A Glossary for Crop Improvement Compiled by T. Nagur, D.L. Oswalt, and Faujdar Singh Skill Development Series no. 1 ICRISAT Human Resource Development Program International Crops Research Institute for the Semi-Arid Tropics Patancheru, Andhra Pradesh 502 324, India 1991 A Glossary for Crop Improvement Compiled by T. Nagur, D. L. Oswalt, and Faujdar Singh Skill Development Series no. 1 Human Resource Development Program International Crops Rasearch Institute for the Semi Arid Tropica Patancheru, Andhra Pradesh 502 324, India 1991 H u m a n R e s o u r c e D e v e l o p m e n t P r o g r a m P u b l i c a t i o n s i n t h i s S k i l l D e v e l o p m e n t S e r i e s (SDS) a r e i s s u e d s e m i f o r m a l l y f o r l i m i t e d d i s t r i b u t i o n t o p r o g r a m p a r t i c i p a n t s , c o l l e a g u e s , a n d c o l l a b o r a t o r s . C o p i e s m a y b e r e q u e s t e d b y t h e S D S n u m b e r . C o n s t r u c t i v e c r i t i c i s m f r o m r e a d e r s i s w e l c o m e d b y : Program Leader, Human Resource Development Program, IC R I S A T . Acknowledgements R e f e r e n c e m a t e r i a l s c o n s u l t e d i n c o m p i l a t i o n i n c l u d e : A l l a r d , R . W . 1 9 6 0 . P r i n c i p l e s o f p l a n t b r e e d i n g . N e w Y o r k , U S A : J o h n W i l e y . 4 8 5 p p . D u t t a , A . C . 1 9 8 9 . B o t a n y f o r d e g r e e s t u d e n t s . C a l c u t t a , I n d i a : O x f o r d U n i v e r s i t y P r e s s . 9 0 9 p p . G a r d n e r , E . J . , a n d S n u s t a d , D . P . 1 9 8 4 . P r i n c i p l e s o f g e n e t - i c s . 7 t h e d . N e w Y o r k , U S A : J o h n W i l e y . 5 8 0 p p . P o e h l m a n , J.M., a n d B o r t h a k u r , D . 1 9 6 9 . B r e e d i n g A s i a n f i e l d c r o p s . N e w D e l h i , I n d i a : O x f o r d a n d I B H P u b l i s h i n g C o . 3 8 5 p p . R a w a l , K . M . , a n d W o o d , M . N . 1 9 8 3 . C r o p b r e e d i n g . M a d i s o n , W i s c o n s i n , U S A : A m e r i c a n S o c i e t y o f A g r o n o m y a n d C r o p S c i e n c e S o c i e t y . 2 9 4 p p . R i e g e r , R., M i c h a e l i s , A . , a n d G r e e n , M . M . 1 9 6 8 . A g l o s s a r y o f g e n e t i c a n d c y t o g e n e t i c s , c l a s s i c a l a n d m o l e c u l a r . N e w Y o r k , U S A : S p r i n g e r - V e r l a g . 5 0 7 p p . S i n g h , B . D . 1 9 8 3 . P l a n t b r e e d i n g p r i n c i p l e s a n d m e t h o d s . L u d h i a n a , I n d i a : K a l y a n i P u b l i s h e r s . 5 1 6 p p . S n e e p , J., a n d H e n d r i k s e n , A . J . T . ( e d s . ) , a n d H o b e k , O . ( c o e d . ) 1979. Plant breeding perspectives. Wageningen, the Netherlands: Center for Agricultural Publishing and D o c u m e n t a t i o n . 4 3 5 p p . S o m a n i , L . L . , a n d T i k k a , S . B . S . 1 9 8 3 . D i c t i o n a r y o f a g r i c u l t u r e . N e w D e l h i , I n d i a : A g r i c o l e P u b l i s h i n g A c a d e m y . 4 7 6 p p . W e g r a t e f u l l y a c k n o w l e d g e t h e c o n t r i b u t i o n s m a d e b y s c i e n t i s t s , I n f o r m a t i o n S e r v i c e s s t a f f , a n d s e c r e t a r i a l s t a f f o f I C R I S A T . CONTENTS P a g e Adaptation 4 B o t a n y 1 6 G e n e t i c s 1 0 B r e e d i n g m e t h o d s 2 1 Biochemistry 3 2 E n t o m o l o g y a n d p a t h o l o g y 3 3 ADAPTATION acclimatization: the adaptation of an individual to a changed climat e or the adjustment of a species or a population to a changed environment over a number of generations. adaptation: the process by which individuals, populations, or species change in form or function in such a way that they may survive under given environmental conditio n s . a u x i n : a plant hormone that promotes cell elongation, fruit initiation, callus production, and other plant functions. biological yield: the total biomass of the plant. b i o m a s s : the mass of the plant measured by including the roots. bud blasting: suppression of the development of a flower beyond the stage in which the corolla emerges. competition: the mutually exclusive use of the same limited resources by two or more organisms. e c o t y p e : a race (within a species) genetically adapted to a certain environment. environment: the sum of the external conditions that affect grow t h and development of an organism. etiolation: abnormally long internodes and 3mall yellowish leaves caused in plants that grow where light has been reduced. h a b i t a t : the natural abode of an organism. harvest index: ratio of economic yield to biological yield. (Ratio of dry matter in the grain to the above-ground dry mat t e r in the plant). leaf area index: the area of leaf per unit area of ground. photoperiod: relative length of time a plant is exposed to light (influence of uninterrupted period of darkness): affects the life cycle and physiological process of the plant. photoperiodism: the response of organisms to varying periods of darkness. In plants, for example, the photoperiod controls the flowering of light-sensitive genotypes .