logging in or signing up APOMIXIS chhabra61 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 1437 Category: Education License: All Rights Reserved Like it (1) Dislike it (0) Added: August 10, 2010 This Presentation is Public Favorites: 2 Presentation Description No description available. Comments Posting comment... By: abbas1434 (3 month(s) ago) sir plz u give me this presentation i requires it.plz allow it 2 download r send me on my email id abbas1434@yahoo.com Saving..... Post Reply Close Saving..... Edit Comment Close By: jawadulhassan (7 month(s) ago) sir plz u give me this presentation i requires it for my seminar topic plz allow it 2 download r send me on my email id jadi_naqvi2009@yahoo.com Saving..... Post Reply Close Saving..... Edit Comment Close By: shafetoye (8 month(s) ago) please i like this presentation and so other related ones. I will appreciate it if you can allow me download them. Thank you Saving..... Post Reply Close Saving..... Edit Comment Close By: skdas123 (20 month(s) ago) nd a copy of the presentation at sambit.nitrkl@gmail.com Thanks a lot, sambit Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Slide 1: APOMIXIS IN CROP PLANTS Copyright of original figures used in this presentation from other sources is duly acknowledged and the copyright remains with its original creator. These have not been used for commercial purpose but for educational use only. DEFINATION : DEFINATION 1. Apomixes is a form asexual reproduction that occurs via seeds in which embryos develop without fertilization.2. In apomixis, seeds are formed but the embryo develops without fertilization.3. Synonymous with angiosperm seed formation, without fertilization of egg cell is also known as apomixis.4.Asexual reproduction of seed is called the apomixis. Classification of Apomixis : Classification of Apomixis Adventive Embryonic:- In this case the embryo develop from the vegetative cell of the ovule, such as nuclleus integument and chalaza .Development of embryo does not involve production of embryo sac .It occurs commonly in mango (Mangifera indica), citrus plants, etc. Apospory:- : Apospory:- Some vegetative cell of the ovule develop into unreduced embryosac after meiosis . The embryo may be develop from the egg cell or some other cell of the embryo sac. It occurs in some species like hieraceum, malus, crepis etc. Diplospory:- : Diplospory:- Embryosac is produced from the megaspore which may be haploid or diploid. They generally diploid. Parthenogenesis:- : Parthenogenesis:- The embryo develops from the egg cell. Depending upon weather the embryosac is haploid or diploid parthenogenesis is termed as haploid or diploid parthenogenesis. Haploid parthenogenesis occurs in Solanum Nigrum, Nicotiana and Maize. Diploid parthenogenesis occurs in many grasses, e.g. Taraxacum. Apogamy:- : Apogamy:- In apogamy synergids antipodal cell develop into an embryo. Like parthenogenesis, apogamy may be haploid or diploid depending upon the haploid or diploid state of embryo sac. Diploid apogamy occurs in Allium and many other plant secies. Apomixis in crops : Apomixis in crops Substitute for sexual production. Development of embryo without sexual reproduction. Identification in over 300 species across 37 families . Not rare but relatively uncommon . Reproductive Behavior : Reproductive Behavior Obligate Apomitic :- a plant which reproduce only by asexual reproduction. Facultative Apomitic:- a plant which reproduce either sexually or asexually. Both process may be occurs simultaneously or one may predominant. With in a genus or species, all reproduction strategies may be possible. Cytoplasmic in apomicts : Cytoplasmic in apomicts Meiosis in microsprogenesis usually irregular. However in some cases only the female gametophyte is affected and normal pollen is produced. Genetics of Apomixis : Genetics of Apomixis Apomixis genetically controlled in most cases studied. Control is complex (mutagenic) and recessive to sexual reproduction. Polyploidy may effect apomatic reproduction. Hybridization tends to increase apomixis. Use of Apomixis in Breeding : Use of Apomixis in Breeding Production of exact replicas of diploid. Fix hybrid vigor. Fix heterozygous status. Identification of Apomixis : Identification of Apomixis Pollination control. Seeds w/o pollination, apomixis present. Progeny