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.
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.
Mark J. Bassett and Phillip N. Miklas
for allelism of bicolor with known genes for flower color or pattern, and 4) to make the allelism test crosses t × wb and wb × p mic to complete the testing for allelism in all possible combinations of the genes T , P , V , and Wb
Nihat Guner, Zvezdana Pesic-VanEsbroeck, Luis A. Rivera-Burgos, and Todd C. Wehner
the conclusion, so we presented the data without the correction to avoid the tendency of Yate’s to overcorrect ( Haviland, 1990 ). Allelism test. To determine the allelic association between the resistance genes in the three PI accessions (PI 244017
Juan M. Osorno, Carlos G. Muñoz, James S. Beaver, Feiko H. Ferwerda, Mark J. Bassett, Phil N. Miklas, Teresa Olczyk, and Bill Bussey
resistance to BGYMV ( Blair et al., 2007 ). A population of F 2:3 lines from the cross ‘Morales’ × I9557-9 was developed to conduct an allelism test to determine whether I9557-9 had the same bgm or Bgp-1 resistance genes present in the cultivar Morales
Mark J. Bassett and Kafui Awuma
Two new mutants for the reclining foliage (RF) character were induced by treating seed of dry bean (Phaseolus vulgaris L.) breeding lines B-351 and 182-1 with 20 krad of γ-radiation. These two mutants were shown to be monogenic and recessive. Allelism tests between the common RF gene rf and the two new mimic mutants for RF indicated that each of the three mutants has an independent locus. The symbols rf2 and rf3 were given to the new mutants. F2 data from the allelism tests showed that the rf2 stock carries a recessive epistatic gene i that does not affect rf2 but suppresses expression of rf and rf3. The rf locus was shown to be independent of the Sur locus for RF in linkage group VII.
M. Lobo, M. J. Bassett, and L. C. Hannah
A single recessive gene was found to be responsible for the abnormal fruit ripening of ‘Alcobaca’ tomato (Lycopersicon esculentum Mill.). This gene causes a ripening syndrome characterized by attenuated respiratory activity and ethylene production, delayed softening of the fruit, low polygalacturonase (PG) activity, and extended shelf life. Allelism tests showed that the mutant gene of ‘Alcobaca’ is allelic to nor. It is proposed that the symbol nor A be used to refer to this mutant. The nor A allele is dominant to the nor allele.
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.
Richard L. Fery and Judy A. Thies
Greenhouse experiments determined the inheritance of resistance to the peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1] in Capsicum chinense Jacq. germplasm lines PA-353 and PA-426. Evaluation of parental, F1, F2, and backcross populations of the crosses PA-353 × PA-350 and PA-426 × PA-350 (PA-350 is a susceptible cultigen) indicated that resistance in both C. chinense germplasm lines was conditioned by a single dominant gene. Evaluation of the F1 × resistant parent backcross populations in the cytoplasm of their respective resistant and susceptible parents indicated that the cytoplasm of the resistant parent is not needed for full expression of resistance. Allelism tests indicated that the dominant resistance gene in both PA-353 and PA-426 is allelic to a resistance gene in C. annuum L. `Carolina Cayenne'. However, these allelism tests did not demonstrate conclusively that the M. arenaria race 1 resistance gene in C. chinense is the N gene that conditions resistance to the southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] in C. annuum. The ease and reliability of evaluating plants for resistance to root-knot nematodes and the availability of simply inherited sources of resistance makes breeding for peanut root-knot nematode resistance a viable objective in C. chinense breeding programs.
F. W. Zink
The inheritance of resistance to California race(s) of downy mildew in lettuce was studied in cvs. Bourguignonne, Meikoningin, Proeftuin’s Blackpool, Red Salad Bowl, Salad Trim, Ventura, and PI 164937. Resistance in cvs. Bourguignonne, Red Salad Bowl, and Salad Trim is conferred by a single dominant allele. This is the same allele found in resistant cvs. Calicel, Calmar, E-4, Imperial 410, Valrio, Valtemp, and Valverde, and is derived from resistant PI 91532. Resistance in ‘Meikoningin’ is controlled by a single dominant allele different from the one derived from PI 91532. Allelism tests indicate that the 2 alleles are independently inherited. ‘Proeftuin’s Blackpool’ and ‘Ventura’ each have 2 dominant alleles for resistance that are different from the single dominant allele derived from PI 91532. Allelism tests of ‘Proeftuin’s Blackpool’ and ‘Ventura’ indicate resistance is conferred by the same 2 dominant alleles. The 2 alleles in cvs. Proeftuin’s Blackpool or Ventura and the single allele derived from PI 91532 are independently inherited. Resistance in PI 164937 is conferred by 2 dominant alleles, one of which is the same as the single dominant allele derived from PI 91532.