An estimation of the minimum number of SSR loci needed to reveal genetic relationships in wheat varieties: Information from 96 random accessions with maximized genetic diversity

Genetic relationships among common wheat varieties from the 10 wheat growing regions of China were assessed using SSR markers. The wheat varieties included 33 modern varieties and 63 landraces selected from the national gene bank collection of China. One hundred and four pairs of selected primers detected a total of 802 alleles, of which 234 were specific to A genome, 309 to B genome, and 221 to D genome. The average genetic richness per locus (A _ij /loci) for A, B and D genomes were 6.88, 7.92 and 7.62, respectively. Their average genetic dispersion indices (H _t ) were 0.637, 0.694 and 0.656, respectively. The B genome showed the highest genetic diversity among the three wheat genomes. The landraces had a higher genetic diversity than the modern varieties, and the major difference between the landraces and the modern varieties in China existed in the D genome, followed by B and A genomes. The majority of the accessions (65.6%) had heterogeneity at the 112 loci detected. The highest heterogeneity locus percentages were 9.09 and 12.73 in the modern varieties and the landraces, respectively. SSR data were analyzed with NTSYS-pc software. The genetic similarities between accessions were estimated with the DICE coefficient. The accessions clustered into two groups, the modern varieties and the landraces by the un-weighted pair-group method using arithmetic average (UPGMA). The trend of correlation coefficients between genetic similarity matrices based on different numbers of random alleles and that of 802 alleles showed that 550 alleles were sufficient to construct a robust dendrogram. The separated simulations from six sub-samples revealed that 550 alleles were the minimum number required to confidently determine the genetic relationships. It was shown that the number of alleles (loci) needed do not have a strong association with the number of wheat lines in the sample size. These data suggested that 73 loci with good polymorphism are needed to reflect genetic relationships among accessions with more than 90% certainty. In the dendrogram, most accessions from the same wheat region were clustered together, and those from geographically adjacent regions usually appeared in the same small group. This indicated that genetic diversity of Chinese common wheat has a close association with their geographic distribution and ecological environment.     

Current state of the genetic polymorphism in spring barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) from Russia assessed by the alleles of hordein-coding loci

Starch gel electrophoresis was performed to study the polymorphism of hordeins encoded by the Hrd A, Hrd B, and Hrd F loci in 211 varieties of spring barley. For 41 of these varieties, the genetic formulas were established for the first time. In the two samples of varieties, the comparative analysis of allelic diversity and allele frequencies of hordein-coding loci was carried out. The first sample consisted of 101 spring barley varieties approved for the use on the territory of the Russian Federation in 1999, while the second sample included 160 spring barley varieties that were approved in 2014; 49 of these varieties were common for both samples. It is demonstrated that the current tendency to reduction of the proportion of heterogeneous spring barley varieties is mainly due to the introduction of foreign varieties homogeneous for the hordein-coding loci. At the same time, there is an increase in polymorphism of hordein-coding loci in modern spring barley varieties. The number of alleles for the Hrd A locus increased by five alleles, and for the Hrd B locus, by nine alleles. Along with the alleles recorded earlier in barley landrace populations and varieties bred in 20th century, three novel alleles of the Hrd A locus and four alleles of the Hrd B locus were identified. The number of alleles of the Hrd F locus remained unchanged (four), and the changes in their frequencies were small. At the same time, the changes in frequency observed for some alleles of the Hrd A and Hrd B loci were statistically significant. All newly identified alleles of hordein-coding loci were found with low frequencies (from 0.003 to 0.006), so despite the increased number of alleles, no statistically significant increase in genetic diversity in terms of μ and PIC indices was observed.     

Genetic diversity in Chinese modern wheat varieties revealed by microsatellite markers

Genetic diversity of 1680 modern varieties in Chinese candidate core collections was analyzed at 78 SSR loci by fluorescence detection system. A total of 1336 alleles were detected, of which 1253 alleles could be annotated into 71 loci. For these 71 loci, the alleles ranged from 4 to 44 with an average of 17.6, and the PIC values changed from 0.19 to 0.89 with an average of 0.69. (1) In the three genomes of wheat, the average genetic richness was B>A>D, and the genetic diversity indexes were B>D>A. (2) Among the seven homoeologous groups, the average genetic richness was 2=7>3>4>6>5>1, and the genetic diversity indexes were 7>3>2>4>6>5>1. As a whole, group 7 possessed the highest genetic diversity, while groups 1 and 5 were the lowest. (3) In the 21 wheat chromosomes, 7A, 3B and 2D possessed much higher genetic diversity, while 2A, 1B, 4D, 5D and 1D were the lowest. (4) The highest average genetic diversity index existed in varieties bred in the 1950s, and then it declined continually. However, the change tendency of genetic diversity among decades was not greatly sharp. This was further illustrated by changes of the average genetic distance between varieties. In the 1950s it was the largest (0.731). Since the 1960s, it has decreased gradually (0.711, 0.706, 0.696, 0.695). The genetic base of modern varieties is becoming narrower and narrower. This should be given enough attention by breeders and policy makers.     

