150 SEED PRODUCTION IN PASTURE AND FORAGE CROPS

150
SEED PRODUCTION IN PASTURE AND
CROPS
FORAGE
Abdelmounim(I.C.A.R.D.A.)
The im_pactof any breedingprogram on.agricultureis fully realized
only when farmers decideto replacean old veriety with a new one. This is
possibleonly if the breederis ableto maintainthe geneticintegrityof a new
variety and if the seedis produced and distributed in commercialscale.
The maintenanceof genetic integrity of a new variety is important
becauseit is the base of of certification procedure, and certification is
important becauseit is the only guaranteeof the nameand geneticqualities
of a new variety.
The processby which the small amount of breeder'sseedis multiplied
into tons of certifiedseeds,requiresthe solutionof both geneticand agronomic problems,which are different in specieshaving different utilization,
propagatedspecies
and system matings e.g. vagetalivel-"self-pollinated
speciesand cross-pollinated
species.
It is alsoimportant to mentionthat foragecropsare bred and growm
for high dry matterin contrastwith other crops(cereals,Iegumes)in which
seedproductionis omportant.
PasturesForages,and LivestockImprovementProgramat ICARDA
is concernedmainly with annual forageswhich are annuallyresowncrops
i.e., foragevetches"Vicia spp" and foragepeas"Pisum sativum,and
pastureswhich are self-regenerating
communitiesusedmainly for grazing,
spp.
Therofore,I will focus on the prosuchas arlnualmedics,Medicaqo
cessof seedproduction of thesecrops, and the constrainsof producing
certifiedseedsin the ICARDA region.
With respectto annualforages(vetchesand peas)the maintenanceof
geneticintegrityof thesespectesmust rely upon a carefulmaintenance
selection.
fhe agronomicpracticesfor seedproductionin annualforages,often
differ greaily when fhe crop is usedfor forageproduction.For example,
Low piantingrate has beenshownto increaseseedproductionover dense
planting.
SEED PROIJUCTION IN t'ASILRL
, A ' N DI - O R A C E C R O P S
151
Most of forage vetch varietiesare characterizedby podshatteringsat
maturity causingà great loss of seed,therefore breedersshould look for
non-shatteringvarietiesto avoid of seed.
Harvesting also is one of the most critical atebsin foragesand seed
production,delayedor early harvestcausessomeproblems'as shattering
ànd reducingthe viability. Seedlossesdue to shatteringmay be prevented
by selectionfor high seedretention capacity.
Weedcontrol alsois essentialfor the growth of stonghelthyplants.In
weedsnon only competewith the sown_formoisa seedcrop establishment
but
becauseof the presenceof weeds.Thus effilight
and
ture, nutrients
cieni weedcontrol with the selectionof fields relativelyfree of weedsis
to producegood seeds.
necessary
Annual Medics :
At presentthereis no production of medic seedin the R Région. If the
annualpasturesystemis to be adoptedit is most important that development of seedindustriescommencein the nearfuture. the technologyis new
to the Region and differs grealty from that used to produce cereal, food
legumeor even forage legumeseed.
The important differenceis that in selectingmedicsthe breederselects
for self-regéneration,which means that the criteria important for seed
production - non shatteringseedsand pods, non dormantseeds- are
ielectedagainst.For exampleit is important that medic pods fall to the
Thisground, pieferablybeneaththe surfaceif they are to self regenerate.
presentsspecialproblems for the seedproducer'
In order to overcometheseproblemsa specialseedharvesterhasbeen
developed.This machineactslikê a giantvacuumcleanerand suksthe seed
from tire surfaceof the soil. For the machineto work the soil surfacemust
be leveledplant residuesmust be removed,and the soil surfaceloosened.
The machinewill alsoharvesta largeamountof fine and coarsesoil particles,which must be removedfrom the seed.The machineis producedin
Australia by Horwood - Baqshawand is calleda cleaverharvester.
Most medicseeds,whenharvestedare dormant,and must be scarified
(the seedcoat is impermeableto water and must be physicallydomaged
This often takesplaceduringthe thresùeforethe seedwill germinante).
hing process,but to makesurethat it hasgerminationtestsneedti be carried out duringthe certificationprocess.
of genetic
The problemsof producingmedicseed- the maintenance
of orther
those
to
similar
are
diseases
weeds
and
from
purity, frèedom
crops.
152
Résumdde I'exposéde Monsieur Ali Abdelmoneim
de I'ICARDA
,!l
Le programmede I'ICARDA sur les fourrages,Iesprairieset l,élevage
est concernéessentiellementpar des fourrages-annuelsqui sont resemés
annuellement(Pois et vesces)et des espècesprairialesautorégénératrièes
tellesque les espèces
annuellesdu genretutiaiôugo.
,En g. qui concern€les vesceset les pois fourragers, le maintien de
I'intégritégénétiquedoit reposersur la seléctionconr.îuutîi"., iË, techniquescllturales pour la production de semences
différent très sensiblement
de.-celles
utilliséespour Ia production de matièreverte. par exemple,une
faible dosede semis'estrévéléeplus adéquatequ'une aoseeteuge.
La plupart desvariétésde vescesont caractérisées
par la déhissence
des
goussesà la mâturité, entrainantde grossespertesde semences.
Aussi les
améliorateur'sdevront rechercherdes variétéi non déhissentes.La récolte
est aussiune desétapesles plus critiquesdansla productiondessemences
fourragères.une récolteprécoceou-tardive cauient certainsproblèmes,
comme la déhissence
et la perte de viabilité. Le contrôle des^mauvaises
herbesest essentielpour la croissance
de plantessaineset vigoureuses.
Pour ce qui est des espècesannuellesdu genre Medicago,il n'y a
actuellementaucuneproduction de semencedans la région d;Airique'du
Nord et du Proche-orient.Si le systèmedesprairiesarinuellesest âdapré
dansla région,il esttrèsimportant que I'indusiriedessemen..,.o--"n..
dansle procheavenir..La.technologie
estnouvellepour la régionet diffère
beaucoupde cellesutiliseespour les céréaleset lés légumin-eures
"t'r-àntaires.et fgurragesclassiques.La différenceimportait. est qu. dans la
sélectiondu Medicago,I'autorégénération
est le critère le plus décisif,ce
qui veut dire que lescritèresimportantspour la productionàe sem"rrc.,en
gén&al
- non déhissence
et non dormance- ne sont pasrecherchés
pour le
Medicago.
une récolteusespécialea été développéepour le Medicago.Elle est produite en Australiepar la sociétéHarwood-Baqshaw.
EllJagit commeun
aspirateurgéantqui aspirelesgousses
de la surfacedu sol. Èour quecette
machinetravaille,il faut que le sol soit bien niveléet lesrésidusËnlevés.