Progress 04/08/08 to 04/07/13

Outputs
Progress Report Objectives (from AD-416): Fusarium head blight (FHB) or scab,caused by the fungus Fusarium graminearum Schwabe, is a serious disease of wheat. The research objective is to develop genetic resistance to FHB in durum, or macaroni, wheat (Triticum turgidum L., 2n = 4x = 28; AABB genomes) by exploiting novel sources of resistance in the wild relatives. It has been difficult to identify effective sources of resistance in durum wheat cultivars. However, several wild grasses, including diploid wheatgrasses in the secondary or tertiary gene pool of wheat, are excellent sources of FHB resistance that may be incorporated into durum germplasm. Improved durum germplasm with reliable FHB resistance could then be used to incorporate resistance genes into durum and bread wheat cultivars. Specific subobjectives of this project are to: a. Develop alien addition lines involving chromosomes or chromatin, with FHB resistance from diploid wheatgrasses, Lophopyrum elongatum (Host) �. L�ve [= Agropyron elongatum (Host) Beauv.] and Thinopyrum bessarabicum (Savul. & Rayss) �. L�ve (= Agropyron bessarabicum Savul. & Rayss). b. Initiate new crosses with other potential donors such as Thinopyrum junceiforme (L�ve & L�ve) L�ve, 2n = 4x = 28; J1J1J2J2 genomes) and Thinopyrum nodosum [= Lophopyrum nodosum (Nevski) �. L�ve] that may provide new sources of alien chromosomes with FHB resistance. c. Characterize the added alien chromosome(s) from the wild relatives that confer FHB resistance to durum wheat. d. Evaluate both FHB resistance and mycotoxin deoxynivalenol (DON) accumulation with the longer-term objective of releasing FHB-resistant germplasm. e. Assess the genomic relationships between wheat and related species in the intergeneric hybrids. Approach (from AD-416): Alien gene transfer into durum wheat will be carried out by tools of classical and molecular cytogenetics. The cytogenetic techniques will involve sexual hybridization between durum cultivars and wild grasses, coupled with induction of pairing among chromosomes of parental species by manipulation of the pairing-control mechanism(Ph1). This approach will facilitate transfer of alien chromatin into the durum genome, which will then be characterized using fluorescent genomic in situ hybridization (fl-GISH) and chromosome-specific markers. Using this approach, alien addition lines involving diploid wheatgrass (Lophopyrum elongatum and Thinopyrum bessarabicum) chromosomes or chromatin with FHB resistance will be developed. In addition to using these two diploid wheatgrasses as donors of FHB resistance, we will initiate new crosses with other potential donors such as Thinopyrum junceiforme and Thinopyrum nodosum (= Lophopyrum nodosum) that may provide new sources of alien chromosomes with resistance. Fertile hybrid derivatives and stable alien addition lines will be screened for FHB resistance using the techniques we have already standardized. This is the final report for the project 5442-21000-032-00D. Research continues under the new project 5442-21000-038-00D. In a previous project, we successfully identified that chromosome 1E of a wheatgrass (Lophopyrum elongatum) had genes for scab tolerance and introduced them into the durum cultivar Langdon by developing a disomic addition line, DGE-1. During the course of the current project, we used this line to develop two disomic substitution lines (DGE-2 with the substitution of chromosome 1E for durum chromosome 1A, and DGE-3 with the substitution of 1E for durum chromosome 1B) and screened for scab tolerance. DGE-2 had higher tolerance than Langdon. We also identified a set of molecular markers to identify each of the seven grass (L. elongatum) chromosomes, designated as 1E, 2E, 3E, 4E, 5E, 6E, and 7E. Using a specialized cytological technique called fluorescent genomic in situ hybridization (fl-GISH), we have shown the usefulness of these molecular markers for identification of desirable alien chromosomes. These markers were used to screen hybrid populations expeditiously during the development of the DGE-2 and DGE-3 substitution lines, saving time and money. We also produced hybrids of durum with a second wheatgrass (Thinopyrum bessarabicum), but these stable durum disomic addition lines have not been screened for scab resistance. Suitable molecular markers were selected to identify the Th. bessarabicum chromosomes in the durum disomic addition lines. The gene Ph1 limits pairing to identical (homologous) chromosomes and does not allow dissimilar chromosomes to pair. This system gives us an excellent means to determine relationships between durum and grass chromosomes and allows us to transfer potentially desirable traits from the wheatgrasses into durum wheat. Toward this goal, we crossed DGE-1 with a Ph1 mutant that allows pairing of dissimilar chromosomes, which in turn should allow interchange of chromosome segments between 1E and its durum chromosome counterpart 1A or 1B.

