Pollination Variant Astringent Research Articles

Multiple Introduction Events of Cultivated Diospyros Kaki L. of and Native Diospyros Species in Taiwan Inferred by Low Copy Nuclear Markers

Diospyros kaki L. is one of the most important fruits in Taiwan. Cultivated D. kaki cultivars are classified into four types, according to their loss of astringency in ripening fruit and their change in flesh color, namely the Pollination-Constant Non-Astringent (PCNA), the Pollination Variant Non-Astringent (PVNA), the Pollination Variant Astringent (PVA) and the Pollination Constant Astringent (PCA). Recently, persimmon breeders are paying more attention to rootstock selection for successful grafting and agricultural production. To identify suitable rootstock and to trace the origins of extant native Diospyros species in Taiwan, the 10 known native Diospyros species together with four D. kaki cultivars were analyzed by using two low-copy, nuclear-encoded DNA markers, ncpGS and PHYA. There was moderate to strong support for the major nodes within the phylogenetic tree, obtained from both the Maximum-likelihood or the Bayesian inference methods. The constructed D. kaki phylogeny using Maximum Likelihood (ML) and Bayesian Inference (BI) algorithms formed three clades. The most basal clade (clade A) comprised species distributed in the South East Asia , then species distributed in East Asia (clade B), and then D. kaki cultivars (clade C). The extant native Taiwan Diospyros species nested into clade A and B, suggesting a northward migration pattern of native Taiwan Diospyros species. In addition, the species D. oldhamii formed a sister clade with the D. kaki cultivars, suggesting that D. oldhamii may be a compatible rootstock. Lastly, D. kaki cultivars sampled from growers that were acquaintances formed corresponding subclades within clade C (C-1, C-2 and C-3), suggesting a high discrimination ability of the ncpGS and PHYA molecular markers used here.

Diversidade genética, produtividade e qualidade de frutos de caqui nos trópicos

Abstract The objective of this work was to determine the genetic diversity, yield, and fruit quality of persimmon genotypes grown in the tropics, in order to select promising genetic materials. DNA extraction was performed on young leaves of 19 persimmon genotypes. For pomological characterization, 15 genotypes were selected. From each genotype, 50 fruit at the physiological maturity stage were harvested in the morning, in order to determine the following parameters: physicochemical characteristics; and the productive variables number of fruit per plant, average fruit fresh mass, average yield, and estimated average yield in two seasons. Twenty SSR markers were tested, out of which 12 were selected to evaluate genetic similarity, which allowed of the identification of distinct groups. The mean genetic diversity value found was 0.41, which is an indicative of low diversity among the analyzed persimmon genotypes. The 'Guiombo', 'Iapar 125', 'Kakimel', 'Mikado RJ', 'Rama Forte Tardio', and 'Taubaté' genotypes show a high yield. The genotypes classified as pollination-constant astringent ('Pomelo', 'Regina', 'Rubi', and 'Taubaté') and those classified as pollination-variant astringent ('Rama Forte', 'Guiombo', and 'Cereja') are potential materials for selection and genetic breeding programs due to their excellent fruit physicochemical characteristics. The investigation through molecular markers is an efficient approach to study the genetic diversity of persimmon genotypes grown in the tropics.

Diversity of Fruit Quality in Astringent and Non−Astringent Persimmon Fruit Germplasm

