Chinensis Genotypes Research Articles

Genetic diversity analysis using SSR marker in Naga King chilli (Capsicum chinense Jacq.) genotypes

The present investigation has been undertaken with the objective to study the genetic variability and diversity among the Naga king chilli genotypes using SSR marker at Medziphema during kharif season of 2018. All total 89 bands were produced by 30 primers, 37 bands being polymorphic and producing average percentage polymorphic bands of 41.66 %. The Primer CAMS-826 showed highest percentage of polymorphic bands (75%), followed by primer CAMS 032, CAMS-117, CAMS- 864 and CAMS-647 which revealed (66.66 %) and primer CAeMS 009, CAMS 163, CAMS 871, HmpsE 047 AND HpmsE 014 exhibited 50% polymorphism which indicates that the primer can be used for genetic diversity study of C. chinense genotypes. Genetic parameters analyzed using Popgene® software indicated that Peren population has higher diversity among the four region populations. Jaccard’s similarity coefficient between the genotypes ranged from 0.64 to 0.96, indicating moderate variation between the genotypes. Clustering analysis depicted three clusters where germplasm collected from Peren and Medziphema showed close relatedness and Principal Coordinate Analysis (PCo A) plot obtained also supports cluster analysis data. Germplasm evaluation is of immense important for genetic crop improvement.

Morpho-Agronomic Characterization, Sample Size, and Plot Size for the Evaluation of Capsicum chinense Genotypes

The Amazon is a center of diversity for Capsicum chinense Jacq., with wide genetic and morphological variability, but little exploration has been performed there to facilitate their improvement. This study aimed to characterize and evaluate C. chinense genotypes for the development of cultivars by determining the optimal size of the experimental plot and the minimum sample size to ensure a precise estimation of yield. A total of 23 genotypes were evaluated, and in multivariate analyses, the plants were characterized by 21 morphological descriptors and eight quantitative traits related to biometry and yield. The recommended sample size for fruit evaluation was defined based on simulations with subsample resampling and evaluation of the semi-amplitudes of the confidence interval of the mean estimate. The optimal plot size was estimated by the modified maximum curvature method. The similarity coefficients among the genotypes ranged from 0.54 to 0.93, indicating that the established clusters contained important information for future crosses. According to the sample size methodologies, 25 to 40 fruits should be sampled for valid evaluations of biometric traits. Experiments with five to eight plants per plot are recommended to test progenies of the species, ensuring good experimental precision combined with high selection accuracy for yield traits.

The Effect of Temperature on Seed Germination in Capsicum chinense Genotypes

Bitkisel üretimde tohum çimlenmesi ve çıkış için gerekli olan optimum sıcaklık değerleri, bitki tür ya da çeşitlerine göre farklıklar göstermektedir. Sıcaklık, çimlenme ve çıkış sürecini etkileyen önemli bir çevresel faktördür. Capsicum chinense biber türü; tohum canlılığı, tohum iriliği, tohum şekli, tohum rengi yönünden yüksek düzeyde varyasyon göstermektedir. Bu çalışmada, C. chinense türüne ait biber tohumlarında sıcaklık faktörünün çimlenme kapasiteleri üzerine olan etkileri incelenmiştir. Araştırmada; C. chinense türüne ait 10 biber genotipinin tohumlarının çimlenme performansları, 11 farklı sıcaklık uygulamasında (9 °C, 12 °C, 15 °C, 18 °C, 21 °C, 24 °C, 27 °C, 30 °C, 33 °C, 36 °C, 39 °C) belirlenmiştir. Araştırma sonucunda; 9 °C ve 15 °C arasında çimlenmenin olmadığı, 21 °C ve 33 °C sıcaklık aralıklarında ise çimlenme hızı ve çimlenme oranlarının yükselen sıcaklıklara bağlı olarak artışlar gösterdiği saptanmıştır. Biber genotiplerinde, 24 °C ve 27 °C sıcaklık uygulamalarında en yüksek çimlenme oranlarına ulaşılmıştır. Çimlenme oranı değerleri yönünden CC-51 ve CC-63 genotiplerinin diğer genotiplere göre daha yüksek olduğu belirlenmiştir. Ayrıca tohumların çimlenmesi üzerine, sıcaklık esas alınarak geliştirilen matematiksel modelleme ile, çimlenme oranın tahmin edilmesi olanağı da araştırılmıştır. Bu amaçla; çimlenme potansiyellerinin tahmini için Uzun ve ark. (2001) tarafından önceden türetilmiş model tarafımızdan geliştirilerek [D= a+(b x T) +(c x T2)] şeklinde kullanılmıştır. Her bir genotip için üretilen denklemlerin regresyon katsayılarının (R2), çimlenme oranı değerleri için 0.33 ile 0.95 arasında değiştiği belirlenmiştir. Çimlenme performans özellikleri yönünden öne çıkan C. chinense genotiplerinin gelecekte biber ıslah programında değerlendirilmesi planlanmaktadır.