Impacts
(N/A)

Publications

• Jauhar, P.P., Peterson, T.S. 2013. Registration of DGE-3, a durum wheat disomic substitution line 1E(1B) involving a wheatgrass chromosome. Journal of Plant Registrations. 7:257-259.
• Jauhar, P.P., Peterson, T.S. 2013. Synthesis and characterization of advanced durum wheat hybrids and addition lines with thinopyrum chromosomes. Journal of Heredity. 104:428-436.

Progress 10/01/11 to 09/30/12

Outputs
Progress Report Objectives (from AD-416): Fusarium head blight (FHB) or scab,caused by the fungus Fusarium graminearum Schwabe, is a serious disease of wheat. The research objective is to develop genetic resistance to FHB in durum, or macaroni, wheat (Triticum turgidum L., 2n = 4x = 28; AABB genomes) by exploiting novel sources of resistance in the wild relatives. It has been difficult to identify effective sources of resistance in durum wheat cultivars. However, several wild grasses, including diploid wheatgrasses in the secondary or tertiary gene pool of wheat, are excellent sources of FHB resistance that may be incorporated into durum germplasm. Improved durum germplasm with reliable FHB resistance could then be used to incorporate resistance genes into durum and bread wheat cultivars. Specific subobjectives of this project are to: a. Develop alien addition lines involving chromosomes or chromatin, with FHB resistance from diploid wheatgrasses, Lophopyrum elongatum (Host) �. L�ve [= Agropyron elongatum (Host) Beauv.] and Thinopyrum bessarabicum (Savul. & Rayss) �. L�ve (= Agropyron bessarabicum Savul. & Rayss). b. Initiate new crosses with other potential donors such as Thinopyrum junceiforme (L�ve & L�ve) L�ve, 2n = 4x = 28; J1J1J2J2 genomes) and Thinopyrum nodosum [= Lophopyrum nodosum (Nevski) �. L�ve] that may provide new sources of alien chromosomes with FHB resistance. c. Characterize the added alien chromosome(s) from the wild relatives that confer FHB resistance to durum wheat. d. Evaluate both FHB resistance and mycotoxin deoxynivalenol (DON) accumulation with the longer-term objective of releasing FHB-resistant germplasm. e. Assess the genomic relationships between wheat and related species in the intergeneric hybrids. Approach (from AD-416): Alien gene transfer into durum wheat will be carried out by tools of classical and molecular cytogenetics. The cytogenetic techniques will involve sexual hybridization between durum cultivars and wild grasses, coupled with induction of pairing among chromosomes of parental species by manipulation of the pairing-control mechanism(Ph1). This approach will facilitate transfer of alien chromatin into the durum genome, which will then be characterized using fluorescent genomic in situ hybridization (fl-GISH) and chromosome-specific markers. Using this approach, alien addition lines involving diploid wheatgrass (Lophopyrum elongatum and Thinopyrum bessarabicum) chromosomes or chromatin with FHB resistance will be developed. In addition to using these two diploid wheatgrasses as donors of FHB resistance, we will initiate new crosses with other potential donors such as Thinopyrum junceiforme and Thinopyrum nodosum (= Lophopyrum nodosum) that may provide new sources of alien chromosomes with resistance. Fertile hybrid derivatives and stable alien addition lines will be screened for FHB resistance using the techniques we have already standardized. Although durum wheat is one of the most important cereal crops in the country, especially in North Dakota, there is no reliable source of FHB resistance in the current durum cultivars. We discovered that diploid wheatgrass (Lophopyrum elongatum), in the tertiary gene pool of durum wheat, is an excellent source of FHB resistance. We, therefore, tapped this grass for breeding FHB resistance into durum cultivars. Through chromosome engineering, we produced a durum alien addition line of the cultivar Langden by introducing in it a double dose of chromosome 1E. This addition line has an enhanced tolerance to FHB and the gene(s) for FHB resistance are located in the chromosome 1E. We released this alien addition as a genetic stock DGE-1 in 2008. We further produced a disomic alien substitution line in which chromosome 1A was substituted by 1E. This substitution was released as a genetic stock DGE-2 in 2011. We have produced another disomic alien substitution in which second homoeologue 1B in the group-1 was replaced by 1E. This substitution is being released as a genetic stock DGE-3. These genetic stocks will be useful in basic studies on FHB resistance. We have been successful in associating molecular markers to individual chromosomes in the durum homoeologous group-1 and to chromosomes of diploid wheatgrass. Thus, we were able to identify the grass chromosomes added into durum wheat. Based on chromosome pairing, we were successful in assessing genomic relationships. Accomplishments 01 New genetic stock of durum wheat. Fusarium Head Blight (FHB) is a very damaging disease of durum wheat, an important cereal crop in the upper Midwest of the United States. However, there is no reliable source of FH resistance for current durum cultivars. ARS researchers in Fargo, North Dakota used a diploid wild grass species as a source of FHB resistance t produce plants in which one pair of durum chromosomes was replaced by a pair of grass chromosomes. Seed from this new genetic stock, called DGE has been deposited at the National Center for Genetic Resources Preservation Center, Fort Collins, Colorado. Molecular markers are very useful in distinguishing durum chromosomes from grass chromosomes and therefore can accelerate resistance breeding work. This unique genetic stock will be particularly useful in basic research on FHB resistance in durum wheat.

