Success
By 2000, the PRI have already released a total of eighteen apple cultivars, containing the scab-resistant Vf gene derived from Malus floribunda 821. Fifty-some PRI germplasm cultivars have also been released worldwide. [2]
The PRI disease resistant apple breeding program is a joint project of the Purdue University, Rutgers University, and the University of Illinois, to breed apple cultivars to be resistant to apple scab. The initialism stands for the three involved universities: Purdue, Rutgers and Illinois. [1]
During the early 20th century, C. S. Crandall carried out intensive studies of crosses between the cultivated apples and crab apples, with the goal of scab resistance. [2] However, Crandall didn't see any fruits of his investigations. [3] L. Fredric Hough, then a graduate student at the University of Illinois, studied Crandall's work. Hough published a paper in 1944, leading to a 1945 collaboration with Purdue University pathologist J. Ralph Shay. Hough then relocated to Rutgers and the collaborative effort was extended there. [2]
The modified backcross breeding strategy used cultivated apple with recurrent parents from selected susceptible members of the wild ancestral genus malus. Several Malus species were screened and utilized to incorporate their resistance factors into the more advanced pomological backgrounds. [2]
By 2000, the PRI have already released a total of eighteen apple cultivars, containing the scab-resistant Vf gene derived from Malus floribunda 821. Fifty-some PRI germplasm cultivars have also been released worldwide. [2]
A cultivar is a kind of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue culture, or carefully controlled seed production. Most cultivars arise from purposeful human manipulation, but some originate from wild plants that have distinctive characteristics. Cultivar names are chosen according to rules of the International Code of Nomenclature for Cultivated Plants (ICNCP), and not all cultivated plants qualify as cultivars. Horticulturists generally believe the word cultivar was coined as a term meaning "cultivated variety".
There are a number of lines of defence against pests and diseases in the orchard, principal among these being the practice of good husbandry, creating healthy soil and ensuring high standards of garden hygiene. But no matter how diverse and healthy the garden eco-system may be, there will always be a degree of disease and pest presence. In many ways, some level of pathogen population in the garden can be not only acceptable but desirable as they are indicative of a generally healthful and diverse environment, and add to the overall robustness of the system as an immunity to such detrimental influences will build up, particularly in a balanced polycultural regime. Indeed, most of the plants we grow will tend to be selected because they are trouble free, and those that are more susceptible to attack will have fallen by the wayside over time. However, most farmers find it unacceptable that the food crops they grow are damaged by pests.
The pecan is a species of hickory native to the southern United States and northern Mexico in the region of the Mississippi River.
Malus is a genus of about 30–55 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple, crab apples and wild apples.
Apple scab is a common disease of plants in the rose family (Rosaceae) that is caused by the ascomycete fungus Venturia inaequalis. While this disease affects several plant genera, including Sorbus, Cotoneaster, and Pyrus, it is most commonly associated with the infection of Malus trees, including species of flowering crabapple, as well as cultivated apple. The first symptoms of this disease are found in the foliage, blossoms, and developing fruits of affected trees, which develop dark, irregularly-shaped lesions upon infection. Although apple scab rarely kills its host, infection typically leads to fruit deformation and premature leaf and fruit drop, which enhance the susceptibility of the host plant to abiotic stress and secondary infection. The reduction of fruit quality and yield may result in crop losses of up to 70%, posing a significant threat to the profitability of apple producers. To reduce scab-related yield losses, growers often combine preventive practices, including sanitation and resistance breeding, with reactive measures, such as targeted fungicide or biocontrol treatments, to prevent the incidence and spread of apple scab in their crops.
