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Summary High humidity during harvest season often causes pre‐harvest sprouting in barley (Hordeum vulgare). Prolonged grain dormancy prevents pre‐harvest sprouting; however, extended dormancy can interfere with malt production and uniform germination upon sowing. In this study, we used Cas9‐induced targeted mutagenesis to create single and double mutants in QTL FOR SEED DORMANCY 1 (Qsd1) and Qsd2 in the same genetic background. We performed germination assays in independent qsd1 and qsd2 single mutants, as well as in two double mutants, which revealed a strong repression of germination in the mutants. These results demonstrated that normal early grain germination requires both Qsd1 and Qsd2 function. However, germination of qsd1 was promoted by treatment with 3% hydrogen peroxide, supporting the notion that the mutants exhibit delayed germination. Likewise, exposure to cold temperatures largely alleviated the block of germination in the single and double mutants. Notably, qsd1 mutants partially suppress the long dormancy phenotype of qsd2, while qsd2 mutant grains failed to germinate in the light, but not in the dark. Consistent with the delay in germination, abscisic acid accumulated in all mutants relative to the wild type, but abscisic acid levels cannot maintain long‐term dormancy and only delay germination. Elucidation of mutant allele interactions, such as those shown in this study, are important for fine‐tuning traits that will lead to the design of grain dormancy through combinations of mutant alleles. Thus, these mutants will provide the necessary germplasm to study grain dormancy and germination in barley.

Pre-harvest sprouting (PHS) is a common threat to cereal crops in which the grain maturation phase takes place under rainy, moist conditions. Susceptibility to PHS is higher in sorghum genotypes displaying low levels of seed dormancy before harvest maturity. Other attributes such as glume or panicle morphology may also affect susceptibility to PHS. Breeding for resistance to PHS in grain sorghum requires the identification of grain physiological and morphological attributes affecting this trait, and a protocol for phenotyping and rating genotypes according to their susceptibility to PHS. In this work, we tested germination under laboratory conditions using detached grains and intact panicles for a panel of 20 sorghum genotypes including 11 parental lines, 6 hybrids and 3 reference inbred lines with contrasting PHS response. Records for natural sprouting in the field for these genotypes were also included in the analysis. Multivariate analyses of germination data allowed separation of genotypes into two major categories (resistant and susceptible to PHS). Laboratory germination data correlated significantly with PHS in the field. In most genotypes, the glumes had a significant, inhibitory effect on germination. The low levels of grain dormancy were observed among high tannin backgrounds, and vice versa, indicating that a pigmented testa alone does not provide resistance to PHS. Altogether, the phenotyping protocol allowed the classification of sorghum genotypes according to their susceptibility to PHS and the identification of different attributes useful for breeding for PHS resistance in this crop.

Evaluation of a set of 65 diverse genotypes of soybean was carried out for their pre-harvest sprouting (PHS) tolerance in a field study during kharif 2019. Percentage of pods ruptured by sprouting seed (PPR) was used as a measure of pre-harvest sprouting tolerance. It ranged from 0-5.8% among the genotypes. High estimates of genotypic (GCV) and phenotypic coefficients of variation (PCV) were recorded for the percentage of pods ruptured by sprouting seed (PPR) indicating the presence of wider variability over which selection can be effective. High heritability coupled with high genetic advance as percent mean was recorded for number of pods ruptured by sprouting seed per plant and PPR. The phenotypic character association revealed a significant negative correlation of PPR with pod wall thickness, number of pods per plant, and number of clusters per plant. Path coefficient analysis revealed number of pods per plant, plant height, and pod wall thickness have a negative influence on pre-harvest sprouting.