Variation and heritability of morphological and physiological traits among Leymus chinensis genotypes under different environmental conditions

Intraspecific trait variation and heritability in different environmental conditions not only suggest a potential for an evolutionary response but also have important ecological consequences at the population, community, and ecosystem levels. However, the contribution of quantitative trait variation within a grassland species to evolutionary responses or ecological consequences is seldom documented. Leymus chinensis is an important dominant species in semi-arid grasslands of China, which has seriously suffered from drought and high temperature stresses in recent decades. In the present study, we measured variation and heritability of 10 quantitative traits, namely the number of tillers, maximum shoot height, number of rhizomes, maximum rhizome length, rhizome mass, aboveground mass, root mass, maximum net photosynthetic rate (Pmax), specific leaf area (SLA), and leaf length to leaf width ratio (LL/LW), for 10 genotypes of L. chinensis under one non-stress (Ck) condition and three environmental stress conditions (i.e., drought (Dr), high temperature (Ht), and both drought and high temperature (DrHt)). Result indicated that (1) the interaction of genotype and environmental condition (G×E) was significant for 6 traits but not significant for the other 4 traits as shown by two-way analysis of variance (ANOVA), suggesting that different selection forces were placed for different traits on the factors dominating phenotypic responses to different environmental conditions. Moreover, these significant G×E effects on traits indicated significantly different phenotypic adaptive responses among L. chinensis genotypes to different environmental conditions. Additionally, individuals could be grouped according to environmental condition rather than genotype as shown by canonical discriminant analysis, indicating that environmental condition played a more important role in affecting phenotypic variation than genotype; (2) by one-way ANOVA, significant differences among L. chinensis genotypes were found in all 10 traits under Ck and Dr conditions, in 8 traits under DrHt condition and only in 4 traits under Ht condition; and (3) all 10 traits showed relatively low or non-measurable broad-sense heritability (H2) under stress conditions. However, the lowest H2 value for most traits did not occur under DrHt condition, which supported the hypothesis of 'unfavorable conditions have unpredictable effects' rather than 'unfavorable conditions decrease heritability'. Results from our experiment might aid to improve predictions on the potential impacts of climate changes on L. chinensis and eventually species conservation and ecosystem restoration.