Hordein Polymorphism in Barley Varieties from Northern Africa

Using starch gel electrophoresis, we examined polymorphism of hordein encoded by loci Hrd A, Hrd B, and Hrd F in 77 accessions of local barley varieties from Northern African countries (9 from Marocco, 22 from Algeria, 7 from Tunisia, and 39 from Egypt). For loci Hrd A, Hrd B, andHrd F, respectively 35, 43, and 5 alleles were found. The existence of families of blocks of hordein components encoded by Hrd A and Hrd Bwas demonstrated. The estimation of genetic distances and cluster analysis showed similarity of barley populations from different Northern African countries with regard to alleles of the hordein-coding loci. We suggest that polymorphism at the hordein-coding loci in the populations examined has been mainly formed beyond Northern Africa, where barley has been repeatedly introduced. Apparently, the examined populations from Ethiopia and Egypt are not directly associated.     

Molecular markers linked to genes affecting plant height in wheat using a doubled-haploid population

 Plant height in wheat (Triticum aestivum L. em Thell) is known to be under polygenic control. Crosses involving genes Rht-B1 and Rht-D1, located on chromosomes 4BS and 4DS, respectively, have shown that these genes have major effects. Two RFLP loci were found to be linked to these two genes (Xfba1-4B with Rht-B1 and Xfba211-4D with Rht-D1) by genotyping a population of F₁-derived doubled-haploid lines [‘Courtot’ (Rht-B1b+Rht-D1b)בChinese Spring’]. Using a well-covered molecular marker map, we detected three additional regions and one interaction influencing plant height. These regions, located on chromosome arms 4BS (near the locus Xglk556-4B), 7AL (near the locus Xglk478-7A) and 7BL (near the locus XksuD2-7B) explained between 5% and 20% of the variability for this trait in this cross. The influence of 2 loci from chromosome 4B (Xfba1-4B and Xglk556-4B) suggests that there could be a duplication of Rht-B1 on this chromosome originating from Cv ‘Courtot’. Moreover, an interaction effect between loci from chromosome arms 1AS (near the locus Xfba393-1A) and 1BL (near the locus Xcdo1188-1B) was comparable to or even higher than those of the Rht-B1b and Rht-D1b alleles. A model including the main effects of the loci from chromosomes 4B and 4D (Xfba1-4B, Xglk556-4B and Xfba211-4D) and the interaction effect between Xfba393-1A and Xcdo1188-1B is proposed, which explains about 50% of the variation in plant height. The present results are discussed in relation to those obtained using nullisomic or substitution lines. Received: 13 June 1997 / Accepted: 13 October 1997     

Polymorphism of microsatellite loci of European chickpea cultivars

The polymorphism of 13 microsatellite loci in 61 chickpea varieties from the National Center of Genetic Plant Resources of Ukraine was studied. Forty-seven alleles were detected. Three loci were monomorphic; the rest showed polymorphism. The genetic diversity of chickpea varieties in all loci was 0.41 according to the Nei polymorphism index (D). It was concluded that chickpea varieties from Europe had insignificant microsatellite loci diversity. The most polymorphic group included chickpea varieties from Russia (D = 0.38); the least polymorphic group, Spanish varieties (D = 0.25). A consensus tree representing the most credible divergence of Europe chickpea varieties was constructed. The possible reasons for clustering chickpea varieties in a common cluster are discussed.     

