Growth Analysis of Tall Fescue Genotypes Differing in Yield and Leaf Photosynthesis

1 976 Annual Meetings AMERICAN SOCIETY OF AGRONOMY CROP SCIENCE SOCIETY OF AMERICA SOIL SCIENCE SOCIETY OF AMERICA Houston, Texas November 28-December 3,1976 Crop Science Divisions Growth Analysis of T a l l Fescue Genotypes D i f f e r i n g i n Yield and Leaf Photosvntheses. W. W. Wilhelm* and C. J. Nelson, Univ. of Missouri. Leaf growth, d r y mat ter d i s t r i b u t i o n , and carbohydrate content of four t a l l fescue (Festuca arundinacea Schreb.) genotypes s e l e c t e d f o r high and low n e t C02 exchange (NCE) and forage y i e l d were s tud ied i n con t ro l l ed environments t o eva lua te t h e l e a f NCE-yield re la t ionsh ip . High y i e l d genotypes produced g r e a t e r amounts o f a l l p l a n t p a r t s and carbohydrate than t h e low y i e l d genotypes. Within each y i e l d l e v e l t h e high NCE genotypes produced more d ry mat ter and carbohxdrate. Leaf growth of a l l g e n o t y p e s ~ s l i n e a r throughout l i g h t and d a r k q e r i o d s , bu t r a t e s were 50% g r e a t e r f o r high y i e l d genotypBB.RGR was s i m i l a r f o r a l l genotypes. NAR and RLaGR were g r e a t e r f o r high y i e l d genotypes while LAR was g r e a t e r f o r low y i e l d genotypes. Yield r e l a t e d f a c t o r s such as dry mat ter d i s t r i b u t i o n and l e a f growth tended t o overcome NCE differences .