Summary Pre‐harvest sprouting (PHS), the germination of grain before harvest, is a serious problem resulting in wheat yield and quality losses.Here, we mapped the PHS resistance gene PHS‐3D from synthetic hexaploid wheat to a 2.4 Mb presence–absence variation (PAV) region and found that its resistance effect was attributed to the pleiotropic Myb10‐D by integrated omics and functional analyses.Three haplotypes were detected in this PAV region among 262 worldwide wheat lines and 16 Aegilops tauschii, and the germination percentages of wheat lines containing Myb10‐D was approximately 40% lower than that of the other lines. Transcriptome and metabolome profiling indicated that Myb10‐D affected the transcription of genes in both the flavonoid and abscisic acid (ABA) biosynthesis pathways, which resulted in increases in flavonoids and ABA in transgenic wheat lines. Myb10‐D activates 9‐cis‐epoxycarotenoid dioxygenase (NCED) by biding the secondary wall MYB‐responsive element (SMRE) to promote ABA biosynthesis in early wheat seed development stages.We revealed that the newly discovered function of Myb10‐D confers PHS resistance by enhancing ABA biosynthesis to delay germination in wheat. The PAV harboring Myb10‐D associated with grain color and PHS will be useful for understanding and selecting white grained PHS resistant wheat cultivars.

Pre-harvest sprouting (PHS) influences yield and end-use quality of bread wheat. Developing varieties with PHS resistance is the most effective way to reduce this problem. In this study, a panel of 725 Chinese wheat accessions were evaluated for PHS resistance in three environments. There was abundant variation in PHS resistance and 63 accessions showing high resistance had germination rates of less than 10% across three experiments. The distribution of three causal single nucleotide polymorphisms in TaPHS1 at bases −222, +646, and +666 were assessed and frequencies were determined. Favorable alleles conferring PHS resistance were identified for each locus. Haplotype analysis showed that bases C, G, and A at each of the three loci comprised the best haplotype for PHS resistance, whereas TAT showed the highest sprouting rate. Accessions with the superior TaPHS1 haplotypes proved to be resistant to PHS providing a basis to develop varieties with PHS resistance through marker assisted breeding.

Background: pre-harvest sprouting (PHS) is a significant cause of yield loss in cereal crops, and is an important topic of study for the improvement of wheat quality. Many studies have focused on PHS in wheat during the last 10 years, especially on the involvement of abscisic acid (ABA) in PHS, however, a lot remained unknown about this topic.Results: In this study, a PHS resistant line was isolated from an ethylmethane sulfonate (EMS) mutant population derived from the wheat cultivar ‘Long 13-3778’, namely ‘LQ18’. The mutant line LQ18 showed highly significant resistance to PHS compared with the wild-type. Transcriptome sequencing was conducted to determine the differences between the LQ18 mutant and the wild-type at the level of gene expression. The results showed no conclusive evidence that the ABA biosynthesis and signaling pathways contribute to the differences in PHS between the mutant and the wild-type, and some genes and their alleles associated with PHS tolerance showed differential expression between the mutant and wild-type lines. The most interesting result of this study was that the expression levels of the chitinase family genes showed significant differences between the mutant and the wild-type as determined by GO enrichment analysis, and a subsequent analysis of differential expression profiling of the chitinase genes led to the same conclusion.Conclusions: Transcriptomic analysis in this study have revealed the global transcriptome profiles of the PHS sensitive wheat cultivar ‘Long 13-3778’ and its PHS resistant mutants. Furthermore, this study has proposed a possible explanation of the connection between PHS and the chitinase family for the first time, which added to our understanding of PHS and seed dormancy in common wheat.

