KAZAKH RESEARCH-PRODUCTION CENTER OF GRAIN PRODUCITON AND CIMMYT.
Almaty, Kazakhstan.
Yu.I. Zelenskiy and A.I. Morgounov (CIMMYT).
Spring wheat is the main food crop in northern Kazakhstan. The wheats cultivated in this region have some great disadvantages: low yield potential in dry years, susceptibility to lodging, and low disease and pest resistance.
Germ plasm with various biological and agronomic characteristics is a basis of plant-breeding programs (Vavilov 1935; Kronstad 1996). To develop new cultivars meeting the requirements of modern agricultural production, we utilize new, primary breeding material developed by the leading agricultural research centers.
Despite considerable difficulties in transferring germ plasm across CIS country borders, a significant number of new accessions where obtained during the last year from different institutions in the Russian Federation (Omsk, Krasnoyarsk, Novosibirsk, Kurgan, and Barnaul) and Byelorussia within the germ plasm exchange network. Considerable contributions to germ plasm collections were made by CIMMYT (International Maize and Wheat Improvement Center). During 19962003, we evaluated more than 10,000 entries of spring wheat.
After several years of study, the CIMMYT material has shown that germ plasm from international nurseries, such as the SAWYT (Semi-Arid Areas Wheat Yield Trial), SAWSN (Semi-Arid Areas Wheat Screening Nursery), ESWYT (Elite Selection Wheat Yield Trial), and IDYN (International Durum Yield Nursery), are not always well adapted to the extreme conditions of our region because of poor drought tolerance, little growth, or long vegetative periods. Therefore, our search for new, better-adapted material during the last 2-3 years has included nurseries such as the GAWYT (Global Adaptation Wheat Trial), FAWWON (Facultative and Winter Wheat Observation Nursery), and HLWSN (High Latitude Wheat Screening Nursery), and among cultivars of North American origin (USA, Canada).
When breeding for resistance to leaf rust, the most widespread and harmful disease of wheat in northern Kazakhstan, the IDTN Candidates nursery, including isogenic lines of cultivars with known Lr genes deserves, the greatest interest. Shuttle breeding has been employed with the participation of CIMMYTMexico, and new improved germ plasm has been developed from CIMMYT material and cultivars from the U.S. and Canada.
Shuttle breeding is implemented through the following plan: crosses and multiplication of segregating populations are made in Mexico, selections from segregating populations are made at various sites in Kazakhstan and western Siberia depending on the aim of the breeding. Developed material combines resistance to fungal diseases, which is conferred by Mexican germ plasm, and high adaptability to local conditions, which is contributed by the local cultivars. Presently, selections are carried out in F3-F5 segregation populations of improved germ plasm, which were developed from the crosses with the Kazakhstan cultivars Akmola 2, Akmola 3, Ishimskaya 92, Kazakhstanskaya early maturing, Tselinnaya 24, Tselinnaya 3C, Skent 1, and Tselinnaya yubileinaya were used as parents. Progeny of the elite spikes is studied at the initial stages of the breeding process (F3 and F5 observation nursery).
Along with the study of the yield components in the collection nurseries, CIMMYT material, we evaluated for resistance to diseases and pests, which are widespread in the region in the special disease nurseries using artificial inoculation. Lines are selected based on yield and other valuable agronomic characters and further evaluated in breeding nurseries and advanced trials. The best entries are distributed annually to the breeders in Kazakhstan and Siberia for the further evaluation and practical use in their programs.
References.
REPUCLICAN STATE ENTERPRISE, BARAYEV RESEARCH-AND-PRODUCTION CENTRE OF GRAIN FARMING, AND THE MINISTRY OF AGRICULTURE OF THE REPUBLIC OF KAZAKHSTAN
Akmolinskaya oblast, Shortandy district, village Nauchny, 021601, Kazakhstan.
Irina Victorovna Rukavitsina and Zorya Petrovna Karamshuk.
In the intensive agricultural production conditions in northern Kazakhstan, one factor limiting the growth of grain crop productivity on chernozem soils is a fungal disease caused by pathogenic species Alternaria, Fusarium, and Bipolaris. Among existing measures of control, the most widespread and effective are chemical. However, the use of chemicals quite often promotes environmental pollution and has a negative effect on public health. Attention now is given to searching for biological means of plant protection using fungal antagonists. Antagonism is widely distributed among fungi and can be a result of competition for nutrients, the activity of antibiotics developed by fungi, and the direct effect on pathogenic fungi (hyperparasitism). Our interests include studying the antagonism between fungi causing black germ disease and root rots in grain crops.
As an antagonist against plant pathogenic species Alternaria, Fusarium, and Bipolaris, we investigated the fungus Trichoderma lignorum (strain 156-T). The study of antagonistic mutual relationship between the these fungi was done using counter cultures on Chapek-Dox medium. Fungi were isolated from soil in the germination zone, the surface of wheat seeds, and infected tissue in the root-zone of wheat stems. Isolated, pure-culture, plant pathogenic fungi were identified according to specific composition.
The results showed that Tr. lignorum has the greatest antagonistic activity, shown in the form of hyperparasitism related to Alternaria tenuis. On the Chapek-Dox nutrient medium, Tr. lignorum mycelium overgrew that of A. tenuis that had colonized the surface. When growing on A. tenuis, Tr. lignorum uses the nutritional substances produced for growth. In this case, Tr. lignorum is hyperparasitic on A. tenuis.
In the interaction between Fusarium oxysporum and species of Trichoderma, territorial antagonism has been discovered. In the presence of F. oxysporum, Tr. lignorum actively increases in biomass. Upon encountering F. oxysporum mycelium the Trichoderma actively occupies the medium around F. oxysporum and then oppresses and stops the development of the fungus.
Mutual aggressive antagonism was noted between Tr. lignorum and Bipolaris sorokiniana. Active growth stops in both fungi at a distance between the colonies. The basic biomass of both species is at the border of the colony. The antagonism is expressed by defusing antibiotics into agar. In this case, the mutual influence of antibiotics is the short growth of aerial mycelium both fungi.
This research has shown mutual aggressive antagonism between B. sorokiniana and Tr. lignorum, territorial antagonism between Tr. lignorum and F. oxysporum, and hyperparasitism between Tr. lignorum and A. tenuis. Developing a biological substance on a basis of Tr. lignorum strain 156-T will promote the increase plant protection against pathogenic species of Alternaria, Fusarium, and Helmintosporium.