Genetic Diversity, Phylogenetic Tree and Principal Component Analysis Based on Morpho-Metric Traits of Assam Chilli

We evaluated a set of 37 chilli genotypes collected and maintained at Assam Agricultural University, Jorhat for 27 different traits related to plant habit (5), leaf (6), flower (2), fruit (13) and biotic stress (1). The variation in fruit yield among the genotypes could be attributed to high coefficients of variability for component traits viz., number of fruits per plant (91.7%), plant height (80.8%), leaf breadth (55.9 %), fruit weight (49.7%), leaf length (45.4%) fruit length (35.8%), fruit breadth (35.5%) and number of branches per plant (22.2%). Maximum phenotypic variants were observed for fruit traits followed by leaf characteristics. Phylogenetic analysis revealed Euclidean distances varying from a minimum of 2.065 and a maximum of 13.311 indicating the diverse nature of the genotypes. UPGMA clustering grouped the genotypes into 5 distinct clusters. The largest one, cluster I, had 26 genotypes belonging to Capsicum annuum var. acuminatum. Cluster II consisted of Capsicum annuum var. conoides with cone-shaped fruits. Cluster III included Moni Jolokia, a perennial shrub with cone-shaped globose erect fruits which clustered in between the other local C. annuum sp. Bireek and Mem Jolokia. The fourth cluster (IV) included the local chilli genotypes - Mem Jolokia, Bhekuri Jolokia and Haitha Jolokia which were perennial, with green stem and leaves. Cluster V included the C. chinense genotypes consisting of Manipuri Bhut, Bor Bhut and Lota Bhut. The first principal component explained 34.93% of the total variation contributed by mostly leaf and fruit characteristics. The fruit characters in this component showed significant positive correlation with leaf length, breadth and plant height indicating their importance in the morphological characterization of the chilli genotypes.

Genetic diversity analysis among male and female Jojoba genotypes employing gene targeted molecular markers, start codon targeted (SCoT) polymorphism and CAAT box-derived polymorphism (CBDP) markers

To detect genetic variations among different Simmondsia chinensis genotypes, two gene targeted markers, start codon targeted (SCoT) polymorphism and CAAT box-derived polymorphism (CBDP) were employed in terms of their informativeness and efficiency in analyzing genetic relationships among different genotypes. A total of 15 SCoT and 17 CBDP primers detected genetic polymorphism among 39 Jojoba genotypes (22 females and 17 males). Comparatively, CBDP markers proved to be more effective than SCoT markers in terms of percentage polymorphism as the former detecting an average of 53.4% and the latter as 49.4%. The Polymorphic information content (PIC) value and marker index (MI) of CBPD were 0.43 and 1.10, respectively which were higher than those of SCoT where the respective values of PIC and MI were 0.38 and 1.09. While comparing male and female genotype populations, the former showed higher variation in respect of polymorphic percentage and PIC, MI and Rp values over female populations. Nei's diversity (h) and Shannon index (I) were calculated for each genotype and found that the genotype “MS F” (in both markers) was highly diverse and genotypes “Q104 F” (SCoT) and “82–18 F” (CBDP) were least diverse among the female genotype populations. Among male genotypes, “32 M” (CBDP) and “MS M” (SCoT) revealed highest h and I values while “58-5 M” (both markers) was the least diverse. Jaccard's similarity co-efficient of SCoT markers ranged from 0.733 to 0.922 in female genotypes and 0.941 to 0.746 in male genotype population. Likewise, CBDP data analysis also revealed similarity ranging from 0.751 to 0.958 within female genotypes and 0.754 to 0.976 within male genotype populations thereby, indicating genetically diverse Jojoba population. Employing the NTSYS (Numerical taxonomy and multivariate analysis system) Version 2.1 software, both the markers generated dendrograms which revealed that all the Jojoba genotypes were clustered into two major groups, one group consisting of all female genotypes and another group comprising of all male genotypes. During the present investigation, CBDP markers proved more informative in studying genetic diversity among Jojoba. Such genetically diverse genotypes would thus be of great significance for breeding, management and conservation of elite (high yielding) Jojoba germplasm.

Rapid development of microsatellite markers for Callosobruchus chinensis using Illumina paired-end sequencing.

