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The development of efficient, robust, and high-throughput SNP genotyping platforms is pivotal for crop genetics and breeding. Recently, SNP genotyping platforms based on target capture sequencing, which is very flexible in terms of the number of SNP markers, have been developed for maize, cassava, and fava bean. We aimed to develop a target capture sequencing SNP genotyping platform for rice. A target capture sequencing panel containing 2565 SNPs, including 1225 SNPs informative for japonica and 1339 SNPs informative for indica, was developed. This platform was used in diversity analysis of 50 rice varieties. Of the 2565 SNP markers, 2341 (91.3%) produced useful polymorphic genotype data, enabling the production of a phylogenetic tree of the 50 varieties. The mean number of markers polymorphic between any two varieties was 854. The platform was used for QTL mapping of preharvest sprouting (PHS) resistance in an F8 recombinant inbred line population derived from the cross Odae × Joun. A genetic map comprising 475 markers was constructed, and two QTLs for PHS resistance were identified on chromosomes 4 and 11. This system is a powerful tool for rice genetics and breeding and will facilitate QTL studies and gene mapping, germplasm diversity analysis, and marker-assisted selection.

Pre-harvest sprouting (PHS) leads to serious economic losses because of reductions in yield and quality. To analyze the quantitative trait loci (QTLs) for PHS resistance in japonica rice, PHS rates on panicles were measured in 160 recombinant inbred lines (RILs) derived from a cross between the temperate japonica varieties Odae (PHS resistant) and Unbong40 (PHS susceptible) under two different environmental conditions—field (summer) and greenhouse (winter) environments. Genome re-sequencing of the parental varieties detected 266,773 DNA polymorphisms including 248,255 single nucleotide polymorphisms and 18,518 insertions/deletions. We constructed a genetic map comprising 239 kompetitive allele-specific PCR and 49 cleaved amplified polymorphic sequence markers. In the field environment, two major QTLs, qPHS-3FD and qPHS-11FD, were identified on chromosomes 3 and 11, respectively, whereas three major QTLs, qPHS-3GH, qPHS-4GH, and qPHS-11GH, were identified on chromosomes 3, 4, and 11, respectively, in the greenhouse environment. qPHS-11GH and qPHS-11FD had similar locations on chromosome 11, suggesting the existence of a gene conferring stable PHS resistance effects under different environmental conditions. The QTLs identified in this study can be used to improve the PHS resistance of japonica varieties, and they may improve our understanding of the genetic basis of PHS resistance.

To obtain transgenic rose (Rosa hybrida) plants resistant to drought stress, we transferred the superoxide dismutase 2 (SOD2) (from Escherichia coli) gene, which was harbored by the pPZP200 vector, into embryos and embryogenic calluses derived from a rose breeding line, KR056002, using an Agrobacterium tumefaciens-mediated transformation technique. We obtained seven regenerated plants. The presence of the transgene in the seven lines was validated by PCR analysis and it was determined by Southern blot analysis that two to five copies of the transgene were transferred to seven SOD2-transgenic plants. When the SOD2-transgenic lines were rooted, acclimatized, and placed in a chamber at 25 °C, without water for 7 days, the relative ion leakage of SOD2-transgenic plants was lowered by 5–74% than that of non-transgenic (NT) plants, and the relative water content of the SOD2-transgenic plant leaves was higher (0.1–11%) than that of NT plants. In addition, real-time quantitative PCR analysis confirmed that the transgene expression in SOD2-transgenic lines (five of seven lines) after drought treatment was significantly higher than that before drought treatment. Moreover, when the plants were re-watered after drought treatment, all NT plants died, whereas all SOD2-transgenic plants recovered. Collectively, these results suggest that the over-expression of SOD2 enhances drought tolerance in rose plants.