Impacts
(N/A)

Publications

• Jauhar, P.P., Peterson, T.S. 2012. Registration of DGE-2, a durum wheat disomic alien substitution line 1E(1A) involving a diploid wheatgrass chromosome. Journal of Plant Registrations. 6:221-223.
• Jauhar, P.P. 2012. Polyploidy in relation to plant speciation and evolution. In: Sharma, A.K., editor. Biological Diversity: Principles and Processes. New Delhi, India: Viva Books Pvt. Limited. p. 13-31.
• Jauhar, P.P., Peterson, T.S. 2012. Synthesis and cytological analyses of hybrids between hexaploid wheat, with and without Ph1, and diploid wheatgrass. The Nucleus. 54:57-63.

Progress 10/01/10 to 09/30/11

Outputs
Progress Report Objectives (from AD-416) Fusarium head blight (FHB) or scab,caused by the fungus Fusarium graminearum Schwabe, is a serious disease of wheat. The research objective is to develop genetic resistance to FHB in durum, or macaroni, wheat (Triticum turgidum L., 2n = 4x = 28; AABB genomes) by exploiting novel sources of resistance in the wild relatives. It has been difficult to identify effective sources of resistance in durum wheat cultivars. However, several wild grasses, including diploid wheatgrasses in the secondary or tertiary gene pool of wheat, are excellent sources of FHB resistance that may be incorporated into durum germplasm. Improved durum germplasm with reliable FHB resistance could then be used to incorporate resistance genes into durum and bread wheat cultivars. Specific subobjectives of this project are to: a. Develop alien addition lines involving chromosomes or chromatin, with FHB resistance from diploid wheatgrasses, Lophopyrum elongatum (Host) �. L�ve [= Agropyron elongatum (Host) Beauv.] and Thinopyrum bessarabicum (Savul. & Rayss) �. L�ve (= Agropyron bessarabicum Savul. & Rayss). b. Initiate new crosses with other potential donors such as Thinopyrum junceiforme (L�ve & L�ve) L�ve, 2n = 4x = 28; J1J1J2J2 genomes) and Thinopyrum nodosum [= Lophopyrum nodosum (Nevski) �. L�ve] that may provide new sources of alien chromosomes with FHB resistance. c. Characterize the added alien chromosome(s) from the wild relatives that confer FHB resistance to durum wheat. d. Evaluate both FHB resistance and mycotoxin deoxynivalenol (DON) accumulation with the longer-term objective of releasing FHB-resistant germplasm. e. Assess the genomic relationships between wheat and related species in the intergeneric hybrids. Approach (from AD-416) Alien gene transfer into durum wheat will be carried out by tools of classical and molecular cytogenetics. The cytogenetic techniques will involve sexual hybridization between durum cultivars and wild grasses, coupled with induction of pairing among chromosomes of parental species by manipulation of the pairing-control mechanism(Ph1). This approach will facilitate transfer of alien chromatin into the durum genome, which will then be characterized using fluorescent genomic in situ hybridization (fl-GISH) and chromosome-specific markers. Using this approach, alien addition lines involving diploid wheatgrass (Lophopyrum elongatum and Thinopyrum bessarabicum) chromosomes or chromatin with FHB