BackgroundThe adzuki bean weevil, Callosobruchus chinensis L., is one of the most destructive pests of stored legume seeds such as mungbean, cowpea, and adzuki bean, which usually cause considerable loss in the quantity and quality of stored seeds during transportation and storage. However, a lack of genetic information of this pest results in a series of genetic questions remain largely unknown, including population genetic structure, kinship, biotype abundance, and so on. Co-dominant microsatellite markers offer a great resolving power to determine these events. Here, we report rapid microsatellite isolation from C. chinensis via high-throughput sequencing.Principal FindingsIn this study, 94,560,852 quality-filtered and trimmed reads were obtained for the assembly of genome using Illumina paired-end sequencing technology. In total, the genome with total length of 497,124,785 bp, comprising 403,113 high quality contigs was generated with de novo assembly. More than 6800 SSR loci were detected and a suit of 6303 primer pair sequences were designed and 500 of them were randomly selected for validation. Of these, 196 pair of primers, i.e. 39.2%, produced reproducible amplicons that were polymorphic among 8 C. chinensis genotypes collected from different geographical regions. Twenty out of 196 polymorphic SSR markers were used to analyze the genetic diversity of 18 C. chinensis populations. The results showed the twenty SSR loci were highly polymorphic among these populations.ConclusionsThis study presents a first report of genome sequencing and de novo assembly for C. chinensis and demonstrates the feasibility of generating a large scale of sequence information and SSR loci isolation by Illumina paired-end sequencing. Our results provide a valuable resource for C. chinensis research. These novel markers are valuable for future genetic mapping, trait association, genetic structure and kinship among C. chinensis.

Pollen parent effects on fruit attributes of diploid Actinidia chinensis ‘Hort16A’ kiwifruit

When used to pollinate flowers of diploid Actinidia chinensis ‘Hort16A’, pollen from tetraploid A. chinensis or hexaploid A. deliciosa males produced fruit with higher fresh weight than did pollen from a diploid A. chinensis male. The dry matter content of the fruit was also increased once differences in the dry matter content of the seed were taken into account. These increases occurred despite slightly delayed harvest maturity and fewer well-formed seed in fruit following pollination by the higher ploidy males. Variation in seed development following different pollen treatments could be explained largely by the genomic ratios expected in the endosperm, and the tendency of ‘Hort16A’ to produce a proportion of 2n gametes. The results suggest that, in contrast to many other diploid A. chinensis genotypes, pollination of ‘Hort16A’ by males of higher ploidy may be beneficial in terms of fresh fruit weight.

Ethylene-regulated (methylsulfanyl)alkanoate ester biosynthesis is likely to be modulated by precursor availability in Actinidia chinensis genotypes

The limiting steps of ethylene-dependent (methylsulfanyl)alkanoate ester biosynthesis have been investigated in this study, using closely related Actinidia chinensis genotypes and the commercial cultivar ‘Hort16A’. Quantification of methylsulfanyl-compounds from the headspace of ethylene-producing kiwifruits revealed little variation in their volatile composition but remarkable differences in the magnitude of the fruit volatile levels. To test whether the variations in fruit volatile levels can be correlated with the genotype-specific apparent catalytic efficiency, the initial slope of the substrate response curve ( V′ Max K M −1 where V′ Max is the apparent V Max in a crude extract) was evaluated for total alcohol acyltransferase (EC 2.3.1.84) activity. The V′ Max K M −1 values of different (methylsulfanyl)alkyl-CoAs were in a similar range for most genotypes, which suggests substrate availability as the limiting factor for (methylsulfanyl)alkanoate ester synthesis in these kiwifruit. Furthermore, gene expression analysis of acyltransferase expressed sequence tags points towards the action of multiple isozymes for (methylsulfanyl)alkanoate ester synthesis, emphasizing the central role of substrate levels on final ester concentrations. Volatile levels of the potential precursor methional were increased in ethylene-producing A. chinensis kiwifruit and a close connection between (methylsulfanyl)alkanoate ester formation and ethylene synthesis in plants is proposed. Finally, a possible biosynthetic pathway is presented.

