A next-generation marker genotyping platform(AmpSeq)in heterozygous crops:a case study for marker-assisted selection in grapevine

Marker-assisted selection(MAS)is often employed in crop breeding programs to accelerate and enhance cultivar development,via selection during the juvenile phase and parental selection prior to crossing.Next-generation sequencing and its derivative technologies have been used for genome-wide molecular marker discovery.To bridge the gap between marker development and MAS implementation,this study developed a novel practical strategy with a semi-automated pipeline that incorporates trait-associated single nucleotide polymorphism marker discovery,low-cost genotyping through amplicon sequencing(AmpSeq)and decision making.The results document the development of a MAS package derived from genotyping-by-sequencing using three traits(flower sex,disease resistance and acylated anthocyanins)in grapevine breeding.The vast majority of sequence reads(⩾99%)were from the targeted regions.Across 380 individuals and up to 31 amplicons sequenced in each lane of MiSeq data,most amplicons(83 to 87%)had<10%missing data,and read depth had a median of 220–244×.Several strengths of the AmpSeq platform that make this approach of broad interest in diverse crop species include accuracy,flexibility,speed,high-throughput,low-cost and easily automated analysis.

RosBREED:bridging the chasm between discovery and application to enable DNA-informed breeding in rosaceous crops

The Rosaceae crop family(including almond,apple,apricot,blackberry,peach,pear,plum,raspberry,rose,strawberry,sweet cherry,and sour cherry)provides vital contributions to human well-being and is economically significant across the U.S.In 2003,industry stakeholder initiatives prioritized the utilization of genomics,genetics,and breeding to develop new cultivars exhibiting both disease resistance and superior horticultural quality.However,rosaceous crop breeders lacked certain knowledge and tools to fully implement DNA-informed breeding—a“chasm”existed between existing genomics and genetic information and the application of this knowledge in breeding.The RosBREED project(“Ros”signifying a Rosaceae genomics,genetics,and breeding community initiative,and“BREED”,indicating the core focus on breeding programs),addressed this challenge through a comprehensive and coordinated 10-year effort funded by the USDA-NIFA Specialty Crop Research Initiative.RosBREED was designed to enable the routine application of modern genomics and genetics technologies in U.S.rosaceous crop breeding programs,thereby enhancing their efficiency and effectiveness in delivering cultivars with producer-required disease resistances and market-essential horticultural quality.This review presents a synopsis of the approach,deliverables,and impacts of RosBREED,highlighting synergistic global collaborations and future needs.Enabling technologies and tools developed are described,including genome-wide scanning platforms and DNA diagnostic tests.Examples of DNA-informed breeding use by project participants are presented for all breeding stages,including pre-breeding for disease resistance,parental and seedling selection,and elite selection advancement.The chasm is now bridged,accelerating rosaceous crop genetic improvement.