BREAD ABRDC: Genomic approaches to capture Novel Alleles in cultivated peanut to increase smallholder production.

PI：Peggy Ozias-Akins（格鲁吉亚大学）CoPI：Scott A.杰克逊和索拉亚Bertioli（格鲁吉亚大学），H。托马斯斯托克（北卡罗来纳州州立大学）和丹尼尔丰塞卡（CIRAD和ISRA/CERAAS，塞内加尔）种植花生是美国和全球重要的粮食和油料作物。 花生是多倍体，在进化时间上起源于两个二倍体物种之间的杂交，随后是染色体加倍。 这种驯化瓶颈限制了对大多数害虫和疾病的抗性基因之间的变异。 育种方法的进步已经导致从花生的祖先二倍体物种发展出合成多倍体。 将合成多倍体与栽培品系杂交和回交允许将携带期望性状的染色体区段转移到栽培基因组。 鉴于大多数花生产于发展中国家，而且基于遗传改良的增产潜力很大，对这种营养作物的生产将产生重大的长期影响。 与塞内加尔农业研究所的伙伴关系将确保该项目的成果惠及小农，因为他们目前已被纳入一个网络，该网络正被用于评估和预先传播最有前途的种质。 经过充分鉴定的种质也将提供给世界各地的育种计划。栽培花生（Arachis hypogaea L.）在美国和国际上是重要的粮食和油料作物，特别是对于小保持器农民。 异源四倍体栽培种（2n = 4x = 40; AABB基因组）起源于两个二倍体种，A. duranensis（AA）和A. ipaensis（BB）具有非常低水平的DNA多态性，并且对大多数害虫和疾病仅具有中等水平的抗性。 然而，一些二倍体（2n = 2x = 20）花生物种对花生最重要的疾病具有极高水平的抗性或免疫力。 本项目的目标是将四个A基因组抗病物种与两个二倍体B和一个K基因组物种杂交。B-和K-基因组是最近描述的B基因组的细胞学变体，其可能与栽培花生具有不同的重组潜力。 从12个种间杂种组合中产生合成四倍体，然后与花生品种杂交，以便选择早、晚叶斑病、锈病、其他病原体抗性、耐旱性以及有利的荚和茎性状。 此外，来自四种AABB合成材料的先进一代种间杂交种将在非洲进行这些相同性状的田间试验。 利用不断扩大的花生基因组资源，将进行基于序列的基因分型以调查亲本系之间的等位基因多样性，以确认杂交和回交的杂交性质，以表征回交过程中的渐渗，并选择赋予叶斑病和锈病抗性以及沿着荚果和茎秆性状的耐旱性的QTL。 预计所产生的基因分型和表型信息将有助于QTL和基因发现，这些QTL和基因发现对非洲和世界其他花生种植地区小农农业相关性状的花生改良具有重要意义。 这些拟议的活动将推进花生遗传学知识，属内的进化关系，基因组结构和基因功能，使野生等位基因渗入栽培种质更系统的方法。 项目活动将涉及研究生和本科生，并提供一个积极的学习环境，重点是现代植物育种和基因组学。

PI: Peggy Ozias-Akins (University of Georgia)CoPIs: Scott A. Jackson and Soraya Bertioli (University of Georgia), H. Thomas Stalker (North Carolina State University), and Daniel Fonceka (CIRAD and ISRA/CERAAS, Senegal)Cultivated peanut is an important food and oil crop in the U.S. and globally. Peanut is polyploid and originated relatively recently in evolutionary time from hybridization between two diploid species, followed by chromosome doubling. This domestication bottleneck limits variation among genes for resistance to most pests and diseases. Advances in breeding methods have resulted in the development of synthetic polyploids from the ancestral diploid species of peanut. Crossing and backcrossing synthetic polyploids with cultivated lines allows transfer of chromosomal segments carrying desirable traits to the cultivated genome. Given that the majority of peanuts are produced in developing countries and that potential for yield gains based on genetic improvement is large, the long-term impact on production of this nutritious crop will be substantial. Partnership with the Senegalese Institute for Agricultural Research will ensure that the outputs of this project reach smallholder farmers given their current inclusion in a network that is being used both for evaluation and pre-diffusion of the most promising germplasm. Well characterized germplasm also will be made available to breeding programs around the world.Cultivated peanut (Arachis hypogaea L.) is an important food and oil crop in the U.S. and internationally, particularly for small holder farmers. The allotetraploid cultivated species (2n = 4x = 40; AABB genomes) originated from two diploid species, A. duranensis (AA) and A. ipaensis (BB), has very low levels of DNA polymorphism, and only moderate levels of resistance to most pests and diseases. However, several diploid (2n = 2x = 20) Arachis species have extremely high levels of resistance or immunity to the most important diseases of peanut. Objectives of this project are to hybridize four A-genome disease-resistant species with two diploid B- and one K-genome species. The B- and K-genomes are recently described cytological variants of the B genome that likely have different recombination potentials with cultivated peanut. Synthetic tetraploids will be produced from twelve interspecific hybrid combinations and then hybridized with peanut cultivars so that selections can be made for early and late leaf spots, rust, other pathogen resistances, drought tolerance, and favorable pod and haulm traits. In addition, advanced generation interspecific hybrids from four AABB synthetics will be field tested in Africa for these same traits. Taking advantage of the expanding genomic resources for peanut, sequence-based genotyping will be conducted to survey allelic diversity between parental lines, to confirm the hybrid nature of crosses and backcrosses, to characterize introgressions during backcrossing, and to select for QTL conferring leaf spot and rust resistance and drought tolerance along with pod and haulm traits. It is expected that genotyping and phenotyping information generated will contribute to QTL and gene discovery bearing significance for peanut improvement in traits relevant to smallholder agriculture in Africa and other peanut growing regions of the world. These proposed activities will advance knowledge of peanut genetics, evolutionary relationships within the genus, genome structure and gene function enabling a more systematic approach for introgression of wild alleles into cultivated germplasm. Project activities will involve graduate and undergraduate students and provide an active learning environment with emphasis on modern plant breeding and genomics.