Peach Breeding

University of Arkansas

ISSUE: New peach varieties with improved fruit quality will lead to increased consumer enjoyment and consumption and will contribute to the profitability and sustainability of the U.S. peach industry. However, breeding new peach varieties is slow and inefficient. Predicting which selections will be the best parents is difficult. Thousands of seedlings must be grown and tested in the orchard to identify the few with commercial potential. Prior to RosBREED, our breeding program relied solely on traditional breeding methods.

WHAT HAS BEEN DONE: Genetic tests were developed that predict peach maturity date and fruit quality traits including fruit texture, flavor, size, and skin color. These new genetic tests enable us to determine the best parents to use in future crosses and the best seedlings to advance, reducing the need to grow out and sort through thousands of seedlings with unacceptable fruit quality.

Using this strategy, called Marker-Assisted Breeding (MAB), we can now more efficiently, accurately, and creatively develop superior new peach varieties that meet the needs and desires of consumers and producers.

IMPACT: As a result of genetic testing in the Arkansas peach breeding program:

• We selected four varieties and advanced 16 selections and 136 seedlings for fieldtesting. MAB has increased our efficiency by focusing resources on seedlings that have the greatest potential for commercial success.
• We discovered new peach flesh types in our genepool, one of which, “nonsoftening” flesh, maintains its firmness and quality for three or more weeks in postharvest storage and the fruit is more resistant to mechanical damage. Another discovery, the “slow-melting” type, also maintains its firmness for a longer period, then, upon full ripeness, melts and reaches the same texture as that of melting types. Both these new flesh types may provide a wider range of fruit quality options for the consumer.
• We are confident now in moving beyond traditional breeding to using MAB to improve peach traits such as texture, size, flavor, skin color, bacterial spot resistance, bloom date, and fruit maturity date.

Peach Breeding

University of California – Davis

ISSUE: New processing peach varieties with improved fruit quality will lead to increased consumer enjoyment and consumption and will contribute to the profitability and sustainability of the U.S. peach industry. However, breeding improved processing peach cultivars is slow and inefficient. Related species, such as almond, offer sources of valuable new traits but this approach is particularly challenging genetically.

WHAT HAS BEEN DONE: Genetic tests were developed that predict peach maturity date and fruit quality traits including fruit texture, flavor, size, and skin color. These genetic tests enable us to identify the best parents to use in future crosses. When related species are used in breeding, the chosen parents have the desirable characteristics, while avoiding the undesirable ones. Genetic tests also help us avoid planting in the orchard many seedlings predicted to be undesirable.

Using this strategy, called Marker-Assisted Breeding (MAB), we are now more efficiently, accurately, and creatively develop superior processing peach varieties that meet the needs and desires of consumers and producers.

IMPACT: As a result of genetic testing of 409 peach selections in the UC Davis Processing Peach Breeding Program:

• The pedigrees for 200 selections were corrected. Accurate pedigrees are desired for the official documenting and release of new cultivars.
• Groups of genetically similar plant materials that were detected enabled us to adjust and improve the crossing schemes. Parents were identified that had an increased likelihood of transmitting the desired fruit weight and diameter.
• We also identified previously unknown genetic complications in some advanced interspecific breeding materials that explained unexpected inheritance patterns.

The impact of MAB is an improved understanding of the genetic relationships among current breeding lines and an increased efficiency in identifying peach traits that are controlled by a relatively few number of genetic factors.

Sweet and Tart Cherry Breeding

ISSUE: New sweet cherry varieties with improved fruit quality and new disease resistant tart cherry varieties will lead to increased consumer enjoyment and consumption and will contribute to the profitability and sustainability of the U.S. cherry industries. However, breeding new cherry varieties is slow and inefficient, taking 15 to 25 years from the initial cross to variety release. Predicting which selections will be the best parents is difficult. Thousands of seedlings must be grown and evaluated in the orchard to identify the few with commercial potential.

WHAT HAS BEEN DONE: Genetic tests were developed to predict cherry fruit color, fruit size, fruit firmness, self-fruitfulness, and resistance to leaf spot in tart cherry. These genetic tests enable cherry breeders to determine the best parents to combine and the best seedlings to advance, thereby reducing the need to grow out and sort through thousands of seedlings with unacceptable fruit quality.

Using this strategy, called Marker-Assisted Breeding (MAB), cherry breeders can more efficiently, accurately, and creatively develop superior cherry varieties that meet the needs and desires of consumers and producers.

IMPACT: In the Washington State University sweet cherry and Michigan State University tart cherry breeding programs:

Genetic testing of sweet cherry seedlings, selections and varieties resulted in:

• Forty-two individuals chosen as parents and 146 crosses designed, based on their genetic potential to transmit self-fruitfulness and firm and large fruit.
• 3735 seedlings were discarded prior to orchard planting because they were predicted to be genetically inferior for the above traits.

