IV.11. Current activity at the Barley Genetic Stock Center at Colorado State University.
T. Tsuchiya, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80521, U.S.A.
1. Collection and distribution of genetic and aneuploid stocks.
Numbers of genetic and trisomic stocks collected and distributed in 1969, 1970, and 1971 were reported in BGN, Volume 2 (p. 147-152). In 1972, 54 genetic stocks were received from three countries, and 133 stocks were sent out to nine countries. No trisomic or other aneuploids have been obtained in 1972, while 41 trisomic lines were sent out to eight geneticists of seven countries. This is summarized in Table 1.
The shipping procedures are summarized as follows:
Most of the stocks for mapped or chromosome-associated genes and commonly used stocks are prepared in a small package and are always ready for shipping. For other materials seeds are prepared as requested.
Seeds are enclosed in a small coin envelope with necessary information on it. Then these packed materials are placed in a 22 cm x 12 cm insulated envelope which is specially suited for shipping them. A list of the seed stocks is also enclosed. Most of the stocks are sent out by airmail -- a few exceptions are local shipments.
2. Procedure for growing and record taking for genetic and aneuploid stocks.
A. Genetic Stocks
In the Genetic Stock Center about 2,000 stocks are maintained. Starting in 1970, 200 to 300 stocks were grown in pots in the greenhouse for detailed record taking. Since many quantitative traits vary according to growing conditions, only qualitative characters were observed and recorded in detail. For most of the so-called lethal chlorophyll mutants, homozygotes were planted in pots or flats to see if any of them were viable. Some of them have been found to be viable, such as orange seedling (or), zebra stripe Colorado (zbc), light green 3 (lg 3), and a few others.
Based on records, the stocks lacking particular genetic traits useful in genetic and linkage studies are dropped from the Stock Center and kept in the National Seed Storage Laboratory (NSSL) in Fort Collins. In this way the number of stocks at the Genetic Stock Center is reduced so that more new stocks such as the mutants collected in Gatersleben in East Germany and other institutions will be collected and added to our Center.
In 1972, 370 stocks were grown in the greenhouse; 80 old stocks, 119 newly introduced stocks, and 171 experimental stocks. For most of the chlorophyll lethal mutants, the new technique proposed in 1971 (Tsuchiya, 1972, BGN 2:120-121) has been used to detect heterozygous plants during their growing period. Thus, all normal green homozygous plants were discarded and heterozygotes were harvested in bulk.
Newly introduced stocks have been grown and characteristics have been observed and recorded. Special attention was paid to the Swedish mutants. The results of the study with these Swedish mutants will be reported in the near future. The Swedish mutant stocks having similar traits to previously established marker stocks were inter-crossed to find their allelic relationships.
B. Aneuploid stocks.
Root tips are collected from young seedlings germinated in germinating
boxes. Seedlings are planted in peat pots in sequential order with which
the root tips are collected. Chromosome numbers are counted using the simple
acetocarmine squash technique (Tsuchiya, 1971, BGN 1:71-72). Trisomic and
other aneuploids are planted in 5 or 6-inch pots individually. Five to
ten trisomic and two diploid plants are grown for each trisomic or other
aneuploid line. In 1972, the following aneuploid stocks were grown:
a. Seven primary trisomics in Shin Ebisu 16
b. Seven telotrisomic lines
c. Two acrocentric stocks (Acro 3A and Acro 4A)
d. A stock for small meta 3A (Pseudoiso 3A)
e. A small telocentric line derived from the Acro 4A stock
f. The original pericentric inversion stock (chromosome 6) and its
derivative types with various karyotypes (a total of 5 stocks)
g. Several trisomics in Betzes.
Telotrisomic strains for Telo 1S, 3L, and 5L have been crossed two or three times with a normal diploid of SE 16 to establish all telotrisomic stocks in the SE 16 background. Also, most of the telotrisomic stocks have been crossed two or three times with Bonus diploids to introduce all telocentric chromosomes into Bonus background. These stocks with Bonus background will be used to locate erectoides genes on a particular arm of respective chromosomes. The telotrisomic stocks in SE 16 background will be used for comparative study of the effect of the extra telocentric chromosome upon morphology, fertility, and breeding behavior.
3. Attempt to establish multiple marker stocks.
Linkage data so far obtained are generally fragmental and very little
has been obtained from designed experiments using multiple marker stocks.
Now, however, we have a considerable number of genes located on the maps, and centromere position in relation to the marker genes is gradually being established by cytogenetic analysis. Therefore, it is now time to start a systematic attempt to develop multiple marker stocks for each arm. It is preferable to develop these multiple stocks in spring type background.
There are some double or multiple marker stocks available.
