RA 00048.pdf - OAR@ICRISAT

taxa retain variation that w a s lost in grain
s o r g h u m during t h e process of d o m e s t i c a ­
tion.
3.3 S o r g h u m descriptors w e r e standardized
during t h e 1970s, and facilitate w o r l d w i d e
c o m m u n i c a t i o n a m o n g breeders and keepers
of g e r m p l a s m . This d o e s not m e a n that
descriptor lists may not be revised. N e w
information f r o m breeders and other scientists
w o r k i n g w i t h collections m u s t c o n ­
tinuously be added to t h e data bank. For
future collections a greater effort m u s t be
m a d e to record m o r e information at t h e
t i m e of collecting. Traditional farmers are
experienced plant breeders, a n d usually can
provide important information on adaptation
to soil and climate, disease and pest resistance,
uses, and t h e nutritive value of t h e
cultivars that they g r o w . Such information is
of vital importance in g e r m p l a s m banks.
Efforts to c o m p u t e r i z e all g e r m p l a s m data
m u s t continue. Computer-assisted retrieval
s y s t e m s are prerequisites for t h e efficient
operation of genetic resources units.
3.4 The value of t h e s o r g h u m g e n e bank can be
fully realized only w h e n collections and
selected g e n o t y p e s are available in packages
useful to breeders. Collections m u s t
be screened for agronomically useful traits,
w h e r e v e r possible in collaboration w i t h
b r e e d e r s , e n t o m o l o g i s t s , p a t h o l o g i s t s ,
physiologists a n d other interested scientists,
as s o o n as possible after t h e y enter
g e n e banks. G e n o t y p e s of significance
m u s t c o n t i n u o u s l y b e sorted out, and
preserved separately f r o m t h e parent collection.
T h e n e e d is also g o i n g to increase
for pools o f g e n o t y p e s a n d collections w i t h
k n o w n resistance t o disease and insects,
d r o u g h t tolerance, exceptional grain qualities,
high yield under diverse e n v i r o n m e n ­
tal conditions, a n d adaptation to specific
g e o g r a p h i c a n d climatic regions. Such
p o p u l a t i o n s c a n s e r v e a s i m m e d i a t e
s o u r c e s of desirable g e n e c o m p l e x e s in
b r e e d i n g projects.
3.5 Conversion projects m u s t be expanded and
accelerated. Tropical lines c o n v e r t e d for
u s e in t h e t e m p e r a t e zone m u s t be incorporated
in g e n e banks for use in t h e tropics.
Selected g e n o t y p e s m u s t also be incorporated
into conventional African and Indian
breeding lines, and the significance of w i l d
g e r m p l a s m in breeding projects m u s t be
explored.
3.6 M e c h a n i s m s for t h e efficient e x c h a n g e of
g e r m p l a s m m u s t be established. It is
essential that outstanding collections be
evaluated and maintained in regional locations
in Africa, the Americas, and at ICRI-
SAT. This will encourage w i d e r use of this
g e r m p l a s m across a broad area of s o r g h u m
cultivation. It will also provide an added
d e g r e e of safety to t h e conservation of
valuable g e r m p l a s m .
3.7 ICRISAT m u s t be c o m m e n d e d for its foresight
in the 1970s in establishing a genetic
resources unit. This, in our v i e w , w a s an
essential step to ensure t h e timely collection,
conservation, and utilization of t h e
rapidly vanishing s o r g h u m g e r m p l a s m . The
current efforts and activities of this unit are
exceptional. W i t h imaginative use of the
a s s e m b l e d a n d still-to-be-collected g e r m ­
plasm, s o r g h u m i m p r o v e m e n t during t h e
1980s will be enhanced.
4. Genetics and Breeding
4.1 D e v e l o p m e n t of superior varieties and hybrids
has occurred over a long period of
t i m e . Interest is increasing to help subsistence
farmers living in harsh environmental
conditions. The contribution of resistance
traits and heterosis to stability is important,
particularly to subsistence farmers, a n d
continues to need further evaluation and
application.
4.2 The g e r m p l a s m base in m o s t traditional
f a r m i n g areas is quite narrow, restricting
gains f r o m selection. The usefulness of
introduction as a m e a n s of g e r m p l a s m
diversification is w i d e l y recognized. The
contribution of local varieties to adaptation
is also recognized. Crossing b e t w e e n local
varieties and selected high-yielding introductions
is a valuable approach to developing
well-adapted varieties and hybrids that
respond to m a n a g e m e n t inputs. It should
be recognized that useful varieties and
hybrids d e v e l o p e d f r o m introduced m a t e ­
rials m a y also contribute to high yield and
stability. This approach has been and should
be further exploited.
4 . 3 Traditional breeding m e t h o d s and popula-
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