Download or read book Loss of Seed Dormancy and the Relationship Between Dormancy and Embryo Culture in Wheat Triticum Aestivum L written by Victor Louis DeMacon and published by . This book was released on 1995 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seed Dormancy and Germination written by J. W. Bradbeer and published by Springer Science & Business Media. This book was released on 2013-03-13 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: The germination of seeds is a magical event, in which a pinch of dust-like material may give rise to all the power and the beauty of the growing plant. The mechanisms of seed dormancy, of the breaking of seed dormancy and of germination itself continue to remain shrouded in mystery, despite the best efforts of plant scientists. Perhaps we are getting there, but very slowly. This book considers germination and dormancy from the point of view of plant physiology. Plant physiologists attempt to understand the relation ship between plant form and function and to explain, in physical and chemical terms, plant growth and development. The place of germination and dormancy in plant ecophysiology is taken into account with attempts to understand the seed in its 'environment, whether the environment be natural, semi-natural or wholly artificial. In due course plant scientists hope to develop a precise understanding of germination and dormancy in cellular and molecular terms, and therefore there is some biochemistry in this book. Biochemists who wish to learn something about seeds should find this book useful.
Download or read book Seed Dormancy Germination and Pre Harvest Sprouting written by Chengdao Li and published by Frontiers Media SA. This book was released on 2019-03-28 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pre-harvest sprouting (PHS) and late-maturity alpha-amylase (LMA) are two of the biggest grain quality defects that grain growers encounter. About 50 percent of the global wheat crop is affected by pre-harvest sprouting to various degrees. Pre-harvest sprouting is a genetically-based quality defect and results in the presence of alpha-amylase in otherwise sound mature grain. It can range from perhaps undetectable to severe damage on grain and is measured by the falling numbers or alpha-amylase activity. This is an international issue, with sprouting damage lowering the value of crops to growers, seed and grain merchants, millers, maltsters, bakers, other processors, and ultimately the consumer. As such it has attracted attention from researchers in many biological and non-biological disciplines. The 13th International Symposium on Pre-Harvest Sprouting in Cereals was held 18-20 September, 2016 in Perth to discuss current findings of grain physiology, genetic pathways, trait expression and screening methods related to pre-harvest sprouting and LMA. This event followed the previous symposium in 2012 in Canada.
Download or read book Seedcoat Color and Dormancy in Triticum Aestivum L written by Russell D. Freed and published by . This book was released on 1972 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Role of the Seed Coat in the Dormancy of Wheat Triticum Aestivum Grains written by Judith Rebecca Rathjen and published by . This book was released on 2006 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pre-harvest sprouting (PHS) is an important economic problem which affects a significant proportion of the Australian wheat crop through quality downgrading. Grain dormancy is the most effective means of overcoming germination in the wheat spikelet at harvest maturity. It has been a consistent observation over a long period of time that dormant red-grained wheat genotypes are almost more dormant than dormant white-grained genotypes. In white-grained wheat, there are two factors which contribute to dormancy, embryo sensitivity to abscisic acid (ABA) and an interacting and unknown seed coat factor. The proposed dormancy model is that complete dormancy can only be achieved with the coordinate expression of these two factors. This primary objective of this project was to determine the role of this putative seed coat factor in grain dormancy of white-grained wheat."--Abstract.
Download or read book Seed Dormancy and Germination written by Jose Carlos Jimenez-Lopez and published by BoD – Books on Demand. This book was released on 2020-01-08 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seed dormancy and germination are critical processes for the development of plants. Seed dormancy allows seeds to overcome harsh periods of seedling establishment, and is also important for plant agriculture and crop yield. Several processes are involved in the induction of dormancy and in the shift from the dormant to the germinating state, and hormones and regulatory genetic networks are among the critical factors driving these complex processes. Germination can be prevented by different factors leading to seed dormancy, which is highly dependent on environmental cues. During and after germination, early seedling growth is sustained by catabolism of stored reserves (proteins, lipids, or starch) accumulated during seed maturation, supporting cell morphogenesis, chloroplast development, and root growth until photo-auxotrophic growth can be resumed.
