Progress 10/30/15 to 09/30/20
Outputs
Target Audience:In technical publications and public speaking: plant breeders, students of biology, biotechnology, and plant science, both undergraduate and graduate, scientists interested in genetics, cytogenetics of cereals and germplasm enhancement. For germplasm: plant breeders and fellow scientists using existing stocks or ordering custom made stocks. Changes/Problems:The project is modified on a continuous basis. The general framework follows the proposal from 2015; however, as the results are often unpredictable (at least to the PI), further steps have to be adjusted. The program in turf grasses was seriously modified, by dropping all work on cool season grasses and a switch to warm season grasses. This was done for two reasons: ever warmer winters do not provide sufficient vernalization and this adversely affects flowering and seed production, and made breeding progress very difficult. On the other hand, Southern California, is a perfect location for studies of warm season grasses, for a number of reasons, including water issues. Substantial funding for warm season grasses was secured and program was re-aligned very rapidly, to the point where the first two entries are now in the early stages of registration. What opportunities for training and professional development has the project provided?Two undergraduate students: Mr. Mariano Resendiz and Christian Neri provided assistance both in the greenhouse and in the laboratory during various periods during the duration of this project. This involvement included training in various techniques and approaches, including running own small research projects. Drs. D. Kopecky from the Institute of Experimental Botany, Olomouc, Czech Republic, and G. Linc from the Hungarian Academy of Sciences, Martonvasar, Hungary, each spent several weeks or months participating in active research projects. Various chromosome constructs and germplasm developed under this project are used as research materials for undergraduate and graduate students in various institutions, from UC Davis, Univ. of Nebraska, Lincoln, to India, Czech Republic, Germany and Poland. How have the results been disseminated to communities of interest?Apart from technical journal publications listed in annual reports, the PI presented 12 talks at various institutions, from UC Riverside do Chengdu, China, presenting and discussing the results, as well as two invited talks at international meetings. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
A system for fertility control in alloplasmic wheats and triticales with cytoplasms of Aegilops kotschyi, Ae. uniaristata and Ae. mutica was developed. The last cytoplasm was dropped as it causes serious delays at flowering and maturity. For the remaining two , five chromosomes were constructed . Three are chromosomes 1BS with the restorer Rfmulti removed; the other two are 1R with the restorer locus inserted, to boost the fertility restoration levels. All chromosomes differ by the size of the inserts. The 1RS arms were translocated to wheat arms 1AL and 1DL, to place the extra restorer in different positions in the genome. Lines with the kotschyi cytoplasm and engineered 1B (restorer removed) sometimes show low levels of male fertility. No such fertility was observed in lines with the entire 1BS removed implying that the 1BS arm may also carry some minor restorer. A serch for that restorer was initiated. Alloplasmic lines with cytoplasms of Ae. kotschyi and/or Ae. uniaristata were produced in 10 wheats and 12 triticales, and distribute. The three cytoplasms, in combination with some rye chromosome arms 1RS, induce haploidy, by a failure of egg fertilization. Arms 1RS from over 20 sources were screened for this ability. An average single copy 1RS produces 3-4% of haploids; the rate doubles for disomics, but there is no further enhancement with the dosage increase up to six. Two 1RS arms were identified with the induction rate at ca. 35-40% when in single dose and up to 80% when disomic. These are now being used to map the position of the locus and identify candidate genes. In wheats with the three cytoplasms and 1BS or 1RS missing, the seed is considerably smaller, by over 50% or more, apparently by a slower rate of nuclear divisions in the early endosperm development. New lines are being developed to test if the endosperm development is also associated with chromosome arms 1AS and 1DS. Two populations of diploid rye, homozygous for wheat storage protein loci Gli-B1/Glu-B3/Glu-D1 and for Gli-D1/Glu-D3/Glu-D1 were developed, tested and retested, and sufficient amounts of grain produced for tests of bread making quality. Tthe Gli-D1/Glu-D3/Glu-D1 population shows a high frequency of necrosis/chlorosis and selection against it does not show much progress. Multiple attempts to transfer the engineered chromosome FC2 from triticale to rye were all unsuccessful. It is unclear why this chromosome is consistently rejected at the diploid level. Similarly, attempts to transfer a segment of wheat chromosome 2D with Rht8 and Ppd2 into diploid rye