Persimmon (Diospyros kaki Thunb.) is an economically important tree with a long history of cultivation in China. So far, a total of approximately 1000 varieties have been found in China. To systematically evaluate the diversity of persimmon fruit quality, 22 quality measures of appearance, intrinsic, and sensory quality were evaluated using 61 typical persimmon fruit. According to the findings, the coefficient of variation (CV) of 15 appearance and intrinsic quality index values ranged from 13.81% (fruit shape index) to 165.80% (firmness), and the CV values of 7 intrinsic quality attributes were all higher than 50%, with the CV of total polyphenols and ironic soluble pectin contents (ISP) being as high as 159.82% and 143.80%, respectively. These findings showed that several persimmon germplasm resources had a highly diverse range of fruit quality, wide variation, and distribution. Insoluble tannin and soluble sugar were shown to have a substantial positive correlation with the sensory flavor indexes (p < 0.05), indicating their significance in influencing the flavor quality of persimmon fruit. Cluster analysis was performed utilizing 15 indexes of appearance, intrinsic quality, and 7 indexes of sensory quality. The samples were divided into two groups: group I consisted of 52 pollination−constant and astringent (PCA) and 1 pollination−-variant astringent (PVA) persimmon resources, and group II consisted of 6 pollination−constant non−astringent (PCNA) and 2 pollination−variant non−astringent (PVNA) persimmon resources. The results were consistent with the classification based on the mode of astringency loss, indicating that there was a significant difference in the quality of astringent and non−astringent persimmon fruit. This study provides theoretical references for the development and application of persimmon germplasm resources.

Molecular Assisted Selection for Pollination-Constant and Non-Astringent Type without Male Flowers in Spanish Germplasm for Persimmon Breeding

Persimmon (Diospyros kaki Thunb) species is a hexaploid genotype that has a morphologically polygamous gyonodioecious sexual system. D. kaki bears unisexual flowers. The presence of male flowers resulted in the presence of seeds in the varieties. The fruits of persimmon are classified according to their astringency and the pollination events that produced seeds and modify the levels of astringency in the fruit. The presence of seeds in astringent varieties as pollination variant astringent (PVA), pollination variant non-astringent (PVNA) and pollination constant astringent (PCA) resulted in fruits not marketable. Molecular markers that allow selection of the varieties according to the type of flowers at the plantlet stage would allow selection of seedless varieties. In this study, a marker developed in D. lotus by bulk segregant analysis (BSA) and amplified fragment length polymorphism (AFLP) markers, named DlSx-AF4, has been validated in a germplasm collection of persimmon, results obtained agree with the phenotype data. A second important trait in persimmon is the presence of astringency in ripened fruits. Fruits non-astringent at the ripen stage named pollination constant non-astringent (PCNA) are the objective of many breeding programs as they do not need removal of the astringency by a postharvest treatment. Astringency in the hexaploid persimmon is a dominant trait. The presence of at least one astringent allele confers astringency to the fruit. In this paper we checked the marker developed linked to the AST gene. Our goal has been to validate both markers in germplasm from different origins and to test the usefulness in a breeding program.

Effects of packing materials and ethanol concentrations on removal of astringency of 'Rojo Brillante' at room temperature.

Most of the persimmons grown in Afghanistan are astringent and hence their fruits require de-astringency treatments in order to become edible at harvest time. CO2 with or without ethanol treatment provides an optimal method for the rapid removal of the persimmon astringency, but it is a bit sophisticated and currently not feasible for most of farmers. The present study is therefore carried out to assess a simple and suitable technique for de-astringency of the persimmons at farmer level. The fruits of ‘Rojo Brillante’, a Pollination Variant Astringent (PVA) Spanish cultivar which is astringent, were harvested in yellow-orange color and then quickly dipped in 0, 10, 20, and 40% ethanol concentrations. The treated fruits were packed and sealed in the paper cartons, plastic bags or left open in the room temperature. Firmness, total soluble solids and astringency level of fruits were measured each three days. The astringency of ‘Rojo Brillante’ was removed when fruits treated with 20% or 40% ethanol and packed in the plastic bags for 9 days. Total soluble solids content was not affected by any of the treatments, while commercial firmness (1.5-2.5 kg) obtained by packing the fruits in the plastic bags or paper cartons alone.

