Development of low-N tolerant maize varieties

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Maize genotypes with improved N-use efficiency (greater grain yield per unit available soil N) can increase productivity of maize based system.

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Development of low-N tolerant maize varieties

  1. 1. Development of low-N tolerant maizevarieties International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  2. 2. Savannas ofWCA • Savannah is the most productive environment for maize production • Soils in the savannas are generally low in organic matter and available nitrogen • Availability and use of fertilizer also limit maize productivity International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  3. 3. ConcernAlthough,Combined use of organic manure and nitrogenfixing cover crop can make a difference tomaize productionHowever, there is the concern on - declining levels of soil fertility - high proportion of crop residue being fed to livestock, burned or consumed by termites International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  4. 4. Therefore,Maize genotypes with improved N-useefficiency (greater grain yield per unitavailable soil N) can increase productivity ofmaize based systemEspecially,In combination with technologies that improvesoil fertility - crop rotation - organic manure - judicious use of inorganic fertilizers. International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  5. 5. Need Generate - N-efficient maize that can be used in rotation with - legumes to reduce fertilizer requirement in a cereal- legume system International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  6. 6. Model >N - use efficiency (>grain yield/unit of available N Mechanism > N uptake efficiency > N utilization efficiency > grain yield Genotypic differences for the N-use mechanism traits usually significant but G X N usually not significant International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  7. 7. Root • Maximum rooting depth – To capture N moving out of themorphology root zone especially at flowering • Root size – Exploratory tendency Vertical root pulling strength directly related to root characteristics of maize (standability) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  8. 8. Phenology traits - Anthesis – Silking-Interval (ASI) - Duration of grain fillingSignificant G x N interaction in some locations International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  9. 9. Important • Vertical root pulling resistant and N-uptakecorrelations • Grain yield and number of ears/plant • Grain yield and N-utilization • Grain yield and Plant ht • Grain yield and ASI but with low R² • Grain yield and Stay green (low-N) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  10. 10. Selectioncriteria • Grain yield (low-N) • Grain yield (high-N) • Stay green (1-10) • ASI • Ears/plant (Prolificacy) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  11. 11. Selectionenvironment • Low - N 0 kg N/ha 30 kg N/ha • High – N 90 kg N/ha International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  12. 12. Breeding methodology• Generation of low-N tolerant populations• Screening of germplasm from diverse sources• Recurrent selection to improve on levels of N-tolerance in desirable populations• Line development to generate inbreds tolerant to low soil-N International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  13. 