II.5. Varietal variation of water sensitivity in Asian barley varieties.
K. Takeda and T. Fukuyama, Institute for Agricultural and Biological Sciences, Okayama University, Kurashiki, Okayama, Japan.
Water sensitivity of barley seeds has been defined as the reduction of germinability under excessive moisture condition. A study was made of varietal variation of water sensitivity in ca. 2000 Asian local varieties.
Fifty seeds each were sown on two pieces of 7 cm filter papers set in a Petri dish, and incubated in a humidified germinator for 4 days at 25° C. According to the preliminary examination to determine the moisture condition, the germination bed of excessive water plot was moistened with 6 ml deionized water. Only viable seeds with more than 96% germinability under ordinary condition were examined.
Table 1. Varietal variation of water sensitivity in Asian barley varieties.
Naked varieties were generally tolerant to excess water with little variation, viz., about 80% of naked varieties tested showed less than 10% reduction in germinability under excessive water condition (Table 1). On the contrary, covered varieties showed a wide range of water sensitivity from 0 to 100%. It may be interesting to note the following: Malting varieties in Japan were most insensitive to excess water. This might have resulted from artificial selection. Also, Japanese native varieties were highly tolerant to excess water, which were followed by Korean and Chinese varieties, and finally by those from southwest Asia. Difference in water sensitivity of varieties from the Far East and southwest Asia may indicate the effect of natural selection through climatic factors.
Genetical analysis of water sensitivity is under way.
