Dormancy Of Fresh Seeds Research Articles

Insights from Morpho-Physiological Traits Imparting Tolerance for Preharvest Sprouting of Mungbean Genotypes

Due to the absence of fresh seed dormancy (FSD) in mung bean seeds makes them susceptible to pre-harvest sprouting (PHS). Mung bean yield has been proved to be 60–70% reduced in response to PHS, an abiotic stress. By understanding this problem present study was carried out at at experimental field, Department of Agricultural Botany (Plant Physiology) (20.70060N, 77.03710E), PGI, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola during kharif (rainy) season 2012-13. The experiment entitled “Insights from morpho-physiological traits imparting tolerance for preharvest sprouting of munbean genotypes”. The design of experiment is Randomized block design in three replications with sixteen genotypes. It was observed that on the basis of morpho-physiological traits viz., high hard seed %, pod pubescence, lower germination in pod and seed, less seed and pod moisture genotype AKM-9801, AKM-9907, BM-2002-1 and AKM-10-05, genotypes were found to be tolerant to preharvest sprouting. And more interesting fact is the seed yield per hector found efficient in AKM-8802 and AKM-9907. So, it was found that AKM 9907 is best suitable variety of mungbean in kharif season to prevent crop from whether damage and improve yield also.

Effects of various pre-treatments on dormancy-break and seed germination of Saussurea veitchiana (Asteraceae), an endemic medicinal herb of southwest China

Subalpine Saussurea veitchiana (Asteraceae) is useful for the treatment of various diseases and is vulnerable to extinction. Methods to break seed dormancy and enhance germination of this species, as well as the response of seeds to different temperatures, were investigated. Freshly harvested seeds germinated to very low percentages at ten temperature regimes in light conditions. Gibberellic acid (10 - 200 μM) partially broke the dormancy of fresh seeds, and the highest germination was 54% when seeds were treated with 200 μM GA3 and incubated at 20°C or 25/15°C. Cold stratification significantly increased germination over that of the control (i. e., seeds dry stored at room temperature, approximately 18°C). Seeds cold stratified at 4°C for 60 or 90 days germinated to 83 and 87%, respectively, at 25/15°C and had a MGT of 7.11 and 6.37 days, respectively. Taken together, the seeds of S. veitchiana have non-deep physiological dormancy, and cold stratification for 60 days or longer is recommended as a practical dormancy-breaking treatment for propagation of this species from seeds.

Identification of Donors for Fresh Seed Dormancy and Marker Validation in a Diverse Groundnut Mini-Core Collection

Domestication and extensive selection in the development of modern, high-yielding commercial groundnut cultivars have resulted in the selection of an undesirable trait known as in situ germination, which is also referred to as the pre-harvest sprouting of seeds. This is particularly prevalent in regions where humid weather coincides with the harvest season. Delayed harvesting and pre-sprouting can cause production losses and increase the chances of aflatoxin contamination, thereby impeding the quality and kernel yield. Breeding early maturing groundnut cultivars with 2–3 weeks of fresh seed dormancy, particularly in Spanish-type cultivars, enhances the sustainability of agriculture. In this context, we conducted a comprehensive evaluation of a groundnut mini-core collection, a major resource for genetic diversity, for fresh seed dormancy using an in vitro germination assay for two seasons, viz., rainy 2022 and post-rainy 2022–2023 at ICRISAT (Hyderabad). To enhance the effectiveness and accuracy of traditional breeding methods via the use of markers for marker-assisted selection, we performed molecular screening of the mini-core accessions using two allele-specific markers. The GMFSD1 marker was successfully validated by effectively differentiating dormant and non-dormant genotypes. By employing phenotypic and marker data, we identified a set of accessions, viz., ICG 5827 (Virginia Runner), ICG 11457 (Virginia Runner), ICG 7000 (Virginia Bunch), and ICG 11322 (Virginia Bunch) of sub spp. hypogaea var. hypogaea and ICG 9809 (Spanish Bunch) of sub spp. fastigiata var. vulgaris that exhibited a fresh seed dormancy period ranging from 2 to 3 weeks. These identified accessions hold potential as donors in breeding programs that are designed to address the groundnut production needs in various cropping systems across different countries. The validated marker, particularly GMFSD1, demonstrated considerable potential for facilitating faster breeding of groundnut cultivars with the desired dormancy using marker-assisted selection. This research provides a foundation to expediting groundnut breeding programs and offers opportunities to mitigate pre-harvest sprouting, ultimately improving seed quality and productivity in groundnut-producing regions.