13. Low NPopulations • LNTP- Ygenerated • LNTP – W – LNTP X LNP • TZPB Prolific International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  14. 14. Performance of varieties with tolerance to other stresses identified under low-N (30 kg N/ha) in 2006 Grain yield Stay Stay EarsEntry LN green 1 green 2 number ASIAcr 97 TZL Comp 1 2469 2.3 3.3 25 2.9TZL Comp 1-W C6 2343 2.3 3.6 25 3.6DT-SR-W C1 F2 2260 2.3 4.1 25 3.5LNTP-Y C5 2241 2.1 3.8 28 3.0DT SYN-1 W 2239 2.1 4.1 22 3.5TZPB Prol C3 2207 2.1 3.9 24 3.0Mean 2053 2.4 3.9 24 3.0SED 210.2 0.3 0.4 1.9 0.4CV (%) 26.8 29.8 14.9 21.6 32.4 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  15. 15. Performance of top 8 S1 lines from BR 9928 DMRSR evaluated for low-N tolerance in 2007Entry Stay green Ear aspect Ear/plant Grain Yld LN Grain Yld HN 65 4.5 3.0 0.46 725.35 1411.73 92 5.5 3.5 0.47 815.97 1866.07 50 5.5 3.5 0.45 633.55 1904.68 10 4.5 3.5 0.40 677.34 1391.36 138 5.0 4.0 0.45 819.11 1668.39 48 5.5 4.0 0.46 772.62 1346.75 144 4.5 4.0 0.52 728.53 1106.44 166 4.5 3.5 0.53 867.85 743.48Mean of selected 15 5.2 3.8 0.48 750.77 1365.35BR 9928 DMRSR 7 4.5 0.40 492.99 1611.12SED 1.59 1.12 0.15 254.78 536.08Sel Dif (%) -25.71 -15.56 19.01 52.29 -15.25 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  16. 16. Performance of top 10 S1 lines from TZL Comp 1 C6 evaluated for low-N tolerance in 2007ENTRY Ear/plant Stay green Grain Yld LN Grain Yld HN 18 0.54 8.0 233.87 982.58 8 0.33 8.5 262.59 965.65 3 0.28 9.0 160.02 1145.76 19 0.44 9.0 233.87 975.74 51 0.42 9.0 160.02 1108.16 184 0.29 8.0 160.02 1487.50 26 0.25 8.5 160.02 999.95 44 0.34 9.0 336.44 947.83 89 0.33 9.0 160.02 1419.68 134 0.42 7.5 160.02 925.87Mean of Selected 15 0.32 8.7 188.46 1130.18TZL Comp 1C6 0.19 7 160.02 1178.20SED 0.21 1.4 54.04 381.95Sel Diff (%) 68.88 24.3 17.78 -4.08 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  17. 17. Genetic • Rizzi et al (1993)studies • Below et al. (1997 • Kling et al (1997) σ²A > σ²D • Katsantonis et al (1988) • Bertran et al. (1997) σ²D > σ²A • Meseka et al (2006) σ²D > σ²A International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  18. 18. Genetic studies 2Maize populations LNYP-Y LNTP-W TZPB Prolific WTwo progeny selection types Full-sib family selection S1 Testcross hybrid evaluationEvaluation 2007 and 2008, Mokwa and Zaria, 2Reps, 3 N levels International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  19. 19. Genetic studies 3Testcross (HS) = σ²HS = 1/4σ²AFull sib = σ²FS = 1/2σ²A + 1/4σ²D  σ²A = 4σ²HS σ²D = 4(2σ²HS - σ²FS) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  20. 20. Relative values of add to non- additive variances under low-NTrait Populations σ²A σ²DStay green LNTP-Y 0.00 0.00 LNTP-W 0.00 0.00 TZPB Prolific 0.08 0.04Ears/plant LNTP-Y 0.02 0.00 LNTP-W 0.00 0.00 TZPB Prolific 0.00 0.00Grain yield LNTP-Y 0.03 0.00 LNTP-W 0.02 0.00 TZPB Prolific 0.10 0.04 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  21. 21. Comparison of full-sib and S1 selection evaluated at two location in Nigeria in 2002 and 2003. 