Analysis of genetic diversity among a set of accessions from the IVIA’s persimmon collection

In Spain, persimmon (Diospyros kaki Thunb.; 2n=6x=90) production has become an alternative to producing major fruit crops. The aim of the Instituto Valenciano de Investigaciones Agrarias's (Valencia, Spain) persimmon breeding program is to increase the range of available cultivars. Genetic resources collections are an important tool for breeding. Knowledge of the germplasm's genetic structure is valuable for improving the management of plant materials in a breeding program. Here, 47 new accessions having different origins and two rootstock species were studied using 18 polymorphic microsatellite markers. Genetic structures were estimated using a Bayesian-based model clustering method, while a Neighbor-Joining phylogenetic tree was constructed to visualize the genetic relationships among the samples. Evanno's test of the Bayesian-based model estimation found that three populations were the most informative. Persimmon cultivars are classified in four types, pollination-constant non-astringent, pollination-variant non-astringent, pollination-constant astringent and pollination-variant astringent, based on their astringency. Using these types, most of the pollination-constant and pollination-variant non-astringent accessions were grouped separately from the pollination-constant and pollination-variant astringent accessions, regardless of their origin.

Persimmon breeding in Japan for pollination-constant non-astringent (PCNA) type with marker-assisted selection.

Oriental persimmon (Diospyros kaki) originated in Eastern Asia, and many indigenous cultivars have been developed in China, Japan, and Korea. These cultivars are classified into four groups based on their natural astringency loss on the tree and seed formation: pollination-constant non-astringent (PCNA), pollination-variant non-astringent (PVNA), pollination-constant astringent (PCA), and pollination-variant astringent (PVA). PCNA is the most desirable type because the fruit can be eaten without any postharvest treatment; therefore, one of the goals of our persimmon breeding programs is to release superior PCNA cultivars. The PCNA genotype is recessive to the other three non-PCNA genotypes, and PCNA-type F1 offspring are obtained exclusively from crosses among PCNA genotypes. Moreover, the number of superior PCNA cross-parents have been limited. In the late 1980s, inbreeding depression became obvious, especially in terms of fruit size, tree vigor, and productivity. To mitigate the inbreeding, a backcross program using PCNA [(non-PCNA × PCNA) × PCNA] was started in 1990. This process, however, was inefficient because only 15% of the offspring were PCNA, and all offspring had to be grown to the fruiting stage. Therefore, molecular markers linked to the PCNA locus were developed for discriminating PCNA offspring. A molecular marker linked to Chinese PCNA has also been developed.

TWO ASTRINGENT PERSIMMON CULTIVARS RELEASED BY NARO INSTITUTE OF FRUIT TREE SCIENCE, JAPAN

The national institute in Japan has conducted persimmon breeding since 1938, emphasizing the improvement of pollination constant non-astringent (PCNA) cultivars. However, PCNA cultivars of Japanese origin is a recessive trait, and its genetic resources are very limited, and repeated crossings within the narrow gene pool led to inbreeding, which hinders tree vigor, productivity, and fruit weight. Therefore, a strategy of obtaining PCNA offspring through the backcross (PCNA×non-PCNA)×PCNA has been going on since 1990. Two astringent selections from the first phase were released as new pollination variant astringent (PVA) cultivars ‘Taiten’ and ‘Taigetsu’ in 2007, both of which are derived from the cross of ‘Kurokuma’ (a local PVNA cultivar in Japan) × PCNA cultivar ‘Taishu’. Trees of both new cultivars are vigorous and productive. Crosses between each of those new cultivars and PCNA genotype yielded around one fifth PCNA offspring of the total. The ‘Taiten’ fruit ripens in late November, comparable to ‘Fuyu’ at the national institute in Akitsu. Its fruit weighs an average of 506 g. The flesh is soft, moderately coarse and very juicy. The soluble solids concentration in juice after removing astringency (SSC) averages 16.5%, which is comparable to ‘Fuyu’. Fruit cracking at the calyx or stylar end is rare. However, small areas of shallow concentric cracks on fruit skin (SCCS) occur in a considerable ratio of the fruit. The ‘Taigetsu’ fruit ripens in early November at Akitsu. Its fruit weighs an average of 459 g. The flesh is soft, moderately coarse and very juicy. The SSC averages 15.4%, which is comparable to ‘Hiratanenashi’. Fruit cracking at the calyx or stylar end is rare. SCCS are likely to occur in a considerable ratio of the fruit. Parthenocarpy in ‘Taigetsu’ is high.

