Isozyme polymorphism and genetic differentiation in natural populations of an endemic tetraploid species <Emphasis Type="Italic">Avena maroccana</Emphasis> in Morocco

A wild tetraploid oat Avena maroccana Gdgr. was collected from the 11 populations in the periphery of Rommani and Casablanca geographic groups of Morocco. Genetic diversity of the species was investigated using six allozyme systems. Allelic frequencies were scored representing eight polymorphic and five monomorphic loci. Coefficient of gene differentiation (Gst) was 0.3019, which indicated great genetic differentiation. The number of alleles per locus was 2.6154, the percentage of polymorphic loci was 61.54, and the expected heterozygosity was 0.2462 in all populations. Genetic diversity in A. maroccana was high in comparison to self-pollinated species. In total, nine heterozygotes resulting from outcrossing were found in the progeny from M1, M3, M4, M22 and M26. The population of M7 had peculiar alleles Pgd–2SS and Pgd-1SS in high frequency. M9 had the lowest level of diversity out of the 11 populations. Geographic and genetic distances between all the populations were not significantly correlated with each other (r = 0.0996). Cluster analysis showed that two groups, (M1, M22, M2 and M4) and (M3, M23, M8, M5 and M26) were apparently differentiated. Two populations of the Casablanca group, M7 and M9 were independent from each other, and were separated distinctly from the other populations. Genetic diversity of the Rommani and Casablanca groups was almost the same in all the parameters. This was due to the similar man-made habitat such as roadside or rich fertile soil and brown clay soils. The population size of A. maroccana was small and restricted to the narrow central Morocco with great genetic differentiation so that genetic diversity may be reflected from the results of genetic drift and outcrossing heterozygote segregation.     

Genetic diversity and local population structure of fragmented populations of Trillium camschatcense (Trilliaceae)

Trillium camschatcense, a long-lived common woodland herb, has been experiencing intensive habitat fragmentation over the last century in eastern Hokkaido, Japan. We examined the genetic diversity and population genetic structure of 12 fragmented populations with different population sizes using allozyme electrophoresis. The percentage of polymorphic loci and mean number of alleles per locus were positively related to population size, probably due to the stochastic loss of rare alleles (frequency of q<0.1) in small populations. Populations with 350 flowering plants or fewer had lost almost all of their rare alleles. While the heterozygosity and inbreeding coefficient were not related to population size, some small populations showed relatively high inbreeding coefficients. In spite of the low genetic differentiation among overall populations (F_ST=0.130), local population structuring was recognized between the two geographically discontinuous population groups. Within groups, sufficient historical gene flow was inferred, whereas a low dispersal ability of this species and geographical separation could produce apparent differentiation between groups.     

Genetic diversity in populations of wild diploid wheat Triticum urartu Tum. ex. Gandil. revealed by isozyme markers

Genetic variation and its distribution within and among 23 populations of Triticum urartu collected from Syria, Lebanon, Turkey, Armenia, and Iran was estimated using isozyme markers at eight polymorphic loci. The number of alleles per locus (A= 1.21), percentage polymorphic loci (P= 20.1%), and mean gene diversity (H_e= 0.024) were relatively low. In a population from Lebanon, a high number of alleles per locus (A= 2.13) and percentage polymorphic loci (P= 87.5%) was found. On average, genetic variation among populations (G_ST= 0.407) was smaller than within-population variation (0.593). However, different patterns of genetic structure were found among various geographic regions. Interpopulation variation was highest for the Iranian populations (0.89) followed by the Turkish populations (0.66). A reverse pattern was observed for the Syrian (0.11) and for the Lebanese (0.13) populations. The Armenian populations exhibited similar interpopulation and within-population variation. Principal component and cluster analyses resulted in distinct grouping of the geographically proximal populations, with the exception of the two Iranian populations. The Turkish populations were different from the neighboring Armenian populations compared to other countries. The populations from southern Syria and those from Lebanon also exhibited a high degree of genetic diversity. The two most heterozygous loci, Mdh-2 and Pgi-2, separated the populations along the first and second principal components, respectively. Most of the rare alleles were scattered sporadically throughout the geographic regions. Rare alleles with high frequencies were found in the Turkish and Armenian populations. These results indicated that different geographic regions require specific sampling procedures in order to capture the range of genetic variation observed in T. urartu populations.     

