Do delay tactics affect silking date and yield of maize inbreds? Stephen Zimmerman Creative Component November 2015
Overview Acknowledgements My Background Introduction Materials and Methods Results and Discussion Conclusion Questions
Acknowledgements Major Professor Dr. Allen Knapp Program of Study Committee Dr. Thomas Loynachan and Dr. Kenneth Moore Program Coordinator Dawn Miller Mentors/Supporters Patrick McMullan, Adda Sayers, Darrin Roberts, and John Schmidt DuPont Pioneer Production Research staff
My Background Grew up near Harlan, IA on a family farm. Currently, my wife Beth and I live in Ankeny, IA. Enjoy, the outdoors, gardening, visiting family, and attending ISU sporting events.
Career DuPont Pioneer 2011 2015 Production Research Group KMR Carroll, IA 2010 2011 Independent research company that conducts yield trials across the Midwest. ISU Bachelors of Science in Agronomy 2008 2010 Bizy Farms Inc. 2006 2008 Corn/soybean farm with swine confinements. Iowa Western Community College AAS 2003 2005 Ag Business degree
Production Research Production of hybrid corn requires a female parent to be pollinated by a male parent. Production Research conducts research on parents going into production. Research projects focus on practices that influence seed quality, yield, and reliability.
Introduction To facilitate a proper nick standard practice is to delay the male by planting at a later date or by mechanical means after emergence. Because of weather or other unforeseen issues, planting the male at the recommended delay is not possible. The results in a poor nick, which can result in reduced yield, and increased outcrossing due to a low pollen environment. Currently, even if the agronomist realizes this is going to occur, few corrective actions are available.
The Nick Ideal Situation Desired. planting timing with 200 GDU delay Female 1400 GDUs Male 1200 GDUs Problem Rain causes male to be planted at 300 GDU delay. Female 1400 GDUs Male 1200 GDUs
Materials and Methods Trial conducted in 2013 & 2014 Locations in 2013 Alleman, IA; Windfall, IN; Champaign, IL; York, NE Locations in 2014 Alleman, IA; Windfall, IN; Champaign, IL; Constantine, MI Split plot design with 4 replications Whole plot: Entry SP: Treatment Plot represented by four rows of female parent with one row of mixed male pollinator on each side. Data collected on center two female rows. M F F F F M Plot length 17.42 FT. 4 rows wide or 10 FT.
Materials and Methods Entries whole plot Entry No. GDUs to silk Plant Height (inches) 1 1422 76 2 1508 86 3 1524 93 4 1547 79 Treatments split plot Treatment No. Treatment Timing Comments 1 Untreated check UNT 2 Cut at V2 V2 Leave 1 inch of stalk above soil 3 Cut at V5 V5 Standard cut leave 4 in. stalk 4 Vertical Cut at V5 V5 Cut plant vertically leaving stalk intact
V2 Cut Treatment
V5 Cut Treatment
V5 Vertical Cut Treatment
Data Collected Early Stand count not presented Late stand count not presented GDUs calculated from 10 50 90% silking dates Growing Degree Unit = (Tmax +Tmin)/2 Tbase (50 degree F min) Barren count not presented Yield 80k units/female acre (Weight, moisture, kernels/pound, saleable seed %) Small discard Large discard not presented Percent cold germination Warm germination not presented