Differential Reactions on Mature Green and Ripe Chili Fruit Infected by Three Colletotrichum spp.

Differential reactions on mature green and ripe chili fruit of 10 genotypes from four cultivated Capsicum spp. (i.e., Capsicum annuum, C. baccatum, C. chinense, and C. frutescens) were investigated after being inoculated with 33 isolates of Colletotrichum capsici, C. gloeosporioides, and C. acutatum originating from Thailand. The inoculation was performed using an injection method. Differential reactions, based on qualitative host reactions (i.e., lesion development versus no infection) grouped the Colletotrichum isolates into different pathotypes. C. capsici was grouped into three pathotypes based on differential reactions on ripe fruit stage of two Capsicum chinense genotypes (PBC932 and C04714) and two pathotypes based on differential reactions on mature green fruit stage of C04714. Colletotrichum gloeosporioides was grouped into five and six pathotypes on their reactions in ripe and green fruit maturity stages, respectively. C04714 and two Capsicum annuum genotypes (Jinda and Bangchang) acted as differential hosts with ripe fruit, whereas C04714 with all C. annuum and C. frutescens genotypes acted as differential hosts with green fruit. No pathotype of Colletotrichum acutatum was identified on ripe fruit but three pathotypes were identified on green fruit based on differential reactions in two Capsicum baccatum genotypes (PBC80 and PBC81).

DNA profiling of Capsicum landraces of Manipur

Seven chilli landraces of Manipur belonging to three cultivated species of Capsicum ( Capsicum annuum, Capsicum frutescens, and Capsicum chinense) form economically important food crops of the region. The genotypes were characterized using ten random amplified polymorphic DNA (RAPD) markers. The cluster analysis based on Jaccard's similarity coefficient calculated by UPGMA method differentiated the genotypes into two main cluster groups. One cluster represented the C. annuum genotypes while the other cluster represented the C. frutescens and the C. chinense genotypes. C. chinense genotypes were more close to C. frutescens genotypes. Genetic variation between the C. frutescens genotypes was more than among the C. annuum genotypes and the C. chinense genotypes were the least similar ones.

Pathotypes of Colletotrichum capsici, the Causal Agent of Chili Anthracnose, in Thailand.

Eleven isolates of Colletotrichum capsici were screened on nine chili genotypes derived from four cultivated species of Capsicum: Capsicum annuum, C. baccatum, C. chinense, and C. frutescens. Host reactions were assessed 9 days after inoculation by microinjection of spores into the pericarp of red fruit. A set of disease scales, with 0 to 9 scores, were developed for anthracnose infection of each Capsicum sp. based on percent lesion size in relation to fruit size, appearance of necrotic or water-soaked tissue, and presence of acervuli. Three pathotypes, PCc1, PCc2, and PCc3, were identified according to differential qualitative infection of fruit of C. chinense genotypes PBC932 and C04714. PCc1 was the most virulent pathotype, infecting all genotypes of C. annuum, C. chinense, and C. frutescens, whereas PCc3 was the least virulent pathotype, infecting only the genotypes C. annuum and C. frutescens. Quantitative infection occurred in all chili genotypes except for genotypes of C. baccatum, where no infection occurred, demonstrating various levels of aggressiveness of isolates within pathotypes.

Field isolates ofTomato spotted wilt virusovercoming resistance in capsicum in Australia

In 2002 at Virginia, South Australia, capsicum cultivars having the Tsw resistance gene against Tomato spotted wilt virus (TSWV) developed symptoms typical of TSWV infection and several glasshouse-grown crops were almost 100% infected. Samples reacted with TSWV antibodies in ELISA. Virus isolates from infected plants induced severe systemic symptoms, rather than a hypersensitive reaction, when inoculated onto capsicum cultivars and Capsicum chinense genotypes (PI 152225 and PI 159236) that carry the Tsw resistance gene. Isolates virulent towards the Tsw gene had molecular and biological properties very similar to standard TSWV isolates, including a hypersensitive reaction in Sw-5 (TSWV-resistant) tomato genotypes. Tsw-virulent isolates were found during surveys at Virginia in 2002 and 2004 in both TSWV-resistant and susceptible cultivars of capsicum and tomato.

