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Fall Regrowth Response of Ranger and Vernal Alfalfa as Related to Generations of Increase and Area of Seed Production 1
Author(s) -
Bula R. J.,
Garrison C. S.
Publication year - 1962
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1962.0011183x000200020023x
Subject(s) - crop , library science , division (mathematics) , crop production , agricultural science , biology , geography , agronomy , mathematics , agriculture , computer science , archaeology , arithmetic
t HE benefits of a plant breeding program are not real-*• ized until seed of the new and improved variety is available in quantities large enough to satisfy the total farmer demand. It is equally important that seed supplies of a newly released variety be built up as rapidly as possible in order that the consuming farmer can take advantage of the superior variety shortly after it is released by the plant breeder. In an attempt to accomplish this, the production of foundation, registered, and certified seed of superior grass and legume varieties has migrated to the most efficient seed producing areas. The new seed areas are located primarily in the western United States. They represent a vastly different plant environment for alfalfa varieties adapted to the northern half of the humid areas. Yet, seed that the consuming farmer obtains should be essentially the same in genetic make-up as that released by the plant breeder. In a seed increase system of the magnitude necessary for adequate alfalfa seed supplies, there is always the possibility of shifts in gene frequencies for certain characteristics during the seed production sequence which, if multiplied, may result in the loss of superior varietal performance. Reports by Smith (4) and Smith and Graber (7) have shown that measurable changes in plant types and winter hardiness occurred when Ranger was increased in southern latitudes. Subsequently, Smith (6) has shown that the proportion of plant types and level of winter hardiness of Vernal could be increased or decreased depending upon whether the seed was produced north or south of the variety's area of adaptation. Laude et al. (3) have described differences in the flowering response of the parental clones of Pilgrim Ladino clover of sufficient magnitude as to affect materially the performance of composition of the subsequent seed increases. It seemed desirable, therefore, that seed lots of breeder, foundation, registered, and certified Ranger and Vernal be further evaluated in an attempt to determine the magnitude of change in these varieties and whether these varietal