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.
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.
Mark J. Bassett, Rian Lee, Carla Otto, and Phillip E. McClean
Inheritance of the strong greenish-yellow (SGY) seedcoat color in `Wagenaar' common bean (Phaseolus vulgaris L.) was investigated. Line 5-593 is a determinate, Florida dry bean breeding line (with small black seeds) used as the recurrent parent in the development of many genetic stocks, e.g., g b v BC3 5-593. Through crosses with genetic tester stocks, the seedcoat genotype of `Wagenaar' was confirmed to be C J g b v lae Rk. Three randomly amplified polymorphic DNA markers (OAP7850, OAP31400, and OU14950) that cosegregated with the G seedcoat color locus were developed from the F2 population derived from the cross g b v BC2 5-593 × G b v BC3 5-593. From the cross `Wagenaar' × g b v BC3 5-593, 80 F2 plants were classified into 54 non-SGY and 16 SGY seedcoat color plants. When the OAP7850 marker was applied to that population, linkage was not observed with the non-SGY and SGY phenotypes. Conversely, a molecular marker (OAP12400, that was developed from the F2 from the cross `Wagenaar' × g b v BC3 5-593) linked to the locus controlling the SGY phenotype segregated independently of the G locus. Therefore, SGY phenotype is not controlled by the G locus. An F3 progeny test of 76 F2 plants from the cross `Wagenaar' × g b v BC3 5-593 confirmed the hypothesis that a single recessive gene (for which we propose the symbol gy) controls the seedcoat color change from pale greenish yellow (PGY) to SGY. Through crosses with genetic tester stocks, the seedcoat genotype of `Enola' was determined to be C J g b v lae Rk. The test cross `Enola' × `Wagenaar' demonstrated that `Enola' also carries the gy gene. The relationship of `Enola' to the `Mayocoba' market class of common bean and to `Azufrado Peruano 87' is discussed.
E.G. Ernest, J.D. Kelly, and M.J. Bassett
`Redcoat' soldier bean cultivar originated from off-type, virgarcus patterned seeds found in a foundation seed lot of `Red Hawk' dark red kidney bean (Phaseolus vulgaris L.). These off-type seeds were hypothesized to be the result of a single gene mutation. A mutation at either of two loci involved in bean seedcoat pattern expression, T or Z, could convert self-colored seedcoats to a virgarcus pattern. The results of test-crosses of `Redcoat' and `Red Hawk' to lines with known alleles at the seedcoat pattern loci indicate that the dominant T allele of `Red Hawk' mutated to recessive t in `Redcoat'. The mutant t gene prevents expression of red veins in wing petals due to v rk d, and enables expression of the z gene (and possibly other genes) carried cryptically by `Red Hawk'. On the basis of preliminary data, we speculate that the two types of virgarcus patterns observed (classic in `Redcoat' and standard in the tester) may be controlled by different Bip alleles as they interact with t z.
Mark J. Bassett
Common bean (Phaseolus vulgaris L.) seedcoats can have partly colored patterns such as the new two-points pattern, which has an unknown genotype. The gene t cf (derived from PI 507984) expresses partly colored seedcoat pattern with colored flowers. A genetic tester stock t cf two-points BC3 5-593 was derived from PI 507984 by backcrossing to the recurrent parent, Florida dry bean breeding line 5-593, which has black self-colored seeds and purple flowers due to the genotype T P V. A series of test crosses were made between t cf two-points BC3 5-593 and three genetic tester stocks: t z j ers white BC3 5-593, t z bip bipunctata BC3 5-593, and t z virgarcus BC3 5-593. All three test crosses were studied in F1 and F2 populations, and the latter test cross in F3 progenies derived from 80 randomly selected F2 plants. The two-points pattern was never observed with white flower plants expressed by t/t, supporting the hypothesis that tcf is necessary for two-points expression. The complete genotype for two-points was found to be t cf z j ers. The t cf gene expresses more extensive colored zones in partly colored seedcoats than t. For example, t cf z J expresses self-colored seedcoats, whereas t cf/t z J expresses white ends pattern and t z J expresses virgarcus. Similarly, the t cf z j ers genotype expresses two-points pattern, whereas t z j ers expresses white seedcoat; and t cf/-z J/j ers expresses PI type pattern, whereas t z J/j ers expresses weak virgarcus pattern.
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.
Mark J. Bassett, Rian Lee, Tim Symanietz, and Phillip E. McClean
Two common bean (Phaseolus vulgaris L.) genes, J (modifies seedcoat color and pattern) and L (modifies partly colored seedcoat pattern), were tested for allelism using genetic tester stocks. Those stocks have a common genetic background by backcrossing to the recurrent parent, Florida dry bean breeding line 5-593, that has black self-colored seeds and purple flowers due to the genotype T P [C r] Z J G B V Rk. Specifically, the L gene from `Thuringia' and the lers gene from `Early Wax' were tested for allelism with the j gene from various genetic tester stocks. L was found to be identical with j, but l ers was a different allele at J. We propose the gene symbols J (formerly l), j (formerly L), and j ers (formerly l ers). The seedcoat genotype of `Thuringia' was found to be t P C z j g b v lae rk d. A new seedcoat pattern called reverse margo was found to be determined by the genotype T/t z/z j/j ers in a P C G B V genetic background. A randomly amplified polymorphic DNA marker was developed for the j gene (formerly L) from `Thuringia' using bulk segregant analysis in an F2 population segregating for j vs. J in a t z genetic background, i.e., from the cross t z j × t z J in BC1 to 5-593. The linkage distance between marker OL4525 and j was determined to be 1.2 cM. In a population segregating for J and j ers, the distance between the marker and j ers was determined to be 4.7 cM. The utility of marker OL4525 is limited primarily to the Middle American gene pool.