Development of Molecular Markers Linked to the Allele Associated with the Non-astringent Trait of the Chinese Persimmon (Diospyros kaki Thunb.)

Persimmon cultivars are classified into four types depending on the nature of astringency loss of the fruit, namely pollination constant non-astringent (PCNA), pollination variant non-astringent (PVNA), pollination variant astringent (PVA), and pollination constant astringent (PCA). Among these four types, PCNA is the most important cultivar for persimmon breeding due to the stable loss of natural astringency on the tree. The trait of natural astringency loss is recessive in Japanese PCNA cultivars, while that in the Chinese PCNA cultivar, ‘Luo tian tian shi’, is dominant and the latter locus, termed CPCNA, is different from that in Japanese cultivars. In order to develop a molecular marker for the selection of the CPCNA-type cultivar, we performed amplified fragment length polymorphism (AFLP) in combination with bulked segregant analysis for F1 offspring derived from ‘Luo tian tian shi’, which was used as the maternal parent. A total of 384 primer combinations were tested, and three AFLP markers, namely EACT-MCCC-222 (RO1), EGGC-MCTC-309 (RO2), and EGCC-MCGA-105 (RO3), linked to the CPCNA dominant allele were obtained. Among these markers, EGGC/MCTC-309 (RO2) was converted into a sequence-characterized amplified region (SCAR) marker. PCR analysis using F1 offspring (n = 264) revealed that the relevance ratio of the SCAR marker was 94%. The polymorphism of the RO2 marker, which was strongly linked to the CPCNA dominant allele, was detected in only two Chinese PCNA cultivars, namely ‘Luo tian tian shi’ and ‘Tian bao gai’, among the Chinese, Korean, and Japanese cultivars tested. These results indicate that the RO2 marker contributes to marker-assisted selection for breeding programs of new PCNA cultivars having the CPCNA trait.

Isolation and expression of gene encoding leucoanthocyanidin reductase from Diospyros kaki during fruit development

Leucoanthocyanidin reductase (LAR) converts leucoanthocyanidin to (+)-catechin, a precursor of proanthocyanidins abundant in Japanese persimmon (Diospyros kaki Thunb.) fruits. A putative LAR gene (DkLAR) was isolated by rapid amplification of cDNA ends from young fruits. The full-length cDNA of DkLAR gene was 1 356 bp long and encoded an open reading frame of 349 residues. The deduced DkLAR protein was closely related to the homolog in other plant species. The expression of the DkLAR gene in Chinese pollination-constant non-astringent (PCNA) genotype was coincident with the tannin cell development, but was not in Japanese PCNA and Chinese pollination-variant astringent (PCA) genotypes.

GENE EXPRESSIONS INVOLVED IN FLAVONOID BIOSYNTHETIC PATHWAY IS ASSOCIATED WITH TANNIN ACCUMULATION IN JAPANESE PERSIMMON (DIOSPYROS KAKI THUNB.) FRUIT

Japanese persimmons (Diospyros kaki Thunb.) are classified into the following four types depending on the effect of pollination on flesh colour and whether the fruit lose astringency on the tree: 1) pollination-constant non-astringent (PCNA), 2) pollination-variant non-astringent (PVNA), 3) pollination-variant astringent (PVA), and 4) pollination-constant astringent (PCA). Among these four types, PCNA-type is the most desirable persimmon for fresh consumption, since the fruit can be eaten always while firm without any postharvest treatments. The PCNA-type appeared uniquely in Japan probably due to the loss of the ability of tannin accumulation. PCNA-type fruit stops accumulating tannins at an early stage of fruit development. However, the molecular mechanism controlling tannin accumulation in persimmon is not so clear. Persimmon tannins are categorized into condensed tannins consisted of polymeric proanthocyanidins, which are synthesized via flavonoid biosynthetic pathway. So, we investigated varietal and seasonal changes in expressions of five genes involved in flavonoid biosynthesis (PAL, CHS, CHI, F3H, and DFR). The expressions of these genes were high until late stages of fruit growth in astringent-type, whereas those disappeared at an early stage of fruit growth in PCNA-type fruit. The relationship between transcripts of these genes and tannin accumulation in the fruit is discussed.

