Biomass — 19 — Bud-sport 



Block Mutation. — A term used to denote a change in, or the 

 omission of, a group of adjacent genes (Chittenden). 



Blood-line. — Pedigree; relationship; family. 



Bottom Recessive. — An individual homozygous for the re- 

 cessive alleles of all the genes under investigation. 



Bouquet Stage. — The zygotene and pachytene stages in or- 

 ganisms in w^hich a polarization of the chromosomes, with 

 their centromeres towards one side of the nucleus, occurs dur- 

 ing the prophase of meiosis. 



Brachymeiosis. — A modified form of meiosis in which no 

 second division occurs. 



Bracteody. — The replacement of the floral whorls by bracts. 



Bradyauxesis. — A growth relationship in which the growth 

 of a part of an individual is slower than that of the body as 

 a whole. 



Brady telic. — Evolving considerably slower than the modal 

 rate. cf. Horotelic and Tachytelic. 



Branched Chromosome. — See Chromosomes. 



"Breakage First" Hypothesis. — The theory that chromo- 

 somes can suffer fragmentation after which the fragments may 

 either remain loose, or become reattached to restore the original 

 gene arrangement, or may unite with other fragments to 

 form new aggregates (cf. Dobzhansky, 1941). 



Breed. — A group of individuals having a common origin and 

 possessing certain distinguishing characteristics not common 

 to other members of the same species (Winters). 



Breeding. — The science, or art, of improving or changing 

 plants or animals. 



Breeding, 'Family' Method of. — In this system each female 

 is mated to a single male and her offspring recorded. 



Breeding, Sib Method of. — See Breeding, 'Family' Method 

 of. 



Brephic. — Pertaining to primitive or larval growth. 



Brochonema. — The looped spireme thread in mitosis or 

 meiosis. 



Brood. — A number of offspring from a single birth or from 

 a single clutch of eggs. 



Brusque Variation. — A sudden, heritable deviation from 

 type; mutation. 



Budding. — A form of grafting in which the scion consists 

 of a bud which is inserted under the bark of the stock. 



Bud Mutation. — Bud-sport, q.v. 



Bud-sport. — a somatic mutation or variation arising in a 

 bud and producing an abnormal branch. 



WOODS 



HOLE, 



MASS. 