Download or read book Mechanisms of Dormancy Preharvest Sprouting Tolerance and how They are Influenced by the Environment During Grain Filling and Maturation in Wheat Triticum Aestivum L written by Thomas Benjamin Biddulph and published by . This book was released on 2006 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: [Truncated abstract] Wheat is the main crop in Australia and there are stringent quality requirements. Preharvest sprouting induced by rainfall between maturity and harvest lowers grain quality from premium to feed grades and reduces yield. Wheat production has expanded into the southern Western Australian region where preharvest sprouting occurs in ~1 in 4 seasons and development of more preharvest sprouting tolerant genotypes is required. The main mechanism for improving preharvest sprouting tolerance is grain dormancy. There is genetic variation for dormancy based in the embryo and seed coat but dormancy is complex and is influenced by environmental conditions during grain filling and maturation. Screening and selecting for preharvest sprouting tolerance is problematic and the level of tolerance needed for regions which differ in the level of dormancy they impose, requires clarification. The research presented here aims to answer the underlying question for breeders of how much dormancy is required for preharvest sprouting tolerance in contrasting target environments of the central and coastal wheat belt regions of Western Australia. In the central and coastal wheat belt regions, field trials with modified environments were used to determine the environmental influence on dormancy. Water supply (without directly wetting the grain) and air temperature were modified during grain development in a range of genotypes with different mechanisms of dormancy to determine the influence of environment on dormancy. ... Genotypes with embryo dormancy were consistently the most preharvest sprouting tolerant, even though this dormancy was influenced by the environmental conditions in the different seasons. Pyramiding the embryo component with the specific seed coat component and/or awnless head trait removed some of the environmental variation in preharvest sprouting tolerance, but this was generally considered excessive to the environmental requirements. The methods developed here, of field imposed stresses may provide a valuable tool to further understand the influence of environment on the regulation of dormancy, as different phenotypes can be made with the same genotype. Moisture stress, sudden changes in water supply or high temperatures during the late dough stages influenced dormancy phenotype and should be considered and avoided if possible when selecting locations and running trials for screening for genetic differences in preharvest sprouting tolerance. In the Western Australian context, the embryo component of dormancy appeared to be sufficient and should be adopted as the most important trait for breeding for preharvest sprouting tolerance.
Download or read book Effect of High Temperature Shock During Grain Maturation on Dormancy of Wheat Triticum Aestivum L and Analysis of TaDOG1 written by Cong Rong Cheng and published by . This book was released on 2015 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pre-harvest sprouting (PHS) is the germination of seed under wet environmental conditions whilst still on the mother plant prior to harvest. In wheat, PHS causes farmers substantial economic losses due to quality downgrading. A high level of dormancy is regarded as an important mechanism of resistance to PHS in cereal species, such as wheat (Triticum aestivum L.). Many dormancy quantitative trait loci (QTL) have been identified and the corresponding genes that impart tolerance to PHS are actively being sought. Besides genetic factors, environmental conditions during grain maturation have been shown to have profound effects on dormancy. These environmental factors include temperature, light, drought and nutrients. This project aimed to determine the role of high temperature shock during wheat seed maturation on its dormancy at harvest-ripeness. The results of these experiments showed that seed of dormant or intermediate dormant wheat genotypes may have lower dormancy levels after experiencing a high temperature shock (5 days of 40°C). The highest sensitivity towards high temperature shock is limited to a short "window" of approximately five days starting around 25 dpa. The sensitivity increases and reaches a peak at 25 to 30 days post anthesis (dpa), causing an effective and quicker release of dormancy. The sensitivity later decreases and high temperature becomes less influential on dormancy. For the dormant genotype SUN325B, release from dormancy occurred 35 days earlier if treated with temperature shock. There was no significant correlation between the timing of the peak of sensitivity and factors such as daily temperatures before temperature shock, humidity or subsequent grain moisture losses. However, the stronger the intensity (40°C versus 35°C) and longer duration (5 days versus