초위성 마커를 이용한 감(Diospyros kaki Thunb.)의 유연관계 분석

총 20개의 감 SSR primer set을 사용하여 완전단감(PCNA) 12품종, 불완전단감(PVNA) 13품종, 불완전 떫은감(PVA) 15품종, 완전 떫은감(PCA) 8품종 등, 총 48개 유전자원의 유전적 연관성을 분석하였다. 획득된 114개의 다형성 밴드를 이용하여 UPGMA 방식으로 유사도 및 집괴분석을 수행한 결과 48개 품종들은 크게 2개의 그룹(cluster)으로 나뉘어졌으며, 제 1 cluster는 다시 4개의 subcluster를 형성하였다. 이는 탈삽의 특성을 기준으로 분류한 품종군과 대체로 일치 함을 알 수 있고, 품종군간의 유연관계에 있어서는 완전단감군은 불완전 단감군과, 그리고 완전 떫은감은 불완전 떫은감군과 유연관계가 더욱 높은 것으로 관찰되었다. 평균 유사도의 값은 0.499였고 품종간 가장 높은 유사도 값(0.954)를 나타낸 것은 '청도반시'와 '함안반시'였고, 가장 낮은 유사도 값(0.192)를 나타낸 것은 '대마반'과 '애탕'이었다. 본 연구에 사용된 2SSR primer 들은 유럽 감품종으로부터 개발되어 보고되었지만, 일본 및 국내 품종의 연구에서도 효과적으로 사용될 수 있었고, 이들 마커들을 통해, 48개 품종 중 청도반시(Cheongdo-Bansi)와 경산반시(Gyeongsan-Bansi)를 제외한 모든 품종간 구별이 가능하였다. 이는 향후 신품종 개발시 품종보호를 위한 품종 특이적 마커로 효율적으로 사용될 수 있음을 보여준다. The genetic diversity among 48 persimmon (Diospyros kaki Thunb.) accessions, indigenous in Korea and introduced from Japan and China, was evaluated by using simple sequence repeat (SSR) markers. From 20 SSR primer sets, a total of 114 polymorphic markers were detected among 12 pollination-constant non-astringent (PCNA), 13 pollination-variant non-astringent (PVNA), 15 pollination-variant astringent (PVA), and 8 pollination-constant astringent (PCA) cultivars. Analysis of pair-wise genetic similarity coefficient (Nei-Li) and unweighted pair-group method with arithmetic averaging (UPGMA) clustering revealed two main clusters and four subclusters for cluster I. The subclustering pattern was in accordance with the classification of persimmon cultivars based on the nature of astringency loss. Phenetic relationships among the subclusters showed a closer relatedness of the PCNA group with the PVNA group, and the PVA with the PCA group. Genetic similarity co-efficiency was 0.499 on average and the highest (0.954) similarity was observed between 'Cheongdo-Bansi' and 'Haman-Bansi'. The similarity was lowest (0.192) between 'Damopan'and 'Atago'. Identification of each cultivar with the execption of 'Cheongdo-Bansi' and 'Gyeongsan-Bansi' was possible based on the SSR fingerprints, suggesting that these SSR markers are a useful tool for protecting intellectual property on newly developed cultivars.

Segregations of Astringent Progenies in the F1 Populations Derived from Crosses between a Chinese Pollination-constant Nonastringent (PCNA) `Luo Tian Tian Shi', and Japanese PCNA and Pollination-constant Astringent (PCA) Cultivars of Japanese Origin