produced mixed results. A plant heterozygous for the transfer was identified but after pollination with standard rye, the engineered chromosome was pushed out of the genome and is now carried as an extranumerary chromosome. For the time being no evidence of recombination of the wheat segment in rye was observed and it is becoming likely that this transfer will ultimately fail. Populations of doubled haploids of bread wheat were genotyped and phenotyped for several root characteristics, including seminal root angles, and several responsible QTLs were placed on genetic maps. The trade-off between the size of root system and above-ground biomass was studied in data sets from previous experiments and under controlled conditions where roots were forced to chase an ever decreasing water level. The results showed that such a trade-off exists: with reduced water the ratio of root to shoot biomass almost doubles, and at a certain point it negatively affects the above-ground biomass. However, the pattern of reaction may be different in different wheats. In search for genetic polymorphism for root-enhancing loci on rye chromosome arm 1RS, all existing sources of 1RS were screened. That included the 1RS arm from cv. Amigo which was untranslocated from its original position in 1RS.1AL translocation and retranslocated to long arms of all three group-1 chromosomes from cv. Pavon 76 . Screening of various 1RS arms, some in each of the three possible positions in the genome, fdid not detect any major differences in root biomass. It is possible that rye, as a drought tolerant and deep-rooted species, is homogenous for the character, or perhaps the tested arms were pre-selected for the character, as almost all ended up in wheat via triticale. All work with cool season grasses was abandoned in favor of warm season grasses, specifically the Cynodon sp (Bermuda grass). Over 3,000 hybrids were created, by pairwise crosses or by open pollination among all six species in the collection. These hybrids undergo testing for performance as turf for sports use and yards, in several location in CA, under regular maintenance and under reduced irrigation. Two hybrids are now being readied for release. Selection for late onset of dormancy/early greening identified hybrids where the two events were separated buy only one month. Chances are that hybrids with better winter color retention can be produced. An attempt to construct a phylogenetic tree of Cynodon turned out far more complicated than anticipated. As a rule, species did not group, but are intermixed. New samples were requested fand re-genotyped, with the same outcome. Apparently, Cynodon systematics is seriously compromised. Two attempts at androgenesis in kikuyu grass were made. There were clear indication that the switch from the generative to vegetative development of microspores can be induced but no haploids were obtained. The third attempt was rendered impossible by the pandemic. A bag of old seed was discovered in a freezer and used to select for reduced vigor, darker color and finer texture. Ca. 120 promising individuals were selected and and are currently tested under various conditions, including serious water stress. A study of misdivision of telocentrics and isochromosomes has shown that both types of chromosomes do misdivide, and implied that the misdivision frequency is correlated with the centromere size. This suggested another study, on possible association between transmission rates of specific chromosomes and their centromere sizes. A 3-D study of the metaphase I pairing of the telomeric end of one chromosome with the centromeric region of its homologue has been completed, showing that at times telomeres fail to travel into the leptotene bouquet but appear to wander throughout the volume of the nucleus. This probably reflects a failure of the telomere attachment to the nuclear membrane and may be responsible for chromosome instability of new amphiploids. All 1BS-1RS recombinants were re-genotyped and a new map was constructed. Additional 45 2RL-2BL recombinants were selected, bringing the total to 90, and these were genotyped. Together with 2RS-2BS recombinants mapped earlier the total number of homoeologous translocation breakpoints generated by the absence of the Ph1 locus is over 260, of which over 200 were allocated to specific segments of DNA assemblies. Analyses indicate that the difference between homologous and homoeologous crossing over in wheat is quantitative. The study also demonstrated that the Ph1 locus actively controls crossing over of homologues, probably be recognizing some type of DNA polymorphism. Selection among hybrids of T. durum with T. polonicum continued; the highest TKW so far was 97.6 grams, twice the TKW of the recurrent durum parent, but it was an outlier. Typical TKW increases are in the range of ca. 40-50%. No data are yet available on the effects of large glumes in tight stands. Several awnless lines were also selected, per requests of breeders.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Pudzianowska M, Mock TJ, Martin PM, Lukaszewski AJ, Baird JH.
