P.M. Priyadarshan – författare

Tree species are indispensable to human needs. Due to their long life cycle and environmental sensitivity, breeding trees for sustainable production is a formidable challenge in order to meet the demands of growing human population and industries. Fruit crops such as apple, cocoa, mango, citrus, litchi, pear, dates, and coconut or industrial crops including rubber and tea, improving yield under the optimal, sub-optimal and marginal areas call for a unified worldwide effort. While the uniqueness of coconut as ‘kalpavriksha’ (Sanskrit - meaning tree of life) makes its presence in every continent from Far East to South America, tree crops such as cocoa, oil palm, rubber, apple, peach and walnut prove their environmental sensitivity towards tropical, subtropical and temperate climates. Date palm is quintessential for desert climate. Thus, from soft drinks to breweries to oil to tires, the value addition offers a spectrum of products to human kind, enriched with nutritional, environmental, financial, and trade related attributes.

This volume is a compilation of information on breeding of temperate tree species and provides first hand comprehensive knowledge to research, teach, and make policies.

Trees that are indispensably supportive to human life pose a formidable challenge to breed them to suit to human needs. From soft drinks to breweries to beverages to oil to tires, the value added products from trees give a spectrum of products to human kind.  While attempts to tap these resources through conventional breeding are underway, the quick and elegant way of manipulating the genetic systems at the genome level is an essential chapter of modern science.  Books featuring genomics of tree crops are few, and genomics is such a science that changes rapidly.  Genomics of Tree Crops is an earnest attempt towards compiling genomics of tree crops.

Plant genomics has made monumental strides in the last decade providing insights into intra-genomic phenomena such as heterosis, epistasis, pleiotropy and other interactions between loci and alleles within the genome.  In contrast, the investigation of the roles and functions of single genes is a primary focus of molecular biology and is a common topic of modern genetic  research. A genome is the sum total of all of an individual organism''s genes.  Thus, genomics is the study of all the genes of a cell, or tissue, at the DNA (genotype), mRNA (transcriptome), or protein (proteome) levels.  The complete sequencing of the three billion base pair human genome with 25,000 genes identified  and the  invention of DNA microarrays ushered in a new era in the science of genomics leading to explosive advancements in oncology diagnostics. This impetus into the genomics era lead the way toward advances in  plant genomics which started with Arabidopsis thaliana and went through an array of crops such as rice, maize, papaya, various cereals and legumes, with pigeon pea added to the list towards the end of 2011.  Trees, on the other hand, are the least attended taxa  with regard to genomic research. Some of the areas that attained attention of the scientists are: DNA sequencing, bioinformatics,genomics of flowering, gene flow, spatial structure, local adaptation and assisted migration in trees, transformation of fruit trees, genomics of tropical and temperate fruit trees, genomics of Hevea rubber, genomics of papaya and genomics of palms. Genomics of Tree Crops compiles this information with chapters authored by experts on these crops. 

Cash crops are grown and sold for monetary gain and not necessarily for sustenance. They include coffee, tea, coconut, cotton, jute, groundnut, castor, linseed, cocoa, rubber, cassava, soybean, sweet potato, potato, wheat, corn and teff.  While some of these crops have been improved for realizing yield potential, breeding of many of them is still in infancy. Crops that underwent    rigorous breeding have eventually lost much of the diversity due to extensive cultivation with a few improved varieties and the diversity in less bred species is to be conserved. Over the past years, scholars and policy makers have become increasingly aware of the short and long-run impact of climatic factors on economic, food security, social and political outcomes . Genetic diversity, natural and induced, is much needed for the future generations to sustain food production with more climate resilient crops.  In contrast, crop uniformity produced across the farm fields in the form ofimproved varieties is genetically vulnerable to biotic and abiotic stresses. Thus, it is essential and challenging to address the issue of compromising between maximizing crop yield under a given set of conditions and minimizing the risk of crop failure when conditions change. Cash crops are grown in an array of climatic conditions. Many of the world’s poor still live in rural areas.  Many are subsistence farmers, operating very small farms using very little agricultural inputs for achieving marketable outputs.  Conserving the diversity of these crops and addressing all issues of crop culture through modern tools of biotechnology and genomics is a real challenge. We believe the focus of this book is to fill an unmet need of this and other grower communities by providing the necessary knowledge, albeit indirectly via the academics, to manage the risks of cash crops breeding through managing genetic diversity.

In the second edition of this book, the origin, upkeep and latex harvest from the Hevea rubber tree are dealt with succinctly. New chapters have been included on Propagation Systems and Genetic Resources. The importance of Heterozygosis and Breeding is a new theme for the section on Breeding. A new chapter on Genomics and Molecular Breeding that focuses on the latest advancements on gene mapping, marker assisted selection and stimulation has been added. Lastly, ‘textboxes’ that highlight points and topics of significant interest are included in the new addition.