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AARON IN DK AY 
N-22105 
Colchicine is used in studying the effects of chromosome doubling on plant growth and seed set. Here, a geneticist 
examines colchicine-induced tetraploid Pensacola bahiagrass (2n=40 chromosomes) at Tifton, Ga. 
Pensacola bahiagrass (2n=20 chromosomes). 
ae 
BN—29509 
Microscopic examination of embryo sac development is 
essential in studying reproduction of grasses and 
legumes. Normal sexual embryo sacs may be sup- 
planted in later stages of development by asexual cells. 
6 
Left, Diploid 
@ Locating sources of male sterility and incompati- 
bility mechanisms. 
@ Measuring inbreeding depression and _ hybrid 
vigor. 
Cytogenetic Research 
Cytogenetics is the study of heredity at the cellular 
level—the chromosomes, cytoplasm, and associated ele- 
ments. Cytogenetic information is used to plan and 
interpret experiments in genetics, breeding, and hy- 
bridization. Without this information, time and effort 
in breeding work can be wasted. Conversely, cyto- 
genetic research can lead to major breakthroughs in 
improving grasses and legumes. Examples of contri- 
butions from cytonegentic research are: Verification 
of asexual seed-set in some grasses; doubling chromo- 
some number to improve success in wide crosses among 
species; and development of information on expected 
segregation ratios within progenies. 