Analysis Completed using PROC GLIMMIX in SAS EG version 6.1 Entry and treatment run as fixed factors Factors considered significant at alpha level 0.05 Least square means calculated using a LSMEANS statement direct comparisons made with an ESTIMATE statement
Results Cut effect on silking Treatment effects on GDUSLK (growing degree units to 50% silking) delay compared to untreated check GDUs of Delay From UTC 50 45 40 35 30 25 20 15 10 5 0 43 A 33 B 0 C 2.V2_CUT 3.V5_CUT 4.V5_VC LS means with the same letter are not significantly different (P<=0.05) Type III tests of fixed effects GDUSLK (growing degree units to 50% silking) Effect Num DF Den DF F Value Pr > F Entry 3 113.5 39.24 <.0001 Treatment 3 339.9 104.63 <.0001 EntryTreatment 9 342.6 2.22 0.0206
Results GDU s to silking GDUs 1560 1540 1520 1500 1480 1460 1440 1420 1400 1,503 1,504 1456 1450 1466 1,515 1,505 1460 1491 1,545 1,530 1490 Entry 1 Entry 2 Entry 3 Entry 4 1,492 1,487 1465 1467 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC
Results Entry Treatment Contrasts for the V2 cut delay, Entry 4 compared to Entries 1, 2 and 3. Treatment Entry Treatment Entry Estimate Standard DF t Value Pr > t (GDU) Error 2.V2_CUT 1 2.V2_CUT 4 19.7107 8.1882 186.8 2.41 0.017 2.V2_CUT 2 2.V2_CUT 4 17.4191 7.9294 188.2 2.2 0.0293 2.V2_CUT 3 2.V2_CUT 4 26.1978 7.8617 187.1 3.33 0.001
Results Silking Duration Silking duration (GDUs) 80 70 60 50 40 30 20 10 75.5 A 67.3 B 64.2 B 62.5 B 0 2.V2_CUT 1.UNT 3.V5_CUT 4.V5_VC LS means with the same letter are not significantly different (P<=0.05).
Results Small discard 12 10 9.8 A 9.3 A 9.0 A % small discard 8 6 4 7.9 B 2 0 1.UNT 4.V5_VC 3.V5_CUT 2.V2_CUT LS means with the same letter are not significantly different (P<=0.05).
Results Saleable seed 91.5 91.2 A 91.0 % Saleable seed 90.5 90.0 89.5 89.0 90.3 B 90.0 BC 89.4 C 88.5 88.0 2.V2_CUT 3.V5_CUT 4.V5_VC 1.UNT LS means with the same letter are not significantly different (P<=0.05). Type 3 Tests of Fixed Effects % Saleable Seed Effect Num DF Den DF F Value Pr > F Entry 3 112.8 57.8 <.0001 Treatment 3 330.3 7.13 0.0001 EntryTreatment 9 332.5 1.55 0.1301
Results Saleable seed % saleable seed 96 94 92 90 88 86 84 86 88 88 87 87 85 87 86 91 94 93 92 95 95 95 95 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC 82 80 Entry 1 Entry 2 Entry 3 Entry 4 An asterisk indicates a sign. diff. (P<=0.05) with the untreated check within an entry.
Results 80K units % dif. from UNT 3 2 1 0 1 2 2.41 2.V2_CUT 3.V5_CUT 4.V5_VC 3 4 3.49 3.29 An asterisk indicates a sign. diff. (P<=0.05) compared to the UNT.
Results Cold germination Percent cold germination shown entry by treatment. % Cold germination 95 90 85 80 75 89 86 90 90 88 91 89 88 76 82 81 80 91 90 90 90 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC 70 Entry 1 Entry 2 Entry 3 Entry 4
Conclusion V2 Cut treatment most effective at delaying female silking (43 GDUs). V2 effect on seed yield minimal ( 3.5% 80k units/acre). V2 cut did not cause loss of female plant population. V2 cut did not negatively effect warm/cold germination. V2 cut slightly decreased small discard and increased salable seed percentage.
Questions? Thank you!
