Advanced Breeding Tools in Vegetable Crops

Vegetables are key ingredients in a well-balanced nutritious diet. Their worldwide rising consumption reveals the awareness of their health benefits. The major biotic factors affecting vegetable production are pathogens causing diseases, insects and nematodes pests, and weeds. Vegetables are also sensitive to drought, flood, heat, frost and salinity. Plant breeding provides means for introducing host plant resistance, adapting crops to stressful environments, and developing cultivars with the desired produce quality. The genetic enhancement of vegetables aims achieving the market-driven quality along with agronomic performance needed by growers. Trait heritability, gene action, number of genes controlling the target trait(s), heterosis and genotype × environment interactions determine the vegetable breeding method to use. Coupled with the use of dense DNA markers and phenotyping data, quantitative genetic analysis facilitates dissecting trait variation and predicting merit or breeding values of offspring. Genomics, phenomics and breeding informatics further facilitate screening of target characteristics, thus accelerating the finding of desired traits and contributing gene(s) in vegetables. Genomic estimated breeding values are used today for predicting traits, thus replacing the routine of expensive phenotyping with inexpensive genotyping. Genetic engineering protocols for transgenic breeding are available in various vegetables, and may be useful if target trait(s) are unavailable in genebank or breeding population. Transgenic cultivars could overcome some limiting factors in vegetable production such as pathogens, pests, and weeds, thus reducing pesticide residues, human poisoning and management costs in horticulture. Gene editing can be also a useful approach for improving traits in vegetables and speed breeding. Examples are taken from various vegetables (including root and tuber crops) to show how these advances translate in genetic gains and save time and resources in their breeding.