The cropping season of 1997 was very favorable for winter barley at the beginning of plant growth. Timely rains, warm weather in autumn to mid December facilitated good barley growth and crop establishment on all the territory of North Caucasus. Frosts were moderate and only cold susceptible spring type breeding material was damaged. In the northern and central zones of the area barley overwintering was successful and conditioned a bumper crop. Yields of winter barley ranged from 4 to 6 t/ha. In the agrofirms, where mineral fertilizers and other elements of advanced technology were utilized, yields of 7-8 t/ha have been obtained. In the seed producing agrofirm of the Krasnodar Research Institute of Agriculture the average yield winter barley variety Kozir reached 10.2 t/ha from acreage of 530ha.

However because of the crop failure in other zones, average yield for the Krasnodar region was much lower than expected and on the same level as previous seasons, at only 3.8 t/ha. Farmers of the eastern and foot-hill zones, the main barley producers, lost 30-40% of average yield due to diseases, especially snow mold and leaf rust. A very deep snow cover of 40-60 cm depth kept the overgrown barley plants under a thick carpet for three months. That resulted in severe snow mold affecting all barley fields and especially those from early planting. After snow melt some fields were completely covered with a thick cobweb of dead plants with large red spores.

In official yield trials, as well as on-farm verification trials, all 19 tested varieties were affected, but some proved to be more tolerant. A new winter barley variety Michailo and the facultative variety Avans displayed good performance under those environments with a 15-25% yield advantage. State trial yields varied from a minimum 1.9 t/ha at the Sever experimental station to maximum 8.5 t/ha at the Ust-Labinsk station (Table 1). The variety Michailo was at the top of the list in Sever and Kanev Experimental Stations at the yield level of 1.9 to 3.4 t/ha and at Kavkaz and Eisk Stations with yields of 6.5 to 7.6 t/ha.
 

Table 1. Results of winter barley testing in the official state trials

	Yield on different stations, t/ha
Variety	Suscept.* to rust, %	Sever	Kanev	Labinsk	Otrada	Kavkaz	Eisk	Aver. of 11 st. t/ha %
Winter barley
Bastion	43	2.08	2.63	3.37	5.10	7.27	6.24	4.51	100
Vavilon	60	1.98	2.86	3.88	5.35	6.50	7.46	4.92	109
Kozir	75	2.19	3.28	3.86	4.60	6.45	7.61	4.97	110
Michailo	62	2.64	3.49	4.74	6.44	7.14	7.64	5.47	121
Facultative barley
Novator	15	2.06	2.44	4.69	4.93	6.03	5.42	4.12	100
Secret	13	2.11	2.63	2.91	4.33	5.89	7.53	4.58	111
Avans	12	2.18	2.73	4.06	5.49	6.51	6.84	4.85	118
LSD 05	9.8	09.27	0.29	0.38	0.48	0.47	0.44

* percentage of leaf, covered with the pathogen
 

A retrospective glance at the history of barley breeding in the North Caucasus and analyzing the main generating powers, which have been stipulating variety changes, we conclude that many factors contribute to the recognition of a new variety by the State Testing Committee and eventually by farmers. These include achievements in improving economically important characters without sacrificing productivity, such as: cold tolerance (winter barley varieties Start, Debut, Radical, Bastion), resistance to lodging (winter barley varieties Zavet, Cyclon, Vavilon and spring barley Kaskad, Perelom, Piket), earliness (winter barley Skorokhod, spring barley Temp, Mamluk), grain quality improvement (winter barley Novator, spring barley Vicont Kadet), neutral reaction to thermoperiod (facultative barley varieties Secret, Avans). All of these facilitate increased barley adaptation, yield stability, and better crop management. However, the main generator of variety change was disease resistance, especially in the group of highly productive varieties. Our observations have shown that the yield advantage of a new variety was expressed and realized more effectively on the first 3-5 years after variety release when it occupied the major areas in the production. Soon after that it begins to be more susceptible to diseases. As a prominent plant pathologist Van der Plank noted "The increasing popularity of a variety among farmers can be a self-destructive process…". This has happened with the most famous barley variety Cyclon, which was released in 22 different republics and areas of the former Soviet Union,. A high infection of net blotch (Pyrenophora teres) conditioned a considerable loss of productivity and raised the necessity for a fast variety change on farmers’ fields. During three decades the priority order in disease importance changed four times. In the 60’s leaf rust (Puccinia hordei) was prevalent, then net blotch (Perenophora teres) came and determined a big variety change in the region. There were periods, when barley yellow dwarf virus and leaf stripe (Perenophora graminea) were dominated and finally, during the last two seasons, leaf rust is again the most economically important. Powdery mildew (Erysiphe graminis), loose smut (Ustilago nuda) and covered smut (Usdtilago hordei) affect barley plants annually, but their manifestation is not as dangerous as other diseases. Unfortunately, achievements in breeding on disease resistance can not be fixed for a long period of time and the research in this direction should be considered as activities of ongoing programs. The data presented in Table 1 can induce some questions concerning good yield performance of the new varieties Kozir and Michailo which are rather susceptible to leaf rust. This contradiction can be explained by a fortunate combination of morphological and biological traits, conditioning their high productivity. The next reason, which should be taken into consideration, is a strong attractive capacity of heads to transform assimilates from the leaves into heads under the stress. Similarly, as in the last season, winter barley was affected by severe heat, starting from the heading stage. Air temperature in May and June were up to 35-38°C, resulting in a yield decrease for some late and heat susceptible varieties, including those very resistant to diseases. The yield reduction due to heat and drought was higher than from rust infection. But this fact doesn’t mean that disease problems can be neglected. Breeding for resistance to barley leaf rust, which has again become dominant, is urgently needed and should be recognized as a main priority in handling initial material. Germplasm sources, with high levels of resistance to the pathogen, we could recommend the varieties Wysor and Jefferson (USA), as well as the above mentioned facultative varieties Secret and Avans (Russia).

Reference
I.E. Van der Plank. 1968. Disease Resistance in Plants. Academic Press, London, p. 31.