Download or read book Physiological and Biochemical Aspects of Agrobacterium Wheat Triticum Aestivum L Interactions written by David L. Parrott Jr. and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Agrobacterium tumefaciens and A. rhizogenes are the causal agents of gall or hairy root disease, but normally the bacteria do not cause disease in wheat. However, both bacteria grew without inhibition when exposed to intact or wounded wheat roots or embryos, and they colonized wheat root surfaces to levels similar to dicotyledonous plants. A. tumefaciens and A. rhizogenes induced 23% cell death after a 1-h exposure to wheat embryo cells grown in 7.4 mM O2, while the extent of cell death at 2.1 mM 02 was 8%. Contact with A. tumefaciens or A. rhizogenes caused cultured wheat embryo and root cells to rapidly produce H202, which decreased when embryos and roots were cultured at 2.1 mM O2. Browning and autofluorescence, and an increase in ferulic acid in cell walls, were observed in wheat embryo and root epidermal cells exposed to Agrobacterium, but. neither lignin nor callose was detected. Agrobacterium appeared to induce resistance-like responses in wheat that may limit transformation efficiency. The inability to regenerate wheat plants using tissue culture has been a limitation to high efficiency transformation. Regeneration via somatic embryogenesis was improved significantly by simulating the in ovulo environment to which the immature wheat embryos are exposed. Triticum embryo culture medium (TEC) improved callus formation, somatic embryo formation, and regeneration from somatic embryos while reducing precocious germination when compared to growth on Murashige and Skoog medium. Regeneration frequencies were improved when embryos were cultured at the O2 concentration found in the wheat ovule (2.1 mM O2) rather than atmospheric 02concentration (7.4 mM O2). Agrobacterium-mediated transformation of wheat was limited by tissue necrosis following co-cultivation, and by poor plant regeneration. Reduction of necrosis and increased plant regeneration were accomplished by amending the culture medium with antioxidant compounds and by reducing the O2 tension in which the wheat embryos were cu1tured. Twelve days past anthesis (DPA), wheat embryos were co-cultivated with Agrobacterium tumefaciens strains WAg 11 or EHA 101, incubated on TEC medium containing antioxidant compounds (catalase, cysteine and ascorbic acid), and cultured at 2.1 mM O2 concentrations. Transformation was documented in 6.0% of regenerated A. tumefaciens WAg 11 exposed wheat plants using the firefly luciferase (luc) reporter system.
Download or read book The Effect of Glume Pigmentation on the Post harvest Dormancy of Common Wheat Triticum Aestivum L written by Bahman Ehdaie and published by . This book was released on 1968 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seed Longevity and Dormancy in Wheat Triticum Aestivum L written by Mian Abdur Rehman Arif and published by . This book was released on 2012 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was undertaken to map quantitative trait loci (QTLs) and marker trait associations (MTAs) controlling seed longevity and dormancy in wheat using one bi-parental and two association mapping populations. QTL analysis of bi-parental 'International Triticeae Mapping Initiative' population reproduced in two different seasons resulted in the identification of one major and nine minor QTLs for seed longevity. There was one major QTL for dormancy observed on chromosome 4AL. The location of this QTL does not match with any of the longevity QTLs. One set of 96 winter wheat accessions (advanced gemplasm collection) and one set of 183 accessions consisting of a mixture of spring and winter wheat (genebank collection) revealed 73 and 340 MTAs for seed longevity, respectively. Of the 340 MTAs, 134 MTAs were observed after long term cold storage but the others after experimental ageing in genebank collection. The associations were distributed over all the wheat chromosomes except 4D which was not covered with markers. Results obtained after long term cold storage and experimental ageing did match only to some extent in this study which could be due to different quality of seeds produced during different seasons. However, it also can be proposed that different mechanisms are involved during deterioration in cold storage over long periods and decaying during artificial ageing treatments. For dormancy, there were 68 and 118 MTAs identified in the advanced germplasm collection and genebank collection, respectively, in addition to one major QTL on chromosome 4A in the ITMI population. Similarly, pre-harvest sprouting revealed 32 and 193 MTAs in case of advanced germplasm collection and genebank accessions, respectively. Co-linearity was found among wheat, rice and barley for loci influencing dormancy and PHS.
Download or read book The Physiology and Biochemistry of Seed Dormancy and Germination written by Anwar Ahmad Khan and published by . This book was released on 1977 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seed development and germination; Seed dormancy and germination; Seed vigor, stress and seed germination.