Honeycrisp is an apple cultivar developed at the Minnesota Agricultural Experiment Station's Horticultural Research Center at the University of Minnesota, Twin Cities. Designated in 1974 with the MN 1711 test designation, patented in 1988, and released in 1991, the Honeycrisp, once slated to be discarded, has rapidly become a prized commercial commodity, as its sweetness, firmness, and tartness make it an ideal apple for eating raw. "...The apple wasn't bred to grow, store or ship well. It was bred for taste: crisp, with balanced sweetness and acidity." It has larger cells than most apple cultivars, a trait which is correlated with juiciness, as theoretically a higher number of cells rupture when bitten, releasing more juice in the mouth. The Honeycrisp also retains its pigment well and has a relatively long shelf life when stored in cool, dry conditions. Pepin Heights Orchards delivered the first Honeycrisp apples to grocery stores in 1997. The name Honeycrisp was trademarked by the University of Minnesota, but university officials were unsure of its protection status in 2007. It is now the official state fruit of Minnesota. A large-sized honeycrisp will contain about 113 calories.
Malus sieversii is a wild apple native to the mountains of Central Asia in southern Kazakhstan. It has recently been shown to be the primary ancestor of most cultivars of the domesticated apple. It was first described as Pyrus sieversii due to its similarities with pears in 1833 by Carl Friedrich von Ledebour, a German naturalist who saw them growing in the Altai Mountains.
Venturia inaequalis is an ascomycete fungus that causes the apple scab disease.
Malus floribunda, common name Japanese flowering crabapple, Japanese crab, purple chokeberry, or showy crabapple, originates from Japan and East Asia. It may be a hybrid of M. toringo with M. baccata, in which case it would be written as Malus × floribunda.
Claygate Pearmain is an apple cultivar. It was found at Claygate, Surrey in England and brought to the attention of the Royal Horticultural Society by John Braddick in 1821. The apple was a popular eating apple in Victorian times and spread through England and to America.
An apple is a round, edible fruit produced by an apple tree. Apple trees are cultivated worldwide and are the most widely grown species in the genus Malus. The tree originated in Central Asia, where its wild ancestor, Malus sieversii, is still found. Apples have been grown for thousands of years in Asia and Europe and were introduced to North America by European colonists. Apples have religious and mythological significance in many cultures, including Norse, Greek, and European Christian tradition.
The Golden Orange apple is an apple cultivar that was first developed in Italy in the 1970s by crossing PRI 1956-6 and Ed Gould Golden apples.
Liberty is a hybrid apple cultivar developed by the New York State Agricultural Experiment Station. It was a seedling produced in 1955 from pollinating 'Macoun' from 'Purdue 54-12' for the sake of acquiring Malus floribunda disease resistances. It was first released to the public in 1978.
Applecrabs are various hybrids between crabapples and apples. They are bred for varying reasons, including disease resistance and use in cold climates because they are often hardier than apple trees and their fruit has the good eating qualities of apples.
Pristine apple is a hybrid cultivar of 'Co Op 10' x 'Camuzat' domesticated apples, which are descendants of the 'McIntosh' apple and the 'Starking Delicious'. This cultivar was developed and patented in the United States by the PRI disease resistant apple breeding program, in Indiana, United States in 1994, for its resistance to apple scab. It is susceptible to cedar-apple rust.
Enterprise is a modern bred, late-ripening and attractive, red cultivar of domesticated apple with excellent fruit quality combined with disease resistance to scab, cedar apple rust, fire blight and some resistance to powdery mildew. The fruit is large and attractive and retains excellent fresh quality for up to six months at 1°C. Its moderate acidity at time of harvest mellows in storage, and it is best after one month of storage.
The 'Prima' apple is one of the modern disease resistant cultivars of domesticated apple which was bred by the PRI disease resistant apple breeding program in 1958. The disease resistance against apple scab has since been broken.
Sweet Sixteen is a cultivar of domesticated apple.
Aia Ilu is a cultivar of domesticated apple, from Estonia, first developed in 1946 by Aleksander Siimon.
Ralph Merrill Caldwell was an American plant breeder, mycologist, and plant pathologist. Through his work with the U.S. Department of Agriculture and Purdue University, he developed disease-resistant cultivars for a wide variety of plants, including widely-grown wheat cultivars.
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