High-throughput molecular markers with high genotyping accuracy will be helpful for genetic analysis, mapping of interesting genes, and rice breeding program. To develop high-throughput and cost-effective molecular markers for Korean japonica rice varieties, which are closely-related genetically, we designed kompetitive allele-specific polymerase chain reaction (KASP) assays from the sequence data of 13 Korean japonica rice varieties. Of the 504 new KASP assays, 371 (73.6%) showed polymorphisms among the tested varieties. In addition to the 400 previously developed KASP markers, this resulted in 771 KASP markers being applicable for Korean japonica rice varieties. These KASP markers were used to map the quantitative trait loci (QTLs) for rice bakanae disease (BD) resistance. From the results of QTL mapping and determination of the mortality rate of BD in two F2:F3 populations, a major QTL, qFfR1-1, and a novel QTL, qFfR6, were revealed on chromosome 1 in the Junam/Nampyeong F2:F3 population and on chromosome 6 in the Saenuri/Nampyeong F2:F3 population, respectively. Further, the insertion/deletion markers in the qFfR1-1 region were developed to select BD-resistant japonica rice varieties. The 771 developed KASP markers will accelerate the molecular breeding in Korean japonica rice varieties, and the detected QTLs will be helpful in identifying candidate genes for BD resistance.

Background Internode elongation is an important agronomic trait in rice that determines culm length, which is related to lodging, panicle exsertion, and biomass. sui4 (shortened uppermost internode 4) mutants show reduced internode length and a dwarf phenotype due to shortened internodes; the uppermost internode is particularly severely affected. The present study was performed to identify the molecular nature and function of the SUI4 gene during internode elongation. Results Our previous study showed that the SUI4 gene was mapped to a 1.1-Mb interval on chromosome 7 (Ji et al. 2014). In order to isolate the gene responsible for the sui4 phenotype, genomic DNA resequencing of sui4 mutants and wild-type plants and reciprocal transformation of wild-type and mutant alleles of the putative SUI4 gene was performed. The data revealed that the causative mutation of sui4 was a T to A nucleotide substitution at the microRNA172 binding site of Os07g0235800, and that SUI4 is a new allele of the previously reported gene SUPERNUMERARY BRACT (SNB), which affects flower structure. In order to understand the effect of this mutation on expression of the SUI4/SNB gene, SUI4/SNB native promoter-fuzed GUS transgenics were examined, along with qRT-PCR analysis at various developmental stages. In sui4 mutants, the SUI4/SNB gene was upregulated in the leaves, culms, and panicles, especially when internodes were elongated. In culms, SUI4/SNB was expressed in the nodes and the lower parts of elongating internodes. In order to further explore the molecular nature of SUI4/SNB during internode elongation, RNA-seq and qRT-PCR analysis were performed with RNAs from the culms of sui4 mutants and wild-type plants in the booting stage. The data showed that in sui4 mutants, genes deactivating bioactive gibberellins and cytokinin were upregulated while genes related to cell expansion and cell wall synthesis were downregulated. Conclusion In summary, this paper shows that interaction between SUI4/SNB and microRNA172 could determine internode elongation during the reproductive stage in rice plants. Due to a mutation at the microRNA172 binding site in sui4 mutants, the expression of SUI4/SNB was enhanced, which lowered the activities of cell expansion and cell wall synthesis and consequently resulted in shortened internodes. Electronic supplementary material The online version of this article (10.1186/s12284-019-0324-8) contains supplementary material, which is available to authorized users.

Main conclusion A new imaging platform was constructed to analyze drought-tolerant traits of rice. Rice was used to quantify drought phenotypes through image-based parameters and analyzing tools. Abstract Climate change has increased the frequency and severity of drought, which limits crop production worldwide. Developing new cultivars with increased drought tolerance and short breeding cycles is critical. However, achieving this goal requires phenotyping a large number of breeding populations in a short time and in an accurate manner. Novel cutting-edge technologies such as those based on remote sensors are being applied to solve this problem. In this study, new technologies were applied to obtain and analyze imaging data and establish efficient screening platforms for drought tolerance in rice using the drought-tolerant mutant osphyb. Red–Green–Blue images were used to predict plant area, color, and compactness. Near-infrared imaging was used to determine the water content of rice, infrared was used to assess plant temperature, and fluorescence was used to examine photosynthesis efficiency. DroughtSpotter technology was used to determine water use efficiency, plant water loss rate, and transpiration rate. The results indicate that these methods can detect the difference between tolerant and susceptible plants, suggesting their value as high-throughput phenotyping methods for short breeding cycles as well as for functional genetic studies of tolerance to drought stress.