The present study was undertaken for developing pre-harvest sprouting tolerant (PHST) wheat genotypes using marker-assisted backcross breeding (MABB). A major QTL for PHST was introgressed into an elite Indian wheat cv. Lok1 that is PHS susceptible. These PHST lines were also pyramided with one gene each for high grain protein content (Gpc-B1) and leaf rust resistance (Lr24). For introgression of PHST QTL, initially Lok1 was separately crossed with each of the two donors (PHS tolerant white-grained AUS1408 and CN19055). Backcrossing in each generation was followed by foreground and background selections using SSR markers. In advanced lines, KASP assay was also carried out for the candidate gene TaMKK3-A underlying the PHST QTL. The MAS derived lines homozygous for PHST QTL were screened for PHS using simulated rain chambers resulting in the selection of 10 PHST lines. For pyramiding of three QTL/genes (PHST QTL, Gpc-B1, and Lr24), MABB derived BC4F2 plants (from the cross Lok1/CN19055) were crossed with a MAS derived BC2F5 line [Lok1 (Gpc-B1 + Lr24)] developed earlier by us in the same background of Lok1. After foreground MAS followed by PHS screening, four advanced lines carrying all the three QTL/genes in homozygous condition were selected. These lines exhibited high level of PHST (PHS score 2–3) associated with significant improvement in GPC with no yield penalty and resistance against leaf rust under artificial epiphytotic conditions.

The varietal differences in pre-harvest sprouting (PHS) resistance and associated grain characteristics have yet to be understood. We tested the grains of 125–166 soft winter (SW) wheat varieties grown for three years for falling number (FN), α-amylase activity, and degree of sprouting (DS) under field sprouting (FS) and spike wetting conditions, and determined the characteristics of grain produced under non-FS conditions for two years. Eleven to 31 varieties exhibited FNs higher than 200 under spike wetting conditions, and 16 to 99 varieties exhibited FNs above 300 under FS conditions. Red wheat varieties showed significantly (p

Pre-harvest sprouting (PHS), induced by unexpected weather events, such as typhoons, at the late seed maturity stage, is becoming a serious threat to rice production, especially in the state of California, USA, Japan, and the Republic of Korea, where japonica varieties (mostly susceptible to PHS) are mainly cultivated. A projected economic loss by severe PHS in these three countries could range between 8–10 billion USD per year during the next 10 years. Here, we present promising rice germplasm with strong resistance to PHS that were selected from a diverse rice panel of accessions held in the International Rice Genebank (IRG) at the International Rice Research Institute (IRRI). To induce PHS, three panicle samples per accession were harvested at 20 and 30 days after flowering (DAF), respectively, and incubated at 100% relative humidity (RH), 30 °C in a growth chamber for 15 days. A genome-wide association (GWA) analysis using a 4.8 million single nucleotide polymorphisms (SNP) marker set was performed to identify loci and candidate genes conferring PHS resistance. Interestingly, two tropical japonica and four temperate japonica accessions showed outstanding PHS resistance as compared to tolerant indica accessions. Two major loci on chromosomes 1 and 4 were associated with PHS resistance. A priori candidate genes interactions with rice gene networks, which are based on the gene ontology (GO), co-expression, and other evidence, suggested that a key resistance mechanism is related to abscisic acid (ABA), gibberellic acid (GA), and auxin mediated signaling pathways.

A novel application of biospeckle to quantify seed germination is proposed.BLA is the first application of biospeckle as a method of plant growth analysis.Causation is investigated by measuring viable and autoclaved (non-viable) seeds.BLA can differentiate simulated sprouting damaged seeds from healthy seeds. Sprouting Damage is a persistent quality control concern in the cereals industry, as sprouting damaged kernels (SDK) contain enzymes that have a detrimental effect on flour quality. Furthermore, the severity of sprouting damage is difficult to detect using standard visual grading methods. In this work, we present Biospeckle Laser Analysis (BLA) as a diagnostic tool to measure the germination progress and the simulated SDK severity of Canadian Western Red Spring wheat seeds. We first analysed dissected seeds and found that high frequency biospeckle activity in the germ correlated with germination progress. Following this, a novel whole seed grading protocol was developed using qualitative and quantitative data provided by the biospeckle measurement. Using our whole seed grading protocol, seeds subjected to simulated SDK treatments at two levels (10 and 20h pre-trial water exposure) could be differentiated from healthy seeds and from each respective treatment (p

