Duration of pre-plant chilling and its effects on garlic cloving

Abstract

Fall-planted garlic (Allium sativum L.) has higher clove number and higher overall productivity than spring-planted garlic. Most Saskatchewan garlic producers, however, spring-plant their crops to avoid losses associated with winterkill. Pre-plant storage temperature of cloves affects bulbing and cloving of the subsequent crop. Temperature and daylength during crop development also affect bulbing and cloving. Studies were conducted to determine the optimum duration of pre-planting chilling (4 0C) treatment for enhanced cloving and increased bulb yield of the spring-planted garlic cultivars (a local unnamed selection, ‘California Early’ and ‘California Late’). In a greenhouse study, ‘California Early’ and ‘California Late’ cloves were planted after receiving chilling treatments of 4 0C for 0 (control), 30, 45, 60 and 75 days. For field studies, cloves from greenhouse-grown bulbs of all three cultivars were used and chilling treatments were similar to those for greenhouse studies. Pre-plant chilling treatments of cloves produced significant increases in cloving and bulb yield for all cultivars. The treatment effect on cloving and bulbing of garlic in relation to cultivar and environment is discussed. Chilling treatment periods exceeding 30 days (for field) and 45 days (for greenhouse) resulted in an increase of cloving in bulbs of all cultivars. Improved cloving resulted in significant increase in both bulb diameter and bulb weight per plant, particularly in greenhouse-grown garlic. In conclusion, results indicate that improved cloving and bulb yields are obtained if cloves have been stored at 40 C for 45 and 60 days prior to field and greenhouse planting, respectively.