Haploid Wild Species Hybrids In Potato Breeding Genetics And Germplasm Enhancement

The potato (Solanum tuberosum) is the world’s fourth most important food crop after maize, rice and wheat with 377 million tonnes fresh-weight of tubers produced in 2016 from 19.2 million hectares of land, in 163 countries, giving a global average yield of 19.6 t ha-1 (http://faostat.fao.org). About 62% of production (234 million tonnes) was in Asia (191), Africa (25) and Latin America (18) as a result of steady increases in recent years, particularly in China and India. As a major food crop, the potato has an important role to play in the United Nations “2030 Agenda for Sustainable Development” which started on 1 January 2016 (http://faostat.fao.org). By 2030 the aim is to “ensure access by all people, in particular the poor and people in vulnerable situations, including infants, to safe, nutritious and sufficient food all year round”. By then, the world population is expected to reach 8.5 billion and continue to increase to 9.7 billion in 2050. For potatoes, the need is to increase production and improve nutritional value during a period of climate change, a key aspect of which will be the breeding of new cultivars for a wide range of target environments and consumers. The aim of the book is to help this endeavour by providing detailed information in three parts on both the theory and practice of potato breeding. Part I deals with the history of potato improvement and with potato genetics. Part II deals with breeding objectives, divided into improving yield, quality traits and resistance to the most important diseases and pests of potatoes. Part III deals with breeding methods: first, the use of landraces and wild relatives of potato in introgression breeding, base broadening and population improvement; second, breeding clonally propagated cultivars as a way to deliver potato improvement to farmers’ fields; third, as an alternative, breeding potato cultivars for propagation through true potato seed; and fourth, gene editing and genetic transformation as ways of making further improvements to already successful and widely grown cultivars. Included are marker-assisted introgression and selection of specific alleles, genomic selection of many unspecified alleles and diploid F1 hybrid breeding.

This book describes the historical importance of potato (Solanum tuberosum L.),potato genetic resources and stocks (including S. tuberosum group Phureja DM1-3 516 R44, a unique doubled monoploid homozygous line) used for potato genome sequencing. It also discusses strategies and tools for high-throughput sequencing, sequence assembly, annotation, analysis, repetitive sequences and genotyping-by-sequencing approaches. Potato (Solanum tuberosum L.; 2n = 4x = 48) is the fourth most important food crop of the world after rice, wheat and maize and holds great potential to ensure both food and nutritional security. It is an autotetraploid crop with complex genetics, acute inbreeding depression and a highly heterozygous nature. Further, the book examines the recent discovery of whole genome sequencing of a few wild potato species genomes, genomics in management and genetic enhancement of Solanum species, new strategies towards durable potato late blight resistance, structural analysis of resistance genes, genomics resources for abiotic stress management, as well as somatic cell genetics and modern approaches in true-potato-seed technology. The complete genome sequence provides a better understanding of potato biology, underpinning evolutionary process, genetics, breeding and molecular efforts to improve various important traits involved in potato growth and development.

In this volume, world leaders in potato research review historical and contemporary discoveries resulting in a range of advances. Topics include nutritional quality, yield, disease and insect resistance, processing, plant growth and development, and other aspects. The book also examines research yielding significant molecular resources that facilit

Potato is the most significant non-cereal crop. Much attention has been paid to this commercially important crop. The aim of this volume is to capture the recent advances made in improving potatoes using traditional breeding methods as well as genetic engineering technology. The book provides a critical appraisal of the state-of-the-art finding on

