rt vol. 8, no. 2 scuba rice

7/31/2019 RT Vol. 8, No. 2 Scuba rice

1/5

Scuba riceby Adam BarclayStemming the tide in food-prone South Asia

Eve er 17 ds submergece i IRRI reserchs, Sub1 rice ies sh heir err ri she re si sdig he e, righ, d urherbehid IRRI hsigis abde Ismi.Ge

neHettel(2)


2/5

or cope with problem soilstried.And they succeeded. Sort of. Theycreated higher-yielding rice plantsthat could handle major oods,

but they never even got close toreleasing them to farmers. During thebreeding process, which transferredto the modern varieties whichevergenes were giving FR13A its oodtolerance, too many unwanted genesmoved across as well. The resultwas poor-tasting, ood-tolerant ricethat yielded no more than existing

varieties. And so the idea moved tothe back burner.

In 1991, Dr. Mackill left IRRIfor the University of California (UC)at Davis. With FR13A still on hismind, he and his graduate studentKenong Xu took up the challenge ofidentifying the genes responsiblefor FR13As scuba abilities. They

eventually pinpointed the precisestretch of DNA that made the varietyso interesting, and named theassumed geneSUB1.

The group subsequently teamedup with another UC Davis researcher,Pamela Ronald, an expert in isolating

SUB1A into widely grown modernrice varieties without affecting othercharacteristicssuch as high yield,good grain quality, and pest anddisease resistancethat made thevarieties popular in the rst place.

Around the same time, followinDr. Ronalds groups success inproving thatSUB1A was indeed theright gene, Julia Bailey-Serres, a

geneticist from UC Riverside who aworked on the genes identication,began investigating exactlyhowSUB1A confers ood tolerance. Itturns out that the secret is all aboutsaving energy.

With colleague Takeshi Fukao,Dr. Bailey-Serres has determinedthat, when submerged, rice without

SUB1A responds by increasing thepace of its elongation in an attemptescape the submergence. Deepwaterice varieties are able to do thisrapidly enough to succeed. In modehigh-yielding varieties, however, thelongation is insufcient. If the oolasts for more than a few days, thenormal varieties expend so much

energy tryingunsuccessfullytoescape that theyre unable to recove

Submergence of FR13A or any the new Sub1 varieties, on the otherhand, activates theSUB1A gene,which suppresses this elongationstrategy, effectively shunting the ric

DR. ISMaIl d UC Riverside scieis Jui Bie-Serres shre ugh BRRIs Rgur si.

adamb

arclay


3/5

BRRI SCIEntISt M.a. Mzid (second from right) seks kers bu he success rmer MsKms (right) fd-er rice ris. Mr. Kms eighbr, Mhmmd Shhidu Ism (left), is kee gr he e vrieies himse.

ooding, yet retain the characteristicsthat farmers want.

With the Sub1 concept well andtruly proved, seeds were sent for

testing and renement to nationalorganizations in South Asia, includingthe Bangladesh Rice ResearchInstitute (BRRI) and, in India, theCentral Rice Research Institute(CRRI) in Orissa and NarendraDev University of Agriculture andTechnology in Faizabad, UttarPradesh. The trial results there were

also extremely promising.In short, scientists had developed

rice that could handle more than aweeks ooding with almost no lossof yield (1 week is enough to severelydent the harvest of the nontolerantversions) and would recover toproduce a reasonable yield after even2 weeks submergence (enough to

almost wipe out nontolerant versions).Aside from the ood tolerance, thenew varieties were virtually identicalto their counterparts: farmers wouldbe able to manage them in exactlythe same way and, in the absence ofooding, achieve the same yield.

varieties in farmers elds. Inthis setting, there was no way ofcontrolling when ooding wouldoccur, how long it would last, orwhether it would even happen at all.

Moving forward to November

Mohammad Firoze Shah Shikdersays that successful ood-tolerantrice could substantially reduce, if noteliminate, the countrys imports.

Sub1 varieties will add to thetotal production of the country, he

adamb

arclay(5)


4/5

FollowInG a 10-Day fd, oriss rmer BidhuBhus Ru s his Sr-Sub1 recver ehie his er Gri erished. Beeriedig is beer ivig, he ss.