Genotypic variability studies and identification of pre-harvest sprouting tolerant wild Vigna

Seed dormancy is the main component of domesticated traits, loss of which results into rapid and uniform germination, synchronous maturity and ease in harvesting. However, breakdown or loss of fresh seed dormancy (FSD) has made seeds vulnerable to pre-harvest sprouting (PHS). Though, seeds of Vigna species are protected by pod, these are still susceptible to PHS. Identification of donor(s) having short duration of FSD (30-45 days) has become utmost important to transfer the trait to high yielding varieties. The wild progenitors and wild relatives of the cultivated Vigna offer a source of several useful traits; therefore, the experiment was initiated to understand the level of variation in PHS and fresh seed germination (FSG) in wild accessions of Vigna species. PHS and FSG among 59 Vigna accessions ranged between 0-100%, with a mean of 55.86% and 61.19%, respectively. Five accessions (IC276983, IC349701, Trichy Local 1, LRM/13-33 and LRM/13-26) of Vigna trilobata and one accession (IC251440) of Vigna sublobata recorded no pod loss due to PHS with 0% FSG (2.5% in V. sublobata). Seed size showed a positive association with PHS, where smaller seeds (100-SW <1 g) recorded comparably low PHS (30.82%) than bold seeds (69.06 and 62.94% with 100-SW between 1-2 g and > 2 g, respectively). The accessions identified, especially V. sublobata (crossing compatible) could be used as a source of PHS tolerance to transfer dormancy in Vigna species, particularly in mungbean and urdbean.

Discovery of Major Quantitative Trait Loci and Candidate Genes for Fresh Seed Dormancy in Groundnut

Spanish bunch groundnut varieties occupy most of the cultivated area in Asia and Africa, and these varieties lack required 2-3 weeks of fresh seed dormancy (FSD) hampering kernel quality. Genomic breeding can help to improve commercial groundnut cultivars for FSD in a shorter time with greater precision. In this regard, a recombinant inbred line (RIL) population from the cross ICGV 02266 (non-dormant) × ICGV 97045 (dormant) was developed and genotyped with a 5 K mid-density genotyping assay. A linkage map was constructed with 325 SNP loci spanning a total map length of 2335.3 cM and five major QTLs were identified on chromosomes Ah01, Ah11, Ah06, Ah16 and Ah17. Based on differential gene expression using transcriptomic information from dormant (Tifrunner) and non-dormant (ICGV 91114) genotypes, histone deacetylases, histone-lysine N-methyltransferase, cytochrome P450, protein kinases, and ethylene-responsive transcription factor were identified as key regulators involved in the hormonal regulation of dormancy. Six Kompetitive Allele Specific PCR (KASP) markers were successfully validated in the diverse panel including selected RILs of the same population and germplasm lines. These validated KASP markers could facilitate faster breeding of new varieties with desired dormancy using marker-assisted early generation selection.

Whole-genome resequencing-based QTL-seq identified candidate genes and molecular markers for fresh seed dormancy in groundnut.

SummaryThe subspecies fastigiata of cultivated groundnut lost fresh seed dormancy (FSD) during domestication and human‐made selection. Groundnut varieties lacking FSD experience precocious seed germination during harvest imposing severe losses. Development of easy‐to‐use genetic markers enables early‐generation selection in different molecular breeding approaches. In this context, one recombinant inbred lines (RIL) population (ICGV 00350 × ICGV 97045) segregating for FSD was used for deploying QTL‐seq approach for identification of key genomic regions and candidate genes. Whole‐genome sequencing (WGS) data (87.93 Gbp) were generated and analysed for the dormant parent (ICGV 97045) and two DNA pools (dormant and nondormant). After analysis of resequenced data from the pooled samples with dormant parent (reference genome), we calculated delta‐SNP index and identified a total of 10,759 genomewide high‐confidence SNPs. Two candidate genomic regions spanning 2.4 Mb and 0.74 Mb on the B05 and A09 pseudomolecules, respectively, were identified controlling FSD. Two candidate genes—RING‐H2 finger protein and zeaxanthin epoxidase—were identified in these two regions, which significantly express during seed development and control abscisic acid (ABA) accumulation. QTL‐seq study presented here laid out development of a marker, GMFSD1, which was validated on a diverse panel and could be used in molecular breeding to improve dormancy in groundnut.