Mark J. Bassett, Kirk Hartel, and Phil McClean
Inheritance of Anasazi pattern of partly colored seedcoats in common bean (Phaseolus vulgaris L.) was studied in a genetic stock t ana B V Anasazi BC3 5-593, whose Anasazi pattern is derived from Plant Introduction (PI) 451802. Line 5-593 is a determinate, Florida dry bean breeding line (with small black seeds) used as the recurrent parent in the development of many genetic stocks. The F2 from the cross t ana B V Anasazi BC3 5-593 × t z virgarcus BC3 5-593 segregated for two nonparental phenotypic classes and was consistent with the hypothesis that a single recessive gene, with tentative symbol ana, produces the Anasazi pattern with t Z ana and a new partly colored pattern Anabip with t z ana. Thus, the Anasazi factor is not an allele at the Z locus. Analysis of 57 random F3 progenies from the cross t ana B V Anasazi BC3 5-593 × t z virgarcus BC3 5-593 supported a genetic model where: 1) with t Z the Anasazi phenotype is controlled by a single recessive gene ana, i.e., genotype t Z ana, 2) the Anabip phenotype has the genotype t z ana, and 3) t Z/z ana produces a restricted Anasazi pattern. The allelism test cross t z ana Anabip BC3 5-593 × t z l ers white BC3 5-593 produced complementation in the F2, demonstrating nonallelism of Ana (actually Bip) with the L locus. The allelism test cross t z ana Anabip BC3 5-593 × t z bip bipunctata BC3 5-593 failed to show complementation in F1 and F2, demonstrating allelism of Ana with the Bip locus. Using bulk segregant analysis, molecular markers linked in coupling to the Ana (OM9200, 5.4 cM) and Bip (OJ17700, 6.0 cM) genes were discovered. Allelism was also suggested by the result that the same linkage distance and recombination pattern were observed when the Ana marker was used to score the bipunctata population. We propose the gene symbol bip ana for the recessive allele at the Bip locus that produces Anasazi pattern with genotype t Z bip ana and the Anabip pattern with genotype t z bip ana. Although bip ana and bip are both recessive to Bip, their interactions with the Z locus are extraordinarily different. The pattern restrictive power of bip ana expresses partly colored pattern with t Z, whereas bip requires t z to express partly colored pattern.
Mark J. Bassett, Lee Brady, and Phil E. McClean
Common bean (Phaseolus vulgaris L.) plants with partly colored seeds and colored flowers were derived from PI 507984 in two genetic tester stocks, `2-points t cf BC1 5-593' and `2-points t cf BC2 5-593'. These stocks were produced by backcrossing to the recurrent parent, Florida dry bean breeding line 5-593, which has black self-colored seeds and purple flowers due to the genotype T P V. The crosses `2-points t cf BC1 5-593' × 5-593 and `2-points t cf BC2 5-593' × 5-593 produced F2 populations in which all plants had colored flowers. Those results, when considered with previously published work, do not support the previously reported hypothesis that the genes t Fcr Fcr-2 produce partly colored seedcoats and flower color restoration with t. The crosses `2-points t cf BC1 5-593' × `self-colored t BC2 5-593' and `2-points t cf BC2 5-593' × `minimus t BC3 5-593' produced F2 populations that segregated 3:1 for colored:white flowers, respectively. Those results are consistent with the revised hypothesis that t cf can produce partly colored seedcoats without affecting flower color. The RAPD marker OM19400, which is linked in repulsion to T, was used with the F2 populations from the crosses `2-points t cf BC2 5-593' × 5-593 and `2-points t cf BC2 5-593' × `minimus t BC3 5-593' and established that the t cf gene from PI 507984 is either an allele at T or tightly linked to T. F3 data from the cross `2-points t cf BC2 5-593 × 5-593 also support the t cf hypothesis. On the basis of the above experiments, the gene symbol t cf is proposed for an allele at T that pleiotropically produces partly colored seeds and colored flowers.
Mark J. Bassett
Studying the genetics of seedcoat color in common bean (Phaseolus vulgaris L.) in F2 progenies is very difficult because of complex epistatic interactions, and the analysis is complicated further by multiple allelism, especially at the C locus. An alternative approach is to study seedcoat genetics by analyzing the F1 progeny of test crosses between a variety with unknown seedcoat genotype and genetic tester stocks with known genotypes. Twenty varieties, 18 with known genotype at C, were test crossed with the genetic tester stock c u BC3 5-593, where 5-593 is a recurrent parent with seedcoat genotype P [C r] D J G B V Rk. The resulting F1 progenies were classified into seven phenotypic classes and discussed. The crosses g B v BC3 5-593 × c u BC3 5-593 and c u BC3 5-593 × v BC3 5-593 were made and the F2 progeny classified for flower color and seedcoat color and pattern. No tiny cartridge buff flecks were observed in the segregants with C/c u v/v, whereas C/c u V/- always showed such flecks. The contrasting seedcoat color expression at C in different environmental conditions is discussed.