Peanut is an important oilseed and a widely cultivated crop worldwide. Knowledge of the phylogenetic relationships and information on the chloroplast genomes of wild and cultivated peanuts is crucial for the evolution of peanuts. In this study, we sequenced and assembled 14 complete chloroplast genomes of Arachis. The total lengths varied from 156,287 bp to 156, 402 bp, and the average guanine–cytosine content was 36.4% in 14 Arachis species. A total of 85 simple sequence repeats (SSRs) loci were detected, including 3 dinucleotide and 82 polynucleotide SSRs. Based on 110 complete chloroplast genomes of Arachis, a phylogenetic tree was constructed, which was divided into two groups (I and II). A total of 79 different genes were identified, of which six double-copy genes (ndhB, rpl2, rpl23, rps7, ycf1, and ycf2) and one triple-copy gene (rps12) are present in all 14 Arachis species, implying that these genes may be critical for photosynthesis. The dN/dS ratios for four genes (rps18, accD, clpP, ycf1) were larger than 1, indicating that these genes are subject to positive selection. These results not only provided rich genetic resources for molecular breeding but also candidate genes for further functional gene research.

Peanut breeding has passed through various stages, including traditional breeding, hybrid breeding, and molecular breeding. With the rapid development of information technology, biotechnology has also made great progress. The application of biotechnology in breeding mainly includes three aspects: molecular biology, genetic breeding, and transgenic breeding. With the rapid development of genome, transcriptome, proteome, metabolome, epigenome, and phenomics studies and Big Data technology, peanut breeding is also developing intelligent approaches. Compared with traditional breeding, smart breeding has the advantages of high efficiency, speed, and accuracy, and will become an inevitable trend of future breeding work. This chapter reviews the development of peanut breeding technology around the world, highlights the overview, research progress, and application of peanut smart breeding, and provides an outlook on the development trend of peanut smart breeding. Intelligent breeding technology effectively shortens breeding time, accelerates the pace of improvement, and increases efficiency, playing a crucial role in improving yield and quality and reducing production costs. <!----> <!----> <!----> <!---->