Evaluation of Quizalofop-Resistant Rice for Arkansas Rice Production Systems

Table 3

Effect of quizalofop application structure on barnyardgrass, broadleaf signalgrass, and red rice control at Stuttgart, AR, in 2014 and 2015 averaged over time of first application followed by contrast between total quizalofop usage rates.

Application structure	Control
	2014		2015
	ECHCG	BRAPP	ECHCG	BRAPP	ORYSA
g ai ha^−1	%
80/80	89 b	91 b	94a	97a	95a
80/120	90 ab	95 ab	96a	98a	99a
80/160	91 ab	98 a	97a	100a	98a
120/80	91 ab	96 ab	94a	99a	98a
120/120	98 a	99 a	98a	100a	99a
160/80	95 a	98 a	98a	100a	98a
Contrast
g ai ha^−1
240 vs. 160	<0.0001	0.0032	0.0415	NS	0.0150
240 vs. 200	0.0049	0.0311	NS	NS	NS
200 vs. 160	0.0246	0.0099	NS	NS	NS

First rate applied followed by second rate applied 2 weeks later. ECHCG: barnyardgrass, BRAPP: broadleaf signalgrass, ORYSA: red rice. Means within a column followed by the same letter are not different according to Fisher’s protected LSD (). 2015 resulted in no significant difference between quizalofop application structure for any weed species. Total yearly amount of quizalofop applied.