Variation in pre-harvest sprouting tolerance and fresh seed germination in mungbean (Vigna radiata L.) genotypes

AbstractMungbean seeds, despite being protected inside the pod, are susceptible to pre-harvest sprouting (PHS) following rainfall due to lack of fresh seed dormancy (FSD), which deteriorates the quality of the seed/grain produced. Therefore, development of mungbean cultivars with short (10–15 days) period of FSD has become important to curtail losses incurred by PHS. In this study, we investigated variations in PHS, fresh seed germination (FSG) and activity of α-amylase enzyme in diverse mungbean genotypes. There was a wide variation in PHS tolerance and FSG among 163 genotypes examined and 14 genotypes were found to be tolerant (<20%) to PHS. Seed germination in a pod, a measure used to evaluate PHS, varied from 7.14% in germplasm accession Chamu 4 to 82.52% in cultivated variety IPM 2–3. There was a marked increase in α-amylase activity in genotypes showing high FSG and PHS, especially at 48 and 72 h after germination as compared with PHS tolerant genotypes. Therefore, α-amylase can be used as an effective biochemical marker to evaluate a large number of mungbean genotypes for FSD and PHS. Also, the variation in seed germinability as found in this study could be further used for mungbean improvement programme.

Identification of two major quantitative trait locus for fresh seed dormancy using the diversity arrays technology and diversity arrays technology‐seq based genetic map in Spanish‐type peanuts

AbstractSeed quality for both germination in the next generation and for human consumption is adversely affected due to preharvest sprouting in peanut. It also makes seeds more vulnerable to infection by a number of pathogens. Therefore, it is desirable to have 2–3 weeks of fresh seed dormancy (FSD) in the peanut varieties. In this context, one F2 population was developed from a cross between non‐dormant (ICGV 00350) and dormant (ICGV 97045) genotypes. Phenotyping of this population showed control of the trait by two recessive genes. In parallel, genotyping of the population with Diversity Arrays Technology (DArT) and DArT‐seq markers provided a genetic map with 1152 loci covering a map distance of 2423.12 cM and map density of 2.96 cM/loci. Quantitative trait locus (QTL) analysis identified two major QTLs, namely qfsd‐1 and qfsd‐2 explaining 22.14% and 71.21% of phenotypic variation, respectively. These QTLs, after validation in different genetic backgrounds, may be useful for molecular breeding for FSD in peanut.

Seed dormancy, seedling establishment and dynamics of the soil seed bank of Stipa bungeana (Poaceae) on the Loess Plateau of northwestern China.

Studying seed dormancy and its consequent effect can provide important information for vegetation restoration and management. The present study investigated seed dormancy, seedling emergence and seed survival in the soil seed bank of Stipa bungeana, a grass species used in restoration of degraded land on the Loess Plateau in northwest China. Dormancy of fresh seeds was determined by incubation of seeds over a range of temperatures in both light and dark. Seed germination was evaluated after mechanical removal of palea and lemma (hulls), chemical scarification and dry storage. Fresh and one-year-stored seeds were sown in the field, and seedling emergence was monitored weekly for 8 weeks. Furthermore, seeds were buried at different soil depths, and then retrieved every 1 or 2 months to determine seed dormancy and seed viability in the laboratory. Fresh seeds (caryopses enclosed by palea and lemma) had non-deep physiological dormancy. Removal of palea and lemma, chemical scarification, dry storage (afterripening), gibberellin (GA3) and potassium nitrate (KNO3) significantly improved germination. Dormancy was completely released by removal of the hulls, but seeds on which hulls were put back to their original position germinated to only 46%. Pretreatment of seeds with a 30% NaOH solution for 60 min increased germination from 25% to 82%. Speed of seedling emergence from fresh seeds was significantly lower than that of seeds stored for 1 year. However, final percentage of seedling emergence did not differ significantly for seeds sown at depths of 0 and 1 cm. Most fresh seeds of S. bungeana buried in the field in early July either had germinated or lost viability by September. All seeds buried at a depth of 5 cm had lost viability after 5 months, whereas 12% and 4% seeds of those sown on the soil surface were viable after 5 and 12 months, respectively.