A comparative analysis of genetic diversity of North American spring wheat varieties differing in resistance to pre-harvest sprouting was carried out. For identification of sources of resistance the genealogical profiles of 148 red-grained and 63 white-grained North-American spring wheat varieties with full pedigrees were calculated and estimates were made of pre-harvest sprouting. The cluster structure of the populations of red-grained and white-grained varieties was estimated. Analysis of variance revealed significant differences between the average contributions of landraces in the groups of resistant and susceptible varieties. Distribution of the putative sources of resistance in the clusters indicated that varieties having different genetic basis may have different sources of resistance. For red-grained varieties the genetic sources of resistance to pre-harvest sprouting are landraces Crimean, Hard Red Calcutta, and Iumillo, or Button, Kenya 9M-1A-3, and Kenya-U, or Red Egyptian and Kenya BF4-3B-10V1. Tracking of pedigrees showed these landraces contributed to the pedigrees, respectively, via Thatcher, Kenya-Farmer, and Kenya-58, which were likely donors of resistance for red-grained varieties. For white-grained varieties the sources of resistance were landraces Crimean, Hard Red Calcutta, Ostka Galicyjska, Iumillo, Akakomugi, Turco, Hybrid English, Rough Chaff White and Red King, and putative donors of resistance — Thatcher, RL2265, and Frontana. The genealogical profile of accession RL4137, the most important donor of resistance to pre-harvest sprouting in North American spring wheat breeding programmes, contains almost all identified sources of resistance.

Pre-harvest sprouting (PHS) affects wheat (Triticum aestivum L.) yield and end-use product quality leading to massive economic losses. Red wheat cultivars are typically more resistant to PHS than white wheat. The objective of this study was to identify red wheat genotypes capable of donating genes for PHS tolerance to white wheat, independent of red seed coat color. A factorial (M×N) mating was conducted using six white wheat genotypes ‘Cayuga’, ‘Nuplains’, NW97S218, NW99L7068, ‘Peck’, and ‘RioBlanco’ and eight hard red wheat genotypes ‘Arapahoe’, CO960293-2, ‘Jagalene’, NE98466, NI01812, ‘Wesley’, ‘Niobrara’, and ‘Plainsman V’. General combining ability (GCA) for individual parents and specific combining ability (SCA) for specific crosses were used to identify effective red wheat donors. General combining ability and SCA were calculated from a pre-harvest tolerance score (∆) determined after testing heads in a misting chamber and from falling number measurements of field-grown materials. General combining ability among red parents was significant for both ∆ and falling number, but not in white parents. General combining ability or SCA by environmental interactions, with the exception of ∆ from GCA in red wheat, were significant. Jagalene and Niobrara were identified as red wheat genetic reservoirs for additional genes of PHS tolerance useful in white wheat breeding. A significant correlation of SCA of falling number and SCA of ∆ was detected (r = 0. 38, n = 48, P = 0.007). The falling number assay can be replaced by an assay for ∆ to evaluate PHS tolerance in wheat breeding programs in areas in which pre-harvest sprouting is not routinely observed.

Pre-harvest sprouting (PHS) is a primary cause of decreases in quality and economic value in rice seeds. This study examined the inhibitory effects of four combinations of maleic hydrazide, eugenol and uniconazole on rice PHS and seed quality. After the four treatments, delayed grain germination was observed compared with the control, mean germination time was prolonged by 17.5 % and germination index was decreased by an average of 18.2 %. Activity of α-amylase was significantly reduced, by 26.7–83.5 %, during grain germination and early seedling growth. We then used qRT-PCR to further analyze the mRNA expression levels of four genes involved in α-amylase biosynthesis. The expression of OsAMY3B and OsAMY3E was significantly down-regulated by the four combinations of chemicals. In field trials, each of the four combinations resulted in a significantly lower sprouting rate and sprouting index compared with the control. In addition, freshly harvested rice seeds showed no significant differences in the mean germination time or germination index between the four combination treatments and the control. After 1 month of storage, there was still no significant difference between the four combination treatments and the control with regard to the mean germination time and germination index. These results suggest that the selected combinations strongly inhibited the seed germination speed and PHS of rice in the field. However, these combinations had no inhibitory effects on the final germination percentage and showed no negative effect on seed quality after short-term storage. The combinations of inhibitors used in this study can be applied to decrease the PHS damage caused by high temperatures and moist weather during the production of hybrid rice.

