata BC3 5-593' × `virgarcus BC3 5-593'. The data supported the hypothesis of complete dominance of Bip over bip in a t z genetic background highly related to the recurrent parent 5-593, where only the parental phenotypes appear in the F2.