To develop a gene-based DNA selection marker for the purple and red colored root characteristics, multiplex-PCR was performed for genotyping of Raphanus sativus flavonoid 3′ hydroxylase (RsF3′H) in several cultivars and progenies. In cultivars, DNA with an approximately 450-bp in size was amplified from several radishes, such as purple-, white-, green-, and black-root radishes, whereas approximately 750-bp in size was amplified from red-root radishes. In progenies from red- and white-roots, almost F1 progenies had purple-root with DNA fragments of approximately 450- and 750-bp. In F2 progenies, two band patterns which are 450-bp, and both 450- and 750-bp fragments were amplified from purple-root individuals, whereas only 750-bp fragment were amplified from red-root individuals. In contrast, three band patterns were amplified from white-root individuals. Therefore, our data indicated that mutant RsF3′H allele-based marker could select the potential red root genotype effectively in breeding program of purple and red root radishes.

Table S1. List of SNPs in the SUI4 mapped region of Dongjin plants and sui4 mutants. (DOCX 16 kb)

Table S3. qRT-PCR primer sequences (DOCX 14 kb)

The spider-type azalea cultivars, Rhododendron kaempferi ‘Kin-kujyaku’ and Rhododendron macrosepalum ‘Seigaiha’, are characterized by extremely narrow leaves and choripetalous flowers with narrow petals. Previous morphological analysis of these cultivars revealed that narrowed organs would be a common mutation in the growth of lateral organs in the transverse plane. In the present study, we focused on the analysis of WUSCHEL-related homeobox (WOX) genes, WOX1 and WOX3, which regulate the laminar width and development of lateral organs. Sequence analysis of the two genes confirmed a fatal mutation in Rk/RmWOX3/SPIDER of ‘Kin-kujyaku’ and ‘Seigaiha’. To demonstrate the role of SPIDER in the spider-type phenotype in azalea, we performed genotyping using DNA markers developed for multiplex PCR that can distinguish between the wild-type and the spider-type allele based on the partial mutated region of RkWOX3/SPIDER in ‘Kin-kujyaku’. The investigation of BC1 population derived from ‘Kin-kujyaku’ confirmed complete co-segregation between spider-type mutation and Rkwox3/spider band pattern of DNA markers. Therefore, we concluded that SPIDER is responsible for the spider-type mutation in azalea.

Temperate japonica rice varieties exhibit wide variation in the phenotypes of several important agronomic traits, including disease resistance, pre-harvest sprouting resistance, plant architecture, and grain quality, indicating the presence of genes contributing to favorable agronomic traits. However, gene mapping and molecular breeding has been hampered as a result of the low genetic diversity among cultivars and scarcity of polymorphic DNA markers. Single nucleotide polymorphism (SNP)-based kompetitive allele-specific PCR (KASP) markers allow high-throughput genotyping for marker-assisted selection and quantitative trait loci (QTL) mapping within closely related populations. Previously, we identified 740,566 SNPs and developed 771 KASP markers for Korean temperate japonica rice varieties. However, additional markers were needed to provide sufficient genome coverage to support breeding programs. In this study, the 740,566 SNPs were categorized according to their predicted impacts on gene function. The high-impact, moderate-impact, modifier, and low-impact groups contained 703 (0.1%), 20,179 (2.7%), 699,866 (94.5%), and 19,818 (2.7%) SNPs, respectively. A subset of 357 SNPs from the high-impact group was selected for initial KASP marker development, resulting in 283 polymorphic KASP markers. After incorporation of the 283 markers with the 771 existing markers in a physical map, additional markers were developed to fill genomic regions with large gaps between markers, and 171 polymorphic KASP markers were successfully developed from 284 SNPs. Overall, a set of 1225 KASP markers was produced. The markers were evenly distributed across the rice genome, with average marker density of 3.3 KASP markers per Mbp. The 1225 KASP markers will facilitate QTL/gene mapping and marker-assisted selection in temperate japonica rice breeding programs.

This article has been published with an erroneous version of Table 2. Please find the correct Table 2 in this document.