Kikuyugrass germplasm collections in the United States and Australia show low levels of genetic diversity as revealed by DArTseq genotyping. Crop Science 2020;114.
https://doi.org/10.1002/csc2.20231
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Progress 10/01/18 to 09/30/19
Outputs
Target Audience:Breeders of cereals, especially wheat and triticale, plant cytogeneticists, turfgrass industry Changes/Problems:The project continues more or less as planed, but plants do not always cooperate fully. It is now obvious that diploid rye is very reluctant to accept a segment of wheat chromosome 2D with Rht8 and Ppd2. A system will have to be devised to screen for possible crossover events reducing the wheat segment length. As mentione above, the cytoplasm of Ae. mutica causes serious developmental delays both in wheat and triticale and as such it may have no practical utility in wheat breeding. It will be dropped from the program, with focus now on only the cytoplasms of Ae. kotschyi and Ae. uniaristata. Recent observations suggest that chromosome arm 1BS may carry another Rf locus, apart from Rfmulti. Exploratory steps will be taken to locate it, but given low and unpredictable seed set in absence of Rfmulti, this may be difficult and long. The issue of species nomenclature in Cynodon has to be resolved as DNA data do not support current systematics of the genus. What opportunities for training and professional development has the project provided?Ms. Faolan Chan from Sichuan Agricultural University spent another six months in the lab to continue research for her PhD project on crossing over in wheat under different chromosome pairing regimes. Dr. D. Kopecky from the Institute of Experimental Botany. Olomouc, Czech Republic came back for in March to initiate a new project on chromosome instability in wide hybrids; Dr. Sabina Mehdijeva from Azerbaijan started her Fulbright scholarship visit in September, working on her own wide hybrids of triticale. Christian Neri, an undergraduate student at UCR, continues in the lab working on issues involved in failure of double fertilization in alloplasmic wheats with A. kotschyi cytoplasm How have the results been disseminated to communities of interest?Three technical journal articles were published; PI gave several talks to interested audiences on chromosome manipulation techniques and karyotype evolution. What do you plan to do during the next reporting period to accomplish the goals?Attempts will continue to incorporate Rf8 and Ppd2 loci from chromosome 2D of wheat into diploid population rye. With cooperators cooperating, breadmaking qualify effects of wheat glutenin loci in diploid rye will be tested. Transfers of 1RRf and 1Brf to triticales and wheats will continue; all alloplasmic lines (cytoplasms of Ae. kotschyi, Ae. uniaristata) will be advanced by hopefully two generations; the effects of 1RRf and 1Brf on male fertility will be assessed both in alloplasmic wheats and triticales. Chromosome arms 1RS from various sources will be screened in search of polymorphism for the failure of double fertilization in wheat with the cytoplasm of Ae kotschyi and a mapping population of 1RS recombinants will be created to locate the responsible factor. Dosage effects of the 1RS arms (one to five copies) on this character will be assessed. Crosses and backcrosses of several characteristics of T. polonicum into T. durum will continue, coupled with strong selection for desirable agronomic performance. New wide hybrids of Cynodon accessions will be field tested and selected for turf characteristics; selection for reduced vigor among kikuyou grass will continue. Retirement will be pondered and a transfer of the collection of cytogenetic stocks of wheat, rye and triticale to the Genetic Resource Center at the Kansas State University will be initiated.
Impacts
What was accomplished under these goals?
