UBC Theses and Dissertations
The effects of temperature, light, and variety on sterility in Barley (Hordeum vulgare L. and H. distichum L.) Tingle, James Nisbet
The effects of 12°, 13°, 24° and 30°C temperatures; 24, 20, 16 and 12 hour photoperiods; 2000 and 500 ft.-c. light intensities and light high and low in far-red energy on numbers of florets and percent sterility per head and per plant were studied on combinations of seventeen barley varieties. Numbers of florets per head and per plant were reduced with an increase in temperature. Numbers of florets were increased with a decrease in photoperiod at low, but not at high, temperature. At the low light intensity there was a slight decrease in number of florets per head and a pronounced reduction in tillering. The virtual absence of far-red energy had no effect on tillering, but caused a significant increase in number of florets per tiller head. Plant sterility was lowest at 18°C. Main head sterility was low at 12° and 18°C but was markedly increased at 24° and 30°C. Tiller head sterility was much higher than that of main heads at all temperatures and was as high at 12°C as at 24°C. Photoperiod had little effect on main head sterility except for causing a marked increase at 12 hour. At the optimum temperature for development (13°C), intermediate photoperiods had the lowest plant sterility. The reduction in light intensity caused a 30 percent increase in plant percent sterility. Light low in far-red energy caused an average increase of 25 percent in plant sterility. Varieties had significant interactions with temperature, photoperiod, light intensity, and light quality in determining the numbers of florets differentiated per head and per plant. Temperature and light intensity were the only factors to interact with variety for percent sterility. The varieties Aria, Asa, Betzes, O.A.C. 21, Palliser, Pirkka, Titan, Trebi, and Vantage were especially sensitive to the stress conditions imposed.
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