Routes Pathways from Origin to Release

In order to analyse more formally the impacts of IRGC, IRPB and INGER, it is useful to trace the routes by which varieties were released. Table 13.3 provides a tabular summary of released varieties by pathway or route. These routes are defined to be mutually exclusive categories, so that each variety in the data set falls into exactly one of the following categories:

• Borrowed varieties.

R1. IRRI line, borrowed through INGER (IRRI/INGER).

R2. IRRI line, borrowed independently of INGER (IRRI/NO INGER).

R3. Variety from another national programme, borrowed through INGER (OTHER NATL/INGER).

R4. Variety from another national programme, borrowed independently of INGER (OTHER NATL/NO INGER).

• Nationally developed varieties, borrowed parents.

R5. At least one parent from IRRI, borrowed through INGER (IRRI PAR-ENT/INGER).

R6. At least one parent from IRRI, borrowed independently of INGER (IRRI PARENT/NO INGER).

R7. No IRRI parents, but at least one parent borrowed from another national programme via INGER (OTHER NATL PARENT/INGER).

R8. No IRRI parents, but a least one parent borrowed from another national programme independently of INGER (OTHER NATL PARENT/NO INGER).

• Nationally developed varieties and parents, borrowed grandparents.

R9. At least one grandparent from IRRI, borrowed through INGER (IRRI/ GPARENT/INGER).

Table 13.3. Number of varieties released by route, by date.

Pre-

1966-

1971-

1976-

1981-

1986-

1965

1970

1975

1980

1985

1991

Total

IRRI/INGER

0

0

5

50

52

39

146

IRRI/NO INGER

1

37

50

38

16

6

148

OTHER NATIONAL/INGER

0

0

0

10

15

12

37

OTHER NATIONAL/NO INGER

5

10

16

13

9

6

59

IRRI PARENT/INGER

0

0

0

46

89

79

214

IRRI PARENT/NO INGER

0

52

110

117

15

19

313

OTHER NATIONAL PARENT/INGER

3

2

15

34

69

85

208

OTHER NATIONAL PARENT/

NO INGER

9

30

50

22

13

27

151

OTHER

7

10

33

63

90

85

288

PURE NATIONAL

8

18

24

24

29

42

145

Total

33

159

303

417

397

400

1709

See text for definitions of categories.

R10. At least one grandparent from IRRI, borrowed independently of INGER (IRRI/GPARENT/NO INGER).

R11. No IRRI grandparent, but at least one grandparent borrowed from another national programme via INGER (OTHER GPARENT/INGER).

R12. No IRRI grandparents, but at least one grandparent borrowed from another national programme independently of INGER (OTHER GPAR-ENT/NO INGER). • Nationally developed varieties, parents, grandparents.

R13. All parents and grandparents from country of release (PURE NATIONAL).

In practice, virtually no varieties fell into categories 9 or 11, since INGER has not been in existence long enough to provide many grandparent materials. Moreover, many varieties with borrowed grandparents also have borrowed parents, or are even borrowed varieties. Thus, in some of the tables that follow, routes 9-12 are collapsed into a single category labelled 'OTHER'.

International genetic exchange has been enormously important. Since 1970, only 7.8% of new varieties have been of 'pure' national development. The most significant channels of release have been the use of IRRI parents. Before 1975, IRRI parents were obviously not channelled through INGER, but in recent years, the largest single pathway for developing new varieties has been to use IRRI parents taken from INGER.

The importance of INGER can be seen by looking at the time trends on borrowing through INGER. Since 1981, more than half of released varieties (440 out of 797) have either been borrowed through INGER or were bred from parents borrowed through INGER.11

Table 13.4 reports numbers of ancestors and proportions of rare traits by route and by region. This table shows that IRRI material has been the conveyor of high landrace content and high rare trait content. In other words, IRRI materials have provided multiple single-gene traits packaged into readily usable breeding lines. IRRI has not, however, been the primary source of new ancestral material; most of the influx of landraces and other ancestral material has occurred through national and local breeding programmes. In these programmes, breeders are combining modern varieties with popular local and traditional varieties.

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