Seed dormancy, germination, emergence and seed longevity in Galinsoga parviflora and G. quadriradiata

SummaryGalinsoga quadriradiata (hairy galinsoga) and Galinsoga parviflora (smallflower galinsoga, gallant soldier) are very troublesome weeds in many vegetable row crops in Europe. To optimise management strategies for Galinsoga spp. control, an in‐depth study of germination biology was performed. Germination experiments were conducted to evaluate the impact of light and alternating temperatures on germination of a large set of Galinsoga populations. Seedling emergence was investigated by burying seeds at different depths in a sandy and sandy loam soil. Dormancy of fresh seeds harvested in autumn was evaluated by studying germination response in light at 25/20°C with and without nitrate addition. Seed longevity was investigated in an accelerated ageing experiment by exposing seeds to 45°C and 100% relative humidity. Galinsoga spp. seeds required light for germination; light dependency varied among populations. Seedling emergence decreased drastically with increasing burial depth. Maximum depth of emergence varied between 4 and 10 mm depending on soil type and population. In a sandy soil, emergence percentages were higher and seedlings were able to emerge from greater depths than in a sandy loam soil. Freshly produced G. parviflora seeds, harvested in autumn, showed a varying but high degree of primary dormancy and were less persistent than G. quadriradiata seeds that lack primary dormancy. Lack of primary dormancy of freshly harvested G. quadriradiata seeds and light dependency for germination may be used to optimise and develop Galinsoga management strategies.

In situ sprouting and regulation of fresh-seed dormancy in Spanish type groundnut ( Arachis hypogaea L.)

Two hundred groundnut ( Arachis hypogaea L.) germplasm accessions and 21 cultivars belonging to the Spanish group (ssp. fastigiata var. vulgaris) were screened for pod loss due to sprouting of seed in the field. Some cultivars were also tested for germination of the fresh-seed with or without testa and treated or untreated with ethrel or abscisic acid (ABA). Large variation in pod loss due to in situ sprouting of seed, and fresh-seed dormancy (FSD) was found among the accessions and cultivars. Fresh-seed dormancy index (FSDI) varied from 2% in Chico to 88% in ICGS 44 (the check with high FSD). Cultivars with an FSDI value of less than 10% showed more pod loss in situ than the cultivars with high FSDI. Thus pod loss due to in situ sprouting increased with a decrease in FSDI. Cultivar SB XI did not show any in situ sprouting or pod loss. A direct relationship ( r, 0.86 ∗∗) existed between fresh-seed germination of accession/cultivar in the laboratory and the percentage of its plants with sprouted seed in the field. Seed of two Spanish cultivars ICGS 11 (dormant) and GG 2 (non-dormant) when tested for germination after treatment with ethrel or ABA at various seed development stages showed different germination response to these chemicals. Seed of GG 2 showed up to 40% germination even at an early stage (S 1) of seed development, whereas the seed of ICGS 11 responded to the ethrel only at maturity (S 4). Regulation of FSD appeared to be more under the control of the testa than the cotyledons. The variation in the degree of in situ sprouting can be used for breeding Spanish cultivars with various desirable levels of FSD.

Inheritance of Fresh Seed Dormancy in Peanut

Incorporation of seed dormancy limited duration in Spanish peanut (Arachis hypogae L. ) genotypes is required to avoid loss in pod yield and seed quality because of in situ germination in unpredictable rainfall environments. Knowledge of inheritance of fresh seed dormancy is important to peanut breeder for developing fresh seed dormant early‐maturing Spanish cultivars. This study was conducted to determine the inheritance of fresh seed dormancy using three Spanish peanut genotypes. Two dormant (ICGV 86158 and ICGV 87378) and one non‐dormant (JL 24) genotypes were crossed in all possible combinations, including reciprocals. The fresh seeds from mature pods from parents F1, F2, F3, and backcross populations were evaluated for their dormancy by germination test in the laboratory at 35 ± 2°C in the dark. Results showed that the fresh seed dormancy in these genotypes is controlled by a dominant allele of a single gene. The two dormant parents, ICGV 86158 and ICGV 87378, possess the same allele for fresh seed dormancy.