Isozyme studies of genetic diversity and evolution in Hippophae

Summary To provide information on the genetic variation, differentiation and evolution in Hippophae seed samples of 25 populations from China, Finland and Russia were electrophoretically analyzed. Of six loci investigated, four were good genetic markers for identifying species and subspecies. The percentages of polymorphic loci per population were 40.3% and 62.5% at 0.95 and 0.99 polymorphic criteria respectively. The mean number of alleles per locus per population was 2.1. Total genetic diversity in the material was 0.4614. Genetic diversity partitioning showed that there was a large amount of diversity residing within geographical populations (0.1354), between subspecies within species (0.1046) and between species (0.2566) but not between geographical populations (0.0114). There were nearly twice as many negative fixation indices as positive ones in Hippophae populations. The phylogenetic tree agreed very well with botanic classifications of the species and subspecies and their geographical distributions, and quantitatively presented the genetic relationships of 25 populations. A detailed view of the evolutionary stages in Hippophae showed clearly a general decline of similarity as evolutionary divergence continued, which further explained the evolution process in Hippophae.     

Geographical, altitude and agro-ecological differentiation of isozyme and hordein genotypes of landrace barleys from Ethiopia: implications to germplasm conservation

An analysis of the variability of genes encoding six isozyme systems (15 loci) and two storage proteins (2 loci) in landrace barley from Ethiopia is reported. The materials consisted of populations collected from sites as low as 1650 and as high as 3750 meters, covering a wide range of agro-ecological conditions and geographical areas. Of the 17 loci 7 were polymorphic and 10 monomorphic when the 95% criterion of polymorphism was applied. Despite the disproportionate monomorphic loci, polymorphism was detected in all populations when this criterion is used. The populations were found to possess fairly low mean number of alleles per locus (A = 1.5), low mean value of expected heterozygosity (H = 0.134) and a fairly high mean percentage of polymorphic loci (P = 35.3%). The mean F_ST= 0.474 for the populations is typical of inbreeding species. The result indicated that allelic richness is concentrated in altitude class 3 (2500–3000 m) followed by altitude class 1 (<2000 m). Altitude class 2 (2000–2500) holds an intermediate place though it is the highest in terms of expected heterozygosity (H = 0.245). Higher genetic diversity is concentrated in some geographical regions such as Shewa, Arsi, Bale compared to others (Welo, Gamu Gofa, Gojam). Genetic differentiation among the agro-ecological zones was more profound than both among the altitudes and among regions. Correlation analysis between phenotypic diversity (Shannon-Weaver diversity index) and expected heterozygosity (H) for isozyme/hordein loci revealed non significant associations except with respect to agro-ecological zones. In general, it was detected that sites in highland areas in central and northern regions may be more desirable for in situ conservation than sites in peripheral regions in terms of isozyme/hordein diversity and current rate of varietal replacement.     

Cross-amplification and characterization of microsatellite loci for three species of <Emphasis Type="Italic">Theobroma</Emphasis> (Sterculiaceae) from the Brazilian Amazon

This study reports on the cross-species amplification of 23 microsatellite markers previously developed for Theobroma cacao L. (Sterculiaceae), source of chocolate in three economically important Amazonian species of Theobroma (T. grandiflorum, T. subincanum, T. sylvestre). Thirteen of the 23 microsatellite loci tested were polymorphic across the three species at 2–13 alleles per locus. The observed heterozygosity per locus varied from 0.18 to 0.84 and expected heterozygosity ranged from 0.28 to 0.87. The high level of transferability and genetic information content of these microsatellite loci indicate their usefulness for population genetic, mating system and breeding studies of these economically important Amazonian fruit trees.     

江西野生毛花猕猴桃群体SSR遗传多样性研究

为分析江西野生毛花猕猴桃群体遗传多样性,以江西省境内的5个野生毛花猕猴桃雄性群体(72个个体)为试验材料,采用SSR分子标记技术,选取15对多态性引物,利用聚丙烯酰胺电泳对PCR产物进行检测。结果表明,15对SSR引物共检测到86个位点,多态性位点百分率为100.0%;观察到的平均等位基因数为5.733,有效等位基因数为3.002,Shannon信息指数为1.046。表观杂合度介于0.111~0.819之间,预期杂合度介于0.041~0.876之间,遗传分化系数为2.01,野生毛花猕猴桃雄性群体间存在较大的遗传分化。5个毛花猕猴桃雄性群体遗传距离范围为0.102~0.409,遗传相似度范围为0.665~0.903,群体间遗传距离与地理距离无相关性。群体的遗传多样性丰富度依次为庐山>井冈山>南源山>武功山>麻姑山,江西地区供试的野生毛花猕猴桃雄性群体在分子水平上具有丰富的多态性。本研究结果为毛花猕猴桃雄性品种选育、种质创新与利用提供了一定的理论基础。     