resistance will be developed. In addition to using these two diploid wheatgrasses as donors of FHB resistance, we will initiate new crosses with other potential donors such as Thinopyrum junceiforme and Thinopyrum nodosum (= Lophopyrum nodosum) that may provide new sources of alien chromosomes with resistance. Fertile hybrid derivatives and stable alien addition lines will be screened for FHB resistance using the techniques we have already standardized. Current durum cultivars do not have resistance to Fusarium Head Blight (FHB), a serious disease of cereals. We found earlier that a diploid wheatgrass (Lophopyrum elongatum) is highly resistant to this ravaging disease. A durum disomic addition line was produced by incorporating two doses of chromosome 1E of this wheatgrass, making the addition line more tolerant to the disease. We have since been attempting to transfer resistance from the added chromosome 1E into the homoeologous group-1 chromosomes of durum. In the course of these studies we have produced disomic alien substitution lines in which chromosome 1A and 1B of durum, respectively, were replaced by chromosome 1E of the diploid wheatgrass. Since 1E has genes for FHB resistance we expect to produce FHB-tolerant durum substitution line. The two disomic substitution lines 1E(1A) and 1E(1B) that we developed were initially screened for FHB tolerance in the greenhouse. We are still awaiting the tabulation of the results from this initial screening. We have been consistently using molecular markers to identify individual group-1 chromosomes of durum and diploid wheatgrass. Large hybrid populations and their derivatives were thus screened for the presence of Ph1 and chromosome 1E. After screening the F2 and F3 generations of Cappelli (ph1cph1c) x DGE-1 we identified plants with chromosome 1E but they had Ph1 also and that prevents or reduces homoeologous recombination. We are still trying to obtain plants with chromosome 1E in the presence of ph1cph1c to induce segmental interchange between 1E and its counterpart in the durum complement. We are in the process of raising the F4 generation. Accomplishments 01 Improvement in durum wheat genetic resources. Durum wheat is used to ma pasta and noodles and is widely used in the U.S., Canada, and several European countries. Current durum wheat cultivars lack resistance to a serious disease of cereals called Fusarium head blight (FHB). In attemp to transfer FHB resistance genes into durum from distant relatives, ARS researchers in Fargo, North Dakota, produced numerous hybrids between durum and distant relatives. They isolated unique genetic combinations and using appropriate DNA markers, confirmed substitutions of distant relative genes into durum. These new hybrids may be useful for impartin head blight resistance in durum cultivars and provide a new pool of important seed storage proteins. New sources of durum wheat resistance head blight could help limit the spread and impact of this devastating disease and thereby increase profitability for US durum wheat producers, as well as reduce the input of pesticides into the environment.

