were to confirm the ploidy level of the androgenic genotypes by flow cytometry; to confirm the zygosity state of the androgenic genotypes by SSR markers; to analyze S -alleles of the androgenic genotypes by the specific polymerase chain reaction (PCR
Hatsuhiko Okada, Yoshitaka Ohashi, Mamoru Sato, Hideyuki Matsuno, Toshiya Yamamoto, Hoytaek Kim, Tatsuro Tukuni, and Sadao Komori
Shao-Ling Zhang and Shin Hiratsuka
Cultivars of the Japanese pear [Pyrus pyrifolia (Burm.) Nakai] have variable degrees of self-incompatibility (SI) and can be classified into at least three groups: strong, intermediate, or weak SI; as shown by the extent of self-pollen tube growth in the style, and the percentage of fruit set following self-pollination. Following self-pollination, the elongation of pollen tubes in the detached styles of `Kosui' and `Kikusui' became increasingly suppressed from 4 days before anthesis (–4 DAA) to 2 days after anthesis (2 DAA). Tube growth of `Kosui' was more suppressed than that of `Kikusui' during this period. In `Osa-Nijisseiki', however, the rate of tube growth did not vary with stage of stylar development, from –8 to 2 DAA. Pollen tubes elongated much better after cross-pollination than after self-pollination at all stages tested, and the extent of the elongation increased as the styles matured. The concentration of total S-protein (sum of two S-proteins per buffer-soluble protein) increased with stylar development, but the rate of increase varied with the cultivar. The rate was significantly greater in the strongly self-incompatible `Kosui' than in the moderately self-incompatible `Kikusui', and was slowest in the weakly self-incompatible `Osa-Nijisseiki' at all developmental stages. During stylar maturation, the concentration of S4-protein, which is common in all cultivars, was highest in `Kosui', followed by `Kikusui' and `Osa-Nijisseiki'. Thus, the cultivar differences in SI expression in the Japanese pear are determined about –4 DAA and appear to be regulated, in part, by the concentration of S-proteins produced in the style.
Kentaro Kitahara, Shogo Matsumoto, Toshiya Yamamoto, Junichi Soejima, Tetsuya Kimura, Hiromitsu Komatsu, and Kazuyuki Abe
We examined the genetic diversity and relatedness among apple (Malus ×domestica Borkh.) cultivars in Japan. The 42 apple cultivars, including major cultivars in Japan, were divided into five groups based on SSR genotypes. Most economically important cultivars belong in three groups: Fuji-Delicious, Golden Delicious, and Jonathan groups, and their genetic backgrounds seemed to be narrow. We also investigated the parent-offspring relationships of nine apple cultivars. `Jonathan', `Fuji', and `Rero 11' were identified as the respective paternal parents of three cultivars described as having unknown paternal parents (i.e., `Akagi', `Ambitious', and `Hokuto'). `Starking Delicious', `Senshu', and `Golden Delicious', rather than `Ralls Janet', `Hatsuaki', and `Indo', seemed to be the paternal parents of `Kinsei', `Kiou', and `Mellow', respectively. `Carolina Red June' was excluded as a paternal parent of `Ranzan'. Both attributed parents of `Scarlet' (`Akane' and `Starking Delicious') were excluded, and it was suggested that `Fuji' was used as either a maternal or a paternal parent of `Scarlet'. `Jonathan' rather than `McIntosh' seems to be a maternal parent of `Yukari'.
Shawn A. Mehlenbacher
(haplotypes), and the stigmatic surface is the site of the incompatibility reaction ( Thompson, 1979a ). Thompson (1979b) listed the alleles of several cultivars. Additional early work on S-allele identification was reviewed by Germain (1994) . Hampson et
Attila Hegedüs, Zoltán Szabó, József Nyéki, Júlia Halász, and Andrzej Pedryc
The most commercially grown peach [Prunus persica (L.) Batsch.] cultivars do not require cross-pollination for reasonable fruit set; however, self-incompatibility is a well-known feature within the Prunoideae subfamily. Isoelectric focusing and native polyacrylamide gel electrophoresis of S-ribonucleases; PCR analyses of S-RNase and S-haplotype-specific F-box genes as well as DNA sequencing were carried out to survey the self-(in)compatibility allele pool and to uncover the nature of self-compatibility in peach. From 25 cultivars and hybrids with considerable diversity in phenotype and origin, only two S-haplotypes were detected. Allele identity could be checked by exact length determination of the PCR-amplified fragments and/or partial sequencing of the peach S 1-, S 2-, and Prunus davidiana (Carr.) Franch. S 1-RNases. S-RNases of peach were detected to possess ribonuclease activity, and a single nucleotide polymorphism in the S 1-RNase was shown, which represents a synonymous substitution and does not change the amino acid present at the position in the protein. A 700-bp fragment of the peach SFB gene was PCR-amplified, which is similar to the fragment size of functional Prunus L. SFBs. All data obtained in this study may support the contribution of genes outside the S-locus to the self-compatible phenotype of peaches.
Colton Ives, Vidyasagar R. Sathuvalli, Brooke C. Colburn, and Shawn A. Mehlenbacher
-pollination is enforced by sporophytic incompatibility ( Thompson, 1979a , 1979b ), which is controlled by a single locus (the S-locus) with multiple alleles (haplotypes). The S-alleles of leading cultivars have been identified and dominance relationships among
Loren C. Stephens
allele of the pollen gametophyte matches either of the S alleles present in the female sporophyte, pollen-tube growth is inhibited or blocked, and successful double fertilization is prevented; in short, an incompatible pollination. A plant with a
Audrey M. Sebolt and Amy F. Iezzoni
selected as the genetic marker because over 35 different S -alleles have been identified in cherry to date ( Bošković and Tobutt, 2001 ; Choi et al., 2000 ; Hauck et al., 2001 ; Sonneveld et al., 2001 ; Tao et al., 1999 ; Tsukamoto et al., 2006
Kenji Sakurai, Susan K. Brown, and Norman F. Weeden
The S alleles of 15 Japanese apple cultivars were determined by using the allele-specific polymerase chain reaction amplification and restriction enzyme digestion system developed by Janssens et al. (1995). Both S alleles were identified in eight diploid cultivars, two S alleles in three triploid cultivars, and one S allele in the remaining four diploid cultivars. Two cultivars had S alleles different than those predicted by their parentage, and in one comparison of a cultivar with its sport, an identity problem was discovered. The technique helped to indicate the parent contributing the unreduced gamete in triploids.
Rafel Socias i Company, Àngel Fernández i Martí, Ossama Kodad, and José M. Alonso
the ability of a genetically self-compatible cultivar to pollinate itself in the absence of insects ( Weinbaum, 1985 ). Additionally, a good cultivar must always be productive with a crop of good kernel quality. Identification of S alleles was