Resulting from the search for wheat cultivars with high yield potential, plant health, processing quality and tolerance to pre-harvest sprouting, CD 1252 was developed from the cross between cultivar IPR 85 and line OR1/3/BOW/GLENSON//BAGULA. Cultivar CD 1252 was tested in preliminary grain yield trials in 2005 and 2006, and then tested to determine the Value for Cultivation and Use (VCU) from 2007 to 2014, labelled CD 0711. All tests were arranged in an experimental design of randomized blocks, with three replications. The yield of cultivar CD 1252 was 5%, 4% and 1% higher than the average yield of the two best controls, respectively, in the wheat-growing regions VCU 2, 3 and 4. The wheat quality, potential for grain yield, and tolerance to pre-harvest sprouting of this cultivar are superior and it is tolerant to the main wheat diseases. Buscando cultivares de potencial produtivo, sanidade, qualidade industrial e tolerância a germinação na espiga, foi desenvolvida a cultivar de trigo CD 1252, obtida do cruzamento entre a cultivar IPR 85 e a linhagem OR 1/3/BOW/GLENSON//BAGULA. A cultivar CD 1252, participou dos Ensaios Preliminares de rendimento de grãos em 2005 e 2006, sendo em seguida testada em Ensaios de Valor de Cultivo e Uso (VCU), nos anos de 2007 a 2014, com a sigla CD 0711. Todos os ensaios foram conduzidos em delineamento experimental de blocos ao acaso, com três repetições. A cultivar CD 1252 apresentou rendimento 5%, 4% e 1% superior à média das duas melhores testemunhas, respectivamente, nas Regiões Tritícolas de VCU 2, 3 e 4. A referida cultivar tem qualidade superior (trigo melhorador), alto potencial de rendimento de grãos, tolerância à germinação na espiga e tolerância às principais doenças.

Seed germination is the first critical step of the plant life cycle and the foundation of agricultural production...

Pre-harvest sprouting (PHS) constrains wheat production worldwide by reducing both wheat grain yield and end-use quality. TaPHS1 on wheat chromosome 3AS and TaMKK3-A on chromosome 4AL are two cloned genes with major effects on PHS resistance and they are independent from grain color (GC). In this study, we used marker-assisted backcrossing (MAB) to introgress TaPHS1 and TaMKK3-A from two PHS resistant sources&mdash, &lsquo, Tutoumai A&rsquo, and &lsquo, AUS1408&prime, &mdash, into a sprouting-susceptible white wheat line, NW97S186. Progeny were tested in four environments to investigate individual and combined effects of those two genes. TaPHS1 significantly reduced PHS and its effect on PHS varied with environments and gene sources. In contrast, the TaMKK3-A gene also significantly reduced PHS but its effectiveness was influenced by environments. The two genes had additive effects on PHS resistance, indicating pyramiding those two quantitative trait lici (QTLs) could increase PHS resistance. The additive effects were greater in a mild environment, such as a greenhouse, than in a dry and hot environment during maturation.