Pollination-constant and nonastringent (PCNA) is one of the most desirable traits in persimmons as this type of cultivar loses its astringency while still on the tree before harvest. Among Japanese PCNA cultivars, the trait is qualitatively inherited and recessive to pollination-constant, astringent (PCA), pollination-variant, nonastringent (PVNA), and pollination-variant, astringent (PVA) types. However, in a previous trial, both astringent and nonastringent types segregated in the F1 population that resulted from a cross between a Chinese PCNA `Luo Tian Tian Shi' and a Japanese PCNA cultivar. Because of the unusual segregation, in this study, we crossed another Japanese PCNA `Okugosho' with `Luo Tian Tian Shi' to confirm the segregation of astringent types by measuring the tannin cell size and tannin concentration at harvest. Previously, we found that astringent types have larger tannin cells than PCNA-type. The F1 hybrid progenies from the cross segregated into both PCNA and astringent-type individuals in approximately 1:1 ratio. Likewise, the F1 population from the astringent-type `Yotsumizo' and `Iwasedo' × `Luo Tian Tian Shi' were ascertained to contain both PCNA and astringent types, which indicates that the PCNA trait of `Luo Tian Tian Shi' was dominant. Thus, this Chinese cultivar has the potential to become an important parental material for future breeding of PCNA persimmons.

Segregation of Astringency in F1 Progenies Derived from Crosses between Pollination-constant, Nonastringent Persimmon Cultivars

Japanese persimmon (Diospyros kaki Thunb.) cultivars are classified into four types depending on the nature of astringency loss of the fruit. The pollination-constant, non-astringent (PCNA) persimmons lose their astringency on the tree as the fruits develop. This PCNA trait is qualitatively inherited and recessive to the other three types, pollination-constant, astringent (PCA), pollination-variant, nonastringent (PVNA), and pollination-variant, astringent (PVA). In fact, crosses among Japanese PCNA cultivars yield only PCNA type in F1 generation as shown in recent breeding programs at the National Institute of Fruit Tree Science. Despite these previous results, we demonstrated here that non-PCNA (PVNA, PVA, and PCA) type offspring were derived at relatively high rates in the F1 generation from a cross between `Luo Tian Tian Shi', a PCNA accession from China, and the Japanese PCNA cultivar, `Taishu', despite the fact that `Luo Tian Tian Shi' was confirmed to be a true PCNA type by measuring tannin cell size, a principal morphological characteristic to distinguish PCNA cultivars from non-PCNA ones. When segregations of tannin cell size and tannin content in three progenies of the breeding populations derived from Chinese PCNA `Luo Tian Tian Shi' × Japanese PCNA `Taishu', Japanese PCNA `Shinshu' × Japanese PCNA `Taishu', and Japanese PVNA (non-PCNA) `Kurokuma' × Japanese PCNA `Taishu' were investigated, all offspring between Japanese PCNA cultivars contained only small tannin cells and were PCNA types, and those between Japanese PVNA × PCNA cultivars contained only large tannin cells and were non-PCNA types. However, hybrids between `Luo Tian Tian Shi' and `Taishu' segregated into populations of small and large tannin cells, indicating that `Luo Tian Tian Shi' is likely heterozygous for astringency. Therefore, Chinese PCNA `Luo Tian Tian Shi' should be different from Japanese PCNA cultivars in genetic makeup.

日本原産のカキ品種における果実成熟期, 果実重及び可溶性固形物含量の変異

One hundred and eighty-eight cultivars of oriental persimmon (Diospyros kaki Thunb.) native to Japan were evaluated for fruit ripening time (FRT), fruit weight (FW), and soluble solids content (SSC). A high heritability for each of these traits was conserved in this population; the overall mean and SD of FRT, FW and SSC were early to mid-November and 15 days, 200 g and 72 g, and 17.0% and 1.7%, respectively. Subgroups of PCA (pollination constant-astringent) and PVNA (pollination variant-nonastringent) showed wide variations for each trait. As to mean values, the PVNA group had slightly earlier FRT and higher SSC than the PCA group but their FW were similar. PCNA (pollination constant-nonastringent) group showed the latest FRT and the SSC was intermediate between those of PCA and PVNA groups; whereas, PVA (pollination variant-astringent) had the earliest FRT with the lowest SSC. The PCNA and PVA groups had larger fruits than the PCA and PVNA groups. Variations in FRT and SSC of PCNA were characteristically small, which suggest that these cultivars evolved later than the others.There is a weak, negative correlation between FW and SSC and a weak, positive one between FRT and FW. The percentage of early ripening cultivars was higher in cultivars which originated in the northern areas of Japan in contrast to those developed in southern regions.

