xvi CONTENTS 



CHAPTER XXIII 

 BUD SELECTION 



PAGE 



Introductory 385 



Efficacy and practicability of bud selection . r 385 



Bud variation in plants 385 



Bud selection in Coleus 386 



Bud selection in horticultural practice 391 



Performance records as a basis for bud selection 391 



Bud mutations in Citrus 392 



Deciduous tree fruits 393 



"Pedigreed" nursery stock 394 



Bud selection in the potato 394 



Certified seed potatoes 397 



Other crops in which bud selection may apply 398 



Limitations of bud selection 399 



CHAPTER XXIV 

 BREEDING DISEASE RESISTANT PLANTS 



Introductory 400 



The causes of plant diseases 400 



The nature of disease resistance in plants 401 



Disease resistance in natural species 401 



Phylloxera-resistant grapes 402 



Endothia-resistant chestnuts 405 



Blight-resistant pears 407 



Breeding disease resistant varieties by hybridization 408 



Creating rust-resistant wheats 411 



Inheritance of disease resistance in other plants 413 



Breeding disease resistant plants by selection 416 



CHAPTER XXV 

 PLANT BREEDING METHODS 



Introductory 419 



Need of systematic methods 419 



Pedigree culture 419 



The Svalof system 425 



Variety tests purposes; difficulties involved 427 



Establishing varietal types 427 



Determining best varieties for given locations 428 



Strain tests purpose; difficulties involved 432 



Plant-to-row tests 433 



Factors that affect experimental results 433 



CHAPTER XXVI 



GENERAL CONSIDERATIONS AND CONCLUSIONS 

 Introductory 437 