Genetic diversity among East Asian accessions of the barley core collection as revealed by six isozyme loci

 Studies of allelic variations at six isozyme loci revealed genetic diversity of 380 East Asian accessions of the Barley Core Collection. Genetic variation was found in both cultivars and landraces in different regions. Allelic variations at the Aco-1 and Aco-2 loci were detected for East Asian barley for the first time. Moreover, the Aco-1 locus displayed the highest genetic diversity among the six loci assayed. Indian cultivars showed the highest diversity, followed by Korean and Chinese cultivars. Landraces from Bhutan and Nepal showed the lowest diversity. Cultivars had generally higher diversity than landraces within as well as among regions. The cluster analysis of genetic identity showed that all landraces from different countries can be placed in one group; the cultivars from Japan, India and Korea each form independent groups. Gpi-1 Gu, Pgd-1 Tj, Aco-1 Si, Ndh-2 D and Aco-2 A were rare alleles found in only a few accessions of 6-rowed barley. The Pgd-2 Tn allele was very rare in East Asian accessions. Received: 29 July 1998 / Accepted: 2 November 1998     

Efficacy of pyramiding elite alleles for dynamic development of plant height in common wheat

Plant height is an important botanical feature closely related to yield. Two populations consisting of 118 and 262 accessions respectively were used to identify elite alleles for plant height and to validate their allelic effects. Plant height was measured from the early booting to the flowering stages. Simple sequence repeat markers for candidate quantitative trait locus (QTL) regions with large effects identified in a doubled haploid (DH) population (Hanxuan 10 × Lumai 14) were selected for further verification by association analysis. Nine loci significantly (P < 0.001) associated with plant height were detected 13 times in the population with 118 accessions. Three loci (Xgwm11-1B, Xwmc349-4B and Xcfd23-4D) were identified in three, two and two periods of plant height growth, respectively. Markers Xbarc168-2D, Xgwm249-2D, Xwmc349-4B, Xcfd23-4D and Xgwm410-5A located at or near additive QTL regions in the DH population proved to coincide with known Rht loci. The results showed a consistency between linkage analysis and association mapping, and also confirmed the value of fine mapping of QTL through combined linkage and association analyses. For final plant height, the alleles Xgwm11-1B ₂₀₈ , Xwmc349-4B ₁₀₃ and Xcfd23-4D ₂₀₂ exhibited negative effects, i.e. reducing plant height; Xwmc349-4B ₁₀₁ and Xcfd23-4D ₂₀₅ showed significant positive effects. A second larger population (262 accessions) was used to validate the effects of these large-effect alleles and the efficacy of pyramiding in eight environments (year × site × water regime combinations). Strong correlations between final plant height and numbers of large-effect alleles indicated that the alleles contributed additively to plant height. The additive effects showed that pyramiding elite alleles for target traits has significant potential for wheat breeding.     

Association and Validation of Yield-Favored Alleles in Chinese Cultivars of Common Wheat (Triticumaestivum L.)

Common wheat is one of the most important crops in China, which is the largest producer in the world. A set of 230 cultivars was used to identify yield-related loci by association mapping. This set was tested for seven yield-related traits, viz. plant height (PH), spike length (SL), spikelet number per spike (SNPS), kernel number per spike (KNPS), thousand-kernel weight (TKW), kernel weight per spike (KWPS), and sterile spikelet number (SSN) per plant in four environments. A total of 106 simple sequence repeat (SSR) markers distributed on all 21 chromosomes were used to screen the set. Twenty-one and 19 of them were associated with KNPS and TKW, respectively. Association mapping detected 73 significant associations across 50 SSRs, and the phenotypic variation explained (R²) by the associations ranged from 1.54 to 23.93%. The associated loci were distributed on all chromosomes except 4A, 7A, and 7D. Significant and potentially new alleles were present on 8 chromosomes, namely1A, 1D, 2A, 2D, 3D, 4B, 5B, and 6B. Further analysis showed that genetic effects of associated loci were greatly influenced by association panels, and the R² of crucial loci were lower in modern cultivars than in the mini core collection, probably caused by strong selection in wheat breeding. In order to confirm the results of association analysis, yield-related favorable alleles Xgwm135-1A₁₃₈, Xgwm337-1D₁₈₆, Xgwm102-2D₁₄₄, and Xgwm132-6B₁₂₈ were evaluated in a double haploid (DH) population derived from Hanxuan10 xLumai14.These favorable alleles that were validated in various populations might be valuable in breeding for high-yield.     

