Frank L. Haynes Graduate Student Research Award Competition

Monday, July 20th 
11:00 am - 1:30 pm (ET)

A graduate student award fund honoring the late Dr. Frank L. Haynes, long time professor of Potato Breeding and Genetics at North Carolina State University was initiated by his wife, Dr. Kathy Haynes, USDA-ARS Potato Breeder at Beltsville, MD and family to the PAA Endowment and presented at the organization’s annual meeting held July 27, 2000 in Colorado, Springs, Colorado.

The PAA has been making the Graduate student cash awards honoring outstanding student research presentations given during paper presentation sessions at the organization's Annual Meeting. Each participating student is presented a certificate showing the name of the title of presentation when they receive their evaluation from the Chair of the Graduate Student Competition Committee. Winners shall be announced at the General Business Meeting on Wednesday, July 23rd.


General Criteria for Judging

Papers and presentations will be judged on the following basis:

A. Abstract (16.6%)
B. Organization (16.6%)
C. Effective use of time (16.6%)
D. Effective use of visuals (16.6%)
E. Presentation style (16.6%)
F. Impact of the research (16.6%)

Up to five awards may be made at the discretion of the committee in the amounts of:

1st Place: $1,000 - WINNER: Rabecka Hendricks
2nd Place: $750 - WINNER: Fatemeh Ekbataniamiri
3rd Place: $400 - WINNER: Thilani Jayakody
Congratulations to our winners and a well done for all of our presenters!



Committee Chair: 
Paul Bethke

Committee Members:

Kenneth Frost
Aymeric Goyer
Dennis Halterman
Helen Tai
Lincoln Zotarelli




Sarah Lee, Michigan State University
Felix Enciso, Michigan State University
Dan Zarka, Michigan State University
David Douches, MSU

The Gametic Self-Incompatibility (GSI) System in diploid commercial potato (Solanum tuberosum) poses a substantial barrier in potato breeding by hindering the fixation of desirable alleles within potato lines which facilitates breeding efforts. A possible solution is to develop self-compatible diploid potato breeding lines which allows generation of new lines with fixed combinations of possible favorable alleles. Pollen rejection mediated by the S-RNase gene has been established as a major contributing factor in self-incompatibility in the solanum family, but we hypothesize there are other genes are involved in self-incompatibility in S. tuberosum. One of the non-S-RNase contributing factors may be the stylar-expressed protein from several candidate genes which are shown to have a role in pollen rejection in Nicotiana alata and other Solanum species. These candidate genes will be targeted for gene knockout via CRISPR-Cas9 knockout as separate transformation events. Phenotypic analysis of the self-compatibility trait will be performed using fruit set as a quantitative measure. Stylar squashes will also be observed for analysis of pollen tube growth.

Thilani B. Jayakody, Michigan State University
Jacob Jensen, Michigan State University
Katie Acheson, Michigan State University
Daniel Zarka, Michigan State University
Satya S. Nadakaduti, University of Florida
Robin Buell, MSU
David Douches, MSU

Genome editing reagents used in plant systems are quickly evolving, however the specificity of many of these emerging reagents have yet to be validated in crop species. In order to evaluate the target specificity of current genome editing reagents in potato, tuber expressed polyphenol oxidases (StuPPO1-4) were targeted for gene knock-out via CRISPR/Cas9, CRISPR/Cas12a, CRISPR/HypaCas9,and TALENs with a goal to compare specificity of genome-editing reagents using whole genome resequencing and evaluate genome wide off-target frequencies across reagents. Diploid potato germplasm was screened for characteristics such as high regeneration rate, self-compatibility and quality tuber traits to identify a suitable clone for gene-editing and off-target analysis. A Solanum tuberosum Group Phureja diploid clone, 1S1, developed at Virginia Tech, was selected based on the above criteria. A high quality genome assembly is required to identify off-targets; thus, to create a contiguous genome assembly, a doubled monoploid of 1S1 (DM1S1) was sequenced. Genomic DNA of DM1S1 was sequenced using Oxford Nanopore Technology and an assembly is under-way. Following assembly, Illumina 150 nt paired end reads of 1S1 with 42X coverage will be aligned to identify allelic differences in the 1S1 clone. This assembly will facilitate searching for genome wide off-target effects in this study but can also be used for future genome editing target design and comparative genomic analysis to further advance diploid breeding.