analysis. Uniform, all progeny maternal like. Cytological observation. Unexpected chromosome from cross with 2 polidy levels i.e. (2nx4n=2n or 4n). Developmental observation. Megaspore, embryosac and embryo. Powerful Breeding Tools : Powerful Breeding Tools Apomixis is potentially a powerful breeding tool to fix heterosis. But it has mostly been regarded as barrier for the breeder; because recombination of crossing is very difficult or evenly impossible. Ideal Apomatic system : Ideal Apomatic system An ideal apomatic system from the point of view of plant breeding should have the following features: The apomatic geomtotype should preferably be fully male fertile and self-incompatible and reproduce via pseudogamy. Pollen production essential for the transfer of gene controlling apomixis to normal sexual gamatotype . Apomixis should be dominant over sexual reproduction. Continued… Ideal Apomatic system : Usually apomixis governed to or more seldom many genes. Expression of apomixis should be little affected by the environment . In case of diplospory,chromosome should not pair or recombine during first meiotic division, this is because recombination would generate new gene combinations on the various chromosomes which may give rise to variation among the progeny. Ideal Apomatic system Application of Apomixis : Application of Apomixis Apomixis can be used to achieve the following objective. Fixation of heterosis. Production of homozygous lines. Development phenotypically stable population called hybrids. Problems in utilization of Apomixis : Problems in utilization of Apomixis Utilization of apomixis in plant breeding presents several problems which are outline below. Apomixis is very complicated phenomenon. Therefore its utilization necessities reorientations of breeding procedures as well as seed artification . Estimation of the level of apomixis in case of facultative apomixis is tedious and time consuming. In case facultative apomatics the proportion of sexual progeny is affected by environmental factor like day- length and temperature are more important. The genetic base of apomixis is not clear in most cases. You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
APOMIXIS chhabra61 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 1437 Category: Education License: All Rights Reserved Like it (1) Dislike it (0) Added: August 10, 2010 This Presentation is Public Favorites: 2 Presentation Description No description available. Comments Posting comment... By: abbas1434 (3 month(s) ago) sir plz u give me this presentation i requires it.plz allow it 2 download r send me on my email id abbas1434@yahoo.com Saving..... Post Reply Close Saving..... Edit Comment Close By: jawadulhassan (7 month(s) ago) sir plz u give me this presentation i requires it for my seminar topic plz allow it 2 download r send me on my email id jadi_naqvi2009@yahoo.com Saving..... Post Reply Close Saving..... Edit Comment Close By: shafetoye (8 month(s) ago) please i like this presentation and so other related ones. I will appreciate it if you can allow me download them. Thank you Saving..... Post Reply Close Saving..... Edit Comment Close By: skdas123 (20 month(s) ago) nd a copy of the presentation at sambit.nitrkl@gmail.com Thanks a lot, sambit Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Slide 1: APOMIXIS IN CROP PLANTS Copyright of original figures used in this presentation from other sources is duly acknowledged and the copyright remains with its original creator. These have not been used for commercial purpose but for educational use only. DEFINATION : DEFINATION 1. Apomixes is a form asexual reproduction that occurs via seeds in which embryos develop without fertilization.2. In apomixis, seeds are formed but the embryo develops without fertilization.3. Synonymous with angiosperm seed formation, without fertilization of egg cell is also known as apomixis.4.Asexual reproduction of seed is called the apomixis. Classification of Apomixis : Classification of Apomixis Adventive Embryonic:- In this case the embryo develop from the vegetative cell of the ovule, such as nuclleus integument and chalaza .Development of embryo does not involve production of embryo sac .It occurs commonly in mango (Mangifera indica), citrus plants, etc. Apospory:- : Apospory:- Some vegetative cell