Two extra hectares is a big jump.So, how did the ood-tolerant

varieties fare? Twenty-three daysafter the 8 July transplanting of

the 2008 wet-season crop, the farmwas hit by a 15-day ood. When thewaters receded, Mr. Kamal witnesseda wonderful thing. In his Sub1 plots,9598% of the plants recovered. Inthe non-Sub1 plots, the gure was1012%. Many of his neighboringfarmers, who were not involvedin the trial, lost their entire crops.

So encouraged was Mr. Kamal, heplanned to give awaynot sellakilogram of ood-tolerant seeds toeach of his neighbors.

When I saw Mostafas eldooded, and then saw it recover, I wassurprisedit was like magic, recallsMr. Kamals neighbor, MohammadShahidul Islam. The annual ash

oods mean that Mr. Islam growsrice on only the upper half of his 1.6-hectare farm in the wet season. Eachyear, he needs to buy 1 to 2 monthsworth of rice to cover his familysshortfall. He believes that ood-tolerant varieties will allow him to

he says, will mean more food, higherincome, and a better livelihood.

Observing the success of theood-tolerant varieties in Bangladeshwas a watershed moment for SigridHeuer, an IRRI molecular biologist

natural ooding for 15 daysthemaximum time we thinkSUB1Ashould be able to withstandand itworking. Its really fantastic.

A short ight away in easternIndia, it is the same story. The stateof West Bengal and Orissa, alongwith Uttar Pradesh in the northeasthave all seen equally promising triaresults and plan to completely replaSwarna with Swarna-Sub1 as soonas it is ofcially released by stateseed certication agencies. In West

Bengal, Swarna dominates, with 80of the rice area already planted tothe variety. A move to Swarna-Sub1would therefore be relatively easy astands to have enormous impact.

Forget Swarna! Go for SwarnaSub1! is the advice from BasantKumar Rao, a rice farmer fromNuagaon Village near Cuttack in

Orissa. I trust Swarna-Sub1. Ill kegrowing it. I got good money for it i2007, he says.

That year, his farm was hit bytwo oods, one of 11 days and oneof 7 days. The ood-tolerant ricerecovered after both oods and,


5/530 Rice TodayApril-June 2009 Rice TodayApril-June 2009

ExamInInG trIals BrrI hedque i Gziu, K.m. Iekhuddu ( right) h bed fd ecei u Bgdehi ice viey Br11, hich ccu e h e-hid he cuye-e ig.

a patCH he u ice viey sie feed d dyig e eve dy fdig. I c, he fd-e vei,s-sub1, ebud gd heh.

IrrI molECUlar bigi sigid Heue ( center) ih he ph.D. ude n sigh (i ciei Dee schez he Chiuh rice reech si, i we Beg

After a 10-day ood, the Sub1 plantsrecovered well, while the Gayatriplants perished.

According to CRR I Director

T.K. Adhya, the release of ood-tolerant rice has become more andmore important as India has growneconomically.

People used to grow rice in morefavorable areas, where you had anassured source of water and good soilquality, he explains. Now, those

interior areas are being taken overby human habitation and industry,so farmers are forced onto marginallands in the coastal areas whereooding, salinity, and many otherproblems occur. In the past, farmers

simply had to face ooding and blametheir luck if they didnt get a harvest.

IRRI plant physiologistAbdel Ismail, who is studying the

mechanism ofSUB1As action, saysthere is a strong case for rapid releaseof the new varieties.

When you develop varieties

using marker-assisted selection, hesays, you do not change the varietymuch. Because theSUB1A gene is

very specic in its expression and

action during submergence, the Sub1varieties should not have any otherproblemssuch as susceptibilityto diseases or insectsthat theirnontolerant counterparts wouldnthave also. In the future, we expect

many new varieties to come outas products of MAS. If you have asubmergence-tolerant or salt-tolerant

variety, for example, you want it to

go to the eld as quickly as possible,where it can make a big difference.

N. Shobha Rani, principal scientistat Indias Directorate of Rice Research,

says that traditionally bred rice mustundergo testing for 3 years in all-Indiatrials, but this has been reduced to 2

years for MAS-derived varieties.