Kirk R. Amundson, University of California Davis
Michelle M. Fossi, University of California Davis
Xin Zhao, University of California Davis
Guilherme T. Braz, Michigan State University
Benny Ordoñez, University of California Davis
Isabelle M. Henry, University of California Davis
Jiming Jiang, Michigan State University
Luca Comai,  University of California Davis

Understanding the processes by which genetic variation accumulates in clonally propagated plants is critical for exploring their adaptive potential and maintaining their lasting viability. This has been investigated in clonally propagated diploids, especially in the context of grapevine and tree crop bud sports of agronomic interest, but less so in polyploids, where genetic redundancy and buffering of gene dosage imbalance permit exploration of additional variation space. Somatic variation also has been documented after cultured cells are induced to regenerate whole plants; the resulting “somaclonal variation” is noticeable because of its severe and often undesirable phenotypic effects. To investigate genomic variation among polyploid clones, we compared whole-genome sequencing of five clones of the tetraploid potato cultivar Desiree and eight protoplast-regenerated derivatives of one Desiree clone. We document single-nucleotide and structural variation among clonally propagated isolates of Desiree. In protoplast-regenerated clones, we found chromosome structural variation consistent with homologous and non-homologous DNA repair with apparent preferences for certain chromosomal locations. These events are consistent with a connection between genome instability and fragile sites, which resulted in chromoanagenesis or copy-neutral loss of heterozygosity. Our observations provide a framework for understanding genome instability and its consequences in clonally propagated polyploids, and may even suggest strategies for plant genome engineering.

Edoardo Poletti, North Dakota State University
Gary Secor, North Dakota State University
Asunta L. Thompson, North Dakota State University

The potato soft rot complex can cause extensive damage to potato vines and tubers in the field and in storage. Primary symptoms are macerated tissues produced by pectinolytic bacteria belonging to the Pectobacterium and Dickeya genera. Dickeya dianthicola is one of the most aggressive species present in the US affecting the potato crop since it was first found in 2014. Most research on soft rot resistance has concentrated on the Pectobacterium species, and on tuber resistance. Only a few cultivars with resistance to Pectobacterium are reported, and avoiding infected tubers is the best strategy to reduce the presence or the spread of the disease in the field. Genetic resistance to soft rot remains a key objective for disease management. This work reports on the development of procedures to apply in a potato breeding program to screen for foliar and tuber resistance to Dickeya dianthicola.  A screening protocol was developed and used to evaluate foliar resistance. Petioles from 288 genotypes from the NDSU potato breeding program were inoculated with Dickeya dianthicola ME23 in replicated growth chamber trials. Most genotypes were susceptible to petiole infection and decay; however, 20 genotypes were found to be significantly resistant to foliar blackleg, with two NDSU breeding lines rated as highly resistant. Preliminary tuber resistance after inoculation (n=30) was evaluated using image analysis to speed and automatize the screening procedure. This work provides useful information for application of screening procedures for resistance to Dickeya dianthicola to a potato program Genotypes with foliar and/or tuber resistance were successfully identified. Research needs to be expanded for efficient introgression of resistance into new cultivars.

William L. Behling, Michigan State University
Felix Enciso, Michigan State University
David Douches, Michigan State University

Understanding interspecific compatibility is a critical part of many breeding programs as it affects our ability to introgress valuable traits from wild species. There are several barriers to successful interspecific hybridization between wild and domestic potato species, but the underlying genetic mechanisms of these barriers are not well understood. Recent research has shown that the mechanisms that govern self-compatibility may also regulate interspecific compatibility. Self-compatibility is a valuable trait of high priority for diploid potato breeding programs and is regulated by a set of tightly linked genes. Reproductively isolated EBN1 species are of special interest as they provide broad and durable resistance to many diseases and pests of potato. Understanding the relationship between self-compatibility and interspecific compatibility is necessary to integrate these species into cultivated germplasm. The premise of this study is to demonstrate that the mechanisms that govern gametophytic self-compatibility (GSI) also regulate interspecific compatibility. To elucidate the contribution each of the factors that regulate GSI in interspecific compatibility, we will cross EBN1 species Solanum bulbocastanumS. pinnatisectum and S. jamesii with known self-compatible species S. verrucosum and the clone M6 of S. chacoense, in conjunction with Cas9 knockout lines of important GSI factors in S. tuberosumclone DRH-195. As a result, the data generated will allow breeding programs to optimize introgression efforts and open possibilities that weren’t otherwise feasible.