Floral shape in higher plants typically requires genetic regulation through MADS transcription factors. In Japan, hundreds of azalea cultivars including flower shape mutations have been selected from the diversity of endogenous species and natural hybrids since the early 17th century, the Edo era (1603–1867). The long-lasting trait, known as “Misome-shō” in Japanese, has been identified in several species and cultivar groups of evergreen azaleas (Rhododendron L.) from three hundred years ago in Japan. However, the natural mutation conferring the long-lasting trait in azalea remains unknown. Here, we showed MADS-box gene mutations in long-lasting flowers, R. kaempferi ‘Nikkō-misome,’ R. macrosepalum ‘Kochō-zoroi,’ R. indicum ‘Chōjyu-hō,’ and R. × hannoense ‘Amagi-beni-chōjyu.’ All of the long-lasting flowers exhibited small-sized corollas with stomata during long blooming. In the long-lasting flowers, transcript of the APETALA3 (AP3)/DEFICIENS (DEF) homolog was reduced, and an LTR-retrotransposon was independently inserted into exons 1, 2, and 7 or an unknown sequence in exon 1 in gDNA of each cultivar. This insertion apparently abolished the normal mRNA sequence of the AP3/DEF homolog in long-lasting flowers. Also, long-lasting flowers were shown from F2 hybrids that had homozygous ap3/def alleles. Therefore, we concluded that the loss of function of the AP3/DEF homolog through a transposable element insertion may confer a stable long-lasting mutation in evergreen azaleas.

Morphological mutations have been admired and preserved in the classical cultivars of the Japanese evergreen azalea since the Edo era (1603–1867). One such mutation is the presence of narrow leaves and petals. In this study, we investigated the characteristics and inheritance patterns of the narrow leaf-type mutational form of Rhododendron macrosepalum ‘Seigaiha’, R. kaempferi ‘Kin-kujyaku’, and R. kiusianum Yanagi-ba mutant. The leaves of all cultivars showed weak development in the transverse plane and thickened margins. Subsequently, based on this qualitative character, the inheritance of the narrow leaf mutation was investigated. F1 seedlings of cross combinations between normal and narrow leaf-type plants had normal leaf-type. All F1 progenies of cross combinations between narrow leaf-type plants had narrow leaves like their parents. In addition, seedlings obtained from backcross and sib-cross tests using narrow leaf mutants segregated into normal and narrow leaf-types at a 1:1 and 3:1 ratio, respectively. These results indicate that the narrow leaf trait of three different azalea cultivars, ‘Seigaiha’, ‘Kin-kujyaku’, and R. kiusianum Yanagi-ba mutant, is probably a recessive mutation caused by a single, common gene.

To develop a gene-based DNA selection marker for the hose-in-hose flower phenotype, we used a simple multiplex-PCR approach to detect the RoPI-1 mutant allele in several azalea cultivars and their progenies. Amplified fragments approximately 470 and 730 bp in size were obtained from hose-in-hose phenotypes, whereas single flower phenotypes only presented the approximately 730-bp product; this was amplified from six Edo-kirishima cultivars, 46 Kurume azalea cultivars, and several progenies. In contrast, the hose-in-hose cultivars of Rhododendron indicum and Rhododendron transiens only presented the approximately 730-bp product. Therefore, our data indicated that multiplex-PCR might be used to select the hose-in-hose flower phenotype at the seedling stage, contributing to reduce breeding cycles, as Rhododendron obtusum cultivars takes 3–4 years to flower.

Bakanae disease (BD), caused by the fungal pathogen Fusarium fujikuroi, has become a serious threat in rice-cultivating regions worldwide. In the present study, quantitative trait locus (QTL) mapping was performed using F2 and F3 plants derived after crossing a BD-resistant and a BD-susceptible Korean japonica rice variety, &lsquo, Samgwang&rsquo, and &lsquo, Junam&rsquo, respectively. Resequencing of &lsquo, genomes revealed 151,916 DNA polymorphisms between the two varieties. After genotyping 188 F2 plants, we constructed a genetic map comprising 184 markers, including 175 kompetitive allele-specific PCR markers, eight cleaved amplified polymorphic sequence (CAPS) markers, and a derived CAPS (dCAPS) marker. The degree of BD susceptibility of each F2 plant was evaluated on the basis of the mortality rate measured with corresponding F3 progeny seedlings by in vitro screening. Consequently, qFfR9, a major QTL, was discovered at 30.1 centimorgan (cM) on chromosome 9 with a logarithm of the odds score of 60.3. For the QTL interval, 95% probability lay within a 7.24&ndash, 7.56 Mbp interval. In this interval, we found that eight genes exhibited non-synonymous single nucleotide polymorphisms (SNPs) by comparing the &lsquo, genome sequence data, and are possibly candidate genes for qFfR9, therefore, qFfR9 could be utilized as a valuable resource for breeding BD-resistant rice varieties.

