【目的】研究新疆红肉苹果(Malus sieversii f.neidzwetzkyana)与‘富士’苹果品种(M.domestica cv.Fuji)杂交后代绵/脆肉株系果实质地差异的分子机理,旨在为进一步完善功能型苹果育种的理论与技术体系提供科学依据。【方法】以新疆红肉苹果杂交后代‘红绵2号’和‘红脆2号’不同发育时期的果实为试材,检测乙烯释放量、果实硬度与脆度以及ACS1等4个乙烯生物合成基因和PG等30个果实软化相关基因的相对表达量,观察其变化。【结果】‘红绵2号’和‘红脆2号’苹果果实发育期间的硬度和脆度均呈下降趋势,但‘红脆2号’各时期果实硬度和脆度均明显高于‘红绵2号’。‘红绵2号’花后120 d乙烯释放速率明显上升,并出现明显的乙烯释放峰;而‘红脆2号’花后120 d乙烯释放速率上升不明显,且无明显的乙烯释放峰。‘红脆2号’苹果果实各时期的ACS1、ACS3、ACO1和ACO2 4个乙烯生物合成相关基因表达量均明显低于‘红绵2号’;4个乙烯生物合成相关基因的表达模式存在明显差异,其中‘红绵2号’ACS1、ACO1和ACO2三个基因在果实发育后期的表达量均在94%以上,而ACS3a在果实发育前、后期表达量分别占50%,表现为组成型表达。所检测的与果实软化相关的30个基因表达的时间顺序存在明显差异,其中PL、AF1、EG2及XET1等15个基因主要在果实发育前期表达,PG、AF3、XET2、XET10和XET11 5个基因主要在果实发育后期表达,基因表达量均占总表达量的70%以上;除PL和AF1等6个基因外,‘红脆2号’PG等24个基因的总表达量均极显著低于‘红绵2号’。【结论】果实发育后期乙烯释放高峰的到来以及果实发育前、后期不同乙烯生物合成与果实软化相关基因的上调表达,是导致‘红绵2号’果实在采收前就已软化变绵及其与‘红脆2号’质地差异的主要原因。 【Objective】 The objective of this study was to investigate the molecular mechanism of the difference in texture of fruit between two cultivars, Malus sieversii f. Neidzwetzkyana and M. domestica cv. Fuji, Type apple breeding theory and technology system to provide a scientific basis. 【Method】 The fruits of different developmental stages of ’Hongmian 2’ and ’Hongbian 2’ were crossed with the hybrids of red-fleshed apple in Xinjiang. The ethylene production, fruit firmness and crispiness, and four ethylene biosynthesis The relative expression levels of 30 genes related to fruit softening, such as PG and PG, were observed and their changes were observed. 【Result】 The results showed that the firmness and crispness of ’Hongmian No.2’ and ’Hongcai No.2’ decreased during fruit development, but the hardness and crispiness of ’Hongbu No.2’ were significantly higher than those of ’Red’ Mian No. 2 ’. Ethylene release rate increased significantly at 120 days after flowering of ’Red Mian 2’ and obvious ethylene emission peak was observed. On the contrary, there was no significant increase of ethylene release rate at 120 days after flowering of ’Hongbing 2’. The expression levels of four ethylene biosynthesis related genes in ACS1, ACS3, ACO1 and ACO2 were significantly lower than those in ’Hongmian 2’ at ’Hongfenbake 2’. The expression patterns of four ethylene biosynthesis related genes were obvious The results showed that the expression of ACS1, ACO1 and ACO2 were all higher than 94% in the late stage of fruit development, while the expression of ACS3a was 50% in the early and late stage of fruit development, which was expressed as constitutive expression . There were significant differences in the time sequence of 30 genes related to fruit softening. Among them, 15 genes such as PL, AF1, EG2 and XET1 were mainly expressed in early fruit development stage, and 5 genes of PG, AF3, XET2, XET10 and XET11 Mainly expressed in the late stage of fruit development, the gene expression amounts accounted for more than 70% of the total. Except for 6 genes, PL and AF1, the total expression of 24 genes such as PGDH2 was significantly lower than ’Red cotton on the 2nd’. 【Conclusion】 Up-peak expression of ethylene and the up-regulation of genes related to ethylene biosynthesis and fruit softening before and after fruit development in the late stage of fruit development led to the softening and softening of ’Hongmian 2’ fruit before harvest And ’red crispy 2’ the main reason for the difference in texture.