Abstract only

Yellow rust is one of the most harmful wheat diseases. During the last years, the weather conditions promoted development of yellow rust and high yield losses were recorded due to the epidemics across the republic. Development of resistant varieties is almost the only way to control the disease. Evaluation of segregating populations combined with high selection pressure is the main method of our breeding program. Right choice of the parents is determined by the presence of the desired traits and their combinations, as well as by the combining ability and breeding value of the genotypes. Study of inheritance of disease resistance allows for revealing the genetic mechanism of plant resistance to yellow rust. The other important principle was the crossing of geographically distant forms and selection of desired plants under field conditions based on resistance to yellow rust, straw strength and number of grain per spike. We had in the first place involved in crosses selections selected from ICARDA germplasm, which was regularly tested at the Absheron Experimental Base of RI of Agriculture for adaptation to local environment for many years. The objective of the present study was evaluation of yellow rust resistance in the segregating populations and selecting plants with high resistance to the disease. Inheritance of resistance was studied through analyses of the segregating populations obtained from the crosses between resistant and susceptible varieties. Crosses and evaluation of the segregating populations were carried out at the Absheron Experimental Base of RI of Agriculture. Simple crosses were carried out by the Tvirl method. To improve yellow rust resistance in hybrid populations, F I plants were backcrossed with the resistant parent, which contributed to higher number of resistant plants in the consequent populations. Reaction to the disease was evaluated by the Cabb's scale. AII entries were sown under the challenging environment promoting development of yellow rust. Mirbashir-50 and Taraggi were crossed with Yrl/6 Avocet S. Both single crosses and backcrosses were carried out. The study results showed that most of the lines (65 %) obtained from crosses involving Mirbashir-50 were susceptible to yellow rust, while only 25% and 10% were moderately susceptible, and resistant, respectively. Among the lines produced by crosses of Taraggi by Yrl/6AvocetS, about55%was susceptible, while about 29% and 16% were moderately susceptible and resistant, respectively. Based on the obtained data, we can purposefully develop varieties possessing resistance genes or their combinations that are effective against the races of the yellow rust pathogens existing in the republic.

English

0408|AGRIS 0401|AL-Wheat Program

Juan Carlos Mendieta

CIMMYT Publications Collection