Pigments in the Fruit of Red-Fleshed Kiwifruit (Actinidia chinensis and Actinidia deliciosa)

Kiwifruit cultivars (Actinidia chinensis and A. deliciosa) generally have fruit with yellow or green flesh when ripe. A small number of genotypes also have red pigments, usually restricted to the inner pericarp but varying in intensity and in distribution within the fruit. Carotenoids, chorophylls, and anthocyanins were extracted from the fruit pericarp of such red-fleshed kiwifruit selections. Pigments were analyzed by HPLC and identified by comparison with authentic standards and by liquid chromatography-mass spectroscopy to obtain a tentative identification of the major anthocyanins in red-fleshed kiwifruit. The yellow and green colors of the outer fruit pericarp are due to different concentrations and proportions of carotenoids and chlorophylls. The red color found mainly in the inner pericarp is due to anthocyanins. In the A. chinensis genotypes tested the major anthocyanin was cyanidin 3-O-xylo(1-2)-galactoside, with smaller amounts of cyanidin 3-O-galactoside. In the A. deliciosa genotypes analyzed, cyanidin 3-O-xylo(1-2)-galactoside was not detected; instead, the major anthocyanins identified were cyanidin 3-O-galactoside and cyanidin 3-O-glucoside. However, the two species did not differ consistently in anthocyanin composition.

Development of sequence characterized amplified region (SCAR) primers for the detection of Phyto.5.2, a major QTL for resistance to Phytophthora capsici Leon. in pepper

Phytophthora capsici causes devastating disease on many crop species, including Capsicum. Resistance in Capsicum annuum is genetically and physiologically complex. A panel of Capsicum germplasm that included genotypes from both C. annuum and C. chinense showing highly resistant, highly susceptible and intermediate or tolerant responses to the pathogen, respectively, was screened with a series of randomly amplified polymorphic sequence primers to determine which genomic regions contribute to the highest level of resistance. One primer, OpD04, amplified a single band only in those C. annuum and C. chinense genotypes showing the highest level of resistance. The amplified product was cloned, sequenced and used to design longer primers in order to generate a sequence characterized amplified region marker which was then mapped in a reference mapping population and a screened population segregating for resistance to P. capsici. These primers were observed to define a locus on pepper chromosome 5 tightly linked to Phyto.5.2, one of six quantitative trait loci (QTL) previously reported to contribute to P. capsici resistance. These results indicate that the Phyto.5.2 QTL may be widely distributed in highly resistant germplasm and provide improved resolution for this QTL. This work also defines the first breeding tools for this system, allowing for the rapid selection of genotypes likely to be highly resistant to P. capsici.

Identifying flavour targets for fruit breeding: A kiwifruit example

The current study illustrates that fruit breeding should not only target elite fruit that are significantly more liked than existing cultivars, but also target special unique fruit that create major new flavour niches. Breeding targets can be identified in terms of consumer preferences for new and defined flavours. A trained panel was used to assess the flavours of a wide range of kiwifruit, and these characteristics were systematically arranged into flavour and odour wheels. These wheels describe some of the diversity found within the kiwifruit germplasm. Next, consumers from Japan and New Zealand rated their overall liking of fruit from each of 10 genotypes. Consumer preference mapping was used to explore the relationships between consumer liking and flavour. Cluster analysis was used to explore the diverse responses consumers may have to the same fruit. Individual consumers varied in their preferences, but there was a marked split associated with preference or rejection of fruit from the new cultivar ‘Hort16A’ and associated A. chinensis genotypes. These preferences were related to consumer responses to ‘sweetness’, ‘honest cooked sugar’ and ‘blackcurrant’ flavours that were predominantly associated with A. chinensis genotypes, and absent in previous commercial kiwifruit cultivars. The first significant export of ‘Hort16A’ fruit occurred in 1998. Thus, we have discussed these results from consumer studies on kiwifruit genotypes in relation to the subsequent market success of ‘Hort16A’.