Silk timing and delay Type III Tests of Fixed Effects GDUSLK Effect Num DF Den DF F Value Pr > F EntryNUM 3 113.5 39.24<.0001 TRT 3 339.9 104.63<.0001 EntryNUMTRT 9 342.6 2.22 0.0206 Estimates Label Estimate Standard DF t Value Pr > t Error GDUs to 50% silk 1520 1510 1500 1490 1480 1470 1460 1465 C 1508 A 1498 B 1465 C 1.UNT vs 2.V2_CUT 43.19 3.05 339.7 14.16<.0001 1450 1.UNT vs 3.V5Cut 32.65 3.19 339.6 10.22<.0001 1440 1.UNT vs 4.V5_VC 0.2233 3.08 340.2 0.07 0.9423 TRT Least Squares Means 1560 TRT Estimate Standard DF Dif. in 1540 Error GDUs 1,504 from 1520 1,503 UNT 1.UNT 1465.4 31.98 7.044 1500 2.V2_CUT 1508.6 31.98 7.042 43 1480 3.V5_CUT 1498.0 31.99 7.055 33 4.V5_VC 1465.1 31.98 7.045 0 1,457 1460 1,450 GDUs to 50% silk/10 1440 1420 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC 1,515 1,505 1,466 1,461 1,545 1,530 1,492 1,490 1,492 1,487 1,465 1,468 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC 1400 Entry 1 Entry 2 Entry 3 Entry 4 Asterisk indicates sig. dif. from UNT at.05 level
80k/acre Female yield Type III Tests of Fixed Effects 80K/acre yield Effect Num Den DF F Value Pr > F DF EntryNUM 3 114.8 2.18 0.0938 TRT 3 328 10.36<.0001 EntryNUMTRT 9 330.4 1.08 0.3791 Estimates Label Standard DF t Value Pr > t Error 1.UNT vs 2.V2_CUT 1.5033 327.5 2.88 0.0043 % yield change from UNT 3 2 1 0 1 2 2.41 2.V2_CUT 3.V5_CUT 4.V5_VC 1.UNT vs 3.V5Cut 1.5668 326.6 2.61 0.0095 3 1.UNT vs 4.V5_VC 1.5199 327.9 1.97 0.0502 4 3.49 3.29
Duration of silking Type 3 Tests of Fixed Effects Effect Num DF Den DF F Value Pr > F EntryNUM 3 454.7 0.49 0.6864 80 75.5 A TRT 3 454.7 7.38 <.0001 EntryNUMTRT 9 454 1.17 0.3109 Estimates Label Estimate STD ERR DF Pr > F 1.UNT vs 2.V2_CUT 8.1971 2.9753 454.0061 1.UNT vs 3.V5Cut -3.1133 3.1023 455.4.3161 Length of silking (GDUs) 70 60 50 67.3 B 64.2 B 62.5 B 1.UNT vs 4.V5_VC -4.7767 2.9632 454.1077 40 2.V2_CUT 1.UNT 3.V5_CUT 4.V5_VC GDUs 160 155 150 145 140 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC 135 10slk 50slk 90slk
Percent Saleable Seed Type 3 Tests of Fixed Effects Effect Num DF Den DF F Value Pr > F EntryNUM 3 112.8 57.8 <.0001 TRT 3 330.3 7.13 0.0001 EntryNUMT RT 9 332.5 1.55 0.1301 Contrasts Label Estimate STD ERR DF Pr > F 1.UNT vs 2.V2_CUT 1.UNT vs 3.V5Cut 1.UNT vs 4.V5_VC 1.8408 0.4024 329.9 <.0001 0.9426 0.4216 329.2 0.0261 0.7003 0.407 331 0.0862 Effect TRT Estimate Diff. from UNT TRT 1.UNT 89.1882 TRT 2.V2_CUT 90.9921 1.80 TRT 3.V5_CUT 90.1275 0.93 TRT 4.V5_VC 89.8618 0.67 % saleable seed % saleable seed 96 94 92 90 88 86 84 82 92 91 90 89 88 91 A 90 B 90 BC 89 C 2.V2_CUT 3.V5_CUT 4.V5_VC 1.UNT 88.788.9 87.4 86.7 86.8 85.9 86.2 85.2 91.2 93.9 92.5 92.0 95.2 94.9 94.9 95.0 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC 80 1 2 Entry 3 4 Asterisk indicates sig. dif. from UNT at.05 level