Use of recombinant inbred lines of wheat for study of associations of high-molecular-weight glutenin subunit alleles to quantitative traits

Summary The high-molecular-weight glutenin subunits (HMW glutenin), encoded by alleles at homoeologous lociGlu-A1,Glu-B1, andGlu-D1 on the long arms of chromosomes1A,1B, and1D of a set of F₈ random recombinant inbred lines (RIL) derived from the bread wheat cross Anza × Cajeme 71, were classified by SDS-PAGE. Anza has poor breadmaking quality and HMW-glutenin subunits (Payne numbers) null (Glu-A1c), 7+8 (Glu-B1b), and 2+12 (Glu-D1a); Cajeme 71 has good quality and 1 (Glu-A1a), 17+18 (Glu-B1i), and 5+10 (Glu-D1d). The combinations of these alleles in the RIL were examined for associations with grain yield and four indicators of grain quality — protein content, yellowberry, pearling index, and SDS sedimentation volume. Data were obtained from a field experiment with three nitrogen fertilization treatments on 48 RIL and the parents. Orthogonal partitioning of the genetic variance associated with the three HMW glutenin subunit loci into additive and epistatic (digenic and trigenic) effects showed strong associations of these loci with grain yield and the indicators of quality; however, the associations accounted for no more than 25% of the differences between the parents. Genetic variance was detected among the RIL, which had the same HMW glutenin genotype for all traits. Epistatic effects were absent for grain yield and yellowberry, but were substantial for grain protein content, pearling index, and SDS sedimentation volume. All three loci had large single-locus additive effects for grain yield, protein, and SDS sedimentation volume. Yellowberry was largely influenced byGlu-B1 andGlu-D1, whereas pearling index was associated withGlu-A1 andGlu-B1. Even though the observed associations-of effects of HMW glutenin loci with the quantitative characters were small relative to the total genetic variability, they are of considerable importance in understanding the genetics of wheat quality, and are useful in the development of new wheat varieties with specific desired characteristics.     

Genetic Diversity and Core Collection Evaluations in Common Wheat Germplasm from the Northwestern Spring Wheat Region in China

Fluorescence microsatellite markers were employed to reveal genetic diversity of 340 wheat accessions consisting of 229 landraces and 111 modern varieties from the Northwest Spring Wheat Region in China. The 340 accessions were chosen as candidate core collections for wheat germplasm in this region. A core collection representing the genetic diversity of these accessions was identified based on a cluster dendrogram of 78 SSR loci. A total of 967 alleles were detected with a mean of 13.6 alleles (5–32) per locus. Mean PIC was 0.64, ranged from 0.05 to 0.91. All loci were distributed relatively evenly in the A, B and D wheat genomes. Mean genetic richness of A, B and D genomes for both landraces and modern varieties was B > A > D. However, mean genetic diversity indices of landraces changed to B > D > A. As a whole, genetic diversity of the landraces was considerably higher than that of the modern varieties. The big difference of genetic diversity indices in the three genomes suggested that breeding has exerted greater selection pressure in the D than the A or B genomes in this region. Changes of allelic proportions represented in the proposed core collection at different sampling scales suggested that the sampling percentage of the core collection in the Northwest Spring Wheat Region should be greater than 4% of the base collection to ensure that more than 70% of the variation is represented by the core collection. Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.     

Polymorphism of hordein-coding loci in cultivated barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) in Afghanistan

Polymorphism of hordeins encoded by the Hrd A, Hrd B, and Hrd F loci was analyzed in 84 accessions of local barley (Hordeum vulgare L.) varieties from major agricultural regions of Afghanistan using starch gel electrophoresis. Forty alleles of the Hrd A locus with the frequencies from 0.12 to 32.73%, 62 alleles of the Hrd B locus with the frequencies from 0.12 to 14.29%, and five alleles of the Hrd F locus with the frequencies from 0.59 to 32.15% have been identified. The conclusion about genetic similarity of barley populations from different regions of Afghanistan is made on the basis of cluster analysis of the matrix of allele frequencies in barley populations from 31 localities. The local barley populations form four unequal clusters. The largest cluster I includes populations from 14 localities of Afghanistan. The second largest cluster IV consists of populations from ten localities, and clusters II and III comprise populations from four and three localities, respectively. Each of the four clusters includes populations from different regions of northern and southern Afghanistan. Based on our results, we conclude that the diversity of hordein-coding loci and the distribution of their alleles among different regions of Afghanistan are the consequences of introduction of barley landraces and their distribution over trade routes.     