Registration of Five Spanish Peanut Germplasm Lines with Fresh Seed Dormancy

ICGV 86155, ICGV 86156, ICGV 86158, ICGV 87378, and ICGV 87921 Spanish peanut (ArachishypogaeaL. subsp.fastigiata Waldron var. vulgaris Harz) improved germplasm lines (Reg. no. GP-79 to GP-83, P1 594969 to P1 594973) were bred at the Asia Center of the International Crops Research Institute for the Semi- Arid Tropics (ICRISAT), Patancheru, Andhra Pradesh, India. These five lines were released in 1995 by the Plant Materials Identification Committee of ICRISAT for their fresh seed dormancy in the Spanish background.

Propagation of yellow bells (Geleznowia verrucosa Turcz., Rutaceae) from seed

Geleznowia verrucosa Turcz. (Rutaceae) is a commercially important, bush-picked wildflower that has no known commercial means of propagation. This study examined factors influencing seed dormancy and likely to restrict germination of the species. Germination of entire, untreated seed was low (less than 2%), but removal of a small portion of the testa at or near the radicle end of the seed improved germination. This response was affected by the temperature under which the seed germinated, but was unaffected by exposure of the seed to light while germinating. The percentage germination of nicked seeds 52 days after sowing increased from 8% to 16-19% by increasing the temperature from 15/10�C to 20/15�C; 55-60% of nicked seed germinated when the germination temperature was increased to 23/15�C. The germination of nicked seed was reduced by leaching in running tap water. Following 1 week of leaching the germination percentage of nicked seed at day 52 in the glasshouse was reduced from 16% to 9%, with a further decrease to 5% after 2 weeks of leaching. There was also no stimulatory effect on the germination of entire seeds by stratifying the seed at 5�C after periods of solarisation. It is concluded that dormancy of fresh seeds of G. verrucosa is caused, in part, by the mechanical restriction of the testa on embryo growth and elongation.

In vitro culture of a root parasite,Aeginetia indica L.

Seed germination and further growth of seedlings of an obligate root parasiteAeginetia indica L. are described. (1) Germination: dormancy of fresh seeds can be broken by sodium hypochlorite treatment, but seeds stored for 1–5 years at 5 C did not necessarily require halogen treatment for good germination. (2) Formation of the tendril, which facilitated the organic connection with the host, was stimulated greatly byMiscanthus root extract. (3) Septation (cell division) of tendril was promoted by addition of sucrose to the basal medium. (4) Rhizogenesis of the seedlingin vitro was stimulated by deproteinized coconut milk.

Dormancy and Germination of Seed of Eight Populations of Themeda australis

Seed of eight populations of Themeda australis (R.Br.) Stapf from sites nith the widest range of climates in Australia and Papua New Guinea (P.N.G.) was tested for its dormancy status and germination responses to different temperature and moisture regimes. The populations were from Lae. P.N.G.. Katherine. N.T.. Mundubbera. Qld. Alice Springs. N.T.. Tantangara. N.S.W.. Adelaide Hills. S.A.. Bunbury, W.A. and Hobart. Tas. Dormancy of fresh seed was negligible in Lae and Mundubbera populations. considerable in the Alice Springs population and intermediate in populations from Katherine and all temperate sites. Addition of gibberellic acid hastened the release from dormancy of seed from Katherine and Bunbury. Exposure of plants to three different temperature regimes during seed formation had an effect on dormancy of the Katherine population. Stratification at 4°C and high alternating daily temperatures (45 20°C) hastened the loss of dormancy of fresh seeds of some populations. Germination of non-dormant seed of the different populations was relatively unaffected b) temperatures between 20 and 40°C. Germination of the Alice Springs population was the most sensitive to increasing water stress and that from Lae the least sensitive. Radicle elongation of seedlings from Alice Springs was significantly greater than that of most other populations at a water potential of - I .0 MPa. The differences reported for seed dormancy and germination characteristics of T. australis populations do not reflect a strong physiological adaptation to the climatic characteristics of the sites from which they were collected.