Cultivated peanut (Arachis hypogaea) is an allotetraploid with closely related subgenomes of a total size of ~2.7 Gb. This makes the assembly of chromosomal pseudomolecules very challenging. As a foundation to understanding the genome of cultivated peanut, we report the genome sequences of its diploid ancestors (Arachis duranensis and Arachis ipaensis). We show that these genomes are similar to cultivated peanut's A and B subgenomes and use them to identify candidate disease resistance genes, to guide tetraploid transcript assemblies and to detect genetic exchange between cultivated peanut's subgenomes. On the basis of remarkably high DNA identity of the A. ipaensis genome and the B subgenome of cultivated peanut and biogeographic evidence, we conclude that A. ipaensis may be a direct descendant of the same population that contributed the B subgenome to cultivated peanut. A r t i c l e s npg © 2016 Nature America, Inc. All rights reserved.Nature GeNetics VOLUME 48 | NUMBER 4 | APRIL 2016 4 3 9 subgenomes of A. hypogaea. Progeny are vigorous, phenotypically normal and fertile and showed lower segregation distortion 16,17 than has been observed for some populations derived from A. hypogaea intraspecific crosses [18][19][20][21] . Therefore, as a first step to characterizing the genome of cultivated peanut, we sequenced and analyzed the genomes of the two diploid ancestors of cultivated peanut. RESULTS Sequencing and assembly of the diploid A and B genomesConsidering that A. duranensis V14167 and A. ipaensis K30076 are likely good representatives of the ancestral species of A. hypogaea, we sequenced their genomes. After filtering, the data generated from the seven paired-end libraries corresponded to an estimated 154× and 163× base-pair coverage for A. duranensis and A. ipaensis, respectively (Supplementary Tables 1-6). The total assembly sizes were 1,211 and 1,512 Mb for A. duranensis and A. ipaensis, respectively, of which 1,081 and 1,371 Mb were represented in scaffolds of 10 kb or greater in size (Supplementary Table 7). Ultradense genetic maps were generated through genotyping by sequencing (GBS) of two diploid recombinant inbred line (RIL) populations (Supplementary Data Set 1). SNPs within scaffolds were used to validate the assemblies and confirmed their high quality; 190 of 1,297 initial scaffolds of A. duranensis and 49 of 353 initial scaffolds of A. ipaensis were identified as chimeric, on the basis of the presence of diagnostic population-wide switches in genotype calls occurring at the point of misjoin. Chimeric scaffolds were split, and their components were remapped. Thus, approximate chromosomal placements were obtained for 1,692 and 459 genetically verified scaffolds, respectively. Conventional molecular marker maps (Supplementary Data Set 2) and syntenic inferences were then used to refine the ordering of scaffolds within the initial genetic bins. Generally, agreement was good for maps in euchromatic arms and poorer in pericentromeric regions (although one map 22 showed large inversions in two lin...

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Pearl millet [Pennisetum glaucum (L.) R. Br., syn. Cenchrus americanus (L.) Morrone], is a staple food for over 90 million poor farmers in arid and semi-arid regions of sub-Saharan Africa and South Asia. We report the ~1.79 Gb genome sequence of reference genotype Tift 23D2B1-P1-P5, which contains an estimated 38,579 genes. Resequencing analysis of 994 (963 inbreds of the highly cross-pollinated cultigen, and 31 wild accessions) provides insights into population structure, genetic diversity, evolution and domestication history. In addition we demonstrated the use of re-sequence data for establishing marker trait associations, genomic selection and prediction of hybrid performance and defining heterotic pools. The genome wide variations and abiotic stress proteome data are useful resources for pearl millet improvement through deploying modern breeding tools for accelerating genetic gains in pearl millet.publishersversionPeer reviewe

Apomixis, asexual reproduction through seeds, has the potential to revolutionize agriculture if its genetic basis can be elucidated. However, the genetic control of natural apomixis has remained obscure until quite recently, owing to all the complications of Mendelian genetics, such as epistatic gene interactions, components that are expressed sporophytically and gametophytically, expression modifiers, polyploidy, aneuploidy, segregation distortion, suppressed recombination, etc., that seem to have accumulated during the evolution of apomixis. In this review we show how molecular markers and superior phenotypic methods have been used to clarify the genetics of apomixis in monocots as well as dicots during the past 15 years. Many of the complexities in the genetics of apomixis are likely secondary and have evolved as a consequence of the reproductive process. New mapping techniques, such as comparative mapping, linkage disequilibrium mapping, and deletion mapping, and new high-throughput sequencing methods, will help to penetrate the core of apomixis chromosomal regions. If the evolutionary genetic load can be exposed and removed, the apomixis genes may be used in agriculture as a tool to fix elite genotypes.