Alloplasmic lines of wheat and triticale, with cytoplasms of Aegilops kotschyi, Ae. uniaristata and Ae. mutica were advanced by two backcrosses. As before, the cytoplasm of Ae. mutica produced serious delay in heading and some morphological abnormalities, which makes it unsuitable for practical use. It will be dropped from the program. The four new chromosomes for fertility control in such lines, two chromosomes 1B with Rfmulti removed and two chromosomes 1RS with Rfmulti inserted were advanced by two backcrosses into triticale, and were made homozygous in wheat. Observations of seed set, both in wheat in triticale have indicated that all four chromosome behave as expected. However, chromosome 1B1:6 developed earlier was found to restore male fertility to a very small degree (2-3 seeds per spike) suggesting that another Rf locus, with a minor effect, may be present on chromosome 1B. The single diploid rye plant heterozygous for the wheat-rye translocation 2R.2B with Rht8 and Ppd2, backcrossed to population rye, showed very low transmission of the translocation, as feared. Eleven progeny with this translocation were recovered. Unfortunately, ten of those were trisomics. Clearly, the translocation chromosome is not welcome and tolerated in standard haploid gametes. However, all plants with the translocation were shorter and earlier, as expected for the presence of Rht8 and Ppd2. Therefore, the effort will continue for at least 1-2 more generations. Populations of diploid rye homozygous for wheat storage protein loci Gli-B1/Glu-B3, Gli-D1/Glu-D3, and Glu-D1 were reselected, both by protein gel electrophoresis and cytologically, and are readied for a test of bread making effects. Extensive maps of breakpoints in 1BS-1RS and 2B-2R recombinants were created and the translocations breakpoints were allocated to specific segments on the DNA sequence assemblies for both chromosomes. Their locations and distributions were compared to reference wheat and rye maps. Apart from frequencies, no clear differences between the ph1b induced homoeologous recombinants and natural homologous crossovers with Ph1 present were detected. Selection among hybrids of T. durum with T. polonicum for awnlessness, large glumes and large kernels continued; additional crosses and backcrosses were made. The highest 1000 kernel weight so far is 97.6 gr. Field performance of these lines is yet unknown but germplasm was distributed to a durum wheat breeder. In turfgrass, no attempts at androgenesis in kikuyu grass were made, primarily for lack of funding and qualified candidates for the job. Observations were made on kikuyu selections from among existing accessions, and seedlings obtained from an old bag of seed, for reduced vigor, better texture and deeper color. Clear differences were evident. Hybridization among a set of collection bermuda (Cynodon) accessions stopped for now as there is a backlog of new hybrids: with ca. 1500 already planted in the field another ca. 750 have to be maintained in the greenhouse, for lack of field space. The issue of accession duplication and mislabeling has not yet been resolved but botanists were invited to verify species assignments. Among earlier produced hybrids several appear well adapted to SoCal conditions; talks are underway about commercial release of one or more of these hybrids. Analyses were re-fined on diversity among kikuyus from California, Hawaii and Australia but no new information was gained. A larger study was initiated to test the possible relationship between telomere positioning in somatic nuclei and genetic instability of new amphiploids.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Kopecky, D., & Lukaszewski, A. J. (2019). Misdivision of Telocentrics and Isochromosomes in Wheat. Cytogenet and Genome Res, 157(3), 179188
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Tulpov�, Z., Toegelov�, H., Lapitan, N. L. V., Peairs, F. B., Macas, J., Nov�k, P., & `imkov�, H. (2019). Accessing a Russian Wheat Aphid Resistance Gene in Bread Wheat by Long-Read Technologies. The Plant Genome 12:1-11
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Pernikov�, K., Kol�kov�, V., Lukaszewski, A., Fan, C., Vr�na, J., Duchoslav, M., & Kopeck�, D. (2019). Instability of Alien Chromosome Introgressions in Wheat Associated with Improper Positioning in the Nucleus. Int. J of Molecular Sci, 20(6), 1448
|
Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Breeders of cereals, especially wheat and triticale, plant cytogeneticists, turfgrass industry Changes/Problems:As noted previously, problems have been encountered in the development of diploid rye populations with wheat storage proteins. These may continue as rye appears quite unpredictable in its behavior, especially its willingness to accept foreign introgressions. The same will very likely be true with the new introgressions of Rf8 and Ppd2. Transfers of modified 1RS and1B (with or without the Rfmulti locus) follow an established tract, but suprises do happen. New crosses among Cynodon will be attempted but there were seasons in the past when nothing seemed to work. Search for a suitable candidate to advance androgenesis in kikuyou grass will continue; if one is found, a new round of trials will commence. What opportunities for training and professional development has the project provided?Ms. Faolan Chan from Sichuan Agricultural University spent several months in the lab to initiate her PhD project on crossing over in wheat under different chromosome pairing regimes. Dr. D. Kopecky from the Institute of Experimental Botany. Olomouc, Czech Republic came back for in April to complete the project on isochromosome and telocentric misdivision. Christian Neri, an undergraduate student at UCR joined the lab and trains in DNA data analysis and basic cytogenetics How have the results been disseminated to communities of interest?Three articles were published; PI gave several talks to interested audiences on chromosome manipulation techniques and karyotype evolution. What do you plan to do during the next reporting period to accomplish the goals?Selection for rye populations homozygous forwheat storage proteins will continue, primarily to increase population sizes and remove any inbreeding depression. An attempt will be made to incorporate Rf8 and Ppd2 loci from chromosome 2D of wheat into diploid population rye. Transfer of 1RRfand 1Brf to triticales and wheats will continue; all alloplasmic lines (cytoplasms of Ae. kotschyi, Ae. uniaristata, Ae. mutica) will be advanced by hopefully two generations; the effects of 1RRf and 1Brf on male fertility will be assessed, at least in wheat. The search for the location of a factor on rye 1RS responsible for the failure of double fertilization will commenceas the first set of testcrosses has been completed and progeny seed produced. An attempt will be made to locate the factor on 1BS that appears responsible for production of very small grain in the Ae. kotschyi cytoplasm. Backcrosses of several characteristics of T. polonicum into T. durum will continue, coupled with strong selection for desirable agronomic performance. Additional crosses among Cynodon accessions will be attempted; selection for reduced vigor among kikuyou grass will continue. Retirement will be pondered and the fate of the collection of cytogenetic stocks of wheat, rye and triticale will have to be addressed.
Impacts
What was accomplished under these goals?
Alloplasmic lines of wheat and triticale, with cytoplasms of Aegilops kotschyi, Ae. uniaristata and Ae. mutica were advanced by two backcrosses. As before, the cytoplasm of Ae. mutica produces serious delay in heading and some morphological abnormalities, so it will be unsuitable for practical use, but it is retained in the program. Of the four new chromosomes for fertility control in such lines, homozygotes for two chromosomes 1B with Rfmulti removed were created and tested against one of the three cytoplasms. Two chromosomes 1RS with Rfmulti inserted were crosses and backcrossed into triticale. In wheat, these two chromosomes 1R were misdivided across the centromere and translocated to wheat chromosome arms 1AL and 1DL. All four such translocations appear to have been recovered but are yet to be verified. These chromosomes (complete 1R in triticale and centric translocations in wheat) will serve as an additional boost to fertility restoration. After some five cycles of attempts, a single diploid rye plant was recovered heterozygous for the wheat-rye translocation 2R.2B with Rht8 and Ppd2. This plant was moderately fertile and was cross pollinated by a population rye. Seed set was about 50% raising some suspicion that gametes carrying the translocations are non-functional. Populations of diploid rye homozygous for wheat storage protein loci Gli-B1/Glu-B3, Gli-D1/Glu-D3, and Glu-D1 were recreated. The population with Gli-D1/Glu-D3/Glu-D1 is large enough and probably will produce enough grain for bread making tests. Population Gli-B1/Glu-B3/Glu-D1 was small and must be increased by incorporation of other genotypes to avoid inbreeding depression. All 1BS-1RS recombinants were re-genotyped and a new map constructed. Efforts are underway to