Genetic testing of tart cherry seedlings, selections, and varieties resulted in:

• Twenty-five crosses designed based on their potential to transmit bright red fruit color to their progeny.
• About 30 percent of seedlings, predicted to be inferior, discarded prior to orchard planting.
• Seedlings predicted to be disease resistant propagated on a rootstock to induce early flowering. This leap-frog action should decrease the number of years to release of a disease resistant variety.

The collective impact of MAB is increased efficiency in identifying superior cherry varieties. Resources can therefore be spent on individuals with a greater chance of having desired trait attributes. For example, without MAB, approximately 3.5 acres of sweet cherry seedlings, with little commercial potential, would have been planted, maintained, and evaluated for years – a very resource-intensive process. A projected cost to the Washington State University program of $75,000 was avoided.

Sweet Cherry Breeding

Washington State University

ISSUE: New sweet cherry varieties with improved fruit quality will lead to increased consumer enjoyment and consumption and will contribute to the profitability and sustainability of the U.S. sweet cherry industry. However, breeding new sweet cherry varieties is slow and inefficient and can take 15 to 25 years from the initial cross to variety release. Predicting which selections will be the best parents is difficult. Thousands of seedlings must be grown and evaluated in the orchard to identify the few that have commercial potential.

WHAT HAS BEEN DONE: Genetic tests were developed to predict cherry fruit color, fruit size, fruit firmness, and self-fruitfulness. These genetic tests enable sweet cherry breeders to determine the best parents to combine and the best seedlings to advance, reducing the need to grow out and sort through thousands of seedlings with unacceptable fruit quality.

Using this strategy, called Marker-Assisted Breeding (MAB), cherry breeders can more efficiently, accurately, and creatively develop superior cherry varieties that meet the needs and desires of consumers and producers.

IMPACT: As a result of genetic testing of 7000 seedlings, selections, and varieties in the Washington State University sweet cherry breeding program:

• Forty-two selections were chosen as parents based on their genetic potential to transmit self-fruitfulness and firm and large fruit.
• 146 crosses were designed based on their efficient paired ability to generate selffruitfulness, large fruit, and good firmness in the next generation.
• Sixteen advanced selections were characterized for their genetic potential for key traits to increase confidence in their adoption as potential new varieties
• 3735 seedlings were discarded prior to field planting based on the prediction that the flowers will be self-sterile and the fruit will be small and soft.

The collective impact of MAB is increased efficiency of identifying sweet cherries that are large, firm, and self-fruitful with potential to extend the marketing window and increase profitability. Without MAB, approximately 3.5 acres of sweet cherry seedlings with little commercial potential would have been planted and evaluated. Therefore, a projected cost of $75,000 to the Washington State University program was avoided.

Tart Cherry Breeding

Michigan State University

ISSUE: New disease resistant tart cherry varieties with improved fruit quality will lead to increased consumer enjoyment and consumption and will contribute to the profitability and sustainability of the U.S. tart cherry industry. However, breeding a new tart cherry variety is slow and inefficient. Predicting which selections will be the best parents is difficult. Hundreds of progeny individuals must be grown and tested in the orchard to identify the few with commercial potential.

WHAT HAS BEEN DONE: DNA tests were developed to predict cherry fruit and pit size, cherry skin and flesh color, self-fruitfulness, and resistance to cherry leaf spot fungus. These genetic tests enable tart cherry breeders to determine the best parents to combine and the best seedlings to advance, reducing the need to grow out and sort through hundreds of seedlings with unacceptable fruit quality or disease susceptibility.

Using this strategy, called Marker-Assisted Breeding (MAB), cherry breeders can more efficiently, accurately, and creatively develop superior tart cherry varieties that meet the needs and desires of consumers and producers.

IMPACT: As a result of genetic testing in the Michigan State University tart cherry breeding program:

• About 30 percent of seedlings from one cross were discarded prior to orchard planting because DNA tests identified them as derived from unintended parentage.
• Twenty-five crosses were designed based on their increased potential for transmitting the desired red skin and light red juice color to their offspring.
• Seedlings predicted to be resistant to cherry leaf spot were propagated on a rootstock that induces early flowering. This new activity will reduce by two years the time required to breed disease resistant varieties.
• In 2014, seedlings from 10 crosses will be DNA tested to discard those seedlings that are predicted to have undesirable fruit color, thus avoiding future expenses for growing and evaluating these seedlings.

The collective impact of MAB is increased efficiency of identifying new tart cherry varieties. Resources needed to grow seedlings to maturity can be targeted to those individuals with a greater chance of having the desired trait attributes.