カキの甘渋の遺伝

Inheritance of astringency in Japanese persimmon (Dyospiros kaki Thunb.) was investigated using data collected over 30 years in Okitsu Horticultural Research Station.PCNA (pollination constant non-astringent) and non-PCNA were qualitatively inherited. The former was recessive to the latter. Backcrosses between PCNA and the progeny (PCA) derived from the cross of PCNA×non-PCNA yielded PCNA of approximately 15 percent.Inheritance of astringency in non-PCNA seemed to be quantitative. Few PVNA (pollination variant non-astringent) progenies occured from crosses among PCA (pollination constant astringent) cultivars. Many PCA progenies occured from crosses among PVNA cultivars.In crosses between PCNA and PCA, more PVNA or PVA (pollination variant astringent) progenies were obtained between ‘Fuyu(PCNA)’ and PCA cultivars, compared to crosses between other PCNA cultivars and PCA cultivars.

甘ガキと渋ガキのタンニン物質の化学的特性, 特に超遠心分離における挙動の差異について

Schlieren pattern in analytical ultracentrifugation and reactivity to acetaldehyde of tannins of Japanese persimmon fruit (Diospros kaki) were investigated using cvs. ‘Fuyu’, pollination constant non-astringent (PCNA) type, and‘Hiratanenashi’, pollination variant astringent (PVA) type.1) To study the schlieren pattern, tannins extracted from both cultivars with aqueous acetone were separated into two fractions (F-I and F-II) by size exclusion chromatography on CPG-10 2000A. After the tannin concentrations were equalised, these fractions were incubated at 40°C and subjected to ultracentrifugation at pre-incubation (0 day), 1 and 3 days of incubation. The schlieren patterns revealed that F-I and F-II fractions from both cultivars contained three or four tannin components, and that the sedimentation coefficient of each component from‘Hiratanenashi’ was larger than the corresponding component from‘Fuyu’. Moreover, the components of the F-I fraction from‘Hiratanenashi’changed or shifted remarkably during incubation; two faster components (26S and 23S) disappeared and one slower component (6S) appeared. Conversely, the components of both fractions (F-I and F-II) from‘Fuyu’and F-II fraction from‘Hiratanenashi’were stable.2) To characterize the reactivity of tannins to acetaldehyde, coagulation times of the fruit juice bathed in acetaldehyde vapor were compared between‘Fuyu’and ‘Hiratanenashi’at different tannin concentrations and pHs. A longer time was needed for coagulation as the tannin concentration became lower and when the pH value was between 3.0 and 5.0. The fruit juice from‘Fuyu’coagulated more slowly than that from‘Hiratanenashi’.The present results suggest that tannin substances from‘Fuyu’distribute mainly in a lower molecular weight range and have a milder chemical property compared with those from‘Hiratanenashi’.

Relationships of Ethanol Production by Seeds of Different Types of Japanese Persimmons and Their Tannin Content

Abstract Ethanol production in the seeds and its accumulation in the flesh were compared among 47 Japanese persimmon cultivars (Diospyros kaki L.) in relation to their degree of astringency. Those which produce relatively high amounts of ethanol and accumulate it in the flesh, i.e. pollination-variant/nonastringent (PVNA) cultivars, lose astringency on the tree, while those producing less ethanol, i.e. pollination-variant/astringent (PVA) ones, remain astringent. Pollination-constant/nonastringent (PCNA) and pollination-constant/astringent (PCA) cultivars generally produced little ethanol in the seeds and accumulated small amounts or none in the flesh. Thus, 2 different mechanisms exist that are involved in the loss of astringency. One is associated with PVNA, PVA, and PCA types and is dependent upon the production and accumulation of ethanol and presumably acetaldehyde. The second is associated with PCNA types which apparently do not produce these volatile substances.