Pre-harvest sprouting (PHS) has been a serious production constraint for over two decades, especially in the summer rainfall wheat production regions of South Africa. It is a complex genetic trait controlled by multiple genes, which are significantly influenced by environmental conditions. This complicates the accurate prediction of a cultivar's stability in terms of PHS tolerance. A number of reports have documented the presence of major QTL on chromosomes 3A and 4A of modern bread wheat cultivars, which confer PHS tolerance. In this study, the SSR marker haplotype combination of chromosomes 3A and 4A of former and current South African cultivars were compared with the aim to select for improved PHS tolerance levels in future cultivars. A total of 101 wheat cultivars, including a susceptible cultivar and five international tolerant sources, were used in this study. These cultivars and donors were evaluated for their PHS tolerance by making use of a rain simulator. In addition, five seeds of each entry were planted out into seedling trays and leaf material harvested for DNA isolation. A modified CTAB extraction method was used before progressing to downstream PCR applications. Eight SSR markers targeted from the well-characterized 3A and 4A QTL regions associated with PHS tolerance, were used to conduct targeted haplotype analysis. Additionally, recently published KASP SNP markers, which identify the casual SNP mutations within the TaPHS1 gene, were used to genotype the germplasm. The haplotype marker data and phenotypic PHS data were compared across all cultivars and different production regions. A relative change in observed phenotypic variation percentage was obtained per marker allele and across marker haplotype combinations when compared to the PHS susceptible cultivar, Tugela-DN. Clear favorable haplotypes, contributing 40-60% of the variation for PHS tolerance, were identified for QTL 3A and 4A. Initial analyses show haplotype data appear to be predictive of PHS tolerance status and germplasm can now be selected to improve PHS tolerance. These haplotype data are the first of its kind for PHS genotyping in South Africa. In future, this can be used as a tool to predict the possible PHS tolerance range of a new cultivar.

The possibility of obtaining sorghum grains with quality to match the standards for a diversity of end-uses is frequently hampered by the susceptibility to pre-harvest sprouting (PHS) displayed by many elite genotypes. For these reasons, obtaining resistance to PHS is considered in sorghum breeding programs, particularly when the crop is expected to approach harvest maturity under rainy or damp conditions prevalence. As in other cereals, the primary cause for sprouting susceptibility is a low dormancy prior to crop harvest; in consequence, most research has focused in understanding the mechanisms through which the duration of dormancy is differentially controlled in genotypes with contrasting sprouting behavior. With this aim two tannin-less, red-grained inbred lines were used as a model system: IS9530 (sprouting resistant) and Redland B2 (sprouting susceptible). Redland B2 grains are able to germinate well before reaching physiological maturity (PM) while IS9530 ones can start to germinate at 40–45 days after pollination, well after PM. Results show that the anticipated dormancy loss displayed by Redland B2 grains is related reduced embryo sensitivity to abscisic acid (ABA) and increased levels of GA upon imbibition. In turn, transcriptional data showed that ABA signal transduction is impaired in Redland B2, which appears to have an impact on GA catabolism, thus affecting the overall GA/ABA balance that regulates germination. QTL analyses were conducted to test whether previous candidate genes were located in a dormancy QTL, but also to identify new genes involved in dormancy. These analyses yielded several dormancy QTL and one of them located in chromosome 9 (qGI-9) was consistently detected even across environments. Fine mapping is already in progress to narrow down the number of candidate genes in qGI-9. Fil: Benech-Arnold, Roberto Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Cultivos Industriales; Argentina Fil: Rodríguez, María Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Fisiología Vegetal; Argentina

The seed dormancy characteristic is regarded as one of the most critical factors for pre-harvest sprouting (PHS) resistance. As a wild wheat relative species, Aegilops tauschii is a potential genetic resource for improving common wheat. In this study, an advanced backcross population (201 strains) containing only Ae. tauschii segments was developed by means of synthetic octaploid wheat (hexaploid wheat Zhoumai 18 × Ae. tauschii T093). Subsequently, seed dormancy rate (Dor) in the advanced backcross population was evaluated on the day 3, 5 and 7, in which 2 major QTLs (QDor-2D and QDor-3D) were observed on chromosomes 2D and 3D with phenotypic variance explained values (PVEs) of 10.25 and 20.40%, respectively. Further investigation revealed significant correlation between QDor-3D and Tamyb10 gene, while no association was found between the former and TaVp1 gene, implying that QDor-3D site could be of closer position to Tamyb10. The obtained quantitative trait locus sites (QTLs) in this work could be applied to develop wheat cultivars with PHS resistance.