Impacts
(N/A)

Publications

• Jauhar, P.P., Peterson, T.S. 2011. Cytological and Molecular Characterization of Homoeologous Group-1 Chromosomes in Hybrid Derivatives of a Durum Disomic Alien Addition Line. The Plant Genome. 4(2):102-109.
• Jauhar, P.P. 2011. Genetic control of chromosome behaviour: Implications in evolution, crop improvement, and human biology. The Nucleus. 53:3-12.

Progress 10/01/09 to 09/30/10

Outputs
Progress Report Objectives (from AD-416) Fusarium head blight (FHB) or scab,caused by the fungus Fusarium graminearum Schwabe, is a serious disease of wheat. The research objective is to develop genetic resistance to FHB in durum, or macaroni, wheat (Triticum turgidum L., 2n = 4x = 28; AABB genomes) by exploiting novel sources of resistance in the wild relatives. It has been difficult to identify effective sources of resistance in durum wheat cultivars. However, several wild grasses, including diploid wheatgrasses in the secondary or tertiary gene pool of wheat, are excellent sources of FHB resistance that may be incorporated into durum germplasm. Improved durum germplasm with reliable FHB resistance could then be used to incorporate resistance genes into durum and bread wheat cultivars. Specific subobjectives of this project are to: a. Develop alien addition lines involving chromosomes or chromatin, with FHB resistance from diploid wheatgrasses, Lophopyrum elongatum (Host) �. L�ve [= Agropyron elongatum (Host) Beauv.] and Thinopyrum bessarabicum (Savul. & Rayss) �. L�ve (= Agropyron bessarabicum Savul. & Rayss). b. Initiate new crosses with other potential donors such as Thinopyrum junceiforme (L�ve & L�ve) L�ve, 2n = 4x = 28; J1J1J2J2 genomes) and Thinopyrum nodosum [= Lophopyrum nodosum (Nevski) �. L�ve] that may provide new sources of alien chromosomes with FHB resistance. c. Characterize the added alien chromosome(s) from the wild relatives that confer FHB resistance to durum wheat. d. Evaluate both FHB resistance and mycotoxin deoxynivalenol (DON) accumulation with the longer-term objective of releasing FHB-resistant germplasm. e. Assess the genomic relationships between wheat and related species in the intergeneric hybrids. Approach (from AD-416) Alien gene transfer into durum wheat will be carried out by tools of classical and molecular cytogenetics. The cytogenetic techniques will involve sexual hybridization between durum cultivars and wild grasses, coupled with induction of pairing among chromosomes of parental species by manipulation of the pairing-control mechanism(Ph1). This approach will facilitate transfer of alien chromatin into the durum genome, which will then be characterized using fluorescent genomic in situ hybridization (fl-GISH) and chromosome-specific markers. Using this approach, alien addition lines involving diploid wheatgrass (Lophopyrum elongatum and Thinopyrum bessarabicum) chromosomes or chromatin with FHB resistance will be developed. In addition to using these two diploid wheatgrasses as donors of FHB resistance, we will initiate new crosses with other potential donors such as Thinopyrum junceiforme and Thinopyrum nodosum (= Lophopyrum nodosum) that may provide new sources of alien chromosomes with resistance. Fertile