Jed D. Grow, NDSU
Andy Robinson, NDSU / University of Minnesota
Asunta L. Thompson, North Dakota State University
Gary Secor, North Dakota State University

When new potato cultivars are released growers often grow them as they would traditional cultivars. Not understanding the best agronomic production methods for new cultivars can lead to poor yield performance, problematic tuber size profiles and even undesirable chip quality. The objective of this study was to define the optimal nitrogen and within-row spacing for the advanced chipping selections ND7799c-1 and ND7519-1 compared to the standard ‘Dakota Pearl’. A randomized complete block trial with a factorial arrangement of treatments was established on a non-irrigated farm near Hoople, North Dakota in 2019. Potato clones included ND7799c-1, ND7519-1 and ‘Dakota Pearl’. Nitrogen was broadcast and incorporated at 90, 134, 179, and 224 kg ha-1. Seed pieces were planted at within-row spacing of 15, 23, and 31 cm. Both nitrogen rate and the within-row spacing by cultivar were found to be statistically significant. Across all three clones, the 90 kg nitrogen ha-1 resulted in both the highest marketable and total yields. The other three nitrogen rates yielded much lower and saw no statistical difference. Dakota Pearl had similar yields at all within-row spacings. ND7799c-1 planted at 15 and 23 cm spacings and ND7519-1 planted at 23 cm spacing yielded similarly to the Dakota Pearl for both marketable and total yields. ND7799c-1 planted at 31cm and ND 7519-1 at both 15 and 31 cm produced the lowest marketable and total yields.

Colby J. Robertson, University of Lethbridge
Emily Snowdon, Quattro Ventures

Alberta potato production expanded acres and processing capacity recently. Production faces a yield barrier identified in part due to the potato early dying disease complex. The complex involves the soil-borne causal fungus Verticillium dahliae and causal nematode Pratylenchus penetrans. To address this barrier, in-furrow soil treatments of azoxystrobin and benzovindiflupyr fungicides, fluopyram nematicide, chloropicrin fumigant, and reduced soil disturbance using a bed freshener instead of a power hiller for spring bed preparation were evaluated in two commercial potato fields growing cultivar Russet Burbank. Verticillium spp. were quantified by soil dilution on NP-10 medium and morphological identification using microscope. Pratylenchus spp. were quantified after Baremann pan extraction and morphological identification using stereoscope. Each field showed 40 microsclerotia colonies of Verticillium spp. per gram of dried soil prior to soil treatment. Pratylenchus spp. levels in soil were between 440 and 900 vermiforms counted per kilogram of fresh, undried soil. Fields were selected knowing Verticillium spp. pressure was higher than economic thresholds established for V. dahliae. In-field tuber samples were collected from each treatment strip close to the time of commercial harvest. Treatment strips were sampled eight times by collecting tubers from sections of rows 3 metres in length. Tuber samples were assessed for yield and quality according to local industry standards. Verticillium spp. microsclerotia levels in soil declined when a bed freshener was employed regardless of chemical treatment. Recovery of Verticillium spp. microsclerotia levels, sometimes above pre-treatment levels, was observed regardless of soil treatment or soil disturbance. Pratylenchus spp. levels in soil declined regardless of treatment. Fumigation improved gross tuber yield only in combination with bed freshening. Hail on August 6, 2019 terminated study early. Additional study over a complete growing season is recommended to investigate viability of soil treatments to manage potato early dying complex in Southern Alberta.

Rabecka L. Hendricks, University of Idaho
Nora Olsen, University of Idaho
Mike Thornton, University of Idaho
Lynn Woodell, University of Idaho