30kg N/ha 90 kg N/haEntry Yield Days to Plant ASI Yield Days to Plant (kg/ha) silk ht (cm) (kg/ha) silk ht (cm)LNTP-Y C4 FS 2075 65 172 1.9 4808 60 213LNTP-Y C4 S1 1802 66 174 1.8 5157 61 211LNTP-WC1 FS 1655 65 164 2.0 4974 60 208LNTP-WC1 S1 1415 66 162 2.7 5070 60 214ChecksOba Sup 2 1712 66 158 2.8 4045 61 207TZB-SR 1414 68 183 3.5 3618 63 222Oba Sup 1 1544 67 167 2.6 4699 62 212Mean 1559 67 169 2.7 4362 62 211SED 163.9 0.6 4.8 0.5 276.6 0.5 3.9CV(%) 41.5 4.2 9.3 86.1 19.9 2.7 7.1VAR * ** ** ** ** ** ** International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  22. 22. ON 90 N 1800 23.5 3500 30 N 35 5000 40 A 1600 1400 y = 15.77x + 1400.4 R 2 = 0.0227 23 22.5 3000 y = 0.62x + 24.487 R 2 = 0.1812 30 4500 4000 y = 1.0171x + 27.007 R 2 = 0.3286 35 30 Grain Yield (kg ha-1) Grain Yield (kg ha-1) Grain Yield (kg ha-1) 2500 25 1200 22 3500 Ears harvested Ears harvested y = 138.83x + 2144.6 Ears harvested 2 R = 0.5149 25 2000 20 3000 y = 274.46x + 2729.7 1000 21.5 y = 0.32x + 20.607 2 R 2 = 0.6015 R = 0.2035 2500 20 800 21 1500 15 2000 600 20.5 15 1000 10 1500 400 20 10 Grain yield 1000 200 19.5 500 Grain yield 5 Grain yield Ears harves ted 5 Ears harves ted 500 0 19 Ears harvested Linear (Ears 0 0 0 1 2 3 4 5 6 7 Linear (Ears 0 0 harves ted) 0 1 2 3 4 5 6 7 Linear (Ears Linear (Grain harves ted) Cycles of Selection Linear (Grain 0 harvested) 2 1 3 4 5 6 7 yield) Cycles of Selection Linear (Grain yield) Cycles of Selection yield) B 1350 22.2 22 3500 3000 y = 1.67x + 20.73 35 30 4500 4000 35 1300 R2 = 0.6563 30 y = 26.61x + 1154.3 21.8 3500 y = 2.33x + 19.71 Grain Yield (kg ha-1) Grain Yield (kg ha-1) 2 R = 0.2228 2500 25 R2 = 0.3871 Grain Yield (kg ha-1) 21.6 25 Ears harvested Ears harvested 1250 3000 Ears harvested y = 0.1x + 21.1 21.4 y = 228.91x + 1721.3 2000 20 20 R 2 = 0.0568 R2 = 0.9175 2500 y = 375.23x + 1956.6 R2 = 0.5645 1200 21.2 1500 15 2000 15 21 1150 1500 20.8 1000 10 10 1000 20.6 1100 Grain yield 500 Grain yield 5 Grain yield 5 500 20.4 Ears harves ted Ears harvested Ears harvested 0 0 1050 20.2 0 0 Linear (Ears Linear (Ears 0 1 harves ted) 2 3 4 5 6 0 1 2 3 4 Linear5(Ears 6 0 1 2 3 4 5 6 harvested) Linear (Grain Cycles of Selection harvested) Linear (Grain yield) Linear (Grain Cycles of Selection Cycles of Selection yield) yield) C 1345 1340 y = 1.55x + 14.833 25 3500 3000 y = 504.9x + 1482.5 2 35 30 4000 3500 40 35 R = 0.7337 y = 329.15x + 2376.7 1335 R 2 = 0.7742 20 2 3000 R = 0.3477 30 Grain Yield (kg ha-1) Grain Yield (kg ha-1) Grain Yield (kg ha-1) 2500 y = 3.65x + 17.633 25 1330 2 Ears harvested Ears harvested Ears harvested R = 0.6687 y = 4.45x + 20.433 2500 2 25 1325 15 R = 0.8943 2000 20 1320 2000 20 1500 15 1315 10 1500 15 y = -21.5x + 1363.6 1310 R 2 = 0.9892 1000 10 1000 10 1305 5 Grain yield Grain yield Grain yield 500 5 500 5 1300 Ears harves ted Ears harvested Ears harvested 0 0 1295 Linear (Ears 0 0 0 Linear (Ears Linear (Ears 0 1 2 3 4 0 harvested) 1 2 3 4 harves ted) 0 1 harvested) 2 3 4 Linear (Grain Cycles of Selection Linear (Grain Linear (Grain Cycles of Selection Cycles of Selection yield) yield) yield)Ear number and Grain Yield of different cycles of selections evaluated in Nigeria in 2006 A = LNTP-Y B = LNTP-W C = TZPB Prolific International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  23. 23. Changes in agronomic traits associated with recurrent selection for low-N tolerance in maize 30 N 90 N Days to Plant ht. Days to Plant ht.Population silk (cm) ASI silk (cm) ASILNTP C1 66.1ab* 172.8ab 3.0a 65.9a* 195.1a 2.3aLNTP C2 67.4a 160.6b 2.9a 65.3ab 168.8c 2.0abLNTP-Y C3 63.3c 180.1a 2.6a 63.9bc 186.8ab 1.6bLNTP-Y C4 63.5c 185.0a 2.6a 64.8abc 176.3bc 2.3aLNTP-Y C5 64.1bc 184.4a 3.3a 61.8d 182.8abc 2.0abLNTP-Y C6 63.4c 173.4ab 2.9a 63.5c 180.6abc 2.0ab b-value -0.66 2.27 0.02 -0.62 -1.17 -0.0TZB-SR 66.8ab 185.9a 3.4a 66.8a 183.9a 1.0bTZPB-SR 67.6a 190.4a 2.9a 66.0a 192.5a 0.8bOba Super 1 64.5bc 180.9a 3.3a 63.1b 201.1a 2.0abOba Super 2 64.4bc 177.5a 2.9a 64.5ab 191.4a 2.6a International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  24. 