Plant Breeding and Genetics

Strawberry and blueberry breeding and genetics with Dr. Jim Hancock.

Our research is directed primarily toward virus-host interactions. Our work includes genetic and physiological characterization of naturally occurring potyvirus resistances in cucumber including expression of resistance alleles, interaction with viral protein domains, viral and host determinants of systemic infection, viral host range, and identification of host factors that directly interact with viral proteins.

Other research efforts include study of the molecular basis of sex expression in Cucumis and Phytopthora infection of cucumber. We have developed transformation systems for cucumber and melon and have introduced several genes for virus resistance, sex expression, and abiotic stress resistance. We also are involved in examination of risks associated with transgenic crops.

• Highbush blueberry breeding and genetics
• Strawberry breeding and genetics 
• Marker assisted breeding of strawberry and blueberry
• Reconstruction of the cultivated strawberry, Fragaria x ananassa
• Environmental biosafety of GE crops

Balaton Research

Sour Cherry Breeding

The sour cherry (Prunus cerasus) industry in the U.S. is a monoculture of a 400-year-old variety from France called Montmorency. The goals of the MSU sour cherry breeding program are to develop new cultivars which will have superior fruit quality and disease resistance compared to Montmorency, and will yield consistently over years. To reach these goals, we have an aggressive breeding program which includes approximately 25 acres of seedlings and 15 test sites around the U.S. Currently our disease resistance breeding program involves the introgression of resistance gene(s) for cherry leaf spot (Blumeriella jaapii) resistance from wild Prunus species, P. canescens and P. maackii, into commercially acceptable sour cherry cultivars. The first release from the breeding program, named Balaton®, originated as a landrace variety from Hungary.

Cherry Genetics

Self-incompatibility: The diploid sweet cherry is a classic example of a species exhibiting S-RNase-based gametophytic self-incompatibility. In comparison, individual tetraploid sour cherry selections can be either self-compatible or self-incompatible. Our goal is to understand the genetic control of self-compatibility and self-incompatibility in sour cherry. Our current hypothesis is that self-compatibility arose in sour cherry from the more ancestral state of self-incompatibility due to the occurrence of self-fertile mutants. So far one of these self-fertile mutants has been characterized as having an insertion in the putative promoter region of the S6-RNase.

Fruit Quality Traits: We have a long standing interest in the genetic control of fruit quality traits in both sweet and sour cherry. Our research strategy is to identify QTLs that control fruit quality traits that have been altered during domestication. For this analysis over 900 progeny were generated from the cross between a wild sweet cherry with small highly acid dark fruit and a domesticated variety with large pink sweet fruit.

Our initial focus is on the genetic control of fruit size. Anatomical studies indicate that the fruit of NY 54 is larger than the fruit of Emperor Francis solely due to an increase in cell number, not cell size. Research is ongoing to understand the genetic control and timing of this difference in cell number.

Bloom time: One out of every three years, cherry yields in Michigan are significantly reduced by spring freeze damage. We are currently using a QTL strategy in a sour cherry population that exhibits extensive transgressive segregation for late bloom time, to identify the genomic region(s) that control bloom time. Our long term goal is to fine-map QTL regions identified as a prelude to candidate gene analysis.

Sweet cherry rootstock selection

The breeding program has an ongoing effort to identify precocious dwarfing rootstocks for sweet cherry from the MSU cherry germplasm collection. So far, 93 MSU rootstock selections are under test in replicated trials in Michigan and Washington State with Hedelfingen and Bing scions, respectively.

My primary research objective is to explore the function of transposable elements (TEs) in order to understand the forces underlying eukaryotic genome diversification. It now seems clear that each genome possesses a unique spectrum of transposable elements and a varying proportion of these are active. An open question is how this diversity of TEs influences the evolutionary trajectory of the genomes in which they reside. I use both computational and molecular biology-based approaches to address this question and to analyze the ever-increasing database of genomic sequence from multiple plant species.

• Physiology of carbohydrate metabolism

• Stress physiology

• Carbohydrate partitioning and photosynthesis

Germplasm evaluation for resistance/tolerance to herbivore nematodes of economic significance to Michigan agriculture.

 Cherry Breeding and Genetics

My research has been focusing on improvement of horticultural crops using genomics, genetic, and biotechnological tools. My current work areas include:

Basic research:

Deciphering molecular basis of vernalization-mediated flowering in woody plant using a blueberry vernalization mutant as a model. 

Applied research:

Engineering new generation of genetically modified (GM) crops

1.  Engineer woody plants with modified flowering time using several arabidopisis orthologues (SOC1, FT, AP1, and LEAFY)

2.  Using intragenic transformation to increase abiotic tolerance:  a blueberry derived CBF gene was overexpressed in blueberry for improving freeze tolerance.

3.  Using the RNAi strategy, transformed cherry rootstocks were created in order to achieve PNRSV resistance in the scion cultivars grated.

4.  Engineering nutation value-added tomatos using the celery M6PR. 

Research Interests - Plant Developmental Genetics

What are the underlying genetic mechanisms that determine plant form, and how are these controlled? What are the key genes that influence agriculturally important traits such as flowering? What parallels exist between plant and human development, and can studies in plants shed light on issues such as cancer and stem cell biology?

Postdoc and PhD positions available. For information, email Steve van Nocker

Exploiting chromatin landmarks to characterize complex plant genomes. Genetic information required for development is encoded partly by the proteinaceous matrix called chromatin in which genomic DNA is packaged. This project is expected to help uncover how this so-called "epigenetic" component of the genome is regulated to precisely drive gene activity.

Transcriptional memory and epigenetic mechanisms. As an organism develops, cells may proliferate to maintain a pool of stem cells, or differentiate to form specialized tissues. This project focuses on a transcriptional factor called Paf1C, which is crucial for transcriptional memory and development.

Flowering. Plants have evolved an enormous diversity of strategies to flower at the time of year best suited to their reproduction. We are using genetic and molecular techniques to elucidate the networks of gene expression involved in triggering flowering in plants, using Arabidopsis thaliana as a model.

Juvenility and inflorescence architecture in Malus (apple). The commercial apple industry is limited by various flowering-related problems. The goal of this project is to identify genes and genetic loci that influence flowering-related traits, especially juvenility and inflorescence architecture, in apple.

Fruit abscission. We are taking a multifaceted approach to understand the genetic basis of fruit abscission in the cultivated apple, with the goal of developing tools and providing the basis for efficient production practices to control fruit retention and drop.

• Plant Breeding and Genetics
• Molecular Breeding and Genomics
• Agricultural Biotechnology