Table 1. Non-additively expressed miRNAs in the maize hybrid Yuyu22 and its parental inbred lines.

	Non-additive miRNA type						Total number of non-additive miRNAs
	+ +a	+b	+ −c	Dd	−e	− −f
miRNA families	1	1	4	7	4	14	21
miRNA members	4	6	13	20	28	37	107*

Note: ^a + +: Extremely high parental expression, the difference of expression amounts between hybrid and high expression parental line was beyond the threshold 10%;

^b+: High parental expression, the difference of expression amounts between hybrid and high expression parental line was below the threshold 10%;

^c+ −: additive expression, the difference of expression amounts between hybrid and mid-parental values was below the threshold 10%;

^dD: Different from additivity (mid-parent value), not belonging to any of the other classes, the difference of the expression amounts between hybrid and parental lines and the difference between hybrid and mid-parental value were both indefinable when using 10% as the threshold;

^e−: Low parental expression, the difference of expression amounts between hybrid and low expression parental line was below the threshold 10%;

^f− −: Extremely low parental expression, the difference of expression amounts between hybrid and low expression parental line was beyond the threshold 10%;

^*: miR156k was defined both as + − and −.