Abstract. It is important to understand how environmental factors will affect growth, development and quality. This study was conducted to compare the phenological development of Australian and Canadian two-row barley (Hordeum vulgare L.) cultivars when sown at two-seeding dates in the diverse environments of Northam, Western Australia, Australia, and Lacombe, Alberta, Canada. In Western Australia, barley was sown in a winter environment while in central Alberta, it was sown in a summer environment. More solar radiation, higher temperatures, longer days and more precipitation were recorded at Lacombe than at Northam. Starting early in the season, all phenological stages measured on a growing degree basis were accelerated at Lacombe relative to Northam. Differences between cultivars in phenological development were observed and could be related to combinations of basic vegetative phase and daylength sensitivity. Relative maturity in both environments was similar for all cultivars but Skiff. Later seeding resulted in acceleration of all stages measured except physiological maturity at Lacombe. The impact of later seeding on development was less at Lacombe than at Northam. Adaptability was a complex of interactions between environments and growth.

Introduction. Why do we need to adapt germplasm to an area? Why can’t we bring in the best cultivars from other countries and produce the same product here? These are the types of questions plant breeders are often faced with when applying for funding, justifying research efforts, and speaking at farmer meetings. The answers are not simple. There are needs for adaptation to growing season requirements, soil conditions (high or low fertility, pH, moisture), market demands, and disease resistances. The data presented in this paper is from a study conducted in Western Australia, Australia, and central Alberta, Canada, to compare the phenological development of two-row barley cultivars from Australia and Canada when grown under these diverse environments. We also wished to determine the influence of seeding date on development.

Materials and Methods

Site locations and seeding dates. The site in Australia was at Northam, Western Australia (100 km east of Perth, 31^o35' S 116^o 45' E). Seeding dates were 27 May 1997 and 23 June 1997. The site in Canada was at Lacombe, Alberta (153 km north of Calgary, 52^o 28' N 113^o 44' W). Seeding dates were 7 May 1998 and 28 May 1998. Annual precipitation is similar in both locations with long-term averages close to 440 mm.

Barley cultivars descriptions. Three Canadian and five Australian cultivars, representing the major two-row barley germplasm from each country, were used in this study. The three Canadian cultivars were Harrington, Manley and AC Oxbow. The five Australian cultivars were Fitzgerald, Gairdner, Franklin, Skiff and Stirling. All cultivars but Fitzgerald and Skiff are currently classed as malt types. Stirling, Harrington, Manley and AC Oxbow have erect early growth habit. The semi-dwarf cultivars, Fitzgerald, Gairdner, Franklin and Skiff, have prostrate early growth habit.

Experimental design, measurements, and analyses. Data were analysed by Genstat (Payne et al., 1998) as a split-plot design with blocks analysed as location.replicate/date of seeding/cultivar and treatments as location*date of seeding*cultivar.

Daily rainfall, maximum and minimum air temperatures, and solar radiation were recorded at each location. Daily air temperature data were used to calculate growing degree days (GDD): GDD=(t_min+t_max)/2-b; where t_min is the minimum daily temperature; t_max, the maximum daily temperature; and b, the threshold temperature for plant growth (0^oC was used in this study).

On a plot basis (50% of the plot), days to different phenological stages were determined and then related to GDD from emergence. The following stages of plant development were recorded: double ridge (DR), Apex 1 cm (Kirby and Appleyard, 1986), flag leaf fully expanded (Z41, Zadock et al., 1974), awn emergence (Z49), three-quarter ear emergence (Z57), and physiological maturity (loss of green from the peduncle immediately below the head). Basic vegetative phase (BVP) was the shortest period to Z49 under long days (at Lacombe).

Results and Discussion

Location effects. While spring habit barley germplasm was sown in both environments, these environments were very different. In Western Australia, barley was sown in a winter environment under an average daylength between May and October of 10 to 13 hours. In central Alberta, barley was sown in a summer environment under an average daylength between May and August of 15 to 17 hours (average 4.8 hours day^-1 more than Northam). Higher amounts of precipitation (72 mm), solar radiation (4.3 MJ day^-1) and average daily air temperature (2.7^oC) were recorded at Lacombe than at Northam during their respective growing seasons.

