increased. In this sense, breeding programs for cultivars adapted to regions with high temperatures must be intensified. This study aimed to characterize S-alleles in hybrid pear cultivars ( P. communis × P. pyrifolia ) adapted to subtropical climates and
Rayane Barcelos Bisi, Rafael Pio, Daniela da Hora Farias, Guilherme Locatelli, Caio Morais de Alcântara Barbosa, and Welison Andrade Pereira
Javier Sanzol and Timothy P. Robbins
-genotyping are based on polymorphisms of the S-RNase gene. Initial attempts to identify S-RNases associated with S-alleles were based on the existing knowledge about the S-genotype constitutions of cultivars deduced from the assessment of their S-phenotypes after
Sadao Komori, J. Soejima, Y. Ito, and H. Bessho
Cross-incompatible combinations among the main cultivars in apple are rarely reported in Japan. Recently, however, most new Japanese cultivars are progenies of `Ralls Janet', `Delicious', `Golden Delicious', `Jonathan', and `Indo'. Cross incompatibility in apple, therefore, will become a serious problem in the near future. Since the analysis of the S-allele genotypes were not performed, especially in Japanese apple cultivars, the fruit set percentage were examined in several combinations of `Hatsuaki' (`Jonathan' × `Golden Delicious') and `Iwakami' (`Fuji' × `Jonathan') progenies using back crossings. As a result, we found that `Golden Delicious' and `Jonathan' had no common S-allele, while `Fuji' and `Jonathan' had one common S-allele. These facts were used as basics for the S-allele genotype analysis, and fruit set percentage and seed number per fruit were investigated on a large scale. The cross seedlings between `Delicious' and `Jonathan', `Ralls Janet' and `Jonathan', `Iwakami' and `Golden Delicious', `Golden Delicious' and `Delicious', `Hatsuaki' and `Fuji', `Hatsuaki' and `Delicious', `Hatsuaki' and `Jonathan', and `Hatsuaki' and `Golden Delicious' were analyzed. In addition, incompatibility between `Redgold' and `Kinesei' (`Golden Delicious' × `Ralls Janet'), `Senshu' (`Toukou' × `Fuji') and `Iwakami', and progenies of `Northern Spy' also were analyzed. As a result, we have found the existence of six alleles and 15 genotypes, and we have established S-allele standard cultivars and strains as follows: (Sa, Sb) = `Golden Delicious'; (Sa, Sc) (4)-354, (4)-425; (Sa, Sd) = `Toukou'; (Sa, Se) = `Redgold', `Kinsei'; (Sa, Sf) = `Narihokou', (4)-4195; (Sb, Sc) = `Hatsuaki', `Kuifua', `Sekaiichi'; (Sb, Sd) = `Tsugaru', (4)-300; (Sb, Se) = (4)-150, (4)-743; (Sb, Sf) = `Northern Spy', M.9, `Umezawa'; (Sc, Sd) = `Jonathan', `Himekami'; (Sc, Sf) = `Fuji', `Shinkou'; (Sd, Se) =; (Sd, Sf) = `Senshu', `Iwakami'; (Se, Sf) = `Ralls Janet'.
Shogo Matsumoto, Kentaro Kitahara, Sadao Komori, and Junichi Soejima
S-allele genotypes of nine apple (Malus ×domestica Borkh.) cultivars were identified using S-allele–specific polymerase chain reaction (PCR)–restriction fragmentlength polymorphism (RFLP) analysis. A new S-allele, Sg, was proposed to be present in `American Summer Pearmain', `Indo', `Kitanosachi', and `Meku 10'. This allele is very similar to Sf at the nucleotide sequence (92%) and deduced amino acid sequence (94%) levels.
