Genetic Improvement of Maize Genetic Improvement of Maize for Tolerance to Acid Soils infor Tolerance to Acid Soils in

the Tropicsthe Tropics

Alejandro NavasAlejandro Navas

ISU AgronomyISU Agronomy

October 29 / 98October 29 / 98

OUTLINEOUTLINE

1. Acid soils in the world1. Acid soils in the world

2. What are the acid soils?2. What are the acid soils?

3. The problem3. The problem

4. Some solution approaches 4. Some solution approaches

4.1 Liming4.1 Liming

4.2 Genetics of tolerance to soil acidity4.2 Genetics of tolerance to soil acidity

4.3 Physiology of tolerance4.3 Physiology of tolerance

OUTLINEOUTLINE

4.4 Populations: Recurrent Selection4.4 Populations: Recurrent Selection

4.5 Inbred lines 4.5 Inbred lines

4.6 Molecular markers4.6 Molecular markers

5. Summary5. Summary

6. Future Research 6. Future Research

1. Acid soils in the world1. Acid soils in the world 48 developing countries with 1.7 billion ha48 developing countries with 1.7 billion ha 43% world’s tropical land area43% world’s tropical land area 38% of tropical Asia38% of tropical Asia

Indonesia, Thailand, Malaysia, India, China, and the Indonesia, Thailand, Malaysia, India, China, and the Philippines.Philippines.

27% of tropical Africa27% of tropical Africa

Ivory Coast, Zaire, Zambia, Tanzania, Uganda and Ivory Coast, Zaire, Zambia, Tanzania, Uganda and Zimbabwe.Zimbabwe.

10% of Central America, Caribbean and Mexico10% of Central America, Caribbean and Mexico

1. Acid soils in the world1. Acid soils in the world In South America 80% of agricultural In South America 80% of agricultural

areaarea

Brazil, Colombia, Ecuador, Peru and Brazil, Colombia, Ecuador, Peru and VenezuelaVenezuela

Colombia “Llanos Orientales” Colombia “Llanos Orientales”

17 millions ha.17 millions ha. Brazil acid savannas 205 million ha of Brazil acid savannas 205 million ha of

which 112 are suitable for agriculturalwhich 112 are suitable for agricultural

Ref: Sanchez, 1977; Torres et al., 1997

2. What are the acid soils?2. What are the acid soils?

Aluminum ( Al) and Manganese (Mn) Aluminum ( Al) and Manganese (Mn) toxicitytoxicity

pH < 5.6pH < 5.6 Deficiency Ca, Mg, P, Mo, and FeDeficiency Ca, Mg, P, Mo, and Fe Al saturation > 35%Al saturation > 35% P < 16 p.p.m P < 16 p.p.m

Ref: Granados et al., 1993; Duque-Vargas et al., 1994.

Environmental characteristics Environmental characteristics for some acid soils for some acid soils

Country

Colombia

Brazil

India

Indonesia

Site

Carimagua

Sete lagoas

Meghalaya

Sitiung

pH Al P

5.2 60 10

4.9 40 5

4.7 49 1.3

4.0 53 3

% mg kg-1

Source: Granados et al., 1993; Pandey et al., 1994.

3. The problem3. The problem Between 8-20 million ha are plantedBetween 8-20 million ha are planted Maize is more susceptible than rice, wheat, Maize is more susceptible than rice, wheat,

sorghum, cotton and soybean.sorghum, cotton and soybean. Maize produces fewer and smaller rootsMaize produces fewer and smaller roots Reduces survival and function of micro-Reduces survival and function of micro-

organisms in the soil => organic matter => organisms in the soil => organic matter => availability of N, P, Savailability of N, P, S

A survey of 48 developing countries only five are A survey of 48 developing countries only five are conducting research conducting research

Ref: TropSoils, 1991; Pandey and Gardner, 1992; Tan, 1993.

4. Some solution approaches4. Some solution approaches4.1 Liming 4.1 Liming

Lime is a reliable soil amendment Lime is a reliable soil amendment For poor farmers is not an economic For poor farmers is not an economic

optionoption At the sub-soil level is difficultAt the sub-soil level is difficult Temporal solutionTemporal solution Incompatible with conservation tillageIncompatible with conservation tillage

Ref: Pandey and Gardner, 1992; Pandey et al., 1994.

4.2 Genetics of tolerance to soil acidity4.2 Genetics of tolerance to soil acidity

Acid tolerant varieties are reliable, permanent, Acid tolerant varieties are reliable, permanent, economical, and environmental clean solutionseconomical, and environmental clean solutions

Several authors have reported genetic variation Several authors have reported genetic variation for tolerance to acid soils in maize.for tolerance to acid soils in maize.

Quantitative inheritance:Quantitative inheritance: Magnavaca et al., 1987; Magnavaca et al., 1987; Pandey Pandey et alet al., 1994; Borrero ., 1994; Borrero et alet al., 1995; Salazar ., 1995; Salazar et alet al., ., 1997.1997.