환경위해성평가 연구 대상인 형질전환 이벤트로서의 자격을 확인하고자 형질전환세대( $T_0V_0$ )에서와 같이 영양번식 제1세대( $T_0V_1$ )에서도 도입유전자 LeLs-antisense의 발현 특성인 무측지성을 유지한 국화 무측지성 형질전환계통 LeLs80의 영양번식 제2세대( $T_0V_2$ )의 형태적 및 분자 생물학적 특성을 조사하였다. LeLs80 계통의 $T_0V_2$ 에서도 LeLs-antisense 유전자의 발현 특성인 무측지성이 안정적으로 유지되는 것을 확인하였다. 또한, Southern 및 Northern 분석에 의해 LeLs-antisense 유전자가 3 copy 도입되었으며, LeLs-antisense 유전자의 전사체가 정상적으로 발현되는 것도 확인할 수 있었다. 또한 flanking T-DNA sequencing method를 이용하여 LeLs-antisense 유전자의 주변 염기서열 분석 통해 LeLs80 계통의 genome내 LeLs-antisense 유전자 주변에 186 ~ 464 bp의 pCAMBIA2300 T-DNA right border 부근으로 추정되는 염기서열이 확인되었고, pCAMBIA2300 전 염기서열과의 비교 분석한 결과, pCAMBIA2300 T-DNA left border와 right border내 선발마커 유전자 NPT II의 발현 promoter 부분과 LeLs-antisense 유전자 발현 terminator 일부 염기서열과 일치하였다. 【This study examined the phenotypic and molecular characteristics of the $2^{nd}$ clone ( $T_0V_2$ ) plants of LeLs-antisense gene-transgenic chrysanthemum line (LeLs80) that exhibited non-branching, proving the relevance of these characteristics as a factor for use in environmental risk assessment. Results of the Southern blot analysis showed that three copies of the LeLs-antisense gene were introduced into the transgenic line, and northern analysis showed that the transcripted gene was normally expressed in the transgenic line. A flanking T-DNA sequencing method was used to determine that sequences of 184 and 464 bps flanked the LeLs-antisense gene in the transgenic line. These sequences, respectively, matched the 35S promoter for expression of the npt II gene and the NOS terminator for expression of the LeLs-antisense gene within the pCAMBIA 2300 vector.】

The tree peony (Paeonia suffruticosa Andr.) is a valuable ornamental plant. American and French cultivars have desirable flower colors, while, Japanese cultivars have larger flowers with better presentation. We hybridized an American tree peony cultivar ‘High Noon (HN)’ (the seed parent) with 57 different Japanese cultivars (pollen parents) to investigate cross compatibility, with the ultimate goal of obtaining improved hybrids. Of the 1,927 crosses performed, 135 (38 cross combinations) yielded a total of 181 seeds (86 mature) and 22 seedlings. Five of the hybrids have already flowered and exhibited their parent character with large yellow flowers. To investigate the causes of cross incompatibility, we examined pollen tube growth in a cross between ‘HN’ and a Japanese cultivar. The result indicated that there are three most important causes of incompatibility, namely, abnormal pollen tube growth, the failure of fertilized ovules, and poor seed germination. Although cross compatibility in each combination was low, crosses between ‘HN’ and Japanese cultivars might be successful with the right paternal plants. In this study, 13 Japanese cultivars had higher cross compatibility with ‘HN’ than the others. Our results will enhance tree peony breeding and guide the selection of parents for hybridization.

The morphological traits of the floral mutation cultivars ‘Kagaribi’, ‘Kinshibe’ and ‘Kin-kujyaku’ of Rhododendron kaempferi that characteristically exhibit extremely narrow and/or staminoid petals were investigated. In addition, to confirm the causes of the mutations in these cultivars, the MADS-box C class AG gene homologues in R. kaempferi were isolated, and the MADS-box gene expression patterns in the floral organs of the wild-type plants and cultivars were analyzed. A morphological observation of the epidermis showed that the ‘Kagaribi’ and ‘Kinshibe’ cultivars formed staminoid flag petals and staminoid organs in whorl 2, respectively. The epidermal cells of the staminoid organs of whorl 2 in ‘Kagaribi’ and ‘Kinshibe’ resembled those of the stamens in whorl 3. In ‘Kin-kujyaku,’ the petals in whorl 2 and leaves were extremely narrow. The sepals in whorl 1 were absent, and the style in whorl 4 was split into 5 parts. The epidermal cells of the petals in whorl 2 in ‘Kin-kujyaku’ were dissimilar to the epidermal cells of the stamens in whorl 3. The deduced amino acid sequence of the isolated AG homologue from R. kaempferi was well-conserved among the AG orthologues. The expression levels of RkAG in whorl 2 to whorl 3 of ‘Kagaribi’ and ‘Kinshibe’ was approximately 27% and the same level, respectively. In ‘Kin-kujyaku,’ the expression pattern was similar to that of the wild type. These results suggest that the ‘Kagaribi’ and ‘Kinshibe’ floral mutations might be caused by the expression of RkAG in whorl 2.

