Corn Hybrid and Bt Transgene Performance in Yield and Protection from Pre-harvest Losses Caused by Lepidopteran Feeding 1 1 2 3 Luke Pruter , Michael Brewer 1, Mac Young , Julio Bernal 1 Texas A&M AgriLife Research, Department of Entomology, Corpus Christi, TX 2 Texas A&M AgriLife Extension, Department of Agricultural Economics, Corpus Christi, TX 3 Texas A&M University, Department of Entomology, College Station, TX INTRODUCTION OBJECTIVE 1: HYBRID FAMILY 1 OBJECTIVE 1: HYBRID FAMILY 5 CONTINUED OBJECTIVE 2: YIELD RESULTS CONTINUED One of the most common problems facing Texas corn farmers is the injury brought on by corn feeding lepidopteran pests [1]. The HYBRID 1 GENETICS + SS HYBRID 5 GENETICS + VT3P In contrast to ear injury, hybrid family genetics accounted for 34% of the variation of yield fall armyworm and corn earworm are continuous residents of HYBRID FAMILY 1 HYBRID FAMILY 5 (P<0.0001). The Bt transgenes accounted for a significant amount of yield variation (19%, Texas that are known to reduce health and value of corn [2, 3]. YIELD STATISTICS INSECT DAMAGE YIELD STATISTICS INSECT DAMAGE P=0.032), but its contribution was about 2-fold less than hybrid genetics. Although the Bt Ear circumference Cry1A.105, Cry2Ab2, Cry1A.105, Cry2Ab2, 14.06 ± 0.24 Bt proteins expressed transgene effect influenced yield under our modest ear-feeding pressure, hybrid genetics Insect injury can reduce yield although the relationship is variable Ear circumference (cm) 14.82 ± 0.25 Bt proteins expressed Cry1Fa2, Cry3Bb1, (cm) Cry3Bb1 Cry34Ab1/Cry35Ab1 played a much larger role. across hybrids [4]. Advancing technologies in the farming Ear length (cm) 20.2 ± 0.35 Area of ear injury cm² 3.48 ± 1.19 industry have offered a solution to this problem that doesn’t Ear length (cm) 19.52 ± 0.34 Area of ear injury cm² 3.14 ± 0.88 involve increasing pesticide use. Corn growers have the option to Bushels per acre 106.67 ± 9.01 Depth of ear injury cm 2.78 ± 0.59 Bushels per acre 112.01 ± 3.01 Depth of ear injury cm 2.58 ± 0.83 OBJECTIVE 3: REVIEW FINANCIAL INDICATORS combat insect injury on their corn with the use of genetically HYBRID 1 GENETICS + DGVT2P modified seed, however there is added cost to the seed. This OBJECTIVE 1: HYBRID FAMILY 6 First 10 Year Averages Per Acre Cumulative poster compares the effects of hybrid background and their HYBRID FAMILY 1 Total YIELD STATISTICS INSECT DAMAGE Hybrid Bt Selected Input Costs Year Cash Total Cash Net Cash 10‐Yr Cash commercial Bt transgenes in their ability to reduce pre-harvest Family Transgene Ear circumference (cm) 14.44 ± 0.04 Bt proteins expressed Cry1A.105, Cry2Ab2 HYBRID 6 GENETICS + NO Bt (RR) Farm losses due to insect feeding. Seed Cost Hauling Yield/AC Price/ Receipts Costs Income Flow/Acre Ear length (cm) 19.44 ± 0.34 Area of ear injury cm² 2.96 ± 0.83 HYBRID FAMILY 6 YIELD STATISTICS INSECT DAMAGE BACILLUS THURINGIENSIS OR Bt Bushels per acre 107.33 ± 6.14 Depth of ear injury cm 2.68 ± 0.50 Ear circumference (cm) 14.2 ± 0.13 Bt proteins expressed No Bt proteins in $/Bag in $/Ac. in $/Ac in Bu. (a) Bu. (b) x $1,000 x $1,000 x $1,000 x $1,000 2 RR2 200 50 26.60 135.7 3.25 0.48 0.44 0.05 0.49 Ear length (cm) 18.66 ± 0.3 Area of ear injury cm² 6.72 ± 0.55 Bacillus thuringiensis (or Bt) is a bacterium commonly used as a biological pesticide. 2 VT2P 250 62.5 27.10 138.3 3.25 0.49 0.45 0.04 0.43 When Bt toxin is ingested by a lepidopterous insect it begins to crystalize in the gut, OBJECTIVE 1: HYBRID FAMILY 2 Bushels per acre 81.78 ± 9.73 Depth of ear injury cm 3.76 ± 0.25 3 RR2 200 50 22.72 115.9 3.25 0.41 0.45 (0.03) (0.30) and destroys the digestive tract of the caterpillar feeding on it [6]. Since the release of 3 VT3P 280 70 23.46 119.7 3.25 0.43 0.47 (0.04) (0.42) transgenic Bt maize in 1996, many different 4 YHR 240 60 22.04 112.5 3.25 0.40 0.46 (0.06) (0.58) HYBRID 2 GENETICS + VT2P HYBRID 6 GENETICS + VT3P 5 VT3P 280 70 21.95 112.0 3.25 0.40 0.48 (0.08) (0.75) types of Bt traits have been developed for sale. HYBRID FAMILY 2 HYBRID FAMILY 6 5 VT2P 250 62.5 21.43 109.3 3.25 0.39 