View Full Table | Close Full ViewTable 1.

Average monthly weather data at two locations for the period between 1 May and 30 September in 2008, 2009, and 2010. The average daily temperature, Tavg (°C), is for the corresponding month. Precipitation (cm) is the average monthly accumulated rainfall. Values in parentheses are the deviations from the 20-yr average (1991–2010).

 
Location Month
May June July August September
Champaign, 2008
 Tavg, °C 15.1 (–2.1) 23.2 (+0.8) 23.6 (–0.3) 22.5 (–0.6) 19.5 (+0.3)
 Precipitation, cm 14.9 (+3.0) 13.0 (+3.0) 20.2 (+8.4) 1.7 (–8.0) 20.2 (+12.5)
DeKalb, 2009
 Tavg, °C 15.1 (–0.7) 20.1 (–0.9) 18.9 (–3.1) 19.1 (–1.8) 16.3 (–0.5)
 Precipitation, cm 9.3 (+0.8) 10.5 (+1.2) 6.4 (–2.1) 12.5 (+3.1) 2.8 (–5.2)
Champaign, 2009
 Tavg, °C 17.3 (+0.0) 22.8 (+0.4) 21.3 (–2.5) 21.4 (–1.6) 19.2 (+0.0)
 Precipitation, cm 13.0 (+1.1) 10.8 (+0.9) 15.6 (+3.7) 13.7 (+4.0) 1.6 (–6.1)
DeKalb, 2010
 Tavg, °C 16.5 (+0.7) 21.1 (+0.2) 23.1 (+1.1) 22.4 (+1.5) 17.1 (+0.3)
 Precipitation, cm 12.3 (+3.9) 17.5 (+8.2) 9.9 (+1.3) 11.9 (+2.6) 5.0 (–3.0)
Champaign, 2010
 Tavg, °C 18.3 (+1.0) 23.8 (+1.4) 25.2 (+1.3) 25.1 (+2.0) 19.7 (+0.6)
 Precipitation, cm 7.8 (–4.0) 19.8 (+9.8) 9.0 (–2.8) 4.0 (–5.7) 7.6 (–0.1)



View Full Table | Close Full ViewTable 2.

Tests of fixed sources of variation on R6 yield parameters and total nutrient uptake for data collected at two locations during 2008 and 2009. Hybrid pair (H) is indicative of the genetic background of a hybrid comparison (i.e., hybrids of the same genetics differing only in the presence or absence of a Bt protection trait), while transgenic protection from CRW (R) is indicative of insect protection within each hybrid pair.

 
Source of variation Biomass parameters
R6 Nutrient uptake
Yield Biomass Harvest index N P K S Zn
P > F
Location (L) 0.0054 <0.0001 <0.0001 0.0001 <0.0001 0.7895 <0.0001 <0.0001
Hybrid pair (H) 0.0747 0.1334 0.9758 0.1150 0.3824 0.4348 0.3326 0.2992
L × H 0.0001 0.3105 0.0020 0.6662 0.0462 0.0820 0.8270 0.0161
Transgenic protection (R) <0.0001 <0.0001 0.0004 0.0433 <0.0001 0.2019 0.3665 0.0450
L × R <0.0001 0.0008 0.0551 0.1083 0.0108 0.1903 0.2251 0.2039
H × R <0.0001 0.0205 0.0004 0.0370 0.0236 0.1421 0.0131 0.0524
L × P × R 0.0259 0.0003 0.0120 0.0462 0.3214 0.8666 0.0319 0.0217



View Full Table | Close Full ViewTable 3.

Grain yield, biomass accumulation, and harvest index for non-Bt and Bt maize hybrids evaluated at two locations during 2008 and 2009. Harvest index is the percentage of total aboveground biomass represented by grain. All values are presented on a dry matter basis (0 g kg–1 moisture concentration). Pair 1 is represented by DKC61-72 RR2 and DKC61-69 VT3, and pair 2 is represented by DKC63-45 RR2 and DKC63-42 VT3.

 
Location and comparison Grain yield
Total biomass
Harvest index
Non-Bt Bt P > t Non-Bt Bt P > t Non-Bt Bt P > t
Mg ha–1 %
Champaign (2008)
 Pair 1 8.4 10.8 *** 15.4 19.1 *** 54.7 56.7 ns†
 Pair 2 10.0 10.9 ** 17.9 19.0 * 56.0 57.5 ns
DeKalb (2009)
 Pair 1 9.4 10.0 * 19.2 18.7 ns 47.8 55.3 ***
 Pair 2 9.1 9.6 ns 18.7 19.9 ns 49.1 48.5 ns
Champaign (2009)
 Pair 1 8.8 10.1 *** 18.1 20.3 *** 48.4 50.1 ns
 Pair 2 10.4 10.2 ns 20.2 20.1 ns 51.4 50.5 ns
*Significant at the 0.05 probability level.
**Significant at the 0.01 probability level.
***Significant at the 0.001 probability level.
ns, not significant. Means not significantly different at P ≤ 0.05.