1. 생산지에 따라 벼 종자의 수발아립률 차이가 컸던 호품벼의 출아율과 발아율을 조사한 결과, 수발아율 8%인 시료는 수발아율이 1%인 시료에 비해 발아율과 출아율, 종자활력이 30% 낮았다. 2. 수발아율이 높은 시료는 수발아립의 변색 정도가 심하고 미발아율과 부패율이 높았다. 수발아립은 배가 돌출하고, 변색된 배유와 곰팡이 감염이 관찰되었으며 배유의 1/2이상이 변색된 종자는 발아율이 매우 낮았다. 3. 종자의 발아 진행정도에 따라 현미의 변색이 심해졌는데, 싹이 3 mm이상일 경우 배유의 1/2정도가 변색되었다. 4. 발아 종자는 싹이 3 mm이상일 때부터 재발아율이 크게 떨어졌으며 퇴화촉진처리 후 발아율의 감소가 더 컸다. 특히 퇴화촉진처리한 발아 종자는 싹이 2 mm부터 종자활력이 크게 감소하였다. 결론적으로 수발아 발생이 심할수록 파종기 발아율과 출아율의 감소가 크고, 수발아가 3 mm이상 발생하면 발아율이 크게 저하될 것으로 생각된다. 또한 수발아는 동일 품종과 동일 지역에서도 포장 간 차이가 크게 발생할 수 있으므로 재배관리에 주의해야 한다. 【This study aimed to investigate the effects of pre-harvest sprouting (PHS)-damaged grains of rice on seed viability, germination percentage and seedling emergence rate. As comparing the seed lots of same cultivar 'Hopum' with different PHS percentages, seed lot with 8% PHS (high PHS percentage) showed 30% lower germination than that with 1% PHS (low PHS percentage). The difference of seedling emergence rate and seed viability percentages between the two seed lots was consistent with that of germination percentage. PHS-damaged brown rice was observed protruded embryo, discolored endosperm and fungi infected grains. PHS grains were classified into two groups, PHS-I showing endosperm discoloration in one third of a grain and PHS-II in more than half of a grain. The seed lot with high PHS percentage had much more PHS-II grains than that of low PHS percentage. PHS-II grains showed remarkably lower germination percentage than PHS-I grains and got severely moldy during germination test. In laboratory experiment, morphological changes and re-germination ability of seeds which dried after germination by soaking were tested. Sprouted seeds of 3mm shoot length showed half discolored endosperm and had a strong resemblance with PHS-II grains. Re-germination percentage of 3mm sprouted seeds sharply decreased than 2 mm sprouted seeds. Sprouted seeds which were treated for accelerated-aging (AA) for 24hr at $45^{\circ}C$ were significantly reduced in re-germination percentage compared to that of non-AA-treated sprouted seeds. These results indicate that PHS with over 3mm shoot length can severely damage not only grain appearance but also seed viability, germination percentage and seedling emergence rate. Therefore, we conclude that larger difference of germination percentage or seedling emergence rate between seed lots having smaller difference of PHS percentage might be caused by accelerated seed deterioration in PHS-damaged rice grains.】

The influence of rainfall during the ripening stage on pre-harvest sprouting, seed viability, and seed quality was investigated in two Korean rice cultivars, Shindongjin and Hopum. When the rainfall was artificially treated in a greenhouse, HP started to pre-harvest sprouting at three days of rainfall treatment (DRT), but Shindongjin did not show pre-harvest sprouting at 40 DAH treatment and just 0.3~0.8% at 50 DAH, which was much lower than 15.3~ 25.8% of Hopum in the same treatment. After harvest, the seed germination of Hopum decreased about 10~25% compared to non-treated seeds, but that of Shindongjin decreased much little rate than that of Hopum. The seed longevity tested by accelerated aging decreased with prolonged rainfall period in both cultivars, but the varietal difference was clear; Shindongjin could withstand longer accelerated aging than Hopum. Shindongjin maintained its germination (>50%) ability after 15 days of accelerated aging regardless of the rainfall treatment period and time, but Hopum dropped below 50% germination ability after only 5 days of accelerated aging. In conclusion, rainfall during the ripening stage induced not only pre-harvest sprouting, but also reduced seed quality and longevity during storage, which varied between two cultivars.