Small discard Type 3 Tests of Fixed Effects Effect Num DF Den DF F Value Pr > F EntryNUM 3 114.5 103.18 <.0001 TRT 3 333.4 6.53 0.0003 EntryNUMTRT 9 336.5 0.94 0.4921 Estimates Label Estimate STD ERR DF Pr > F 1.UNT vs 2.V2_CUT 1.8678 0.4368 332.7 <.0001 1.UNT vs 0.8372 0.4579 331.8 0.0684 3.V5Cut 1.UNT vs 4.V5_VC 0.4999 0.4417 334.3 0.2585 % Small Discard 12 10 8 6 4 2 0 9.8 A 9.3 A 9.0 A 7.9 B 1.UNT 4.V5_VC 3.V5_CUT 2.V2_CUT Effect TRT Estimate Diff. from UNT TRT 1.UNT 9.8405 TRT 2.V2_CUT 7.9728 1.8677 TRT 3.V5_CUT 9.0033 0.8372 TRT 4.V5_VC 9.3407 0.4998 % Small Discard 16 14 12 10 8 6 4 2 13.9 14.1 11.111.4 13.2 13.113.5 12.5 8.5 5.4 7.0 7.9 2.9 2.9 2.7 3.2 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC 0 Entry 1 Entry 2 Entry 3 Entry 4 Asterisk indicates sig. dif. from UNT at.05 level
Large discard Type 3 Tests of Fixed Effects Effect Num DF Den DF F Value Pr > F EntryNUM 3 83.3 87.64 <.0001 TRT 3 345 1.64 0.1797 EntryNUMTRT 9 348 0.71 0.6984 Contrasts Label Num DF Den DF F Value Pr > F 1.UNT vs 2.V2_CUT 1 345 0.48 0.4878 1.UNT vs 3.V5Cut 1 345 0.59 0.4444 1.UNT vs 4.V5_VC 1 345 1.44 0.2312 2.5 2 % Large discard 1.5 1 0.5 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC 0 1 2 Entry 3 4
Kernels per pound Type 3 Tests of Fixed Effects Effect Num DF Den DF F Value Pr > F EntryNUM 3 68.2 94.91 <.0001 TRT 3 347 0.87 0.4581 EntryNUMTRT 9 352 0.57 0.8197 Contrasts Label Num DF Den DF F Value Pr > F 1.UNT vs 1 346 0.05 0.826 2.V2_CUT 1.UNT vs 1 345 2.29 0.1314 3.V5Cut 1.UNT vs 4.V5_VC 1 348 0.28 0.5999 Kernels/lb. 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 1 2 Entry 3 4 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC
Harvest stalk count Type 3 Tests of Fixed Effects Effect Num Den DF F Value Pr > F DF EntryNUM 3 99.7 2.29 0.0829 TRT 3 363 0.34 0.7979 EntryNUMTRT 9 366 1.8 0.0669 Contrasts Label Num DF Den DF F Value Pr > F 1.UNT vs 1 363 0.02 0.8831 2.V2_CUT 1.UNT vs 1 363 0.37 0.5422 3.V5Cut 1.UNT vs 4.V5_VC 1 362 0.43 0.5148 50.5 50 49.5 Harvest stalk count 49 48.5 48 47.5 47 1.UNT 2.V2_CUT 3.V5_CUT 4.V5_VC 46.5 1 2 Entry 3 4 One plant in row equal 500 plants per acre
Process of analysis Data checked for outliers and bad data points Performed Bartlett test to confirm normalized data Proc mixed determined if location or year were significant factors PROC GLIMMIX used to determine fixed effects, LSMEANS and significant differences Estimate statement made direct comparisons of treatment effects.
SAS Code proc glimmix plots=residualpanel; class entrynum trt rep loc; model kersalpct = entrynum trt/ ddfm=kr; random rep(loc) entrynumrep(loc) loc; lsmeans entrynum /lines; estimate '1.UNT vs 2.V2_CUT' trt 1 100/cl; estimate '1.UNT vs 3.V5Cut' trt 1 010/cl; estimate '1.UNT vs 4.V5_VC' trt 1 001/cl; run; PROC MIXED METHOD=REML; CLASS entrynum Loc TRT Rep; MODEL warm=entrynum Loc TRT entrynumloc entrynumtrt LocTRT entrynumloctrt/ddfm=kenwardroger; RANDOM Rep(Loc) entrynumrep(loc) / TYPE=VC;; LSMEANS entrynum Loc TRT entrynumloc entrynumtrt LocTRT entrynumloctrt / ; RUN; QUIT;