A dense SNP genetic map constructed using restriction site-associated DNA sequencing enables detection of QTLs controlling apple fruit quality

Table 5 An overview of population features of phenotyping data for each trait

Trait		Year	Maximum	Minimum	Mean(±SD)	Distribution
Fruit weight (g)		2008	253.80	56.80	128.77 (±30.33)	non normal
		2009	205.60	50.00	104.55 (±23.67)	non normal
		2010	193.60	52.00	110.94 (±26.64)	non normal
		2011	170.00	33.00	81.30 (±30.36)	non normal
Firmness (kg cm⁻²)		2010	15.67	3.84	8.78 (±1.81)	non normal
Firmness (kg cm⁻²)		2011	12.16	5.49	8.71 (±1.39)	normal
acidity	total acid	2011	11.547	2.118	6.887 (±2.285)	normal
(mg g⁻¹)	malic acid	2011	11.211	1.653	6.452 (±2.322)	normal
	citric acid	2011	0.200	0.016	0.081 (±0.039)	normal
	tartaric acid	2011	0.310	0.010	0.109 (±0.056)	non normal
	oxalic acid	2011	0.099	0.048	0.070 (±0.011)	normal
	acetic acid	2011	1.021	0.000	0.169 (±0.214)	non normal
	succinic acid	2011	0.027	0.000	0.006 (±0.004)	non normal
sugar content	total sugar	2011	127.175	79.564	104.737 (±10.811)	normal
(mg g⁻¹)	fructose	2011	68.477	33.302	51.014 (±6.854)	normal
	glucose	2011	35.065	9.239	19.690 (±6.176)	non normal
	sucrose	2011	61.584	11.059	34.033 (±9.765)	normal

Fruit weight were measured over 4 years, fruit firmness were determined over 2 years, whereas fruit acidity and sugar content were analyzed only in 2011. Each trait values were obtained from six fruits per n seedlings (n = 1170, 2008; n = 952, 2009; n = 527, 2010; n = 106; 2011). Distributions were calculated using Shapiro-Wilk test