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

PI: Peggy Ozias-Akins（佐治亚大学）CoPIs: Scott A. Jackson和Soraya Bertioli（佐治亚大学），H. Thomas Stalker（北卡罗莱纳州立大学）和Daniel Fonceka（塞内加尔CIRAD和ISRA/CERAAS）。花生是多倍体，起源于较晚的进化时间，由两个二倍体物种杂交，然后是染色体加倍。这种驯化瓶颈限制了对大多数病虫害具有抗性的基因之间的变异。育种方法的进步使花生的祖先二倍体种发育成合成多倍体。将合成多倍体与栽培品系杂交或回交，可以将携带理想性状的染色体片段转移到栽培基因组中。鉴于大多数花生是在发展中国家生产的，而且基于遗传改良的产量增长潜力很大，因此对这种营养作物生产的长期影响将是巨大的。与塞内加尔农业研究所的伙伴关系将确保该项目的产出惠及小农，因为他们目前被纳入了一个网络，该网络正在用于评价和预传播最有前途的种质。性状优良的种质也将提供给世界各地的育种计划。栽培花生（arachhis hypogaea L.）在美国和国际上是一种重要的粮食和油料作物，特别是对小农来说。同种异体四倍体栽培种（2n = 4x = 40； AABB基因组）起源于两个二倍体种A. duranensis （AA）和A. ipaensis (BB)，其DNA多态性水平非常低，对大多数病虫害的抗性仅为中等水平。然而，一些二倍体（2n = 2x = 20）花生品种对花生最重要的疾病具有极高的抗性或免疫力。本项目的目的是将4个a基因组抗病物种与2个B基因组和1个k基因组的二倍体物种杂交。B基因组和k基因组最近被描述为B基因组的细胞学变异，它们可能与栽培花生具有不同的重组潜力。将从12个种间杂交组合中获得合成四倍体，然后与花生品种杂交，以便选择早、晚叶斑病、锈病、其他抗病性、抗旱性以及有利的豆荚和茎干性状。此外，四种AABB合成的先进一代种间杂交种将在非洲进行相同性状的实地试验。利用花生基因组资源不断扩大的优势，利用序列分型技术调查亲本间的等位基因多样性，确定杂交和回交的杂交性质，确定回交过程中的基因渐近特征，选择具有抗叶斑病、抗锈病、耐旱以及荚果和荚果性状的QTL。预计所获得的基因分型和表型信息将有助于QTL和基因发现，对改善非洲和世界其他花生种植区小农农业相关性状具有重要意义。这些提议的活动将促进对花生遗传学、属内进化关系、基因组结构和基因功能的了解，从而为野生等位基因向栽培种质的渗入提供更系统的方法。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.