narrow down the sites of crossovers to specific DNA sequences. Selection among hybrids of T. durum with T. polonicum for awnlessness, large glumes and large kernels continued. The highest 1000 kernel weight so far is 82 gr; homozygotes for the other two characters also developed. Their field performance is yet unknown. In turfgrass, no attempts at androgenesis in kikuyu grass were made, primarily for lack of qualified candidates for the job. On the other hand, hybridization among a set of collection bermuda (Cynodon) accessions was very successful. Over 700 new hybrids were produced and planted in the field for observations. Hybrids from the previous round of hybridization are still being evaluated in four different sites and under different conditions. Several appear well adapted to SoCal conditions and attracted considerable interest from turf producers. Collection accessions and new samples from USDA were re-genotyped using DNA sequence based markers and a phylogenetic tree of Cynodon was produced. As before, individual species didnot group. It appears that there are serious problems with species classification, in addition to quite extensive duplication. An article describing a 3-D study of the mechanism responsible for metaphase I pairing of a telomeric end of one chromosome with the centromeric region of its homologue was returned for additional data. To provide such data somatic nuclei were examined in 3D showing that the problem of improper arrangement of telomeres is not limited to meiosis but is systemic in nature. This suggested a follow up study that may explain the general phenomenon of meiotic instability of new amphiploids.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Lukaszewski AJ. 2017. Chromosomes 1BS and 1RS for control of male fertility in wheats and triticales with cytoplasms of Aegilops kotschyi, Ae. mutica and Ae. uniaristata. Theor Appl. Genet. 130:25212526
Lukaszewski AJ, C. Cowger. 2017. Re-engineering of the Pm21 transfer from Haynaldia villosa to bread wheat by induced homoeologous recombination. Crop Sci 57:25902594
Tyrka M, Oleszczuk S, Rabiza-Swider J, Wos H, Wedzony M, Zimny J, Ponitka A, ?lusarkiewicz-Jarzina A, Metzger RJ, Baenziger PS, Lukaszewski AJ. 2018. Populations of doubled haploids for genetic mapping in hexaploid winter triticale. Mol Breeding 38: 46
|
Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Breeders of cereals, especially wheat and triticale, plant cytogeneticists, turfgrass industry Changes/Problems:As listed above, two major problems were identified during the reporting period: populations of rye presumed homozygous for wheat storage proteins were nt homozygous after all; any speculation on the nature and distribution of crossing over in 1RS-1BS pair requires a craftily devised control. Both issues will be addressed. The fact that Rht8 failed to be incorporated into rye was not all that surprising; more annoying, really. Crosses and backcrosses will be made until such introgression is accomplished. Second attempt at androgenesis in kikuyu grass did not produce any immediate results; if necessary, a third attempt may be made next summer. What opportunities for training and professional development has the project provided?Dr. David Kopecky from the Institute of Experimental Botany, Czech Republic, spent one month studying meiotic behavior of telocentrics and isochromosomes. Dr. Gabriella Linc from Martonvasar, Hungary, spent three weeks setting up the 3-D work on the behavior of telomeres in chromosome pairing initiation; Ms. Katarzyna Makowiak from Plant Breeding Institute, Radzikow, Poland, spent 11 weeks setting up conditions for androgenesis in kikuyu grass, Dr. Suquin Zhang from Guizou University., Guiang, China spent two weeks learning androgenesis in triticale; Ms. Faolan Chan from Sichuan Agricultural University, China, started her visit to collect data for master's dissertation on male fertility control in alloplasmic wheat. How have the results been disseminated to communities of interest?One article published; three articles in press; eight talks to various audiences,from cytogeneticists to plant breeders, participation in turfgrass field day to present bermuda grass hybrids. What do you plan to do during the next reporting period to accomplish the goals?carry on the experiments along the same lines with modifications as dictated by current experience and results. Primarily, develop a mapping population in wheat to serve as an appropriate control for the population of 1RS-1BS recombinants. Along they way, try to identify the candidate gene for Rfmulti.
