Pollination and life history studies of lettuce (Lactuca sativa L.)
AuthorH. A. Jones
Author AffiliationsH. A. Jones was Associate Professor of Truck Crops and Plant Breeder in the Experiment Station.
Hilgardia 2(13):425-479. DOI:10.3733/hilg.v02n13p425. April 1927.
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The lettuce crop is a very important one in California, and the product is shipped in considerable quantity throughout most of the year. The production of lettuce seed is also an important industry. While the variety New York is the only one produced for shipping fresh, almost all of the important varieties are grown for seed. The growing of lettuce for seed is confined almost entirely to the delta lands of the Sacramento and San Joaquin rivers and to the Santa Clara Valley. Wherever a large number of varieties are grown in close proximity, there arises constantly the question of the danger of cross pollination. Pollination investigations reported herein were initiated because of this question. The morphological studies reported in this paper were commenced to furnish information needed in order to prosecute more successfully other lines of investigation that have been started on lettuce.
Material and Methods
The lettuce seed used for growing the material for the morphological studies herein reported, was planted at the University Farm, Davis, California, in December, 1923. The variety employed was Iceberg. The material for study was killed in formalin-alcohol solution, then dehydrated and embedded in paraffin according to the usual procedure. Most of the sections were stained in Delafield’s haematoxylin, or safranin and gential violet.
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