采用负压控水系统将土壤水分控制在不同的水平上, 研究了亏缺灌溉对草莓果实特性、植株生长和产量形成的影响。随着土壤水分的降低, 植株的株高、叶片数、结果数、产量和单果质量逐步减少。不同土壤水分处理条件下果实的理化特性明显不同, 亏缺灌溉降低了果实含水量, 提高了果实硬度、可溶性固形物含量(Brix) 、滴定酸度、糖酸比、维生素C 含量。相关分析表明, 果实的鲜样质量、直径与土壤水分含量呈显著的正相关, 而可溶性固形物含量(Brix) 、糖酸比与土壤水分含量呈显著的负相关。

Climatic factors are of a big importance for the determination of phenological stages of several fruit tree species, including apple, during the pre- and post-blooming periods causing their modifications and consequently affecting the fruit quality and productivity. This study aimed to identify the important dormancy phases (chilling and forcing periods) involved in determination of the flowering time in Gala apple trees in order to estimate temperature and chill/heat requirements, useful to assess the effect of climatic factors and phenological modifications on apple productivity and quality. Phenological and climatic data (temperatures, rainfall, irrigation, chilling and heat requirements) were collected, calculated, and measured from orchard in Imouzzer-Kandar, Morocco. Fruit productivity and quality parameters (total yield, fruit weight, size, firmness, and sweetness) were measured. Results showed a prolonged chilling period basing on the pre-blooming phases identified using partial least squares regression. Inadequate chill during warm seasons (insufficient chilling requirements) induces some phenological perturbations: late flowering, extended flowering duration, and period from flowering to harvesting. These phenological anomalies affect negatively the fruit quality of apple as a cause of inadequate climatic factors, mainly temperature and chilling requirements during the chilling period. Our findings demonstrated that sufficient chilling and heat requirements correlate positively with fruit weight, size, and firmness, although the low irrigation applied during the period from flowering to the harvesting times. In unfavorable conditions, total yield and fruit sweetness could be improved by supplementary irrigation during the same period. Practically, chilling requirements of 645-677 chill hours, 709-1157 chill units, and 43.4-55.2 chill portions according to 0-7 °C, Utah model, and Dynamic model respectively and heat requirements of 26,290-27,057 growing degree hours are sufficient for good fruit quality. These are equivalent to temperature of 9.3-9.9 °C during the chilling period and 11.1-12.5 °C during the forcing period. These findings are useful for eventual management measures in order to improve apple production in their cropping area. At long terms, we propose necessity of rearrangement of high-chill apple varieties by low-chill cultivars as a way of apple crop adaptation to climate variations.