Volume 5 Special Issue 1 2011
Methods in Temperate Fruit Breeding
How to reference: Jules Janick (2011) History of Fruit Breeding. In: Flachowsky H, Hanke V-M (Eds) Methods in Temperate Fruit Breeding. Fruit, Vegetable and Cereal Science and Biotechnology 5 (Special Issue 1), 1-7
Hendryk Flachowsky, Magda-Viola Hanke
Julius Kühn-Institut (JKI), Germany
CONTENTS AND ABSTRACTS
Jules Janick (USA) History of Fruit Breeding (pp 1-7)
Invited Mini-Review: Fruit breeding, the genetic improvement of fruit crops, has an ancient tradition that traces to the domestication process. Thought the millennia genetic improvement has been achieved by grower selection, first from natural seedling populations and then from seedlings that occurred naturally from grower fields with desirable genotypes fixed by vegetative propagation. In the middle of the 19th century hybridization between elite genotypes were made followed by selection in segregating progeny. Conventional fruit breeding is based on continuous selection of superior phenotypes from genetically variable populations using cycles of hybridization and selection and special techniques such as mutation induction, interspecific hybridization, and backcross breeding. Recently biotechnology techniques have been employed including in vitro propagation, embryo rescue, protoplast fusion, marker-assisted selection, and transgenesis.
Henryk Flachowsky, Monika Höfer, Magda-Viola Hanke (Germany) Strawberry (pp 8-26)
Invited Review: The cultivated strawberry Fragaria × ananassa Duch. is the most important berry fruit crop worldwide. Approximately 4.1 Million metric tonnes are produced worldwide each year. Strawberries are cultivated in more than 70 countries worldwide and the standards required for success in a new strawberry cultivar have changed substantially during the past 50 years. Market requirements and cultural practices have shifted the relative importance of different traits and the main objectives of international breeding programs vary according to the environmental conditions of cultivation, the production systems in this area, and the utilization of fruit. In addition to yield capacity and fruit quality resistance to important pests, pathogens and abiotic stress conditions became more and more important. Particular attention is paid to the improvement of resistance to Verticillium wilt, black root rot disease, red stele, anthracnose and grey mould disease for example. However, classical breeding is still hampered by the lack of effective selection strategies which allow a screening of thousands of seedlings within a few weeks or months. Molecular markers which can help to overcome this problem are only available for a handful of traits. Nevertheless, the number of molecular studies is increasing and the first genome sequence of the diploid wild strawberry Fragaria vesca is available. This and the high number of favourable features have lead to the fact that F. vesca has emerged as an attractive model system for structural and functional genomics within the Rosaceous crops. With the publication of the first linkage studies in octoploid strawberry a milestone has been reached to take classical strawberry breeding to a new level. The availability of DNA markers linked to QTLs as well as cloning of individual genes which significantly contribute to complex traits will be very helpful for breeders to select for a specific introgression of interest.
John R. Clark, Chad E. Finn (USA) Blackberry Breeding and Genetics (pp 27-43)
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Invited Review: Blackberry (Rubus L. subgenus Rubus Watson) improvement has made substantial progress with over 400 cultivars named originating from wild selections to many releases from breeding efforts. Public breeding has been ongoing for over 100 years. The result of these improvements is commercial production for processing and fresh markets in a number of countries. There has been excellent progress made in improving several very important traits. Fruit quality has been and continues to be a high priority in breeding, with selection for improved processing quality along with enhanced postharvest handling potential for fresh market expansion. Fruit size has been advanced and a range of berry sizes from small to very large exist among released cultivars. A number of plant characters have been addressed, with thornlessness becoming more common in recent introductions. Likewise, enhanced yield potential, improved disease resistance, and improved cane management characteristics have been achieved. More recently, primocane fruiting has been incorporated into blackberry, expanding production options. Breeding has been done using classical breeding methodology, crossing complementary parents and selecting improved progeny. Research using molecular methods has been limited in blackberry, and has not contributed substantially to cultivar improvement. Although breeding efforts in blackberry are more limited than the major berry crops, a continuous supply of new cultivars should result from ongoing programs. These, along with previous cultivar developments, will contribute to an ever-increasing number of cultivar options resulting in an increased of production of this increasingly popular berry crop.