A CAPS marker to assist selection of tomato spotted wilt virus (TSWV) resistance in pepper

The hypersensitive resistance to tomato spotted wilt virus (TSWV) in pepper is determined by a single dominant gene (resistant allele: Tsw) in several Capsicum chinense genotypes. In order to facilitate the selection for this resistance, four RAPD (among 250 10-mer primers tested) were found linked to the Tsw locus using the bulked segregant analysis and 153 F2individuals. A close RAPD marker was converted into a codominant cleaved amplified polymorphic sequence (CAPS) using specific PCR primers and restriction enzymes. This CAPS marker is tightly linked to Tsw (0.9 ± 0.6 cM) and is helpful for marker-assisted selection in a wide range of genetic intercrosses. Key words: Capsicum sp., PCR marker, bulked segregant analysis, Tospovirus, resistance gene.

A CAPS marker to assist selection of tomato spotted wilt virus (TSWV) resistance in pepper

The hypersensitive resistance to tomato spotted wilt virus (TSWV) in pepper is determined by a single dominant gene (resistant allele: Tsw) in several Capsicum chinense genotypes. In order to facilitate the selection for this resistance, four RAPD (among 250 10-mer primers tested) were found linked to the Tsw locus using the bulked segregant analysis and 153 F2 individuals. A close RAPD marker was converted into a codominant cleaved amplified polymorphic sequence (CAPS) using specific PCR primers and restriction enzymes. This CAPS marker is tightly linked to Tsw (0.9 +/- 0.6 cM) and is helpful for marker-assisted selection in a wide range of genetic intercrosses.

Isozyme Polymorphism in the Genus Actinidia and the Origin of the Kiwifruit Genome

Genetic variation at fifteen putative loci in eight enzyme systems (aconitase, alcohol dehydro- genase, aspartate aminotransferase, phosphoglucose isomerase, phosphoglucomutase, shikimate dehydroge- nase and uridine diphosphoglucose pyrophosphorylase) was studied in nearly 500 plants from 20 taxa of the genus Actinidia by means of starch gel electrophoresis. Eighty-two putative isozyme alleles were identified by analysing polymorphism within and among species, segregation in progeny from controlled crosses of Actinidia chinensis genotypes, and differences in banding patterns between shoot tip and pollen extracts. Cytosolic phosphoglucose isomerase was found to be duplicated in at least one diploid species, Actinidia chinensis. An agglomerative cluster analysis conducted on a genetic dissimilarity matrix did not correspond well with current taxonomic subdivisions of the genus and indicated that relationships between some Actinidia taxa should be reconsidered. For the enzyme systems studied, we identified 34 alleles in Actinidia deliciosa var. chlorocarpa, 39 alleles in Actinidia deliciosa var. deliciosa and 35 alleles in Actinidia chinensis. Actinidia deliciosa, the kiwifruit, (2n = 6x) and Actinidia chinensis (2n = 2x) share 34 of 40 alleles, and are consequently thought to be by far the most closely related species. Our results are consistent with the hypothesis that Actinidia deliciosa was derived by polyploidization solely from Actinidia chinensis without any other Actinidia species being involved. The genus Actinidia belongs to the family Actinidiaceae, closely related to the Theaceae, in the Theales. The genus contains more than sixty species and a number of infraspecific taxa, grouped into four sections on the basis of fruit and vegetative characters (Li 1952; Liang 1984; Fergu- son 1990a). Most Actinidia species occur naturally in China (Li 1952; Liang 1983), with many of the countries bordering China containing a few species.