Rooting cuttings under mist: Leafy softwood cuttings of paradox walnut hybrids rooted successfully in mist propagation tests during summer of 1956
H. T. Hartmann
Authors AffiliationsCurtis Lyn was Graduate Student and Laboratory Assistant in Pomology, University of California, Davis, when this study was made; H. T. Hartmann is Associate Professor of Pomology, University of California, Davis.
Hilgardia 11(5):11-15. DOI:10.3733/ca.v011n05p11. May 1957.
The paradox walnut hybrid—Juglans hindsii x J. regia—is very much in demand by California walnut growers as a rootstock for English walnut varieties due to its vigor and its resistance to crown rot—Phytophthora cactorum—tolerance of excess water, and apparent potential resistance to root lesion nematodes—Pratylenchus vulnus. Such hybrid seedlings are ordinarily obtained from nuts taken from Northern California black walnut—J. hindsii—trees growing in the vicinity of English walnut—J. regia—trees. Since the individual seedlings vary considerably in their vigor and in their resistance to various diseases and nematodes, it would be very desirable to be able to propagate such rootstock trees vegetatively from outstanding selected hybrid parent trees. However, cuttings of these hybrids have been extremely difficult to root and at present vegetative propagation is limited almost entirely to trench layering.
Also in this issue:Frozen strawberries: Study indicates efficiency of mechanical crate dumping in most processing plants
Strawberry fertilizer trial: Tests in new strawberry planting on old potassium deficient apricot land indicated no response to potash or phosphate
Cantaloupe crown blight study: Observations reveal disease to be severe on all commercial varieties of spring harvested cantaloupes in desert regions
Lettuce root aphid: Value of a preplanting soil treatment with parathion proven by tests in 1956
Gibberellin on flower crops: Studies made of response of some commercially grown flowers to applications of plant growth regulating chemical compound
Walnut aphid control: Comparative study of control treatments made during heavy infestations in 1956
Improved pastures: Both sheep production and forage yield increased by range improvement
Swine feeding tests: Supplemented cooked garbage tested in feeding trials in Los Angeles County
The development of resistance to hydrocyanic acid in certain scale insects
The stupefaction of red scale, Aonidiella aurantii, by hydrocyanic acid