Starting early in the season, growth stages were accelerated on a growing degree basis at Lacombe relative to Northam (Table 1). The greatest impact of location was on the period of change from vegetative to reproductive growth by the apex (double ridge) and change from prostrate growth to stem elongation (Apex 1 cm). Days to these two stages at Lacombe were about half the requirement at Northam. The range across cultivars and seeding dates was also smaller at Lacombe than Northam. Thereafter, relative differences between environments and phenological stages became progressively smaller, but the range was similar. The period of stem elongation between Apex 1 cm and Z57 was shorter at Lacombe (29 days, 459 GDD) than Northam (52 days, 592 GDD). The period between flag leaf and heading was short and averaged around 160 GDD at both locations. The period of grain filling between Z57 and physiological maturity was longer at Lacombe (36 days, 647 GDD) than Northam (32 days, 527 GDD). Physiological maturity was reached in an average of 84 days (1359 GDD) at Lacombe and 131 days (1630 GDD) at Northam. Because GDD corrected for differences in temperature, the differences in GDD for phenological development between cultivars, seeding dates, and locations reflected differences in radiation receipt, daylength, and other environmental factors.

Cultivar effects. When measured by BVP, Stirling and Skiff showed strong photoperiod responses under long days. The BVP for Stirling and Skiff was short; for Harrington and AC Oxbow, medium; for Fitzgerald, Gairdner and Manley, medium-long; and for Franklin, long. Relative maturity in both environments was similar for all cultivars but Skiff. Skiff was late maturing at Northam but early at Lacombe.

Seeding date effects. Late seeding resulted in acceleration of all phenological stages measured at Northam and Lacombe, except for physiological maturity at Lacombe. The impact of later seeding on phenolgical development (GDD-basis) was less at Lacombe than at Northam. At Northam, the acceleration of development with later seeding was apparent at all phenological stages measured, and was most pronounced for physiological maturity. This was expected in Western Australian as in the late stage of development the environment was drying out, days were lengthening and radiation receipt was increasing. At Lacombe, all cultivars but AC Oxbow required more GDD to reach physiological maturity with later seeding. The greater GDD requirement with later seeding in the Canadian environment was due in part to better moisture availability at the end of grain filling, combined with shortening days and a decline in solar radiation receipt.

Conclusion. The two environments used in this study were very distinct. In the short-day, cool-temperature, winter environment of Western Australia, well-adapted cultivars such as Stirling and Skiff have a short BVP and pronounced photoperiod response. When these cultivars were grown in the long-day summer environment of western Canada, their growth was extremely compressed due to their photoperiod response. In western Canada, well-adapted cultivars such as Harrington and AC Oxbow have a moderate BVP. Adaptability is a complex interaction of environmental conditions with growth.

Acknowledgements. We would like to thank Peta Dunkerton (Northam), and Donna Westling, Bill Stewart and Dave Dyson (Lacombe) for their technical assistance. Funding for this research was provided by Agriculture Western Australia, Grains Research and Development Corporation (Australia) and Alberta Agriculture, Food and Rural Development (Canada).

References:

Kirby, E.J.M., and Appleyard, M. 1986. Cereal Development Guide. 2^nd ed. Stoneleigh, Arable Unit, National Agriculture Centre.

Payne, R.W., Lane, P.W., Daird, D.B., Gilmour, A.R., Harding, S.A., Morgan, G.W., Murray, D.A., Thompson, T., Todd, A.D., Tunnicliffe-Wilson, G., Webster, R., Welham, S.J., and White, R.P. 1998. Genstat 5 Release 4.1 Reference Manual supplement. Numerical Algorithms Group, Oxford.

Zadok, J.C., Chang, T.T., and Konzak, C.F. 1974. A decimal code for growth stages of cereals. Weed Res. 14:415-421.