of the ovule develop into unreduced embryosac after meiosis . The embryo may be develop from the egg cell or some other cell of the embryo sac. It occurs in some species like hieraceum, malus, crepis etc. Diplospory:- : Diplospory:- Embryosac is produced from the megaspore which may be haploid or diploid. They generally diploid. Parthenogenesis:- : Parthenogenesis:- The embryo develops from the egg cell. Depending upon weather the embryosac is haploid or diploid parthenogenesis is termed as haploid or diploid parthenogenesis. Haploid parthenogenesis occurs in Solanum Nigrum, Nicotiana and Maize. Diploid parthenogenesis occurs in many grasses, e.g. Taraxacum. Apogamy:- : Apogamy:- In apogamy synergids antipodal cell develop into an embryo. Like parthenogenesis, apogamy may be haploid or diploid depending upon the haploid or diploid state of embryo sac. Diploid apogamy occurs in Allium and many other plant secies. Apomixis in crops : Apomixis in crops Substitute for sexual production. Development of embryo without sexual reproduction. Identification in over 300 species across 37 families . Not rare but relatively uncommon . Reproductive Behavior : Reproductive Behavior Obligate Apomitic :- a plant which reproduce only by asexual reproduction. Facultative Apomitic:- a plant which reproduce either sexually or asexually. Both process may be occurs simultaneously or one may predominant. With in a genus or species, all reproduction strategies may be possible. Cytoplasmic in apomicts : Cytoplasmic in apomicts Meiosis in microsprogenesis usually irregular. However in some cases only the female gametophyte is affected and normal pollen is produced. Genetics of Apomixis : Genetics of Apomixis Apomixis genetically controlled in most cases studied. Control is complex (mutagenic) and recessive to sexual reproduction. Polyploidy may effect apomatic reproduction. Hybridization tends to increase apomixis. Use of Apomixis in Breeding : Use of Apomixis in Breeding Production of exact replicas of diploid. Fix hybrid vigor. Fix heterozygous status. Identification of Apomixis : Identification of Apomixis Pollination control. Seeds w/o pollination, apomixis present. Progeny analysis. Uniform, all progeny maternal like. Cytological observation. Unexpected chromosome from cross with 2 polidy levels i.e. (2nx4n=2n or 4n). Developmental observation. Megaspore, embryosac and embryo. Powerful Breeding Tools : Powerful Breeding Tools Apomixis is potentially a powerful breeding tool to fix heterosis. But it has mostly been regarded as barrier for the breeder; because recombination of crossing is very difficult or evenly impossible. Ideal Apomatic system : Ideal Apomatic system An ideal apomatic system from the point of view of plant breeding should have the following features: The apomatic geomtotype should preferably be fully male fertile and self-incompatible and reproduce via pseudogamy. Pollen production essential for the transfer of gene controlling apomixis to normal sexual gamatotype . Apomixis should be dominant over sexual reproduction. Continued… Ideal Apomatic system : Usually apomixis governed to or more seldom many genes. Expression of apomixis should be little affected by the environment . In case of diplospory,chromosome should not pair or recombine during first meiotic division, this is because recombination would generate new gene combinations on the various chromosomes which may give rise to variation among the progeny. Ideal Apomatic system Application of Apomixis : Application of Apomixis Apomixis can be used to achieve the following objective. Fixation of heterosis. Production of homozygous lines. Development phenotypically stable population called hybrids. Problems in utilization of Apomixis : Problems in utilization of Apomixis Utilization of apomixis in plant breeding presents several problems which are outline below. Apomixis is very complicated phenomenon. Therefore its utilization necessities reorientations of breeding procedures as well as seed artification . Estimation of the level of apomixis in case of facultative apomixis is tedious and time consuming. In case facultative apomatics the proportion of sexual progeny is affected by environmental factor like day- length and temperature are more important. The genetic base of apomixis is not clear in most cases.