hybrid derivatives and stable alien addition lines will be screened for FHB resistance using the techniques we have already standardized. Fusarium head blight (FHB) is a serious disease of cultivated wheats. Current durum cultivars have little or no FHB resistance. By transferring chromosome 1E from Lophopyrum elongatum into durum cultivar Langdon, we previously produced a stable durum alien disomic addition line, DGE-1. To produce a resistant durum cultivar it would be desirable to transfer resistance genes from 1E into the durum chromosome complement. Homoeologous group-1 chromosomes 1A or 1B of durum would be the logical chromosomes for such an exchange to occur. Therefore, we crossed DGE-1 with Langdon disomic substitution lines, Langdon 1D(1A) and Langdon 1D(1B) and produced F2 plants segregating for 1A, 1B, 1D, or 1E and any combination thereof. We have also developed stable durum disomic addition lines involving Thinopyrum bessarabicum chromosomes 1J, 5J, 6J, and 7J. We have produced 12 hybrids derived by crossing durum, cultivars and substitution lines with Thinopyrum nodosum with and without Ph1. Chromosome pairing data have been collected and further studies are in progress. Fertile BC1 and later generations will be developed for FHB screening. To identify the individual chromosomes 1A, 1B, 1D or 1E and any possible chromosome interchanges in segregating plants from crosses of DGE-1, we screened several molecular markers and selected the most suitable ones. We used fluorescent genomic in situ hybridization as an adjunct tool for chromosome identification. Molecular markers were selected to identify Th. bessarabicum chromosomes in durum disomic addition lines. To induce homoeologous pairing between the alien chromosome 1E and durum chromosomes 1A or 1B, we made crosses between DGE-1 and Cappelli mutant ph1cph1c. Chromosome pairing was scored in the segregating F2 generation which would be the first generation with or without the Ph1 gene. Segregation for the Ph1 gene and chromosome 1E is being studied, using molecular markers. Xpsr128 and Xpsr574 are being used to determine the presence of Ph1 and Xedm74 and Xedm17 to ascertain the presence of chromosome 1E. Accomplishments 01 Identification and use of molecular markers for chromosome identificatio in wheat hybrids. Fusarium head blight (FHB) resistance in the durum ali disomic addition DGE-1 is located in chromosome 1E of the alien donor, diploid wheatgrass. To transfer this resistance from 1E into group-1 chromosomes of the durum chromosome complement, scientists at the Red River Valley Agricultural Research Center, Fargo, ND made crosses betwee DGE-1 and substitution lines, Langdon 1D(1A) and Langdon 1D(1B). To identify the individual chromosomes 1A, 1B, 1D or 1E and any possible chromosome interchanges in segregating plants from DGE-1 crosses, the scientists selected the best molecular markers that gave consistent results. This research demonstrated that Xwmc333 was most suitable for profiling chromosome 1A, Xwgm18 for 1B, Xwmc147 for 1D, and Xedm17 for 1 These markers can be used expeditiously in screening F1 and F2 populations for the presence of group-1 chromosomes, saving time and mon