Regulation of biosynthesis of pesticidal metabolic complexes inStreptomyces griseus

The complex of pesticidal metabolites produced byStreptomyces griseus LKS-1 consists of a peptide antibiotic (A), nonactic acids (B), macrotetrolides (C), pyrrolizines (D), and of cycloheximide. The latter unwanted phytotoxic compound was eliminated by treatment with mutagens. Combined approaches, including both genetic and physiological manipulations, resulted in the following alterations in the biosynthetic capacity: (1) A more than 80-fold increase in the production of C under a substantial decrease in the yields ofA, B andD, the ratio of the components ofC being steered toward the required more active ones; (2) a more than 300-fold increase in the production ofB under suppression of the formation ofA andC: (3) a 10-fold increase in the yields ofD under suppression ofA andC; (4 a significant increase in the yields ofA with eliminatingB, C andD. The level of inorganic phosphate in fermentation media and the sensitivity of the organism to carbon catabolite repression were important factors participating in the regulation of the above biosynthetic processes.     

Hordein Polymorphism in Ethiopian Barley

Using starch gel electrophoresis, polymorphism of hordein-encoding loci Hrd A, Hrd B, and Hrd Fwas studied in 147 accessions of local Ethiopian barley cultivars. Loci Hrd A, Hrd B, and Hrd Fwere shown to have 26, 36, and 4 alleles, respectively. The allele frequencies in the collection examined varied from 0.17 to 45.72%. For loci Hrd Aand Hrd B, families of blocks of hordein components were found. Based on the allele frequencies and their combinations at loci Hrd Aand Hrd Bas well as the numbers of families of component blocks of hordeins A and B, we identified genotypes that could be considered as the most ancient in Ethiopia. A catalog of hordein variant encoded by these loci was created. The list of hordein genetic formulas for the studied accessions is presented.     

Literature-Informed Analysis of a Genome-Wide Association Study of Gestational Age in Norwegian Women and Children Suggests Involvement of Inflammatory Pathways

BackgroundFive-to-eighteen percent of pregnancies worldwide end in preterm birth, which is the major cause of neonatal death and morbidity. Approximately 30% of the variation in gestational age at birth can be attributed to genetic factors. Genome-wide association studies (GWAS) have not shown robust evidence of association with genomic loci yet.MethodsWe separately investigated 1921 Norwegian mothers and 1199 children from pregnancies with spontaneous onset of delivery. Individuals were further divided based on the onset of delivery: initiated by labor or prelabor rupture of membranes. Genetic association with ultrasound-dated gestational age was evaluated using three genetic models and adaptive permutations. The top-ranked loci were tested for enrichment in 12 candidate gene-sets generated by text-mining PubMed abstracts containing pregnancy-related keywords.ResultsThe six GWAS did not reveal significant associations, with the most extreme empirical p = 5.1 × 10⁻⁷. The top loci from maternal GWAS with deliveries initiated by labor showed significant enrichment in 10 PubMed gene-sets, e.g., p = 0.001 and 0.005 for keywords "uterus" and "preterm" respectively. Enrichment signals were mainly caused by infection/inflammation-related genes TLR4, NFKB1, ABCA1, MMP9. Literature-informed analysis of top loci revealed further immunity genes: IL1A, IL1B, CAMP, TREM1, TFRC, NFKBIA, MEFV, IRF8, WNT5A.ConclusionOur analyses support the role of inflammatory pathways in determining pregnancy duration and provide a list of 32 candidate genes for a follow-up work. We observed that the top regions from GWAS in mothers with labor-initiated deliveries significantly more often overlap with pregnancy-related genes than would be expected by chance, suggesting that increased sample size would benefit similar studies.     

Haplotypes of the BoLA‐A,Bf, CYP21 and DQB loci in Angus cattle

Abstract

The genetic diversity of bovine major histocompatibility complex (BoLA) haplotypes within the Angus breed was studied. Four BoLA loci were chosen for our study; BoLA‐A, complement factor B (Bf), cytochrome P450 steroid 21‐hydroxylase (CYP21) and BoLA‐DQB. Polymorphism of BoLA‐A products was determined by serology. Alleles of the Bf, CYP21 and BoLA‐DQB loci were distinguished by restriction fragment length polymorphism (RFLP) analysis. Thirteen different haplotypes were identified, eleven of which were confirmed by segregation analysis in a paternal half‐sibling family of Angus cattle (n=9 offspring). These thirteen haplotypes were comprised of 9 BoLA‐A alleles and a “blank”, two Bf alleles detected with TaqI, two CYP21 alleles detected with PstI, and eight DQB alleles detected with Taql and PvuII. Two haplotypes containing the supertypic BoLA‐URAA specificity were clearly differentiated by Bf and DQB typing. Two haplotypes distinguished by the BoLA‐A alleles w2 and w3, shared the same DQB?2 allele. Nine and four haplotypes carried the Bf?1 and Bf?2 alleles, respectively. Three haplotypes carried CYP21?A and ten contained CYP21?B. Linkage between BoLA‐A and the CYP21 locus, both previously mapped to chromosome 23 by synteny mapping, was confirmed by segregation analysis. These results demonstrate that extended BoLA haplotypes are useful for studying genetic diversity within a breed.     

