II.18 Efficiency of barley haploid production.
K. M. Ho, N. J. Stokkermans, B. J. Sadler, K. C. McIntosh and L. C. Ho. CIBA-GEIGY SEEDS LTD., Ailsa Craig, Ontario, Canada, NOM 1AQ.
After obtaining high frequency of haploids from the interspecific cross between Hordeum vulgare and H. bulbosum, Kasha and Kao (1970) suggested that haploids could be used in barley breeding programs. In 1973, CIBA-GEIGY SEEDS LTD. (formerly Stewart Seeds Ltd.) decided to develop a barley breeding program based on the haploid technique. A laboratory was gradually set up to produce barley haploids at Nairn, Ontario since the summer of 1974. After two years of expansion, Nairn Laboratory now consists of four growth rooms (totalled 125 m2 growth space), three growth chambers and one embryo culture room. This paper presents the results of haploid production from Nairn Laboratory.
The haploid production technique used at Nairn was according to Kao and Kasha (1969) and Subrahmanyam and Kasha (1971, 1973). In average, the number of caryopses that developed embryos after pollination ranged from 3-6 per head. The frequency of embryos germinating both root and shoot was 15%. Among those embryos 50% developed to the seedling stage at which time chromosome doubling treatments were applied.
Detailed results of haploid production at Nairn are presented in Table 1. The increased haploid production from 1975 to 1977 was mainly due to the expansion of facilities and the increase in personnel. However, the increased efficiency of haploid production was also one of the main reasons. The number of embryos obtained per head after pollination was increased from 2.8 in 1975 to 5.6 in 1977; and the number of haploid seedlings produced per man-week was increased from 14 to 38 during that period. These improvements were attributed to the ability to control growth room conditions (e.g. temperature, moisture and light) and technician's experience in performing haploid production (e.g. emasculation, pollination, embryo culture, etc.).
Table 1 Barley Haploid Production at Nairn from 1975 to 1977.
Kasha (1974) estimated that one technician could produce 100 haploids per week. At Nairn the average production rate was 38 haploids per manweek in 1977. However, the rate in winter time reached 71 haploids per man-week.
The effect of seasonal changes on the efficiency of haploid production at Nairn was examined (Table 2). The number of embryos obtained after pollination was found to be 7.4 in winter, 5.5 in spring and fall, and 4.1 in summer. Again, the percentage of embryo germination was highest in winter (17%) and lowest in summer (10%). These results indicate that the development of haploid embryos is significantly affected by seasonal changes (mainly temperature) with the facilities at Nairn.
Table 2. Seasonal effect on Barley Haploid Production at Nairn.
Acknowledgements:
We thank Dr. K. J. Kasha for technical advice and the I.R.A.P. Cereal 198 Grant for partial financial support. A special thanks to our Research and Development Director, G. E. Jones for reviewing the manuscript.
References:
Kao, K. N. and K. J. Kasha. 1969. Haploidy from interspecific crosses with tetraploid barley. In: Barley Genetics II. pp. 82-88 Ed. R. A. Nilan. Wash. State Univ. Press.
Kasha, K. J. and K. N. Kao. 1970. High frequency haploid production in barley (Hordeum vulgare L.). Nature (London) 225:874-875.
Subrahmanyam, N. C. and K. J. Kasha. 1971. Increased barley haploid production following gibberellic acid treatment. BGN 1:47-50.
Subrahmanyam, N. C. and K. J. Kasha. 1973. Feeding of detached tillers improves haploid production in barley. BGN 3:62-65.