Phylosophy, organization & program development; Utilization of CIP's primitive potato germ plasm to develop improved back-up populations; Development of lowland tropic populations; Development of highland tropic populations; Progress & future plans for the use of neo-tuberosum populations; Progress & future plans for the use of phureja-stenotomum populations; Breeding for virus resistance & its integration with other traits; Breeding at the 2x level for combined pest & disease resistantece using wild species & extracted haploids from selected tetraploid clones; Disease resistance evaluations; Recent progress & future plans for utilizing mexican wild species for pest & disease resistance; Evaluation of cultivated & wild species for glandular trichomes & resistance to potato tuber moth; Breeding for adaptation to TPS propagation; Evaluation of transplanted true potato seed progenies: hybrid vs. open-pollinated; Current status of exploitation of monohaploids & protoplasts, fusion & potential in potato breeding.; A biometric model for predicting the performance of potato clones in different environments; Principles & methods of transfer of genetic materials from CIP to national potato programs; Utilizing CIP's breeding materials - the turkish case -region IV; Potato breeding & productivity in Colombia & the utilization of germ plasm from CIP; Germ plasm management & transfer to national programs - the ecuadorina case - region I.

The majority of cultivated potato varieties (Solanum tuberosum Grp. Tuberosum 2n=4x=48) are tetraploid. For over a 100 years yield increases have been obtained from improvements in production management rather than through genetic improvement. The goal of this study is to develop diploid germplasm that is self-compatible (SC) that can be used as parental material F1 hybrid variety breeding scheme. Producing true F1 hybrid potato seeds requires first developing SC inbred lines. Wild and cultivated species and dihaploid produced from cultivated tetraploid potato are self-incompatible (SI). We designed our study to develop breeding strategies to generate two germplasm pools using the benefit of having the S-locus inhibitor (Sli) gene from Solanum chacoense (M6).The first goal was to create a SC diploid potato multi-species germplasm pool. The objectives of recurrent selection (RS) are to introgress and improve SC in a multi-species potato germplasm pool that has essential cultivated tuber and canopy traits. SC was increased from 16% to 85% in the progeny over five cycles of RS. Genetic variability analysis based on 4885 single nucleotide polymorphisms (SNPs) was maintained in the germplasm based on heterozygosity, and Neighbor-joining tree (NJ), Principal component analysis (PCA), and Structure analyze. Agronomic trait measurements showed that the RS population has genetic variability for many agronomic traits such as tuber appearance, tuber shape, and average tuber weight, average tuber yield, and tuber specific gravity. SC combined with essential tuber traits, is a valuable germplasm resource for inbred/F1 hybrid variety development.The second goal was to introgress self-compatibility into S. tuberosum dihaploids by crossing SC donor lines to cultivated dihaploids (2n=2x=24) produced from cultivated lines with traits such as chip processing, disease resistance, and virus resistance. A set of three crosses with dihaploid selections was used to select against undesirable traits and reduce the genetic contribution of the SC donor parents. The SC progeny were used in each round of crosses to a set of cultivated dihaploids. This set of three crosses is referred to as S. tuberosum backcross. Genetic diversity analysis based on over 6000 SNPs and agronomic traits measurements showed that the backcross (BC) population has genetic variability for many agronomic traits such as tuber appearance, tuber shape, and average tuber weight, average tuber yield, and specific gravity. The SC germplasm is a valuable resource for the future development of dihaploid F1 hybrid varieties.Third, a study was conducted to examine the results of chloroplast counting in stomatal guard cells, SNP genotyping calling, and flow cytometry to determine ploidy level. All three methods of ploidy determination agreed for evaluating ploidy. Twenty-eight clones with known ploidy level were used as reference samples (14 diploid lines (2n=2x=24), 14 tetraploid varieties and advanced breeding lines (2n=4x=48)) and 102 samples of unknown ploidy level from the RS and the BC populations. These results demonstrate the usefulness of chloroplast counting as an efficient and inexpensive method for breeders to differentiate ploidy between diploid and tetraploid potato.SNP-based heterozygosity, an unweighted pair-group method with arithmetic averages (UGPMA), PCA, and Structure analysis were done using the RS and BC germplasm pools. The NJ tree and PC analysis show the BC2 selections are distinct from the cycle 4 RS selections. The BC2 selections were clustered in one distinct group, and genetic variability was maintained within the group. Developing SC multi-species germplasm pool by using recurrent selection and SC S. tuberosum pool using backcross has led to two germplasm pools that could be tested to identify heterotic combinations. These two germplasm pools may help us develop F1 hybrid diploid potato varieties in the future.