FOUR PROTEIN POLYMORPHISMS IN PIGEON BRAIN EXTRACTS DETECTED BY TWO-DIMENSIONAL GEL ELECTROPHORESIS

Abstract— Proteins of the brain extracts of 85 individual pigeons (Columba livia) were mapped by two-dimensional gel electrophoresis. The method is a modification of O'Farrell 'S technique and separates proteins first by charge and then by molecular weight. There were three proteins, A, B and D which had each a variant form. The positions of these six proteins on the gel corresponded to the following pH values and molecular weight values: protein A₁, 6.4/43,000; A₂, 6.6/43,000; B₁, 5.7/41,000; B₂, 5.8/40,000; D₁, 6.2/22,000; D₂, 6.2/21,000. The variants are genetically determined, since protein A, B and D each occurred in three phenotypes (A₁, A₁A₂ and A₂; B₁, B₁B₂ and B₂; D₁, D₁D₂ and D₂) corresponding to the three possible genotypes. From the observed frequencies of the phenotypes the following allele frequencies were calculated: allele A₁, 72%; A₂, 28%; B₁, 15%; B₂, 85%; D₁, 74%; D₂, 26%. A fourth protein named C occurred in four different forms (C₁, 7.2/37,000; C₂, 7.2/36,000; C₃, 7.1/37,000; C₄, 7.1/36,000) and six phenotypes (C₁, C₁C₂, C₂, C₁C₃, C₂C₃ and C₄C₃). This polymorphism is also interpreted as being genetically determined. The four alleles coding for the four protein C forms had the following frequencies: allele C₁, 62%; C₂, 27%; C₃, 10.5%; C₄, 0.5%.     

Genetic diversity of populations of a rare species of Dictamnus gymnostylis Stev. in Bashkir Cis-Urals

We examined genetic diversity in populations of Dictamnus gymnostylis Stev., a rare species growing in the Bashkir Cis-Urals, based on the analysis of 8 gene-enzyme systems and detected a fairly high level of intraspecific genetic diversity and population differentiation. We determined the average number of alleles per locus (A) as 1.57; the portion of polymorphic loci (P ₉₅) as 0.508; the observed heterozygosity (H _o) as 0.139; and the expected heterozygosity (H _e) as 0.169. Of the total genetic diversity, 88.3% stems from variability within populations, and 11.7% is due to variation among populations. The average value for the Nei’s genetic distance (D) constituted 0.028.     

利用产量位点标记分析中国水稻骨干恢复系与南亚及东南亚恢复系的遗传多样性

利用47个根据已报道的QTL位点或者已被精细定位或克隆的与水稻产量性状基因紧密连锁的产量位点标记,对来自中国、印度和越南等国的58份水稻恢复系进行遗传多样性分析。结果表明:(1)在中国恢复系中,47个产量位点标记中有36个具有多态性,共检测到90个等位基因,每个标记检测到等位基因2~4个,平均为2.500个;有效等位基因共62.905个,平均每个标记1.747个;36个有效标记的Shannon信息指数平均值为0.632,变幅为0.271~1.266。(2)在来自国外的材料中,47个产量位点标记均具有多态性,共检测到131个等位基因,每个标记检测到的等位基因数为2~6个,平均2.787个;有效等位基因数共82.686个,平均1.759个;47个标记的Shannon信息指数平均值为0.649,变幅为0.109~1.110。(3)聚类分析显示,在遗传相似系数为0.73水平上,参试资源聚为三大类群,中国资源多聚在第Ⅰ类群下的第1、2、3亚群,越南资源多聚在第Ⅰ-4亚群,孟加拉资源多聚在第Ⅲ-3亚群。由此表明,中国资源遗传基础较为狭窄,而其他国家的恢复系具有较远的亲缘关系。