Harvey K. Hall (New Zealand), Chaim Kempler (Canada) Raspberry Breeding (pp 44-62)
Invited Review: Raspberries have been gathered since the beginnings of history and have been carried to temperate regions worldwide from their Eurasian place of origin. In the last two hundred years deliberate attempts to produce improved types were considerably accelerated as an understanding of reproductive biology was gained and crosses and formal breeding programs were initiated. Initial breeding utilised selections from Europe and North America, resulting in great improvements. These have been focused and expanded with the development of primocane fruiting types and through the use of other Rubus and subgenus Idaeobatus accessions for breeding. The advents of specialised tools and techniques to assess plant material, to examine their genetic structure and inheritance and even to modify the plant genome have also made a major contribution to the present range of new cultivars. This review gives an overview of raspberry genetic resources, environmental and pest and disease challenges encountered in raspberry cultivation, specialised techniques used in the development of new genotypes and propagation of the elite new cultivars. The best is yet to come!
S. Jayasankar, Frank Kappel (Canada) Recent Advances in Cherry Breeding (pp 63-67)
Invited Mini-Review: Sweet and sour cherries belong to the Prunus spp. and are extensively grown both in the old and new world with an estimated annual production of over 3 million tons. Both cherries are believed to be native to the region between Eastern Europe and cold parts of Russia from where it spread to other parts of the world. Several breeding programs aim to continuously improve cherries with different objectives such as season extension, self fruitfulness, resistance to biotic and abiotic factors and yield. Molecular advances that have augmented crop improvement in several other species have also been utilised for acceleration of cherry breeding. In this short review we have discussed the recent advances that have impacted on cherry improvement and culture.
Luis Gea (New Zealand) Sustainable Population Management of Actinidia (Kiwifruit) for Multiple Products (pp 68-78)
Invited Review: The maintenance of genetic variance is the key issue in breeding and conservation. To increase the productivity of kiwifruit, kiwifruit breeders have been exploring methods of selecting the best genotypes. The future success of this programme depends on the availability of sufficient genetic variance in the population. It is feared that continued selection will deplete genetic variance of commercial traits. Increasing the total genetic variance is possible through recombination, mutation and breeding. Methods to generate inter-population variance and its subsequent release through advanced generation ‘hybrids’ are reviewed, to gather knowledge and focus on breeding opportunities from germplasm management relevant to kiwifruit (as well as any other) breeding programme. The use of molecular information and molecular tools has started to transform the approach to conservation and breeding with Actinidia, from allelic diversity analysis link to provenance variation to the implementation of molecular markers for commercially important traits. Increasing the opportunities for selecting new cultivars with traits highly associated with consumer and industry demands are the major drivers of Plant and Food Research strategy; a robust breeding and conservation strategy will guarantee enough sources of variation for the future.
Reinhard Töpfer, Ludger Hausmann, Margit Harst, Erika Maul, Eva Zyprian, Rudolf Eibach (Germany) New Horizons for Grapevine Breeding (pp 79-100)
Invited Review: The introduction of fungi – particularly powdery and downy mildew – and of phylloxera during the second half of the 19th century was the catalyst to initiate enormous grapevine breeding activities in several European countries. These efforts aimed at the combination of resistance traits found e.g. in American Vitis species and quality traits found in the cultivated Vitis vinifera L. subsp. vinifera. It became evident that grapevine breeding is a huge challenge due to the complexity of traits and long breeding cycles of about 25 years. Despite some major drawbacks, at the onset of the 20th century rootstocks became available solving the phylloxera crisis. In contrast to the progress in rootstock breeding for some decades, it was believed that the aim for scions of combining resistance against the mildew diseases and quality can not be achieved. By the end of the 20th century, however, first cultivars were introduced into the market showing high wine quality and good field resistance against powdery and downy mildew. Simultaneously new technologies were developed to genetically dissect traits e.g. by QTL analysis and molecular markers were introduced into breeding research. Genetic fingerprints characterizing cross parents, marker assisted selection, and marker assisted backcrossing recently initated a paradigm shift in grapevine breeding from a purely empirical work to the strictly goal-oriented design of crosses and of gene management. These new tools and next generation sequencing technologies will reduce the breeding cycle by up to 10 years. In addition, genetic engineering opens the door to improve existing cultivars, for which otherwise any improvement of resistance is utterly impossible.
