Plant Biotechnology and Genetics: Principles, Techniques and Applications

(Grace) #1

and disease- and insect-resistance. I
developed numerous breeding lines with
the above traits. IR 36 was the first
variety with all the desirable traits. It had
high yield potential, short vegetative
growth duration, excellent grain quality,
multiple resistance to major diseases and
insects and tolerance to adverse soil con-
ditions such as iron toxicity and zinc
deficiency. It was grown on 11 million
hectares of rice land during the 1980s.
No other variety of rice or any other crop
had been as widely planted before.
Thirty-four varieties were released under
IR designation (IR8–IR74). Seeds of
improved breeding lines were shared
with national program scientists at their
request and through international nur-
series. Thus, seed materials were sent to
87 countries irrespective of geographic
location or ideology. These materials
were evaluated for adaptation to local
growing conditions. Some were released
as varieties and others were used as
parents in local breeding programs.
Thus, 328 IR breeding lines have been
released as 643 varieties in 75 countries.
It is estimated that 60% of the world rice
area is now planted to IRRI-bred varieties
or their progenies. Large scale adoption of
these varieties has led to major increases
in rice production. Average rice yield has
doubled from 2 to 4 tons per hectare.
Rice production increased from 257
million tons in 1966 to 615 million tons
in 2005, an increase of 140 percent. The
price of rice is 40% lower now than in
the mid 1960s. This has helped poor rice
consumers who spend 50% of their
income on food grains. Thus, these
IRRI-bred varieties have had a significant
impact on food security and poverty alle-
viation and fostered economic develop-
ment particularly in Asia, where 90% of
the world’s rice is grown.


I was fortunate to have had the opportu-
nity to lead one of the largest and most
successful plant breeding programs at
IRRI. I had a team of motivated plant
breeders, plant pathologists, entomolo-
gists, and cereal chemists supported by


a dedicated Filipino staff. We had a
large collection of germplasm, liberal
financial support, modern laboratories
and adequate field space. The opportu-
nity to work with scientists in rice
growing countries was another reason
for our success. In addition to conven-
tional hybridization and selection pro-
cedures, my team employed other
breeding approaches such as ideotype
breeding, hybrid breeding, wide hybrid-
ization, rapid generation advance,
molecular marker assisted selection
(MAS), and genetic engineering. I had
the opportunity of working with numer-
ous trainees from rice growing countries
that came to IRRI for a degree (MSc
and PhD) and non degree training.
Upon returning to their countries they
became our valued collaborators.
Several of our trainees are now holding
positions of leadership in their respect-
ive countries. This had a multiplying
effect and all the rice growing countries
are now using crop development meth-
odologies and germplasm initially
developed at IRRI.
The science of plant breeding is now at a
crossroads. Breakthroughs in cellular
and molecular biology have added new
tools to the breeder’s toolbox. MAS
has increased the efficiency of selection
and reduced the time taken for varietal
development. Genetic engineering has
permitted the introduction of genes into
crop varieties from unrelated sources
across incompatibility barriers. In 2006,
102 million hectares were planted to
transgenic crops in 22 counties. The
science of genomics is likely to improve
the efficiency of plant breeding further.
The entire genome of rice has been
sequenced and efforts are underway to
determine the functions of an estimated
40,000 rice genes through functional
genomics. Similar efforts are underway
in many other crops. Once useful genes
for crop improvement are identified, it
will be possible to move these genes
into elite germplasm through conven-
tional or biotechnological approaches.

LIFE BOX 3.1. GURDEV SINGH KHUSH 79
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