Qualitative inheritance:Qualitative inheritance: Rhue Rhue et alet al., 1978; Miranda ., 1978; Miranda et alet al., ., 1984.1984.

4.2 Genetics of tolerance to soil acidity4.2 Genetics of tolerance to soil acidity

Additive genetic variance is generally most Additive genetic variance is generally most important in yield:important in yield: Magnavaca et al., 1987; Pandey Magnavaca et al., 1987; Pandey et alet al., 1994.., 1994.

Dominance genetic variance has been also Dominance genetic variance has been also reported: reported: Duque-Vargas et al., 1994; Borrero Duque-Vargas et al., 1994; Borrero et alet al., ., 1995. 1995.

4.2 Genetics of tolerance to soil acidity4.2 Genetics of tolerance to soil acidity

CIMMYT has conducted several field-based CIMMYT has conducted several field-based studies to determine inheritance of yield: studies to determine inheritance of yield:

GCA ** accounting for 89% of the genotypic GCA ** accounting for 89% of the genotypic variation and SCA n.s for yield.variation and SCA n.s for yield.

Heritability, estimated using half-sib family Heritability, estimated using half-sib family mean averaged 38% for yield.mean averaged 38% for yield.

They suggested that recurrent selection would They suggested that recurrent selection would be effective.be effective.

Ref: Duque-Vargas et al., 1994; Pandey et al., 1994, and Borrero et al., 1995.

4.3 Physiology of tolerance4.3 Physiology of tolerance Aluminum (Al) toxicity is the most severe Aluminum (Al) toxicity is the most severe

limiting factor: limiting factor: Foy, 1988Foy, 1988..

Al resistance is prerequisite for adaptation to Al resistance is prerequisite for adaptation to acid soils. There are some evidences in wheat acid soils. There are some evidences in wheat and barley.and barley.

P and water deficiencies are correlated with Al P and water deficiencies are correlated with Al toxic effect.toxic effect.

Root elongation of seedlings, in nutritive Root elongation of seedlings, in nutritive solutions + Al, can be measured: solutions + Al, can be measured: Horst et al., 1992.Horst et al., 1992.

4.4 Populations: Recurrent Selection4.4 Populations: Recurrent Selection Several authors have reported good results using Several authors have reported good results using

recurrent selection to improve maize yield on acidic soils. recurrent selection to improve maize yield on acidic soils.

Magnavaca Magnavaca et alet al., (1987), in Composto Amplo after four ., (1987), in Composto Amplo after four cycles half-sib selection, reported significant yield cycles half-sib selection, reported significant yield improvementimprovement

Granados Granados et alet al., (1993) in SA3 after 14 cycles MER and ., (1993) in SA3 after 14 cycles MER and two FS reported yield improvement of 2% and 14% per two FS reported yield improvement of 2% and 14% per cycle, respectivelycycle, respectively. .

4.4 Populations: Recurrent Selection4.4 Populations: Recurrent Selection

Ceballos et al., (1995) in five populations and two Ceballos et al., (1995) in five populations and two acidic and one no-acidic environments reported acidic and one no-acidic environments reported 4.72% per cycle.4.72% per cycle.

CIMMYT-NARS has developed six maize CIMMYT-NARS has developed six maize populations: SA3, SA4, SA5, SA6, SA7 and SA8populations: SA3, SA4, SA5, SA6, SA7 and SA8

Narro Narro et al., et al., (1997) diallel study conclude: (1997) diallel study conclude:

(SA3 + SA5 ) x SA4 and (SA7 + SA8) x SA6(SA3 + SA5 ) x SA4 and (SA7 + SA8) x SA6

ETO x Tuxpeño was used as heterotic patternETO x Tuxpeño was used as heterotic pattern

4.4 Populations: Recurrent Selection4.4 Populations: Recurrent Selection

Granados et al., (1994) compared SA3 and Granados et al., (1994) compared SA3 and Tuxpeño across 20 sites, with a wide range of Tuxpeño across 20 sites, with a wide range of acidities, SA3 range from 96 to 1500% of acidities, SA3 range from 96 to 1500% of Tuxpeño. SA3 was released in Colombia as Tuxpeño. SA3 was released in Colombia as

ICA SIKUANI V-110ICA SIKUANI V-110

Brazil has released : 3 hybrids and some Brazil has released : 3 hybrids and some varietiesvarieties

Indonesia: One varietyIndonesia: One variety

4.54.5 Inbred linesInbred lines

CIMMYT-NARS and CNPMS/ENBRAPACIMMYT-NARS and CNPMS/ENBRAPA

are developing maize inbred lines. These are developing maize inbred lines. These lines are being used in:lines are being used in:

- Hybrids- Hybrids

- Inheritance and physiological studies - Inheritance and physiological studies

- Molecular markers.- Molecular markers.

