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- Author or Editor: Mark J. Bassett x
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.