0.47 (0.08) (0.75) YIELD STATISTICS INSECT DAMAGE Bt corn has become increasingly popular over YIELD STATISTICS INSECT DAMAGE 4 RR 200 50 19.83 101.2 3.25 0.35 0.46 (0.09) (0.92) Cry1A.105, Cry2Ab2, Ear circumference (cm) 14.4± 0.21 Bt proteins expressed the last 15 years and has grew from about 8 Ear circumference (cm) 15.3 ± 0.17 Bt proteins expressed Cry1A.105, Cry2Ab2 Cry3Bb1 1 VT2P 300 75 21.04 107.3 3.25 0.38 0.49 (0.10) (1.02) percent of U.S. corn acreage in 1997, to 79 Ear length (cm) 20.12 ± 0.14 Area of ear injury cm² 1.98 ± 0.58 Ear length (cm) 18.78 ± 0.45 Area of ear injury cm² 5.26 ± 0.65 6 VTTP 240 60 19.96 101.9 3.25 0.37 0.47 (0.10) (1.04) 6 SS 270 67.5 20.40 104.1 $3.25 0.37 0.48 (0.11) (1.05) Bushels per acre 138.29 ± 3.28 Depth of ear injury cm 2.1 ± 0.82 Bushels per acre 101.86 ± 8.78 Depth of ear injury cm 2.92 ± 0.23 percent in 2016 [8]. There is a wide range of 1 SS 300 75 20.91 106.7 3.25 0.38 0.49 (0.11) (1.05) Lepidoptera control in corn with commercially 4 VYHR 280 70 19.07 97.3 3.25 0.35 0.49 (0.14) (1.39) available Bt transgenes [5]. This poster HYBRID 2 GENETICS + NO Bt (RR2) HYBRID 6 GENETICS + SS 6 RR 180 45 16.03 81.8 3.25 0.30 0.47 (0.17) (1.71) HYBRID FAMILY 6 HYBRID FAMILY 2 reviews the effectiveness of several Bt YIELD STATISTICS INSECT DAMAGE NOTE: Comparison made across hybrids are valid, the negative cash flow YIELD STATISTICS INSECT DAMAGE transgenes and hybrid families in their ability to Cry1A.105, Cry2Ab2, Ear circumference (cm) 15.26 ± 0.19 Bt proteins expressed No Bt proteins Ear circumference (cm) 14.12 ± 0.52 Bt proteins expressed Cry1Fa2, Cry3Bb1, reflects recent low corn prices. Comparing financial indicators, members of reduce insect feeding, and preserve yield. Cry34Ab1/Cry35Ab1 Ear length (cm) 19.92 ± 0.25 Area of ear injury cm² 3.9 ± 0.37 hybrid family 1 performed similarly. Also, members of hybrid family 6 with Bt Ear length (cm) 18.04 ± 0.74 Area of ear injury cm² 2.76 ± 0.23 Bushels per acre 135.71 ± 3.47 Depth of ear injury cm 2.86 ± 0.32 transgenes both financially performed better than their non-Bt counterpart in TARGET PESTS Bushels per acre 104.07 ± 3.68 Depth of ear injury cm 2.12 ± 0.22 10-year cash flow projection (CFP), even though their seed costs were 50% Heliocoverpa zea or the OBJECTIVE 1: HYBRID FAMILY 3 OBJECTIVE 2: INSECT DAMAGE RESULTS higher. But in other cases, the higher cost of the Bt transgene hybrids did not corn earworm is an active appear to be offset by higher yields due to reduced insect injury. Hybrid family Mean Mean Ear resident of south Texas HYBRID 3 GENETICS + VT3P Bt Means Standard 2 had the highest CFP of all hybrid families. However within family 2, the non- Hybrid Bt Ear Standard Injury FALL ARMYWORM Means Separation Transgene Separation Error throughout the year [7]. HYBRID FAMILY 3 Family Transgene Injury Error (cm²) Bt hybrid ($490/acre) had greater profitability than its VT2P counterpart YIELD STATISTICS INSECT DAMAGE (cm²) ($430/acre). Likewise, the non-Bt hybrid from family 3 had a higher 10-year CFP Cry1A.105, Cry2Ab2, RR A 5.75 0.70 Ear circumference (cm) 14.4 ± 0.15 Bt proteins expressed 6 RR A 6.40 0.56 Cry3Bb1 RR2 A B 3.82 0.70 Spodoptera frugiperda RR A B 6.00 0.56 over its VT3P counterpart. Last, the currently highest cost hybrids associated Ear length (cm) 19.08 ± 0.33 Area of ear injury cm² 1.76 ± 0.36 4 YHR A B C 3.58 0.90 VT3P B C 4.67 0.55 with the VIP transgene were not offset by the high insect injury reduction, The fall armyworm is native Bushels per acre 119.69 ± 3.43 Depth of ear injury cm 1.30 ± 0.18 6 VT3P B C 3.47 0.59 to southern regions of the 3 RR2 C D 3.94 0.56 DGVT2P B C 3.09 0.90 possibly because of the modest insect activity in 2016. In hybrid family 4, the SS B C 3.03 0.70 VYHR hybrid with the VIP transgene had the lowest CFP. CORN EARWORM United States, but it can only HYBRID 3 GENETICS + NO Bt (RR2) 2 RR2 C D E 3.87 0.56 4 YHR C D E F 3.67 0.59 VT2P B C 2.71 0.70 overwinter in the southern HYBRID FAMILY 3 VYHR C 1.18 0.90 CONCLUSIONS 5 VT3P C D E F 3.48 0.55 most regions of Texas [6].