Impacts
(N/A)

Publications

• Jauhar, P.P., Peterson, T.S. 2009. Chromosome Engineering of Durum Wheat with Alien Chromatin of Diploid Wheatgrass. Journal of Crop Improvement. 23(4)319-331.

Progress 10/01/08 to 09/30/09

Outputs
Progress Report Objectives (from AD-416) Fusarium head blight (FHB) or scab,caused by the fungus Fusarium graminearum Schwabe, is a serious disease of wheat. The research objective is to develop genetic resistance to FHB in durum, or macaroni, wheat (Triticum turgidum L., 2n = 4x = 28; AABB genomes) by exploiting novel sources of resistance in the wild relatives. It has been difficult to identify effective sources of resistance in durum wheat cultivars. However, several wild grasses, including diploid wheatgrasses in the secondary or tertiary gene pool of wheat, are excellent sources of FHB resistance that may be incorporated into durum germplasm. Improved durum germplasm with reliable FHB resistance could then be used to incorporate resistance genes into durum and bread wheat cultivars. Specific subobjectives of this project are to: a. Develop alien addition lines involving chromosomes or chromatin, with FHB resistance from diploid wheatgrasses, Lophopyrum elongatum (Host) �. L�ve [= Agropyron elongatum (Host) Beauv.] and Thinopyrum bessarabicum (Savul. & Rayss) �. L�ve (= Agropyron bessarabicum Savul. & Rayss). b. Initiate new crosses with other potential donors such as Thinopyrum junceiforme (L�ve & L�ve) L�ve, 2n = 4x = 28; J1J1J2J2 genomes) and Thinopyrum nodosum [= Lophopyrum nodosum (Nevski) �. L�ve] that may provide new sources of alien chromosomes with FHB resistance. c. Characterize the added alien chromosome(s) from the wild relatives that confer FHB resistance to durum wheat. d. Evaluate both FHB resistance and mycotoxin deoxynivalenol (DON) accumulation with the longer-term objective of releasing FHB-resistant germplasm. e. Assess the genomic relationships between wheat and related species in the intergeneric hybrids. Approach (from AD-416) Alien gene transfer into durum wheat will be carried out by tools of classical and molecular cytogenetics. The cytogenetic techniques will involve sexual hybridization between durum cultivars and wild grasses, coupled with induction of pairing among chromosomes of parental species by manipulation of the pairing-control mechanism(Ph1). This approach will facilitate transfer of alien chromatin into the durum genome, which will then be characterized using fluorescent genomic in situ hybridization (fl-GISH) and chromosome-specific markers. Using this approach, alien addition lines involving diploid wheatgrass (Lophopyrum elongatum and Thinopyrum bessarabicum) chromosomes or chromatin with FHB resistance will be developed. In addition to using these two diploid wheatgrasses as donors of FHB resistance, we will initiate new crosses with other potential donors such as Thinopyrum junceiforme and Thinopyrum nodosum (= Lophopyrum nodosum) that may provide new sources of alien chromosomes with resistance. Fertile hybrid derivatives and stable alien addition lines will be screened for FHB resistance using the techniques we have already standardized. Significant Activities that Support Special Target Populations Current durum cultivars have little or no resistance to Fusarium head blight (FHB). Some of the wild grass species have excellent resistance to this ravaging disease. Therefore, we crossed durum cultivars with the wild grasses and selected fertile hybrid derivatives with FHB resistance. In order to reduce the number of alien chromosomes we isolated addition lines with the chromosome conferring the most FHB resistance. From the crosses between durum cultivars Langdon and Lloyd with the alien species Lophopyrum elongatum and Thinopyrum bessarabicum, we isolated several addition lines with 2n = 29 and 2n = 30 chromosomes. We isolated FHB- resistant disomic addition lines involving L. elongatum chromosomes. After confirming the somatic and meiotic chromosomes we characterized the added alien chromosome using chromosome-specific markers. The alien chromosome in the FHB-resistant durum disomic alien addition line is 1E. Following the same approach we isolated several hybrid derivatives of Lloyd x Th. bessarabicum with chromosome numbers ranging 2n =29 to 2n = 33. These derivatives were advanced by single seed descent (selfing) and we isolated alien additions with 2n = 29 and 2n = 30 chromosomes. Once we had an appropriate addition line with FHB resistance we wanted to know the identity of the chromosome involved. To characterize the added Th. bessarabicum chromosome we used specific molecular markers, some of which had been determined to be specific to L. elongatum chromosomes. Sixteen Xedm primers and twelve Xgwm primers were used that tentatively identified Th. bessarabicum chromosomes 1, 6, and 7. Further study is in progress to identity each of the 7 alien chromosomes. To transfer the desirable gene(s) from the alien chromosome into the durum complement, we made crosses between DGE-1 and Cappelli ph mutant. F1s of the DGE-1 x Cappelli ph mutant were grown to generate seed. Chromosome pairing was scored in the F2 generation which would be the first generation without Ph1 in the segregating population. Chromosome pairing in the F1 hybrids between DGE-1 and the Langdon substitutions was studied to assess the pairing between the added alien chromosome 1E and group-1 homoeologous chromosomes of Langdon.

