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ON FORMS OF THE HOP HUMULUS LUPULUS L. RESISTANT TO MILDEW SPHAEROTHECA HUMULI (DC.)BURR.)V 1
Author(s) -
SALMON E. S.
Publication year - 1921
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1921.tb05542.x
Subject(s) - humulus lupulus , biology , hop (telecommunications) , powdery mildew , sphaerotheca , seedling , greenhouse , horticulture , botany , computer network , pepper , computer science
SUMMARY1 The “wild hop” ( Humulus Lupulus L.) is composed of a number of forms 1 which show distinctive physiological, or “constitutional,” characters, as measured by the grade of susceptibility to the attack of the mildew Sphaerotheca Humuli. These characters vary from extreme susceptibility, shown both in the open and under greenhouse conditions, to a high degree of resistance in the open and complete immunity in the greenhouse. Of 291 ♀ seedlings, 165 seedlings, or 56.70 per cent., show extreme susceptibility, while 18 seedlings, or 6.19 per cent., are “commercially resistant” in the open. The remaining seedlings fall into groups representing intermediate grades of susceptibility. 2 Of 480 seedlings, ♂ and ♀, 27 seedlings, or 5.63 per cent., are completely immune—and 7 seedlings, or 1.46 per cent., semi‐immune—under greenhouse conditions. 3 The majority of the seedlings which show complete immunity under greenhouse conditions show a high degree of resistance in the open. 4 The distinctive degree of susceptibility possessed by a seedling, both as shown in the open and under greenhouse conditions, has shown no change after the plant has been cultivated for five years in a manured hop‐garden.