View Full Table | Close Full ViewTable 4.

Total and grain nutrient accumulation of above ground portions of the plant for non-Bt and Bt maize hybrids grown at two locations during 2008 and 2009. The means shown are for Bt hybrids only and values in parentheses indicate the difference relative to its non-Bt counterpart. All values are presented on a dry matter basis (0 g kg–1 moisture concentration). Significance levels compare means of Bt vs. non-Bt within a nutrient and plant part.

 
Nutrient uptake Champaign, 2008
DeKalb, 2009
Champaign, 2009
Means
DKC61-69 VT3 DKC63-42 VT3 DKC61-69 VT3 DKC63-42 VT3 DKC61-69 VT3 DKC63-42 VT3
kg ha–1
N
 Total 228 (+41)*** 231 (+8) 217 (–5) 232 (+10) 203 (+25)* 195 (–19) 218 (+10)*
 Grain 149 (+30)*** 144 (+8) 136 (+10) 122 (+2) 131 (+22)*** 123 (–9) 134 (+10)***
P2O5
 Total 70 (+17)*** 68 (+9)* 89 (+5) 81 (+4) 70 (+8)* 59 (–4) 73 (+6)***
 Grain 57 (+15)*** 54 (+8)** 70 (+8)** 58 (+3) 57 (+8)** 48 (–3) 57 (+6)***
K2O
 Total 180 (+29)* 175 (+8) 177 (+6) 171 (–1) 184 (+6) 156 (–10) 174 (+6)
 Grain 42 (+8)*** 43 (+6)*** 38 (+3) 37 (+0) 31 (+4)* 32 (–1) 37 (+3)***
S
 Total 22 (+4)*** 21 (–1) 23 (+0) 24 (+1) 26 (+2) 25 (–2)* 24 (+0)
 Grain 12 (+3)*** 12 (+1)* 11 (+0) 11 (+0) 12 (+2)*** 13 (+0) 12 (+1)***
g ha–1
Zn
 Total 320 (+74)*** 311 (+4) 354 (–19) 345 (+20) 429 (+50)* 368 (–22) 354 (+18)*
 Grain 194 (+56)*** 193 (+15) 198 (+21) 199 (+29)* 195 (+13) 209 (–7) 198 (+21)***
*Significant at the 0.05 probability level.
**Significant at the 0.01 probability level.
***Significant at the 0.001 probability level.



View Full Table | Close Full ViewTable 5.

Tests of fixed sources of variation on yield parameters and R6 total nutrient uptake for non-Bt and Bt maize hybrids evaluated at two locations during 2010. Location (L), hybrid pair nested within location (H), and transgenic protection from CRW (R) served as fixed effects.

 
Measurement Source of variation
Location (L) Hybrid pair (H)† Transgenic protection (R) L×R H×R
P > F
Yield and biomass
 Yield 0.0010 0.0013 0.0095 0.0004 0.0001
 Biomass 0.2953 0.0033 0.1109 0.0220 0.0535
 Harvest index <0.0001 0.0071 0.6983 0.6575 0.2647
R6 Nutrient uptake
 N 0.0084 0.0591 0.0400 0.0714 0.0689
 P 0.0023 0.0412 0.0266 0.0976 0.0277
 K 0.3555 0.5030 0.2319 0.0598 0.1889
 S 0.0170 <0.0001 0.8192 0.7616 0.0004
 Zn 0.0046 0.0003 0.5709 0.0959 0.1817
The H-9014 GT (non-Bt) and H-9014 3000GT (Bt) hybrid pair was not included at both locations and as a result, hybrid pair was nested within location.



View Full Table | Close Full ViewTable 6.

Yield, aboveground biomass, and total nutrient uptake (N, P, K, S, and Zn) of non-Bt and Bt hybrids evaluated at two locations in 2010. Hybrids within each comparison pair share a common genetic background and differ in the presence of CRW Bt protection traits. The means shown are for Bt hybrids only and values in parentheses indicate the difference relative to its non-Bt counterpart. All values are presented on a dry matter basis (0 g kg–1 moisture concentration). Significance levels are comparing within a hybrid pair, or for means, the non-Bt to Bt hybrids within a location.

