Pre-transplant conditioning to mitigate heat, drought and biotic stresses in artichoke

Seedling survival and stand establishment of globe artichoke [Cynara cardunculus L. var. scolymus (L.) Fiori] planted in late summer or early fall can be significantly reduced in hot and semi-arid growing regions of the southern US. In some parts of California, annual artichokes are direct seeded, but the majority of the cultivated area is transplanted. These fields typically have less weed pressure, disease problems and more yield and head uniformity as compared to direct seeded crops. In Texas artichokes are grown as annuals using 7- to 8-week-old containerized transplants raised in nurseries and transplanted in the field from late September to early November. In order to mitigate heat and transient drought stresses during establishment, pre-transplant conditioning strategies can enhance transplant quality through improvements in root/shoot growth partitioning and leaf physiology. This review, will discuss past and recent research findings on artichoke seedling and transplant quality, stand establishment, and biotic and abiotic stress tolerance. Some examples include stomatal regulation by applications of exogenous antitranspirants andabscisic acid (ABA), or improved growth performance or artichoke plantlets by pre-inoculation with arbuscular mycorrhizal fungi (Glomus spp.). Finally, we will present findings on root developmental changes caused by nitrogen nutrition and their potential implications to enhance artichoke tolerance to heat and drought stresses after planting.