Impacts
What was accomplished under these goals?
Alloplasmic lines of wheat and triticale, with cytoplasms of Aegilops kotschyi, Ae. uniaristata and Ae. mutica were advanced by two backcrosses. Four new chromosomes for fertility control in such lines were created: two chromosomes 1B with Rfmulti removed and two chromosomes 1RS with Rfmulti inserted. These chromosomes, once placed on proper positions in the genome will allow for full control of male fertility in wheat and triticale hybrid breeding programs. Transfer of Rht8 to diploid rye was advanced by two backcrosses but it was unsucessful. After screening of ca. 700 progeny over two generations no diploid rye with the critical wheat segment was identified. However, three plants were retained that do carry the segment but also carry additional wheat chromosome or chromosomes. Another backcross was made. Along the way it became apparent that the populations of diploid rye presumed homozygous for wheat storage protein loci Gli-B1/Glu-B3, Gli-D1/Glu-D3, and Glu-D1 must have outcrossed and are no longer homozygous. Therefore, a set of crosses was devised to re-create the populations, free of inbreeding depression. The database of crossovers in 1BS-1RS was reanalyzed and several interesting observations was made regarding frequency and distributions of crossovers. However, since the DNA markers used were anonymous, at present it is impossible to determine if irregularities in distribution are a consequence of uneven distribution of markers or of crossovers. Therefore, a new mapping population was assembled and a system of control devised to resolve the issue. In turfgrasses, another serious attempt at androgenesis in kikuyu grass was made. No haploids were obtaind by the end of the reporting period but observations offer some optimism. Hybrids of Cynodon (bermuda grass) are still being evaluated in four different sites and under different conditons. Several appear very well adapted to SoCal conditions and may be released in the future. An attempt to construct a phylogenetic tree of Cynodon, and to establish parentage of some hybrids, failed miserably. With two exceptions, individual species didnot group, as expected, but accessions were intermixed. To clarify the issue a new set of samples was requested from USDA and will be genotyped in near future. A study of misdivision of telocentrics and isochromosomes has been completed, cleary showing that both types of chromosomes do misdivide, and implying that the misdivision frequency is strongly correlated with the centromere size. A 3-D study of the mechanism responsible for metaphase I pairing of a telomeric end of one chromosome with the centromeric region of its homologue has also been completed, showing that in a low proportion of cases telomeres fail to travel into the leptotene bouquet but instead migrate throughout th volume of the nucleus, including the centromere pole. Both studies still need perfect photos for publication. The work with L. perenne x F. pratensis hybrids was abandoned in favor of warm season grasses and there was no activity in this area during the reporting period.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Lukaszewski A.J. 2017. A set of new 1RS translocations from wheat cv. Amigo in a uniform genetic background. Euphytica 213:214
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Progress 10/30/15 to 09/30/16
Outputs
Target Audience:Wheat and triticale breeders; turf grass managers Changes/Problems:As stated above, under pressure from several sources, it was decided to freeze the effort with cool season grasses and considerably expand the effort with warm season grasses. Warm season grasses are far more water efficient; selection for improved drought tolerance may improve this efficiency even more. Two rounds of selection pressure to indroduce Rht8 and Ppd1 from wheat into diploid rye were unsuccessful; the next round of selection is underway. What opportunities for training and professional development has the project provided?One graduate student (C. Hohn) completed his PhD and moved on to a breeding position. One undergraduate student (M. Resendiz) has gone through several seasons of training in experiment design and management, and is nowenrolled in a graduate program. How have the results been disseminated to communities of interest?Some results were presented to wheat, triticale and rye breeders at an international meeting; two articles have been submitted for publication. Some results have been disseminated via informal chanels. What do you plan to do during the next reporting period to accomplish the goals?The effort will focus primarily on fertility control in alloplasmic wheats and triticales with the cytoplasm of Ae. kotschyi, to arrive at a sensible system of fertility control in hybrid production, and on introgression of interesting characteristics (such as large grain and long glumes) from Triticum polonicum into durum and bread wheats. Efforts will continue to test existing hybrids in bermudagras and to create as many new ones as possible. A considerable investment will be made intoandrogenesisin kikuyougrass. Pairing and misdivision of telocentric and isochromosomes will be observed. Hopefully, the study of the alternative (to the leptotene bouquet) system of homologue recognition will be completed.