 
Location and hybrid comparison† Yield Biomass N P2O5 K2O S Zn
Mg ha–1 kg ha–1 g ha–1
Champaign
 Pair 1 12.5 (+1.0) ** 24.3 (+2.6)** 333 (+59)** 134 (+27)** 243 (+41)* 29 (+4)** 561 (+50)
 Pair 2 12.4 (+0.9)** 23.8 (+0.7) 296 (+15) 108 (+16) 207 (+14) 26 (+1) 469 (+15)
 Pair 3 12.5 (+0.6) 23.9 (+0.6) 295 (–4) 103 (+3) 211 (+10) 26 (+0) 485 (+7)
 Pair 4 11.4 (+1.2)** 22.3 (+1.6) 296 (+25) 101 (–1) 202 (+11) 25 (+0) 473 (+9)
 Pair 5 10.9 (–0.1) 22.0 (–1.2) 271 (–5) 109 (+7) 185 (–16) 27 (–8)*** 497 (+10)
 Pair 6 11.6 (+0.6) 24.9 (+2.5)* 302 (+31) 107 (+5) 217 (+38) 25 (+3) 455 (+73)
 Means 11.9 (+0.7)*** 23.5 (+1.1)** 298 (+20)** 110 (+10)** 211 (+16)* 26 (+0) 490 (+27)
DeKalb
 Pair 1 13.0 (+1.7)*** 22.8 (+2.0)* 282 (+33) 134 (+29)** 207 (+16) 26 (+3) 564 (+94)*
 Pair 2 12.5 (+0.0) 23.8 (–0.5) 299 (+8) 120 (+3) 192 (+14) 26 (+0) 553 (–36)
 Pair 3 11.8 (–0.8)* 22.9 (–0.1) 270 (–4) 109 (–2) 217 (+1) 24 (+0) 491 (+1)
 Pair 4 10.9 (–0.7)* 21.0 (–1.1) 258 (+0) 99 (–14) 174 (–15) 23 (–2) 424 (–51)
 Pair 5 12.0 (–0.9)* 22.3 (–1.5) 261 (–31) 130 (–8) 178 (–35)* 27 (–2) 495 (–78)
 Means 12.1 (–0.1) 22.5 (–0.2) 274 (+1) 118 (–2) 194 (–4) 25 (+0) 505 (–14)
*Significant at the 0.05 probability level
**Significant at the 0.01 probability level
***Significant at the 0.001 probability level
Pair 1, DKC61-22 RR2 and DKC61-21 SmartStax; Pair 2, DKC61-72 RR2 and DKC61-69 VT3; Pair 3, DKC63-45 RR2 and DKC63-42 VT3; Pair 4, DKC64-27 RR2 and DKC64-24 VT3; Pair 5, P33W80 RR2 and P33W84 Herculex XTRA; Pair 6, H-9014 GT and H-9014 Agrisure 3000GT (grown at Champaign only).



View Full Table | Close Full ViewTable 7.

Pre and post-flowering biomass and nutrient accumulation for yield responsive and non-responsive hybrid pairs grown at Champaign, IL, during 2010. Yield responsive hybrids are those pairs with significant yield increases resulting from transgenic insect protection and include pairs 1, 2, and 4 (Table 6). Non-responsive pairs did not measure a significant yield increase due to transgenic insect protection and include pairs 3, 5, and 6. The means are shown for Bt hybrids only and values in parentheses indicate the difference relative to the non-Bt counterparts. All values are presented on a dry matter basis (0 g kg–1 moisture concentration).

 
Measurement Non-responsive hybrid pairs
Yield responsive hybrid pairs
Pre-flowering Post-flowering Pre-flowering Post-flowering
Biomass, Mg ha–1 7.9 (–0.2) 15.6 (+0.8) 8.0 (+0.1) 15.5 (+1.6)**
N, kg ha–1 173.5 (–2.2) 115.7 (+9.7) 177.3 (+2.1) 130.1 (+30.5)*
P2O5, kg ha–1 43.6 (+0.9) 62.1 (+6.3) 45.6 (+0.7) 68.8 (+13.2)*
K2O, kg ha–1 127.1 (+3.3) 77.3 (+7.4) 122.8 (–4.1) 94.4 (+25.9)*
S, kg ha–1 11.7 (–0.2) 14.5 (–0.4) 11.7 (+0.0) 14.9 (+1.7)
Zn, g ha–1 224 (–6) 254 (+36) 254 (+24) 248 (+1)
*Significant at the 0.05 probability level.
**Significant at the 0.01 probability level.