The second year of testing is2009, says Dr. Rani, so, April 2010is the earliest time the Sub1 varietiescould be recommended by the Central

Variety Release Committee fornational release. She notes, however,

that release could occur on a statebasis before then.

In fact, on 27 February 2009,only a few months after Dr. Rani

talked toRice Today, the UttarPradesh State Varietal ReleaseCommittee ofcially releasedSwarna-Sub1. Being nearly identicalapart from its ood toleranceto

Swarna, this inaugural release ofa Sub1 mega-variety occurred veryquickly: only 6 years after the rst

cross was made at IRRI.A quick release is also possible

because plants developed throughMAS are not transgenic (that is,genes of interest are transferred tothe target species or variety using

particular biotechnological toolsrather than conventional breeding).Therefore, the new Sub1 varieties are

not subject to the regulatory testingthat can delay release of transgenicproducts for several years.

The Sub1 trait also came along

with an additional bonus, a genelinked toSUB1A that turns thenormally golden color of the hull ofSwarna into a straw color. Although

the hull color is not considered animportant varietal requirement,this allows the seeds of Swarna-Sub1 to be easily distinguished

from those of Swarna. This will beuseful to maintain seed purity asseed producers start ramping up theproduction of foundation seed fordistribution to farmers.

Another success to emerge

from the Sub1 work has beenthe strengthening of nationalorganizations such as BRRI andCRRI.

In India now, MAS has a lot ofsupport from the government, saysDr. Ismail. In Bangladesh, BRRI hasits own lab for MAS, and not just for

SUB1. In the national agricultural

research and extension systems, theproject has boosted capacity throughresources and expertise, and also

through government support.BRRI researcher K.M.

Iftekharuddaula is a good example.He carried out his Ph.D. researchunder Dr. Mackills supervision atIRRI headquarters in the Philippines,

developing a ood-tolerant versionof popular Bangladeshi variety BR11,

which accounts for more than one-

third of the countrys wet-seasonplantings. After completing his thesisresearch, he returned to Bangladesh,

where he is now the BRRI breeder

responsible for rening BR11-Sub1varieties for ofcial release.

We are very much hopeful thatwell be able to release at least twovarieties from our efforts, says Mr.

Iftekharuddaula, who is also workingwith IRRI to i ncorporate diseaseresistance and salinity tolerance intoBR11-Sub1.

As Sub1 varieties are ofcial lyreleased over the next 2 years,the key will be dissemination tosmallholder farmers in ood-proneareas. IRRI is leading this initiative

through the projectStress-TolerantRice for Poor Farmers in Africaand South Asia, funded by the Bill& Melinda Gates Foundation. IRRIis also collaborating with national

organizations to test Sub1 varieties inSoutheast Asian countries, includingLaos, Thailand, Cambodia, Indonesia,

Vietnam, and the Philippines,

through a project funded by JapansMinistry of Foreign Affairs.

Dr. Ismail adds thatSUB1Aseffectiveness offers hope for research

into tolerance of other so-called abioticstresses, such as drought and salinity.

The general notion with abioticstresses used to be that it would be

very difcult to nd a single gene thatcan make much difference, he says.

This work has shown tget a single gene of grea

value. I think this has ssolving other major dif

eld, such as problem soThe story of theSU

underscores the capacitto improve peoples liveas the power inherent in

seems a long and unlikefrom experimental plotPhilippines and the labo

benches in California to

in Bangladesh.For Drs. Ronald anSerres, the chance to gelab and see the Sub1 vafarmers elds has been

experience.It was amazing to

detailed genetic and phanalysis ultimately has grand impact on people

living in pretty desperatDr. Bailey-Serres says.

Even Dr. Heuer, whwork at IRRI, is no stra

rice elds, has been movidea about the impact w

before seeing it with myshe adds. Ive learned a

power of agricultural reI think it will have a hug

Mr. Barclay is a freelanbased in Australia.Seeorg/ood-proof-rice.

Rice TodayApril-June 200930 Rice TodayApril-June 2009

adamb

arclay(4)

rt vol. 8, no. 2 scuba rice

Documents