Nathanael R. Hauck, Amy F. Iezzoni, Hisayo Yamane, and Ryutaro Tao
Correct assignment of self-incompatibility alleles (S-alleles) in sweet cherry (Prunus avium L.) is important to assure fruit set in field plantings and breeding crosses. Until recently, only six S-alleles had been assigned. With the determination that the stylar product of the S-locus is a ribonuclease (RNase) and subsequent cloning of the S-RNases, it has been possible to use isoenzyme and DNA analysis to genotype S-alleles. As a result, numerous additional S-alleles have been identified; however, since different groups used different strategies for genotype analysis and different cultivars, the nomenclature contained inconsistencies and redundancies. In this study restriction fragment-length polymorphism (RFLP) profiles are presented using HindIII, EcoRI, DraI, or XbaI restriction digests of the S-alleles present in 22 sweet cherry cultivars which were chosen based upon their unique S-allele designations and/or their importance to the United States sweet cherry breeding community. Twelve previously published alleles (S1, S2, S3, S4, S5, S6, S7, S9, S10, S11, S12, and S13) could be differentiated by their RFLP profiles for each of the four restriction enzymes. Two new putative S-alleles, both found in `NY1625', are reported, bringing the total to 14 differentiable alleles. We propose the adoption of a standard nomenclature in which the sweet cherry cultivars `Hedelfingen' and `Burlat' are S3S5 and S3S9, respectively. Fragment sizes for each S-allele/restriction enzyme combination are presented for reference in future S-allele discovery projects.
Kristi K. Barckley, Sandra L. Uratsu, Thomas M. Gradziel, and Abhaya M. Dandekar
The California almond industry is the largest supplier of almonds [Prunus dulcis (Miller) D.A. Webb] in the United States and throughout the world. Self-incompatibility is a major issue in almond production as it greatly affects nut set. In this study, we determined full-length sequences for alleles Sa - Si, determined the genotypes of 44 California cultivars, and assigned the cultivars to cross-incompatibility groups (CIGs). Newly identified S-alleles led to an increase in the number of CIGs. A pairwise distance tree was constructed using the aligned amino acid sequences showing their similarity. Four pairs of alleles (Sc and Se, Sg and Sh, Sd and Sj, and Sb and Sf) showed high sequence similarity. Because of its simplicity, reproducibility, and ease of analysis, PCR is the preferred method for genotyping S-alleles.
Ryutaro Tao, Hisayo Yamane, Akira Sugiura, Hideki Murayama, Hidenori Sassa, and Hitoshi Mori
This report identifies S-RNases of sweet cherry (Prunus avium L.) and presents information about cDNA sequences encoding the S-RNases, which leads to the development of a molecular typing system for S-alleles in this fruit tree species. Stylar proteins of sweet cherry were surveyed by two dimensional polyaclylamide gel electrophoresis (2D-PAGE) to identify S-proteins associated with gametophytic self-incompatibility. Glycoprotein spots linked to S-alleles were found in a group of proteins which had Mr and pI similar to those of other rosaceous S-RNases. These glycoproteins were present at highest concentration in the upper segment of the mature style and shared immunological characteristics and N-terminal sequences with those of S-RNases of other plant species. cDNAs encoding these glycoproteins were cloned based on the N-terminal sequences. Genomic DNA and RNA blot analyses and deduced amino acid sequences indicated that the cDNAs encode S-RNases; thus the S-proteins identified by 2D-PAGE are S-RNases. Although S1 to S6-alleles of sweet cherry cultivars could be distinguished from each other with the genomic DNA blot analysis, a much simpler method of PCR-based typing system was developed for the six S-alleles based on the DNA sequence data obtained from the cDNAs encoding S-RNases.
Santiago Vilanova, Carlos Romero, Gerardo Llácer, María Luisa Badenes, and Lorenzo Burgos
This report shows the PCR-based identification of the eight known self-(in)compatibility alleles (S 1 to S 7 and S c) of apricot (Prunus armeniaca L.). Two sets of consensus primers, designed from P. armeniaca S-RNase genomic sequences and sweet cherry (P. avium L.) S-RNase-cDNAs, were used to amplify fragments containing the first and the second S-RNase intron, respectively. When the results obtained from the two PCRs were combined, all S-alleles could be distinguished. The identity of the amplified S-alleles was verified by sequencing the first intron and 135 base pairs (bp) of the second exon. The deduced amino acid sequences of these fragments showed the presence of the C1 and C2 Prunus L. S-RNase conserved regions. These results allowed us to confirm S-genotypes previously assigned by stylar ribonuclease analyses and to propose one self-(in)compatibility group (I) and one universal donor group (O) containing unique S-genotypes and self-compatible cultivars (SC). This PCR-based typing system also facilitates the identification of the S c-allele and might be a very useful tool for predicting self-compatibility in apricot breeding progenies.
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
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