Horizontal starch gel electrophoresis was used to study the inheritance of isozyme phenotypes of four enzyme systems [alcohol dehydrogenase (ADH), 6-phosphogluconate dehydrogenase (6-PGDH), phosphoglucomutase (PGM), and shikimate dehydrogenase (SKDH)] in Allium fistulosum L. by monitoring segregations in backcross and F2 progeny. Segregation for most of the polymorphisms fit the expected Mendelian ratios as tested by the chi-square statistic. Three new isozyme loci were defined for onion. Two loci were found for 6-PGDH. Locus one was dimeric with two alleles, and locus two was monomorphic. SKDH was monomeric with two alleles.
Paul D. Mangum and Ellen B. Peffley
R. Bruce Carle and J. Brent Loy
The recessive leaf trait, fused vein (fv), in Cucurbita pepo L. is expressed by the sixth leaf stage and then throughout vegetative growth. It is characterized by the partial fusion of the lateral leaf veins to the main central vein. Consequently, the dorsal leaf surface is distinctively puckered. Use of fv as a genetic marker in hull-less seeded pumpkin lines is hampered, however, by a low recovery of fv plants in segregating populations. Homogeneity Chi Square analysis of 11 F2 (3:1 X2 = 72.05 P < 0.005) and 16 BC (1:1 X2 = 120.12 P < 0.005) populations indicated significant heterogeneity between populations for fv recovery. Recovery ranged from 0 to 35.5% for 11 F2 populations and from 6.8 to 75.4% for 16 BC populations. There was a significant reduction, 35%, in seed yield/fruit when fv pollen was used to hand pollinate fv, normal (N), and F1 flowers as compared to pollinations with N pollen. In pollen competition studies, reduced competition at low levels of F1 or 50:50 fv/N pollen increased fv recovery in F2 and BC populations. These results are consistent with the hypothesis that the fv trait confers gametic subvitality resulting in distorted Mendelian segregation.
Hongmei Ma, Richard Olsen, Margaret Pooler, and Matthew Kramer
. Table 3. Inheritance of SSR markers in Prunus hybrids from controlled interspecific crosses showing expected Mendelian inheritance and nonparental bands (in bold) in the progeny. Only a partial data set is included for brevity. All species in this
Naofumi Hiehata, Shinji Fukuda, Yoshihiko Sato, Yukiko Tominaga, Osamu Terai, and Masahiko Yamada
segregates with values near the expected values in classical Mendelian inheritance ( Morita et al., 1985 ). In contrast, the resistance to Group C in progenies derived from ‘Shiromogi’ was conferred by a single recessive gene ( pse-c ) in a different manner
Marie C. Pairon and Anne-L. Jacquemart
Tetraploid black cherry (Prunus serotina) is the only Prunus L. species that has commercial importance as a timber tree in North America and is well known in Europe for its invasive behavior. Inheritance studies have never been performed and it is not known whether the species is allo or autotetraploid. Six microsatellite nuclear markers were used to test the inheritance in progenies of controlled crosses. Inheritance was proven to be disomic at all loci and a typical diploid mendelian inheritance was found at two loci. A first screening of a population in the invasive range showed high number of alleles per locus (ranging from 6 to 16) and high level of observed heterozygosity (0.75 to 1). Knowing that inheritance is disomic at six microsatellite loci and that at least two of them can be treated as codominant, diploid markers will be beneficial for future genetic studies.
The biochemistry of flowers is very complex, depending not only on the specific anthocyanin present but also on vacuolar pH, presence of metal ions, type of co-pigment present, and the molar ratio of co-pigment to anthocyanin. Because of the wide array of different flower colors, Petunia hybrida is an excellent model system to study the genetic interaction of all of these factors. The segregation of the different flower colors in an F2 population from a red × violet outcross could be explained through the combined inheritance of anthocyanin pigmentation and pH. The inheritance of anthocyanin pigmentation was controlled by two independent genes (hf and Mf) that followed simple Mendelian genetics. The inheritance of pH was more complex, being controlled by two independent co-dominant genes (Ph1 and Ph2). Linkage of the various pH and anthocyanin genes prevented the expression of all of the potential gene combinations.
Hongwen Huang, Fenny Dane, Zhongzen Wang, Zhengwan Jiang, Rehuang Huang, and Shengmei Wang
Isozyme inheritance and variation in Actinidia was investigated using 23 enzyme systems. Ten isozyme loci from six enzyme systems, Acp-2, Est, Prx-1, Prx-2, Prx-4, Prx-5, Pgi-2, Pgm-2, and Tpi, were found to be inherited as single Mendelian genes in families of two interspecific crosses. Disomic inheritance detected at ten loci in progenies of a cross between the hexaploid A. deliciosa × diploid A. chinensis, provided convincing evidence that A. deliciosa is an allohexaploid. Allelic segregation for tetrasomic inheritance at ten isozyme loci was demonstrated in the progenies of a cross between the tetraploid A. chinesis × diploid A. eriantha, a result suggesting the autotetraploid origin of the tetraploid A. chinensis which apparently originated from its diploid ancestor A. chinensis. A high level of isozyme variation and heterozygosity were observed in the 22 cultivars and 56 plants of 28 Actinidia taxa. Allozyme phenotype can be used effectively for cultivar identification.
Paul D. Mangum and Ellen B. Peffley
Horizontal starch gel electrophoresis was used to study the mode of inheritance of isozyme phenotypes of four enzyme systems (ADH, 6-PGDH, PGM, and SKDH) in Allium cepa L. and A. fistulosum L. by monitoring segregations in backcross and F2 progeny. Segregation for most of the polymorphisms fit the expected Mendelian ratios as tested by the chi-square statistic. Three new isozyme loci were defined for onion. 6-phosphogluconate dehydrogenase was dimeric in structure, with two alleles present at the first locus, while a second locus was monomorphic. Shikimate dehydrogenase was monomeric with two alleles.
Gabriele Gusmini, Luis A. Rivera-Burgos, and Todd C. Wehner
accessions were identified that had resistance to GSB as good as or better than PI 189225 and PI 271778 at the field and greenhouse tests. Two of the best were PI 482283 and PI 526233. The objective of this study was to determine the inheritance of resistance
Marie Pairon, Anne-Laure Jacquemart, and Daniel Potter
of their high level of polymorphism and their codominant inheritance ( Powell et al., 1996 ). Analyses of polymorphic markers such as microsatellites, however, are hindered in allopolyploid species because of the presence of more than two alleles at