This research was implemented to investigate pre-harvest sprouting characteristics in two Korean rice cultivars, Shindongjin (SDJ) and Hopum (HP). The panicles of both varieties were sampled after 15 days after heading (DAH) to 60 DAH at intervals of 5 days. As soon as sampled, the panicles were imbibed in water for 14 days at 25℃ to determine the vigor and germination ability of seeds according to location on panicle. To investigate the cause of non-germination of seeds in panicles, tetrazolium test and dormancy breaking were performed. The preharvest sprouting of HP started at 20 DAH while that of SDJ began at 30 DAH. The germination of seeds located in high rank branches within a panicle and the terminal seeds within a branch were earlier and faster and the germination patterns were same in both cultivars. The times at more than 50% of germination in a panicle were 35 DAH (57.0%) in HP and 45 DAH (56.8%) in SDJ. Preharvest sprouting was more than 80% at 50 DAH (82.6% of HP, 92.3% of SDJ) and more than 99% at 60 DAH (99.5%, 99.4%, HP and SDJ). These results indicated that the rate of PHS in a panicle increased with accumulation of the days after heading. The cause of non-germinated seeds at 15-25 DAH in panicle was immature embryo. After 30 DAH, however, when the non-germinated seeds were hulled, they started to germinate due to dormancy breaking, in which the germination percentage was higher in SDJ than HP. In conclusion, the pre-harvest sprouting varied according to days after heading, the seed position on panicle, and the dormancy intensity of varieties.

Pre-harvest sprouting (PHS) in Sorghum bicolor is one of the main constrains for its production in the central region of Argentina, as grain maturation often coincides with rainy or high environmental humidity conditions. The obtention of more dormant genotypes with higher PHS resistance has always been a desirable trait for breeders but the typical quantitative nature of seed dormancy makes its manipulation difficult through classical breeding. Dissecting this quantitative variability into quantitative trait loci (QTL) is a main concern especially in cereal species. In this work, a sorghum segregating population including 190 families was genotyped with microsatellite markers and the SbABI5 candidate gene. A genetic map encompassing 96 markers and a total length of 1331 cM was built. Seed dormancy was phenotyped in F3 and F4 panicles in two contrasting Argentinean environments (Castelar and Manfredi). Six seed dormancy QTL for mature grains were identified (qGI-1, qGI-3, qGI-4, qGI-6, qGI-7 and qGI-9) with the aid of QTL Cartographer and QTLNetwork, three of them (qGI-3, qGI-7 and qGI9) being co-localised by both approaches. No epistasis was detected for the identified QTL but QTL-byenvironment interaction was significant for qGI-7 and qGI-9. Interestingly, seed dormancy candidate genes SbABI3/VP1 and SbGA20ox3 were located within qGI-3, which makes them noteworthy candidate genes for this QTL. Fil: Cantoro, Renata. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Fernandez Galdeano, Jorge Luis. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas; Argentina Fil: Cervigni, Gerardo Domingo Lucio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Centro de Estudios Fotosinteticos y Bioquimicos. Universidad Nacional de Rosario. Facultad de Cs.bioquímicas y Farmaceuticas. Centro de Estudios Fotosinteticos y Bioquimicos; Argentina Fil: Rodríguez, María Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Jorge Omar, Gieco. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Córdoba. Estación Experimental Agropecuaria Manfredi; Argentina. Universidad Nacional del Litoral; Argentina Fil: Paniego, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Heinz, Ruth Amelia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Benech-Arnold, Roberto Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Cultivos Industriales; Argentina