David Ruiz, Pedro Martínez-Gómez, Manuel Rubio, Cesar Petri (Spain), Antonio Larios (Mexico), José Antonio Campoy (Spain/France), José Egea (Spain) Application of Biotechnology Tools to Apricot Breeding (pp 101-117)
Invited Review: Apricot is a worldwide grown Prunus species originated in China with very appreciate fruit. In this study strategies and methodologies for the breeding of this species are described including germplasm description, classical breeding, main objective breeding, molecular marker application, and improved micro-propagation and genetic transformation protocols. Despite the plasticity expressed by the apricot species and its great diversity, there is a great specificity in the cultivation of the cultivars in each region. In addition, the typical long generation time, along with the extensive space requirements and other limitations to generating the required large segregating apricot progeny population, have restricted the development and testing of new cultivars. The main objectives of apricot breeding are to decrease production costs (pest and disease resistance with special emphasis in Plum pox virus, sharka, resistance), to increase yield (introducing self-compatibility and studying the chilling requirements for adequate adaptation) and to improve fruit quality. Additional advantages encouraging the utilization of new genomic technologies to apricot tree crop improvement include a small genome size, high levels of synteny between genomes, and a well-established international network of cooperation among researchers. To date, different genes and QTLs controlling traits such as self-compatibility, sharka resistance or male sterility have been mapped in genetic linkage maps. More recent efforts are being oriented to the elaboration of physical maps which can be the beginning for the complete genome sequencing of the species. Finally, the increasing availability of other biotechnological techniques such as genetic transformation further complements in vitro culture opportunities. In this sense, at this time several apricot genotypes genetically modified are being assayed.
Andreas Peil, Markus Kellerhals, Monika Höfer, Henryk Flachowsky (Germany) Apple Breeding – From the Origin to Genetic Engineering (pp 118-138)
Invited Review: Apple is the most important temperate fruit crop and ranks fourth in world production of fruits after citrus, grapes and bananas. Although more than 10,000 cultivars are documented, only a few dozen are grown on a commercial scale worldwide. Despite the abundant number of cultivars there is a demand for new cultivars better adapted to climatic conditions/changes and sustainable production. Yet, the challenge for apple breeding is the establishment of improved, multiple disease resistant cultivars with high and regularly yield suited for modern production systems. Due to the fast development of molecular techniques an increasing knowledge on the genome of apple is available, e.g. the whole genome sequence of ‘Golden Delicious’ (Velasco et al. 2010). Molecular markers for a lot of major traits, mostly resistance genes, and QTLs facilitate marker assisted selection, especially the pyramiding of resistance genes to achieve more durable resistance. Mainly the breakdown of the Rvi6 (Vf) scab resistance enhanced the breeding for pyramided resistance genes. But nevertheless, until now there is a gap between the existing molecular knowledge and its application in apple breeding. This paper will focus on the origin and domestication of apple, breeding objectives and classical as well as molecular approaches to achieve breeding aims. Besides this an update on molecular knowledge and the current state and progresses in genetic engineering will be presented.
Michael Neumüller (Germany) Fundamental and Applied Aspects of Plum (Prunus domestica) Breeding (pp 139-156)
Invited Review: The hexaploid European plum (Prunus domestica L.) is one of the most important temperate fruit crops. Its origin is unclear as wild forms are missing. The genetic base which can be used for breeding is highly diverse and provides a good base for further improvement of the fruit crop. Information on the inheritance of single traits are rarely available. Breeding focuses on resistance and fruit quality. Classical breeding is the most important method applied. Very few data is available on the genome sequence. No marker assisted selection systems are available. Genetic engineering is limited to the transformation of embryonic tissue derived from seeds. Prunus domestica is the only Prunus species where genotypes completely resistant to the Plum pox virus exist. This resistance is based on a hypersensitive response of the plant cells to the virus. Interspecific hybridization becomes more important in terms of transferring resistance traits from European plum to related species and of developing hybrids with new fruit characters. Classical breeding is far from being the limit of the improvement of plum genotypes.