To investigate seasonal changes in transcript levels of flowering-related genes corresponding to shoot condition, the endogenous expression patterns of FLOWERING LOCUS T ( FT ), SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 ( SOC 1), LEAFY ( LFY ), TERMINAL FLOWER 1 ( TFL 1), and CENTRORADIALIS ( CEN ) homologs were investigated in evergreen azalea ‘Oomurasaki’. In this plant, in which the floral transition is triggered by the about 25 °C and shortening days of summer under natural conditions, the mRNA levels of the FT , SOC 1, and LFY homologs ( RpFT , RpSOC 1, and RpLFY ) increased in August corresponding to the period of flower bud formation, and the mRNA levels of TFL 1 and CEN homologs ( RpTFL 1 and RpCEN ) increased during July before flower bud formation. RpTFL 1 showed low transcript levels during the period of flower bud formation and development, but RpCEN showed a different expression pattern from RpTFL 1. The expression of RpCEN , RpSOC 1, and RpLFY peaked again during January corresponding to the period of flower bud dormancy. During blooming in May, the expression levels of all the investigated genes were low. In the period of flower bud formation, RpFT expression started to increase, and the expression of RpSOC 1 peaked in mid-July. These results suggest that the shoot apical meristem (SAM) starts to transition from vegetative to reproductive growth in mid-July. Thus, changes in the transcription of RpFT , RpSOC 1, and RpLFY were found to correlate positively with seasonal flowering in the shoot apex of ‘Oomurasaki’, whereas changes in RpTFL 1 and RpCEN transcription correlated negatively with seasonal flowering.

The flowering of the evergreen azalea, ‘Oomurasaki’ ( Rhododendron × pulchrum ), extended over two seasons was studied. During the first season, most of the shoot apical meristems transformed into floral meristems and formed flower buds in August. After the dormancy of the flower buds from November to February, flower bud development continued during the second season and flowering occurred in May. To ascertain the approximate period of flower initiation, we monitored the spring shoot and apical bud growth. The putative period for flower initiation was indicated to occur between late June and August. To identify the genes involved in flower initiation, we isolated homologs of the putative flowering-related genes, LEAFY ( LFY ), TERMINAL FLOWER 1 ( TFL1 ), and APETALA 3 ( AP3 ), and investigated their expression patterns in the shoot apex and apical buds during the first season using Reverse Transcription-quantitative PCR (RT-qPCR). We founding that RpLFY expression increased continually from 14 July to 4 August but that RpTFL1 expression showed trends toward a decrease during the increasing RpLFY expression in apical parts. Subsequently, RpAP3 expression began to increase on 4 August. Collectively, the results estimated that RpLFY and RpTFL1 are involved in flower initiation in ‘Oomurasaki’. We propose that the increased expression of RpLFY and the decreased expression of RpTFL1 at late July mark the beginning of flower initiation.

The trait of long-lasting flower corolla with temporal change of colour exists in Japanese evergreen azalea. This trait called "misome-sho" has been found in several species and cultivar groups from Edo era. For the purpose of application of this trait for breeding, we investigated several characteristics of these cultivars. Wild species of Rhododendron kaempferi, R. indicum and R. macrosepalum and long-lasting flower cultivars were used in this study. All long-lasting flower cultivars have smaller corolla compared to wild types and have stomata in the corolla surface, while wild types do not have stomata in their surface. Pot planted long-lasting flower cultivars kept their corolla more than 100 days and corolla colour was changed from red or purple-red in anthesis to green later. In contrast, wild type plants in pot finished flowering in about 20 days. Microscopic observation of the longitudinal section of flowers revealed that the abscission layer in the basal portion from wild type corollas is not observed in long-lasting flower cultivars. These cultivars have high pollen fertility and stabilized seed set ability. Inheritance of this trait is investigated using cross progenies. The long-lasting trait of corolla would be derived from the sepaloid nature of petals caused by homeotic gene mutation.