Impacts
(N/A)

Publications

• Jauhar, P.P., Peterson, T.S., Xu, S.S. 2009. Cytogenetic and Molecular Characterization of Durum Alien Disomic Addition Line with Fusarium Head Blight Resistance Genome 52:467-483.
• Jauhar, P.P., Xu, S.S., Baenziger, S. 2009. Haploidy in Cultivated Wheats: Induction and Utility in Basic and Applied Research Crop Science Vol 49:737-754

Progress 10/01/07 to 09/30/08

Outputs
Progress Report Objectives (from AD-416) Fusarium head blight (FHB) or scab,caused by the fungus Fusarium graminearum Schwabe, is a serious disease of wheat. The research objective is to develop genetic resistance to FHB in durum, or macaroni, wheat (Triticum turgidum L., 2n = 4x = 28; AABB genomes) by exploiting novel sources of resistance in the wild relatives. It has been difficult to identify effective sources of resistance in durum wheat cultivars. However, several wild grasses, including diploid wheatgrasses in the secondary or tertiary gene pool of wheat, are excellent sources of FHB resistance that may be incorporated into durum germplasm. Improved durum germplasm with reliable FHB resistance could then be used to incorporate resistance genes into durum and bread wheat cultivars. Specific subobjectives of this project are to: a. Develop alien addition lines involving chromosomes or chromatin, with FHB resistance from diploid wheatgrasses, Lophopyrum elongatum (Host) �. L�ve [= Agropyron elongatum (Host) Beauv.] and Thinopyrum bessarabicum (Savul. & Rayss) �. L�ve (= Agropyron bessarabicum Savul. & Rayss). b. Initiate new crosses with other potential donors such as Thinopyrum junceiforme (L�ve & L�ve) L�ve, 2n = 4x = 28; J1J1J2J2 genomes) and Thinopyrum nodosum [= Lophopyrum nodosum (Nevski) �. L�ve] that may provide new sources of alien chromosomes with FHB resistance. c. Characterize the added alien chromosome(s) from the wild relatives that confer FHB resistance to durum wheat. d. Evaluate both FHB resistance and mycotoxin deoxynivalenol (DON) accumulation with the longer-term objective of releasing FHB-resistant germplasm. e. Assess the genomic relationships between wheat and related species in the intergeneric hybrids. Approach (from AD-416) Alien gene transfer into durum wheat will be carried out by tools of classical and molecular cytogenetics. The cytogenetic techniques will involve sexual hybridization between durum cultivars and wild grasses, coupled with induction of pairing among chromosomes of parental species by manipulation of the pairing-control mechanism(Ph1). This approach will facilitate transfer of alien chromatin into the durum genome, which will then be characterized using fluorescent genomic in situ hybridization (fl-GISH) and chromosome-specific markers. Using this approach, alien addition lines involving diploid wheatgrass (Lophopyrum elongatum and Thinopyrum bessarabicum) chromosomes or chromatin with FHB resistance will be developed. In addition to using these two diploid wheatgrasses as donors of FHB resistance, we will initiate new crosses with other potential donors such as Thinopyrum junceiforme and Thinopyrum nodosum (= Lophopyrum nodosum) that may provide new sources of alien chromosomes with resistance. Fertile hybrid derivatives and stable alien addition lines will be screened for FHB resistance using the techniques we have already standardized. Significant Activities that Support Special Target Populations This is a new project initiated in April 2008 for which milestones will be initiated in FY2009. See the former CRIS project 5442-21000-029-00D for FY2008 milestones. We are continuing work on durum disomic additions involving the diploid grass Thinopyrum bessarabicum chromosomes that were isolated previously. We are also developing new addition lines. Monosomic additions were selfed and the progeny are being studied. Disomic additions involving Th. bessarabicum were probed with 28 SSR primers. Chromosome specific markers for grass chromosomes are being isolated. To transfer desirable genes from chromosome 1E into Group 1 chromosomes of durum, we are trying to exploit the Ph system to induce homoeologous pairing and alien introgression. We made crosses between DGE-1 and ph1c ph1c Cappelli. The progeny is being studied. This work relates to NP 301 Component 2: Crop Informatics, Genomics, and Genetic Analyses, Problem Statement 2B: Structural Comparison and Analysis of Crop Genomes, and Component 3: Genetic Improvement of Crops, Problem Statements 3A: Genetic Theory and Methods of Crop Improvement and 3B: Capitalizing on Untapped Genetic Diversity.

Impacts
(N/A)

Publications