中国板栗SSR标记的研究

本研究从中国板栗“艳红”中分离到25个SSR标记。为了鉴定SSR位点，在重复序列的两侧侧翼序列设计引物，并通过化学荧光检测法对6个板栗样品进行检测，共检测到18个多态性位点，每个位点的等位基因数为2~6个。挑选12个位点，通过半自动系统ABI PRISM 377对中国北方24个板栗品种进行分析，这12个标记显示了高达共75个等位基因的遗传多态性，每个位点的等位基因为4~10个，平均为6.3个，预期的平均杂合性为0.743（介于0.680~0.845），检测到的平均杂合性为0.829（介于0.730~0.930）。无效等位基因估算频率显示为3个位点的正向价值，除了一个位点外，这些价值都很低，鉴定机率为7.01×10-11，亲缘关系鉴定机率非常高，为0.999，足够用于花粉流的研究。     

鳜原种群体和养殖群体遗传多样性的微卫星分析

本研究利用20对微卫星引物对鳜（Sinipelrca chuatsi）原种群体和养殖群体进行遗传多样性分析。结果表明,在鳜原种群体中检测到多态性位点14个,养殖群体11个。在两个群体中共检测到等位基因数96个,其中原种群体检测到等位基因数53个,每个位点的等位基因数在1～7之间,平均有效等位基因数为2．7390;养殖群体检测到等位基因数43个,每个位点的等位基因数在1-6之间,平均有效等位基因数为2．1284。原种群体的平均观察杂合度0．5708,Nei氏期望杂合度0．5295,平均多态信息含量PIC0．5353;养殖群体的平均观察杂合度0．3839,Nei氏期望杂合度0．4011,平均多态信息含量PIC0．5043。因此,与养殖群体相比,鳜原种群体仍有丰富的遗传多样性。本研究可为鳜种质资源的保护、监测和遗传育种提供分子水平上的数据。     

Genetic Diversity and Structure of Wild Tunisian Myrtus communis L. (Myrtaceae) Populations

Myrtus communis L. (Myrtaceae), in Tunisia, is closely associated with Quercus suber L. forest which stretched continuously from the North to parts of Cap Bon and Tunisian Dorsal. The destruction of the primary oak forests associated to an over-exploitation of Myrtus for its essential oil quality had led to discontinuous populations exhibiting various levels of degradation. Using starch gel electrophoresis, we analyzed the polymorphism of nine isozymes in order to assess genetic diversity and structuring of 17 natural populations prospected in the three geographical regions and coinciding with subhumid, humid inferior and semi-arid superior bioclimates. The analysis of the level and the distribution of the genetic diversity in this species might help in its conservation. Out of the 18 loci detected for all populations and isozymes analyzed, 12 loci were polymorphic. Allelic frequencies differed according to populations and particular alleles characterized ecological groups. A high level of genetic variation within populations was observed. The mean number of alleles per polymorphic locus was Ap = 1.67, the percentage of polymorphic loci was P = 60.3% and the observed (Ho) and the expected (He) heterozygosities were respectively 0.144 and 0.215. Populations belonging to subhumid (Cap Bon) and semi-arid superior (Tunisian Dorsal) climates, located in degraded sites exhibited the highest level of inbreeding (0.425 < F_IS < 0.450). A high level of differentiation (F_ST = 0.396) and a low gene flow (Nm = 0.337) among populations, as a result of habitat intermediate destruction, were revealed. The differentiation of populations within the same bioclimate (or geographic) group was substantial and relatively higher for semi-arid superior populations (F_ST = 0.262), which were more distant. The three ecological groups exhibited a high level of structuring (F_ST = 0.401). These differentiations might be due to geographic distances and to the variations of ecological factors between sites, including human activities and environmental factors. Nei’s (1972) genetic distances calculated between pairs of populations were globally low (0.006 < D < 0.367) with a mean of 0.15. They indicate a high level of similarity between populations. UPGMA clustering, established through Nei’s genetic distances, showed three population aggregates according to their geographic/bioclimatic appartenances. The high differentiation between populations and the low level of their genetic divergence indicated their recent isolation under anthropic pressures. The species conservation (in situ or ex situ) strategies should take into account the genetic diversity level within populations and its variation between geographic groups.     