Impacts
What was accomplished under these goals?
A new wheat-rye recombinant chromosome was created and tested that removes a restorer locus from chromosome 1B of wheat in cytoplasms of Ae. kotschyi, Ae. uniaristata and Ae. mutica. Critical hybrids were made to createadditional four such chromosomes. This opens a new system of male sterility/fertility restoration for hybrid wheat production. Homozygotes for two transfers of segments of chromosome 6V from Haynaldia villosa with powdery mildew resistance locus Pm21 to chromosome 6A of wheat were created, tested and found completely resistant. Thesetransfers were accomplished by homoeologous recombination; they showed that earlier attempts done by irradiation ended up with an insert in incorrect position on the chromosome. Populations of doubled haploids of bread wheat were genotyped and phenotyped for several root characteristics, including seminal root angles, and several responsible QTLs were placed on the genetic maps. The trade-off between the size of root system and above-ground biomass was studied under controlled conditions and the results showed that while the general trend shows that such a trade-off exists (root biomass increased beyond a certain point negatively affects the above-ground biomass), the pattern may be different in different wheats. This may also indicate that under the experimental conditions used the critical point has not been reached in some wheats. To create a set of experimental lines for testing of root systems, the 1RS arm in the 1RS.1AL translocation from cv. Amigo was untranslocated from 1AL and re-translocated to long arms of all three group-1 chromosomesfrom cv. Pavon 76 wheat. Two generations of selection for the introgression of Rht8 and Ppd1 from wheat to rye were unsuccessful; new round of selection is underway; however, in the process a set of diploid ryes with introgressions of individual wheat chromosomes was created. At this point it is not clear if these chromosomes will be transmitted to next generations.New lines ditelocentric for recombinant 1RS-1BS (wheat-rye) chromosome arm were created for future optical mapping and chromosome sorting to determine the location of recombination points, brining the set to 13. Data were collected on the alternative mechanism of homologoue search and recognition during chromosome pairing initiation; publication cannot proceed for lack of a killer image. Under pressure from various sources concerned with drought and water-use restrictions in CA, the Lolium-Festuca project (cool season grasses) was suspended in favor of expansion of projects dealing with warm season grasses. One of new interspecific hybrids in Cynodon (bermudagrass) showed surprising resistance to drought. First attempt have been made to generate haploids in kikuyugrass, to reduce its vigor, aggressivness and invasivness. Microspore divisions were induced and embryoid-like structures observed.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Hohn C.E, Lukaszewski A.J. 2016. Engineering the 1BS chromosome arm in wheat to removethe Rfmulti locus restoring male fertility in cytoplasms of Aegilops kotschyi, Ae. uniaristata and Ae. mutica. Theor. Appl. Genet. 129:17691774
- Type:
Book Chapters
Status:
Published
Year Published:
2016
Citation:
Lukaszewski, A.J. 2016. Manipulation of Homologous and Homologous Chromosome Recombination in Wheat. In: Kianian S.F., Kianian P.A.A. Eds. Plant Cytogenetics. Methods and Protocols. Methods in Mol Biol 1429:77-89
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