Abstract only

Since the development of the virgin lands, Kazakhstan has joined the group of the ten largest grain exporters of the world. Great variability of environmental zones and subzones, where spring wheat is a major strategic crop, emphasizes import- ance of adaptation in wheat breeding. Large-scale multi-location trials in different regions of Kazakh- stan ( 1960-1980) and studies on inheritance based on segregating populations allowed for identification of a desirab1e plant ideotype for the main spring wheat regions of the country. Results of our studies have suggested that involvement of the Volga steppe, eastern steppe, Central Asian dryland and Andean germplasm in crosses is necessary to develop drought tolerant spring wheat varieties. Arnong the most important traits that drought tolerant varieties must possess are well-developed primary and secondary root systems. In dryland regions, the role of embryo roots is especially impor- tant and their development often determines the fur- ther growth of the nodal roots and biomass accum- ulation. We have been working on the wheat ideotype continuously because the requirements to wheat varieties change depending on new knowledge of plant ontogenesis accumulated by genetics and physiology. Special attention is paid to the depth of the root penetration, levels of primary roots branching, growing capacity of the leaves and stems and their sizes. Varieties of Western and Central Kazakhstan should be of early and intermediately maturity, heat tolerant, with water retaining ability. The stem height should be intermediate (70-85 cm), number of grains per spike should be in the range of 25 and 30 grains, while 1 OOO-grain weight 35-45. In dry years variety should yield about 0.8-1.2 ton/ha, while in favorable years yield should not be less than 2.0-2.5 ton/ha. The difference in yield after fallow and cereal predecessor should be as high as 0.4-0.5 ton/ha. Major traits for dryland steppe regions include grain number and grain weight per main spike, weight of the main tiller at the full maturity stage, harvest index, rate of plant development and photosynthetic traits. Environment of Western and Central Kazakhstan provide for obtaining high quality grain for both bread (hard) and durum wheat. Therefore, quality traits are priority and used for screening of germplasm from Vavilov Plant Institute, CIMMYT and ICARDA. Evaluation of disease resistance is conducted in collaboration with Otar RI. As as result of the multi-year work, several drought-resistant wheat varieties have been developed for bread and durum wheat: Eritrospennum 74, Aktobe 91,92, 2, 130, 10, 14, Lutescence 77, 86, Albidum 97, Steppe 1,2 (bread wheat); Kargala 2,3,9,34,35, Aktyubinsk 74, Melanopus 78 (durum wheat). The new varieties of Aktyubinsk ATS posses not only high production value, but also are important as donors of drought resistance for germplasm improvement.

English

0409|AGRIS 0401|AL-Wheat Program

Juan Carlos Mendieta

CIMMYT Publications Collection