Download or read book Premature Sprouting as it Affects the Germinability and Other Physiological Characteristics of Wheat Seed Triticum Aestivum L written by Shu-Hui Feng Hou and published by . This book was released on 1971 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Endogenous Germination Inhibitors in the Seed Dormancy of Wheat written by Geoffrey Graham Fraser and published by . This book was released on 1980 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physiological and Genetic Studies on Seed Dormancy and Preharvest Sprouting Resistance in Wheat Triticum Aestivum L written by Craig F. Morris and published by . This book was released on 1988 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Temperature on Seed Dormancy and Alpha amylase Activity During Kernel Maturation and Germination in Wheat Triticum Aestivum L Cultivars written by Lekkala Vijayasimha Reddy and published by . This book was released on 1978 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Effect of temperature on seed dormancy, alpha-amylase activity and kernel weight in five wheat (Triticum aestivum L.) varieties was studied. Three ripening temperature conditions - 15.5°C, 26.6 °C and "Field" were used to induce dormancy. Alpha-amylase activity and kernel weight of developing kernels was determined every ten days after anthesis until maturity. Dormancy in kernels was examined at germination temperatures of 15. 5°C, 20°C and 26. 6°C. Alpha- amylase activity during germination of kernels was determined on 1st, 2nd, 3rd and 6th day. In developing kernels alpha-amylase activity peaked at 10 to 20 days after anthesis and dropped or levelled-off as the kernels approached maturity. This was observed at both 15.5°C and 26.6° C . However, the peak was not obvious at 26.6°C because of the enzyme activity was lower at this temperature than at 15.5°C. In kernels ripened in field, the enzyme activity fluctuated apparently depending upon the changes in weather conditions, especially temperature. A faster growth of kernels and higher final dry kernel weight were noticed at 26.6°C and field temperature conditions than at 15.5°C. Significant varietal differences were observed in both alpha-amylase activity in kernels and kernel weight during the development and maturation of kernels. Kernels of all varieties, ripened at 26.6 °C, germinated as fast as non-dormant check kernels at 15.5°C but exhibited varying degrees of dormancy when germinated at 20 °C and 26.6°C. In contrast, kernels of Brevor, Tom Thumb and P.I. 178211, ripened at 15.5 °C showed a high level of dormancy as shown by their failure to germinate at 20 °C and 26.6 °C, and slow germination at 15.5° C. Kernels of Hyslop and Yamhill, ripened at 15.5°C, did not show dormancy at 15.5°C but showed some dormancy at 20°C and 26.6°C. This dormancy, however, was less than in Brevor, Tom Thumb and P.I. 178211. Field ripened kernels of Yamhill and Hyslpp when germinated at 15.5°C, did not show any dormancy; whereas, P.I. 178211, Brevor and Tom Thumb expressed different degrees of dormancy. Kernels of all varieties, ripened in the field, when germinated at 20°C or 26.6 °C, showed different degrees of dormancy except Yamhill. Yamhill did not differ significantly from the one year old non-dormant check kernels at 26.6° C . A substantial increse in alpha-amylase occurred only in germinated kernels. Although kernels of all varieties ripened at 26.6°C showed about the same weighted germination percentage at 15.5°C, germinated kernels of Yamhill, Hyslop and P.I. 178211 and had highly significant greater alpha-amylase activity than those of Brevor and Tom Thumb. In general, lower alpha-amylase activity was observed at higher germination temperatures. However, the data indicate that the enzyme activity depends to some extent on the ripening temperature conditions. Thus the results indicated that seed dormancy, alpha-amylase activity and kernel weight are determined by the genotype of a variety and influenced by the temperature during maturation and germination of kernels.
Download or read book Seeds written by J. Derek Bewley and published by Springer Science & Business Media. This book was released on 2012-10-23 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: This updated and much revised third edition of Seeds: Physiology of Development, Germination and Dormancy provides a thorough overview of seed biology and incorporates much of the progress that has been made during the past fifteen years. With an emphasis on placing information in the context of the seed, this new edition includes recent advances in the areas of molecular biology of development and germination, as well as fresh insights into dormancy, ecophysiology, desiccation tolerance, and longevity. Authored by preeminent authorities in the field, this book is an invaluable resource for researchers, teachers, and students interested in the diverse aspects of seed biology.