Genetic variability in Macadamia

A genetic variability analysis involving 45 accessions of Macadamia including four species, M. integrifolia, M. tetraphylla, M. ternifolia, and M. hildebrandii and a wild relative, Hicksbeachia pinnatifolia was performed using eight enzyme systems encoded by 16 loci (Gpi-1 and 2, Idh-1 and 2, Lap, Mdh-1, 2, and 3, 6Pgd-2, Pgm-2 and 3, Tpi-1 and 2, Ugpp-1, 2, and 3). Forty-three accessions possessed distinct isozyme fingerprints indicating a high level of genetic variation. Examination of multivariate relationships among accessions using a cluster analysis resulted in the identification of four clusters, two of which contained one accession each representing H. pinnatifolia and M. hildebrandii. All Hawaiian cultivars were included in two sub-clusters within the largest cluster, which encompassed all the M. integrifolia and three M. ternifolia accessions, suggesting that: (1) the Hawaiian cultivars must have originated from at least two genetically diverse ancestral populations and (2) M. ternifolia may be a conspecific variant of M. integrifolia. Macadamia tetraphylla has diverged marginally from the M. integrifolia and M. ternifolia complex suggesting that these taxa represent a species complex. The different measures of genetic variability such as mean number of alleles per locus, polymorphic index, and observed and expected levels of heterozygosity, indicated significant levels of genetic variation in the Macadamia collection.     

Population clonal diversity and fine-scale genetic structure in <Emphasis Type="Italic">Oryza officinalis</Emphasis> (Poaceae) from China,implications for <Emphasis Type="Italic">in situ</Emphasis> conservation

Population clonal diversity and fine-scale genetic structure of Oryza officinalis Wall. ex Watt, an endangered species in China recently experiencing habitat degradation, was estimated using inter simple sequence repeat markers. We analyzed the genetic variations of 440 samples exhaustively collected from nine O. officinalis populations. Relatively rich clonal diversity and poor genetic variation were found in the extant populations. We found that the number of genets, the percentage of polymorphic loci, and gene diversity decreased with population decline, suggesting that habitat degradation will lead to further genetic depletion of O. officinalis populations. A pronounced spatial genetic structure occurs at both the ramet and genet levels in several larger populations, which is the result of clonal growth and concomitant inbreeding. The in situ conserved population PS holds much more genotypes than other populations with the similar population size, which might have more seedling recruitments from the soil seed bank due to habitat disturbance, suggesting a moderate disturbance combined with habitat degradation-avoiding measures are effective for in situ conservation of this species.     

Genetic variability in wild populations of <Emphasis Type="Italic">Prunus divaricata</Emphasis> Ledeb. in northern Iran evaluated by EST-SSR and genomic SSR marker analysis

A population genetic analysis based on eight genomic SSR markers and three EST-SSR (expressed sequence tags) markers developed in peach (Prunus persica (L.) Batsch) and Japanese plum (Prunus salicina Lindl.) was carried out in 12 wild populations of cherry plum (Prunus divaricata Ledeb.) sampled along the Iranian coast of the Caspian Sea. A total of 184 alleles (3–31 per locus) were detected with a mean value of 16.7 alleles per locus. None of the loci or populations showed deviation from Hardy–Weinberg equilibrium, and all markers proved to be unlinked. The mean values for the observed and the expected heterozygosity were 0.66 and 0.73, respectively. There was very little genetic differentiation among populations, as was indicated by low overall values of Wright’s F_ST (0.03) and Nei’s G_ST (0.08). An analysis of molecular variance (AMOVA) showed that 96.8% of the total variance was attributable to differences between individuals within populations. Genetic and geographic distances were nevertheless positively correlated, as evidenced by a Mantel test. The high level of genetic diversity and the apparent lack of genetic structure in wild P. divaricata may be attributed to frequent long distance gene flow through frugivorous birds and possibly humans, as has been documented for other Prunus species.     

