The relative freezing resistance of tissues in the stem, foliage and buds of terminal twigs from Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) was investigated at about ten-day intervals from summer until the following spring. Tissues from growing twigs collected before development of dormancy had no freezing resistance and were killed immediately...
Setaria lutescens (yellow foxtail) plants, grown from five seed
sources were compared in California. Seed sources were: Connecticut,
Iowa, Massachusetts, Pennsylvania and California. Morphological
and physiological differences between biotypes include: plant
size, growth habit, time required to mature and reproductive capa
city. Most significant is the prostrate habit of the...
Rapid tiller and root production can improve seedling survival and
benefit stand establishment of perennial ryegrass (Lolium perenne L.)
in commercial seed fields. Environmental conditions after establishment
and inherent morphological factors combine to reduce the commercially
harvested yield below the theoretical potential yield.
These studies were conducted to determine if...
Populations of Douglas-fir seedlings from interior British
Columbia, Vancouver Island, and Arizona received six bi-weekly
foliar spray applications of the growth regulators IAA, CCC, and
B-995, each at three concentration levels under controlled environmental
conditions. Large differences were found among the three
populations in their responses to the growth regulators....
Seed moisture is a primary factor influencing seed quality during harvesting, storage, and marketing of grass seed. However, the Association of Official Seed Analysts' Rules for Testing Seeds do not contain methods for moisture testing. The oven methods in use by seed testing laboratories in the U.S. are diverse and...
Studies were conducted to determine the extent and nature of
sub-lethal effects of herbicides on plant growth. At least one
herbicide from each major chemical class of herbicides was evaluated
under greenhouse conditions. Oat plants were grown in sand
culture to eliminate soil interferences. Herbicides were applied
pre-emergence in nutrient...
Investigations were made in the field, greenhouse, growth
chamber, and laboratory to: (a) observe the general activity of N-
(phosphonomethyl)glycine (glyphosate); (b) determine the extent of its
interaction with certain s-triazine herbicides; and (c) find an explanation
for such an interaction.
Greenhouse and growth chamber studies substantiated other
observations that...
After nearly 20 years of commercial use in orchards without
apparent tree injury in Oregon and Washington, 2,4-D [(2,4-dichlorophenoxy)
acetic acid] was reported in 1970 to cause injury to apple
and pear trees in Washington. In the early 1970's, there was widespread
concern among growers, researchers, and processors in the...