Shatter and blackspot bruise can impact the storability of potatoes by increasing weight loss and increasing decay. Therefore, understanding factors associated with potato susceptibility to bruise can help mitigate quality degradation. Two trials with Russet Burbank and Russet Norkotah addressed if bruises sustained at harvest change during storage and if time in storage alters tuber susceptibility to bruising. In each trial, tubers were bruised using a 100g impact device (18cm drop height) to deliver two uniform bruises on each end of the tuber. All tubers were assessed for blackspot and shatter bruise incidence, blackspot severity (based on color intensity), and depth of blackspot bruise. In trial one, tubers were bruised (pulp temperature 12.7C) at harvest and a subsample taken monthly from harvest to March (six months). In trial two, tubers were bruised (pulp temperature 7.2C) at harvest, subsequent sub-samples bruised each month, and evaluated after 24 hours. Tubers were stored at 7.2C and 95% RH. In trial one, blackspot bruise incidence, severity, and depth were significantly greater after one month in storage compared to at harvest, and then remained at these levels during the following five months for both varieties. There was no consistent difference in shatter bruise incidence with time in storage. In trial two, Russet Burbank susceptibility to blackspot bruising was higher at harvest (87% incidence) compared to March (55% incidence). Blackspot bruise severity and depth decreased with time in storage for Russet Burbank potatoes. The incidence, severity and depth of blackspot bruise all increased significantly between harvest and October in Russet Norkotah. However, in subsequent months these values declined so that by March only bruise depth was significantly higher compared to at harvest. Stored potatoes may be similar or less susceptible to bruising when handled and packed out of storage compared to handling at harvest.


Sandesh -. Dangi, University of Idaho
Most M. Begum, Tuber Crops Research Center, Bangladesh Agricultural Research Institute, Gazipur
Karen Hokanson, University of Minnesota
David Douches, Michigan State University
Phillip Wharton, University of Idaho

To date, 25 genotypes of P. infestans have been reported in the United States (US-1 to US-25), 41 in Europe (EU 1_A1 to EU 41_A2) and more in other countries. Little is known about genotypes of P. infestansin Bangladesh.  Our objective was to characterize P. infestans populations in Bangladesh to determine the genotypes, diversity and relatedness of these isolates to the worldwide Phytophthora infestans population.  A total of 143 isolates (123 from potato and 20 from tomato) were collected on FTA cards from the five major potato growing divisions of Bangladesh, Rangpur, Rajshahi, Mymensingh, Dhaka and Sylhet from 2017 to 2019.  Another 17 isolates were recovered from infected leaf samples shipped in tubers to Aberdeen R&E Center, Idaho.  Isolates were characterized based on one-step multiplex SSR markers, mating type, mitochondrial haplotype and mefenoxam sensitivity. Simple sequence genotypes data were used to analyze population and allele diversity statistics, construct neighbor joining trees, discriminated analysis of principal components and minimum spanning networks.  Results revealed high diversity in the population with 94 multi-locus genotypes from 160 isolates.  Neighbor joining tree analysis showed that when compared to standard isolates, Bangladesh isolates were very closely related to EU 13_A2 but with large sub-clonal variations and with a few isolates that were very similar to EU 6_A1 and EU 1_A1.  Based on discriminant analysis of principal components, there were 4 main clusters in the population. All isolates from potato, except those from Mymensingh grouped together, while isolates from tomato were clustered separately from all the potato isolates.  Mating type characterization of isolates indicated that 158 were A2 and two were A1. Isolates obtained as pure cultures were all insensitive to mefenoxam. Since, all the living isolates were insensitive to mefenoxam, our results suggest that the use of mefenoxam based fungicides in Bangladesh should be avoided.

Fatemeh Ekbataniamiri, University of Maine
Tongling Ge, University of Maine
Steven. B. Johnson, University of Maine
Robert Larkin, University of Maine
Jianjun Hao, University of Maine

An outbreak of blackleg and soft rot of potato has caused significant losses to potato production in the Northeastern US since 2015. To investigate the inoculum source of the seedborne pathogens, surface water was assayed. Water samples were collected from rain, pond, stream, and well water from 2018 to 2020 at 23 locations near potato production areas in Maine. Bacteria were concentrated by centrifugation at 7000 g for 20 min and isolated on crystal violet pectate agar plates. Genomic DNA was extracted from both water samples and bacterial cultures. To detect and identify the pathogen, polymerase chain reaction (PCR) was performed followed by sequencing analysis of target genes dnaX and gapA. Among the obtained bacterial isolates found in pond and stream water, several species were identified, including 6 isolates of D. aquatica (26%), 5 of D. dianthicola, 3 of D. zeae, 1 of D. chrysanthemi, and 2 of P. parmentieri. Pathogenicity tests of a representative strain of D. aquatica 174/2 was conducted using tuber inoculation and stem injection on potato. Results showed that D. aquatica was a pathogenic species with a greater virulence than D. dianthicola, D. zeae and P. parmentieri. This is the first report of D. aquatica causing blackleg and soft rot of potato in the US, yet there is no evidence to support that bacteria in surface water was associated with the recently occurred outbreak.