南宁地区蜈蚣蕨居群的遗传多样性分析

本文采用等位酶电泳技术, 研究了南宁地区的南宁市、武鸣县和隆安县3 个不同的生态环境的野生蜈蚣蕨居群的遗传多样性。所测定的酶系统包括: 氨基肽酶 (AMP)、还原型辅酶I心肌黄酶 (DIA)、异柠檬酸脱氢酶(IDH)、苹果酸脱氢酶 (MDH)、6 磷酸葡萄糖酸脱氢酶 (PGD)、磷酸葡萄糖异构酶 (PGI)、磷酸葡萄糖变位酶 (PGM) 和莽草酸脱氢酶 (SKD) 8 个酶系统, 15 个酶位点。分析结果表明: 南宁地区蜈蚣蕨居群内遗传多样性水平中等偏上, 每个位点的等位基因平均数为1.6, 多态位点百分数为53.3% , 平均期望杂合度为0.242。     

Isozyme variation in species of the section Comopyrum of Aegilops

Genetic variation at 21 enzyme loci was studied in Aegilops comosa and Ae. uniaristata, the two species belonging to section Comopyrum of Aegilops. In Ae. comosa, the mean number of alleles per locus was 2.00 and the proportion of polymorphic loci was 0.667; in Ae. uniaristata they were 1.19 and 0.143, respectively. The two species were genetically distant from each other (I=0.561) supporting the previously assigned different genome symbols, M and N.     

Genetic Diversity in Tunisian Ceratonia siliqua L. (Caesalpinioideae) Natural Populations

The last two centuries witnessed the human-caused fragmentation of Tunisian Ceratonia siliqua L. (Caesalpinoideae) populations which were often represented by scattered individuals. Seventeen populations growing in four bioclimatic zones: sub-humid, upper semi-arid, mean semi-arid and lower semi-arid zones, were sampled for allozyme diversity to assess their genetic diversity and structuration using eight isozymes revealed by starch gel electrophoresis. The species showed high diversity within populations. The average number of alleles per polymorphic locus was 1.98, the percentage of polymorphic loci was 83.4% and the mean observed heterozygosity (Ho) and expected heterozygosity (He) under Hardy–Weinberg equilibrium were respectively 0.247 and 0.316. A substantial level of inbreeding within populations induced by Wahlund effect, was observed (F_IS = 0.231). High diversity resulted from the great number of genotypes in the ancestral population before fragmentation, favoured by the outbreeding of the species. High differentiation and low gene flow were detected among populations (F_ST = 0.200) and among pairs of ecological zones (0.113< F_ST <0.198). However, the differentiation coefficient of the four zones was low (F_ST = 0.085) and similar to the average F_ST for forest trees. Population structuration depends on geographic distance between sites rather than bioclimate, indicating that structuration has occurred slowly and that climatic conditions have had little effect. Nei's genetic distances (D) between populations were low and ranged from 0.004 to 0.201. Mean D value for all population was 0.087. The UPGMA clustering established for all populations through Nei's genetic distances did not clearly show that, for the majority of populations, grouping had resulted from ecological factors or geographic location. The substantial differentiation and the high genetic similarities between populations indicate that populations have been recently isolated as a result of anthropic pressure. In-situ conservation strategies must first focus on populations with a high level of genetic diversity and rare alleles. Appropriate conservation action should take account of bioclimatic zones. Ex-situ preservation should be based on a maximum number of individuals collected within populations in each ecological group and their propagation in different bioclimates by means of cuttings.     

Genetic diversity and population structure of Guinea yams and their wild relatives in South and South West Ethiopia as revealed by microsatellite markers

Genetic diversity and population structure of Guinea yams and their wild relatives collected from south and south west Ethiopia were assessed using microsatellite markers. The total number of alleles amplified for the 7 loci studied was found to be 60, with an average of 8.6 alleles per locus. The average expected heterozygosity for the entire population was found to be 64 % indicating that Guinea yams and their wild relatives in the study area display a high level of genetic diversity. Using allelic richness as a measure of genetic diversity the wild forms exhibited greater allelic diversity than the cultigens. Contrary to what is expected in vegetatively propagated crops, none of the seven loci studied showed a significant excess of heterozygotes. In all the comparisons made, a low mean F_ST (but significant) has been observed, indicating that the majority of microsatellite diversity in the populations under study was found within rather than between populations.     

