Table 2.

Experimental effect terms for all root traits among 20 wheat varieties across two tillage levels and over two trial years at the Sonning trial site (a), and among 16 wheat varieties across two seeding rate treatments and effects of experimental terms on root traits among at the Duxford trial site (b). RA = root angle, CRN = crown root number, NRN = nodal root number, SRN = seminal root number. Asterisks indicate significance level: *** = p < 0.001, ** = p < 0.01, *= p < 0.05, ‘ns’ = not significant. d.f. = degrees of freedom

(a)		RA	CRN	NRN		SRN
Terms	d.f.	F stat	Wald stat/d.f	Wald stat/d.f		F stat
Genotype	19	1.82*	3.14***	8.05***		1.66*
Tillage	1	6.00*	11.19***	4.22*		ns
Year	1	ns	ns	39.05***		7.16*
Tillage x Genotype	19	ns	2.03**	3.16***		ns
Tillage x Year	1	ns	ns	5.34*		ns
Year x Genotype	19	2.14**	ns	2.20**		1.84*
Tillage x Genotype x Year	19	ns	ns	ns		ns
(b)		RA	CRN	NRN	SRN	Yield
Terms	d.f.	F stat	Wald stat/d.f	Wald stat/d.f	F stat	F stat
Genotype	15	2.0*	6.00***	5.69***	2.7***	41.34***
Sowing rate	1	ns	24.3***	ns	ns	16.96***
Sowing rate x Genotype	1	ns	ns	2.96***	ns	ns