THE STATUS OF TRADITIONAL SCOTTISH ANIMAL BREEDS AND PLANT VARIETIES AND THE IMPLICATIONS FOR BIODIVERSITY
CHAPTER FOURTEEN: A DETAILED REVIEW OF THE CONTRIBUTION MADE TO BIODIVERSITY BY SCOTS BERE
14.1 The importance of the historical role of Scots Bere in Scottish agriculture is indicated by the fact that until 1960 the Scottish Agricultural statistics recorded barley and bere together. Scots Bere is a six-row barley and an example of a traditional variety with specific adaptation to soils that are of low pH. According to Jarman (1996) Scots Bere was still grown in Orkney and Caithness, in the late 1990s, as a spring crop, although only 5-15 ha was grown annually. It is susceptible to frost, but grows very rapidly, especially in long summer days such as experienced in Northern Scotland. Because of its very rapid growth it is sown late but is often the first to be harvested and is known locally as the '90-day' barley. Scots Bere is weak strawed and susceptible to foliar disease, especially mildew and is milled to make traditional 'bere bannocks'.
Performance of Scots Bere
14.2 Experimental results at the Scottish Plant Breeding Station showed that Scots Bere was well adapted to the Midlothian environment. In a hand-planted experiment the relative yield of Scots Bere was the highest (Riggs and Hayter, 1975) of the parents under test and this was coupled with early flowering (Riggs and Hayter, 1973). The study was completed with the publication in 1978 of estimates of diastatic power and alpha-amylase showing that Scots Bere had the highest diastatic power (Hayter and Riggs, 1978). A comparison between Scots Bere and cultivars considered to be sources of high diastatic power (Olli, Pirkka) and highly commercial cultivars (Ymer, Golden Promise, Midas) is given in Figure 14.1 as the difference between the scores for Scots Bere and the other cultivars. This plot clearly indicates that yield potential is higher in Scots Bere because it had more ears, a larger number of grain per ear and the grains were larger than many of the other cultivars.
14.3 These data appear to be at odds with the traditional view that Scots Bere is low yielding and this could be for a number of reasons. If grown with lower levels of, or even no lime, Scots Bere will not be as high yielding as barley on the same soil after liming to modern standards. The experimental design used to assess the diallel cross was the most precise (with single plant randomisation) available but lacked flexibility. The wide segregation, due to the deliberate use of diverse parents, for height and heading date resulted in interplant competition that favoured early, tall over short, late lines. A truer estimate of the potential for barley with improved tolerance to low soil pH, to the same level as wheat, would be obtained from a study of random inbred lines from a cross with current dwarf, mildew resistant lines.
Implications for wider biodiversity
14.4 The key characteristics of Scots Bere, earliness, height and weakness of straw allow an estimation of a past contribution to biodiversity. In a system based on non-intensive practises rapid early growth would provide cover in early spring for birds and harbour invertebrates essential for young chicks. Relatively early harvest and natural drying in the field would provide seed for adult birds in the autumn. This contrasts with crops of uniform spring barley that mature later than Scots Bere, although spring barley is more benign than autumn sown crops. Research has been carried out on the amelioration of the effects of intensive cropping with the development of the concepts of "beetle banks" (Boatman, 1999). More recent research has highlighted the interdependence of bird species and particular crops and has resulted in the concept of conservation seed mixtures.
14.5 Effects of crops on birds and insect may be highly visible but it is as likely that "invisible" effects may have even greater consequences. Barley crops tolerant of low soil pH would allow an overall reduction of lime use in arable rotations. As well as reducing the level of inputs the reduction of lime use will also have consequences for soil organisms such as earthworms (Robinson et al, 1992). More research is required into the consequences of changing liming regimes for soil bacteria, fungi and invertebrates.
14.6 Plant nitrogen metabolism is a major area of research that is vital to the future of world-wide farming (Raun & Johnson, 1999) as much applied fertiliser is wasted. Global nitrogen use efficiency (NUE) for cereal production is only 33%, a loss equivalent to about $16 billion annually. It is already known that there are genetic differences between cereal cultivars in nitrogen uptake (Sylvester-Bradley et al, 2002) and retention. Scots Bere represents potential germplasm for the investigation of the genetic control of nitrogen metabolism and this opportunity must not be lost.
Figure 14.1 Characteristics of cultivars relative to the performance of Scots Bere in hand sown experiments grown at the Scottish Plant Breeding Station in 1970/71.