DNA profiling of figs (<Emphasis Type="Italic">Ficus carica</Emphasis> L.) from Slovenia and Californian USDA collection revealed the uniqueness of some North Adriatic varieties

A set of 23 local varieties from Slovenia and 218 fig accessions from Californian fig germplasm collection were compared to determine the identity of genotypes and their possible genetic relationships. Figs were genotyped using twelve microsatellite loci. One hundred alleles were identified over all microsatellite loci with an average of 8.33 alleles per locus and a polymorphic information content of 0.557 per locus. DNA genotyping demonstrated a relatively high level of genetic diversity between analysed figs. Comparison of fig genotypes from Slovenia and California demonstrated that only six Slovenian varieties shared identical DNA profiles with figs from the Californian collection, while the other 17 Slovenian varieties were unique and characteristic to the North Adriatic region. The information obtained will contribute to a better management of fig genetic resources.     

Genetic variation in the endangered Rutaceae species <Emphasis Type="Italic">Citrus hongheensis</Emphasis> based on ISSR fingerprinting

Citrus hongheensis is a critically endangered species endemic to the Honghe river region in southeastern Yunnan, China. Its genetic diversity and differentiation were investigated using Inter-Simple Sequence Repeat (ISSR) markers. One hundred primers were screened, and a total of 245 loci were amplified from seven natural populations by 13 informative and reliable primers. Of these 245 ISSR loci, 233 were polymorphic and the detected variations revealed a relatively high level of intraspecific genetic diversity. At the population level, the mean percentage of polymorphic loci (PPB) was 36.50%, while the average expected heterozygosity (He) and Shannon diversity index (Ho) were 0.1327 and 0.1972, respectively. At the species level (across all populations), PPB was 95.10%, while He and Ho were 0.3520 and 0.5195, respectively. A high Gst value (0.6247) indicated that there is significant differentiation among populations, which was confirmed by AMOVA analysis (Φst = 0.6420). Pairwise genetic identity (I) values among populations ranged from 0.6341 to 0.7675, with a mean of 0.7008. We propose that the high level of genetic differentiation may be the result of habitat fragmentation and limited gene flow (Nm = 0.1502). For effective in situ conservation and population restoration of C. hongheensis it will be important to maintain historical processes, including high outbreeding rates, sufficient gene flow, and large effective population sizes.     

Exploitation of <Emphasis Type="Italic">Malus</Emphasis> EST-SSRs and the utility in evaluation of genetic diversity in <Emphasis Type="Italic">Malus</Emphasis> and <Emphasis Type="Italic">Pyrus</Emphasis>

A total of 8117 suitable SSR-contaning ESTs were acquired by screening from a Malus EST database, among which dinudeotide SSRs were the most abundant repeat motif, within which, CT/TC followed by AG/GA were predominant. Based on the suitable sequences, we developed 147 SSR primer pairs, of which 94 pairs gave amplifications within the expected size range while 65 pairs were found to be polymorphic after a preliminary test. Eighteen primer pairs selected randomly were further used to assess genetic relationship among 20 Malus species or cultivars. As a result, these primers displayed high level of polymorphism with a mean of 6.94 alleles per locus and UPGMA cluster analysis grouped twenty Malus accessions into five groups at the similarity level of 0.6800 that were largely congruent to the traditional taxonomy. Subsequently, all of the 94 primer pairs were tested on four accessions of Pyrus to evaluate the transferability of the markers, and 40 of 72 functional SSRs produced polymorphic amplicons from which 8 SSR loci selected randomly were employed to analyze genetic diversity and relationship among a collection of Pyrus. The 8 primer pairs produced expected bands with the similar size in apples with an average of 7.375 alleles per locus. The observed heterozygosity of different loci ranged from 0.29 (MES₉₆) to 0.83 (MES₁₃₈), with a mean of 0.55 which is lower than 0.63 reported in genome-derived SSR marker analysis in Pyrus. The UPGMA dendrogram was similar to the previous results obtained by using RAPD and AFLP markers. Our results showed that these EST-SSR markers displayed reliable amplification and considerable polymorphism in both Malus and Pyrus, and will contribute to the knowledge of genetic study of Malus and genetically closed genera.