4.6 Molecular markers4.6 Molecular markers

At this level only a few reports are available At this level only a few reports are available in maize for tolerance to tropical acid soilsin maize for tolerance to tropical acid soils

Torres Torres et alet al., (1997) worked F., (1997) worked F22 population population

derived from L53 x L1327 derived from L53 x L1327 (CNMPS/EMBRAPA) with bulked segregant (CNMPS/EMBRAPA) with bulked segregant analysis (BSA) and RFLP markers. They analysis (BSA) and RFLP markers. They concluded that there is a region on concluded that there is a region on Chromosome 8 related to aluminum toleranceChromosome 8 related to aluminum tolerance

4.6 Molecular markers4.6 Molecular markers

Arias et al., (1997) In tolerant and susceptible Arias et al., (1997) In tolerant and susceptible SS66 lines from SA3, SA4, SA5, and Tuxpeño lines from SA3, SA4, SA5, and Tuxpeño

Sequia C8 populations AFLPs were applied. Sequia C8 populations AFLPs were applied. They did not find molecular differences They did not find molecular differences between susceptible and tolerant lines.between susceptible and tolerant lines.

They recommended to include new lines, new They recommended to include new lines, new probes and increase endogamy level at the probes and increase endogamy level at the lines.lines.

5. Summary5. Summary

Acid soils with 1.7 billion ha cover a Acid soils with 1.7 billion ha cover a significant part of a least 48 countries.significant part of a least 48 countries.

Maize is one of the most susceptible crop.Maize is one of the most susceptible crop. Lime is one reliable but expensive and Lime is one reliable but expensive and

temporal solution.temporal solution. Acid tolerant varieties are one reliable, Acid tolerant varieties are one reliable,

permanent, economical and clean solution.permanent, economical and clean solution.

5. Summary5. Summary

Both quantitative and qualitative genetic Both quantitative and qualitative genetic variation have been reported.variation have been reported.

Additive genetic variance is more Additive genetic variance is more important but dominance is present.important but dominance is present.

Aluminum (Al) toxicity is the most severe Aluminum (Al) toxicity is the most severe limiting factorlimiting factor

Recurrent selection has been effective to Recurrent selection has been effective to improve maize yield on acidic soils. improve maize yield on acidic soils.

5. Summary5. Summary

Maize inbred lines are being development in Maize inbred lines are being development in order to use them in: Hybrids, inheritance / order to use them in: Hybrids, inheritance / physiological studies, andphysiological studies, and

molecular markers.molecular markers. There is a region on Chromosome 8 possibly There is a region on Chromosome 8 possibly

related to aluminum tolerancerelated to aluminum tolerance

6. Future Research6. Future Research

In general trials in acid soils have: high In general trials in acid soils have: high experimental error, which reduces heritability experimental error, which reduces heritability and gains from selection.and gains from selection.

Soil acidity involves: HSoil acidity involves: H++ , Al, Mn toxicities and , Al, Mn toxicities and deficiencies of P, Ca, Mg, and OM.deficiencies of P, Ca, Mg, and OM.

More multi-environmental field testing are More multi-environmental field testing are needed. needed.

Mechanisms for tolerance and efficient Mechanisms for tolerance and efficient screening techniques must be research.screening techniques must be research.

6. Future Research6. Future Research

Isogenic and near-isogenic lines must be use Isogenic and near-isogenic lines must be use in molecular studies with RFLP, RAPD and in molecular studies with RFLP, RAPD and SSR.SSR.

Physiological mechanisms of Al tolerance Physiological mechanisms of Al tolerance and P uptake and utilization must be and P uptake and utilization must be studiedstudied

Field data must be supplemented with Field data must be supplemented with Molecular and Physiological informationMolecular and Physiological information

Extension- Expansion- Overlap of the networks Extension- Expansion- Overlap of the networks working in the tropical acid soils.working in the tropical acid soils.

Hannover University: Germany, France, Spain, Brazil, Hannover University: Germany, France, Spain, Brazil, Guadeloupe, and CamerunGuadeloupe, and Camerun

CIMMYT- NARS - NGOs: Brazil, Colombia, Peru, CIMMYT- NARS - NGOs: Brazil, Colombia, Peru, Venezuela, Malawi, Ivory Coast, Indonesia, The Venezuela, Malawi, Ivory Coast, Indonesia, The Philippines, Thailand, VietnamPhilippines, Thailand, Vietnam

Consortium on Developing Maize Cultivars for Consortium on Developing Maize Cultivars for Sustainable Production System in Acid Soils: 5 years Sustainable Production System in Acid Soils: 5 years and ~ 4 U$ millionand ~ 4 U$ million

ACKNOWLEDGMENTSACKNOWLEDGMENTS

CIMMYT

Dr Shivaji Pandey

Dr Carlos De Leon

Dr Luis Narro

Mr. Juan C Perez

ISU

Dr Arnel R. Hallauer

Dr Michael Lee

CORPOICA

MV. Sony Reza

Mr. Jose G. Ospina

Mr. Guillermo Torres

CNPMS/ EMBRAPA: Mr. Sidney N. Parentoni

NARS of CIMMYT’s network for acid soils

University of Hannover: Dr. W. J. Horst