Pre-harvest irrigation regime has the potential to manipulate onion dormancy, thus, helping to extend storage life

Bulb water content and water loss has previously been linked to post-harvest sprouting. We hypothesise that pre-harvest controlled irrigation can influence onion endo and ecodormancy. Two onion cultivars viz. ?Sherpa? and ?Red baron? were planted in John Innes compost (No 3) and grown in the glasshouse for five months. Plants were exposed to differential irrigation upon appearance of 8th and 9th leaves. Soil moisture content (SMC) was the main criterion used for irrigation scheduling and the exact amount of water applied was determined gravimetrically. Control plants were maintained at near 100% field capacity (FC), while 50% FC was used for test plants. Bulbs were harvested at 100% fall-down and cured for six weeks. Yield (bulb weight per pot), respiration rate, sprout and root emergence were assessed throughout storage. Abscisic acid (ABA) in the baseplate tissue was also quantified using mass spectrometry. Yield was 17.4% higher in the control bulbs compared to those subjected to deficit irrigation. After one week of curing, water loss was 3-fold higher in the control compared to test bulbs. Further results for physiological and biochemical analyses are ongoing. Pre-harvest irrigation regime has the potential to manipulate onion dormancy, thus, helping to extend storage life. SourcePhysiological and metabolic regulation of onion dormancy as influenced by preharvest irrigation regime during postharvest storageIkenna C. Ohanenye, M. del Carmen Alamar, Leon A. TerryPlant Science Laboratory, School of Energy, Environment and Agrifood, Cranfield University, MK43 0AL Bedfordshire, United KingdomVIII International Postharvest Symposium, Cartagena, Spain, 21-24 June 2016Picture by?Dreamstime