tomato to Phytophthora infestans, 

 Routley and graduate assistant R. S. 

 Warren determined that tissue culture 

 can be effective in investigation of 

 disease resistance, but isogenic sus- 

 ceptible and resistant lines are re- 

 quired. They also developed a fast, 

 easy and reliable fluorometric method 

 for determining the activity of O- 

 diphenol oxidase, an enzyme that plays 

 a major role in disease resistance in 

 plants. 



G. M. Dunn used as genetic mate- 

 rial corn, bromegrass and legumes. 

 Using inbred lines and their crosses, 

 he and his graduate students investi- 

 gated the genetic bases of forage yield 

 and combining ability, and in a severe 

 infestation of Northern corn leaf 

 blight the effect of gene dosage on 

 resistance to the causative organism 

 Helminthosporium turcicum. Ladino 

 clover, a major pasture crop in the U.S. 

 at that time persisted poorly. Dunn, 

 RA Kilpatrick (a cooperative investi- 

 gator from the Crops Research Divi- 

 sion, U.S.D.A.) and A. E. Rich, plant 

 pathologist, studied the effects of vari- 

 ous treatments on root rot in this 

 legume, a disease known to affect re- 

 sistance, and agents that affect sur- 

 vival of clover during low temperature 

 exposure. Kilpatrick evaluated some 

 50 species of red clover for resistance 

 or susceptibility to leaf and 

 stem spot caused by Stemphylium 

 sarcinaeforme. Eight species were 

 rated resistant suggesting that breed- 

 ing for resistance to the disease should 

 be effective. 



L. C. Peirce conducted a quantita- 

 tive genetics experiment with toma- 

 toes testing whether selection pres- 

 sure was equally effective if applied to 

 high density and low density plots 

 having a mixture of genotypes. 



Haploid sporophytic plants, with 

 one instead of the usual two sets of 

 chromosomes, are relatively rare in 

 nature. But to O. M. Rogers, cytoge- 

 neticist and plant breeder, a method of 

 producing haploids quickly and 

 regularly would be of great value both 

 in breeding programs and cytological 

 research. Protein synthesis is inhibited 

 when basic dyes are administered to 

 biological systems. In one investiga- 

 tion with graduate assistant J. H. Ellis, 

 pollen nuclear division was prevented 

 in some pollen tubes with toluidine 

 blue in Vinca rosea L., in vitro. 



Still unanswered, however, was 

 whether, in vivo, pollen tubes would 

 enter the embryo sac and stimulate the 

 egg to develop into a haploid plant. 

 Later, graduate assistant J. D. Gearhart 

 and Rogers found that generative 

 nuclear division in Tradescantia 

 paludosa could be suppressed with 

 certain phenothiazine and acridine 

 derivatives. The phenothiazine dyes 

 were used because they inactivate the 

 nucleus without apparent damage to 

 the cytoplasm; the acridine dyes be- 

 cause they can produce mutations. 



E. M. Meader had been a Station 

 plant breeder for 1 8 years at the time of 

 his retirement in 1966. During this 

 time he had bred, or contributed to the 

 breeding of, nearly one-half of the some 

 100 varieties of fruits and vegetables 

 introduced by the Station over a 40- 

 year period — an exceptional accom- 

 plishment. He had developed variet- 

 ies of fruits and vegetables adapted to 

 cool, short seasons and cold winters, 

 including 'Reliance' (a hardy peach), 

 'Fall Red' and 'Fall Gold' (everbearing 

 raspberries], 'Royalty' (purple podded 

 bean with resistance to Mexican bean 

 beetle), two varieties of peppers, the 

 'Meader' blueberry and 'Meader' per- 



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