Table 4. Changes in plant height, tiller number, spike length, awn length and internode characteristics of nodes 1 to 5 in the domestication from diploid to tetraploid, tetraploid to hexaploid and diploid to hexaploid of wheats.

Stem characteristics	Internode type	Diploid old wheat	Tetraploid old wheat	Hexaploid modern wheat	Diploid to tetraploid	Tetraploid to hexaploid	Diploid to hexaploid
Plant height (cm)		105.1±4.5	120.4±7.9	127.3±6.5	+	0	+
Tiller number		8.6±1.0	4.8±0.4	1.9±0.2	−	−	−
Internode length (cm)	1st	5.1±0.4	5.2±0.4	8.5±0.8	0	+	+
	2nd	11.4±1.8	11.5±1.6	15.0±2.0	0	+	+
	3rd	15.1±1.3	16.1±1.7	21.5±4.1	0	+	+
	4th	22.5±2.5	22.5±2.6	28.2±3.1	0	+	+
	5th	39.8±6.1	49.5±4.2	42.1±3.7	+	−	0
Internode diameter (mm)	1st	1.6±0.2	2.6±0.3	2.7±0.2	+	0	+
	2nd	2.0±0.2	3.0±0.2	3.2±0.3	+	0	+
	3rd	2.2±0.1	3.3±0.3	3.4±0.5	+	0	+
	4th	2.1±0.3	3.5±0.3	3.6±0.3	+	0	+
	5th	1.7±0.3	2.7±0.2	2.7±0.1	+	0	+
Internode weight-diameter ratio (g/mm)	1st	0.03±0	0.05±0.002	0.06±0.001	+	+	+
	2nd	0.05±0.002	0.08±0.003	0.09±0.005	+	+	+
	3rd	0.04±0.003	0.08±0.003	0.10±0.003	+	+	+
	4th	0.06±0.002	0.1±0.01	0.10±0.006	+	0	+
	5th	0.07±0.003	0.13±0.003	0.12±0.01	+	0	+
Internode specific gravity (g*mm−10)	1st	4.8±0.5	4.1±0.6	4.2±0.3	0	0	0
	2nd	2.2±0.1	2.3±0.2	2.0±0.2	0	0	0
	3rd	1.3±0.2	1.5±0.4	1.4±0.2	0	0	0
	4th	1.2±0.2	1.4±0.2	1.2±0.3	0	0	0
	5th	1.2±0.1	1.1±0.1	1.0±0.1	0	0	0
Spike (cm)	Length	4.5±0.2	7.2±0.3	9.0±0.7	+	+	+
	Awn length	7.0±0.7	9.5±2.1	6.7±0.9	+	−	0

+ represents a significant increase at P<0.01. − represents a significant decrease at P<0.01. 0 represents no change. Results of tiller number were similar between 2009 and 2010, and average data are presented in the table.

Note: The table involved large data, here we showed the final results for clarity and conciseness.