24. Means of top 7 full-sib progenies from LNTP-Y C6 evaluated at Mokwa and Zaria in Nigeria in 2008 Grain Yield low- Stay green Grain Yield High-N Selected entries N (kg/ha) (1- 9) Ears/plant (kg/ha) 5 2742 4 0.98 3712 180 3114 4 0.88 4131 174 3056 4 0.87 4118 8 2422 4 0.91 4690 170 2807 5 0.94 4304 160 3471 4 0.93 3307 127 2841 4 0.92 3327Mean of population 2045 5 0.80 2901Mean of selected 20 2749 4 1 3739*Selection diff (%) 34.43 -20 25 28.89SED 496.37 0.55 0.094 544.50CV (%) 42.6 15.5 21.4 38 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  25. 25. Inbred-Hybrid Correlation• Dominance gene action in some studies – Heterosis can be exploited• Earlier studies from Maize Program (Akintoye 1994) 4 maize inbred 10 single cross hybrids 6 double cross hybrids from the 10 1 synthetic variety from the 4 inbred Single cross > double cross > Synthetic at all N levels International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  26. 26. Inbred-Hybrid Correlation 2 Base Drought IndexInbred lines tolerance value1824 T 21.939006 T 9.024058 T 7.52Pop 10 T 4.639485 S -7.334008 S -7.75Mok Pion Y-S4 S -7.93(KU1403x1368)BC2 S -8.51 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  27. 27. Inbred-Hybrid Correlation 3• Correlation between mid-parent yield values and corresponding hybrids significant (r = 0.22*)• Average heterosis for grain yield (129%) and associated low-N traits highly significant• T x T > T x S > S x T > S x S under low-N.• No dosage effect under high-N Selecting for drought or low-N tolerant lines under low-N for testing in hybrid combinations will lead to the development of good hybrids with tolerance to low soil N. International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  28. 28. On–farm trials of low-N tolerant populations conducted in 2005 – 2008 in Nigeria Location Nasarawa FCT Niger Bauchi GombeVariety (49) (10) (10) (42) (10) AverageLNTP- Y` 5.80 4.42 3.38 5.14 5.07 4.80LNTP-W 3.30 3.30Farmers check 4.87 2.09 1.70 4.16 3.45 3.30 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  29. 29. Summary • Newer generation of improved low-N tolerant populations available • Low-N tolerant synthetics are being generated • Genotypes with tolerance to multiple stresses being developed • Inbred line development for hybrid production initiated • On-farm trials conducted to demonstrate the effectiveness of low-N tolerant populations in N deficient situations. International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  30. 30. 2 OP varieties with tolerance to lowsoil nitrogen for release in 2009 1. LNTP-Y Yellow grained and low soil nitrogen tolerant variety broadly adapted to the savannas. 2. LNTP-W White grained intermediate-late maturing variety with tolerance to low soil nitrogen International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  31. 31. Thank YouContributorsSam AjalaAbebe MenkirAlpha KamaraJenny Kling International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org

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