Goff and Salmeron 2004 Scientific American 291(2) Maize Challenges in Crop Improvement
Yield Gap to Be Filled by Plant Breeding Experimental Station yield Potential Farm yield Theoretical potential Actual Farm yield Yield gap 0 Yield gap I Yield gap II For scientists to conceive and breed potential varieties Nontransferable technology Environmental differences Biological Variety Weeds Pests Problem soils Water Soil fertility Socioeconomic Costs Credit Tradition Knowledge Input Instructions G A P t/ha (Modified from Chaudhary 2000) Rice
Selection without testcrossing Restorability/maintainability, wide compatibility, heterosis Selection independent of environments TGMS/PGMS, insect/disease resistance, stress tolerance Lodging resistance, herbicide response Selection without intensive lab work Grain chemical and physical properties Selection at early breeding stage Grain quality, heterosis, yield potential Whole genome selection Selection for multiple traits Why Marker-Assisted Molecular Breeding Selection for complex traits Xu, Plant Breeding Reviews 23:
Marker-Assisted Plant Breeding Platform Genotyping of Core Materials Chip-based array Genotyping by sequencing Transcriptome and proteome analysis Large-Scale Multi-Location Phenotyping Yield and quality Biotic and abiotic stresses Input use efficiency Natural and Artificial Crop Populations Information Collection, Management and Data Analysis Genetic diversity analysis Gene function analysis GWAS/GS/MARS/MAS Generation Advancement + GS/MARS/MAS Multi-Environmental Trials Novel Germplasm Marker Development and Gene Discovery Phenotyping Platform Breeding Informatics Platform Genotyping Platform E-typing Water Light Temperature Fertilizer Soil Decision Support System DS Revised from Xu et al 2012 Mol Breed 29:833–854
Genetic gains achieved for oil and protein content in 100 generations of selection (Dudley and Lambert 2004) QUESTION Can we achieve the same result in less years with marker- assisted plant breeding?
A plot of the inbred scores on the first two principal components from analysis of SSR marker profiles of the parents of the maize hybrids (SS, Stiff Stalk Synthetic inbred line; NSS, Non Stiff Stalk Synthetic inbred line). (Cooper et al. 2004) Heterotic groups generated through breeding in 8 decades QUESTION Can we diversify the heterotic groups much further and more quickly ?