Irri Seminar_irmolina 5 Feb 09

Genetic diversity for sustainable blast management in China: Adoption and impact

Imelda R. Molina IRRI Thursday Seminar 5 February 2009

“Without rice, even the cleverest housewife cannot cook.” -Ancient Chinese proverb

Study area: Yunnan Province, China

Rice blast disease Causal organism: Magnaporthe grisea

Infection during two growth stages: a) Vegetative - leaf blast b) Reproductive – neck or panicle blast

Two types of rice varieties grown in Yunnan Hybrid rice • High yielding • Low market value • Resistant to blast

Glutinous rice • High socio-cultural and market value • Better eating quality • Low yielding • Highly susceptible to blast

Glutinous rice planted on only 2% of total rice production area

Research on genetic diversification started in 1997

New planting pattern: mixed planting system

15 cm

30 cm

15 cm

30 cm

15 cm

Pure stand of hybrid rice

15 cm 15 cm

30 cm

15 cm

15 cm

Mixed planting glutinous rice & hybrid rice

30 cm

15 cm

Transplanting glutinous rice in between four rows of hybrid rice

Rice mixed planting close to harvest

Separate harvesting of hybrid and glutinous rice varieties

Interplanting reduced blast severity by 94% (Zhu et. al., 2000)

Successful disease suppression Item

Number of sprays

Old system

New system

3.4

0.7

Cost of pesticides (USD)

44.42

15.00

Labor for pesticide application (person-days)

20.76

2.63

Imputed cost of labor (USD)

47.75

6.05

Total cost (USD)

91.95

21.05

Financial benefit (USD)

70.90

How does it work? • Barrier effect • Microclimate modification

• Dilution effect • Induced resistance & competition

Rapid rate of adoption Year

Area under rice mixtures (ha)

Number of counties

1997

12

1

1998

812

6

1999

3,342

10

2000

43,000

41

2001

107,400

62

2002

314,368

102

2003

551,334

205

Source: Plant Protection Stations, Yunnan Province.

Nearly 1 million hectares across 10 provinces sport distinctive pinstripes of rice varietal interplanting.

This study Basic questions addressed in the current study: • Is suppression of blast disease the only advantage of the rice interplanting system? • What are the reasons behind the rapid and large scale adoption of the rice interplanting system?

Additional advantages? Experimental approach Comparing pure stands with mixtures using several mixing ratios of hybrid and glutinous rice

Additional advantages? Main conclusions Hardly any resource complementarity between the two rice varieties Prevention of lodging of glutinous rice is another major advantage of the new system (Revilla-Molina et al., 2009)

In pure stand, lodging of glutinous rice is a serious problem

Rapid adoption by farmers Approach: Farm household surveys – Held in July and October 2000 – 100 Adopters and 30 Non-adopters were interviewed – Several analyses were made: • Cost and return analysis • Tobit analysis • Stochastic frontier analysis

Characteristics of sample respondents Education

6

Age, yr

44

Farm experience, yr

24

Household size

4

Farm size (ha)

0.23

Area under rice (ha)

0.16

Per capita income ($/yr) Share of rice income (%)

206 39

Yield advantage

Yield, t ha-1

12

11.0

10.2 8.9

10

9.1

8.9

9.5

8

Glutinous Hybrid Total

6 4

2.1 1.3

2 0

0.4

1996

1999 Adopters

1999 Nonadopters

Mean yield of glutinous and hybrid rice by type of farmer before and after adoption of rice interplanting.

Additional income Adopters Item Gross value of production

1996 2,385.60

(In US$)

Nonadopters 1999

1999

2,490.04

1,808.10

Price kg-1 of Glutinous rice

0.47

0.37

0.38

Hybrid rice

0.20

0.19

0.19

2.54

1.90

2.67

53.67

46.44

53.30

182.01

179.51

181.68

19.00

15.00

44.20

469.81

472.15

427.06

1,658.57

1,775.04

1,189.19

Cost of production Seeds Glutinous rice Hybrid rice Fertilizer Pesticides Hired labour Net returns above cash costs

Uses of additional income from rice interplanting 13%

20%

savings

food

14%

house repairs 16%

education 12%

appliances

3%

holidays

8%

clothes

14%

farm inputs

Promotes on-farm conservation of traditional varieties 0.4

14000

Area

10000 8000

Huangkenuo

Hongkenuo

Zinuo

Giugu

Huangpangshiew

Zigu

Milexiangmi

Xianggu

Alunuo

Xiangnuomi

0.35 0.3 0.25 0.2

6000

0.15

4000

0.1

2000

0.05

Genetic diversity index

12000

0

0 1997

1998

1999

2000

2001

2002

Proportion of area planted to different traditional varieties and index of genetic diversity, Yunnan Province, China, 1997-2002.

Improved health and environment

Factors influencing technology adoption and diffusion Farmers’ contact with extension workers and perceptions of technology-specific attributes of rice interplanting were major factors determining adoption probability and use intensity.

Impact on technical efficiency of rice farming Farming experience & access to extension workers reduced technical inefficiency of farmers.

Farmer adopters who had been trained made the best out of the interplanting technology and as a result performed better.

Impact on technical efficiency of rice farming With healthier plants, output became more responsive to inputs such as fertilizer, seeds and labor.

Improvement of technical efficiency of rice production results from positive interactions among inputs.

High returns on investment Discount rate

Benefit-cost ratio 1997-2000

1997-2007

15

2.7

22.0

50

2.0

8.7

100

1.3

7.8

Lessons learned The rice interplanting system in Yunnan has shown that genetic diversification is able to control blast disease, to attain acceptable crop yields and to provide high-quality food and income.

Lessons learned Farmers’ early participation in the project is a crucial factor in showing the impact of using the technology and subsequently in its adoption.

Lessons learned The Yunnan experience has demonstrated that the best way to push a technology from concept to actual practice is to strengthen the links among research, extension, policymakers and farmer communities.

Beyond the Yunnan experience • Can a similar approach be extended to other crops? • Will it work in other rice production environments, other countries? • How about for other pests and diseases?

Acknowledgment IRRI-WUR Sandwich PhD Fellowship Asian Development Bank Yunnan Agricultural University YYZhu and staff TWMew, HLeung, MHossain HVKeulen, LBastiaans, MJKropff, GVLaar NCastilla, VBartolome, VSalazar

Thank you!