GENETICS OF THE RESISTANCE TO YELLOW RUST CAUSED BY Puccinia striiformis f. sp. tritici W. IN THREE GENOTYPES OF WHEAT (Triticum aestivum L.)

Abstract

The wheat yellow rust caused by Puccina striiformis f. sp. tritici has become a disease of global importance in the last few years. The genetic resistance in varieties is the strategy that has best supported the control of this disease. Currently several genotypes exist that have shown resistance in different years and environments. The objective of this study was to determine the type of resistance and to estimate the number of genes that condition the resistance to yellow rust in the Glenlea, Romero 73 and Bonza 63 genotypes. The susceptible progenitor used was Avocet-YrA, three populations were developed and advanced until F₅ families were obtained. The populations were evaluated under artificial yellow rust epidemics using a complete randomized blocks experimental design at the experimental station of the INIFAP-CEVAMEX in Chapingo, Mexico, during the Spring-Summer 2015 cycle. Dew formation at 100 % and temperatures between 10 and 20 ºC were favorable for the development of the disease which allowed to determine that the resistance of Bonza 63, Glenlea and Romero 73 genotypes is due to the effects of minor genes of quantitative effects. The performance of families and the analysis of X² indicated the presence of three genes that confer adult plant resistance (APR) to yellow rust in the Romero 73 and Bonza 63 genotypes. It was determined that the Glenlea variety possesses from four to five APR genes. Bonza 63, Glenlea and Romero 73 possess high levels of adult plant resistance to the various races present in the main wheat regions of Mexico and are suitable to be used as progenitors in wheat improvement programs to achieve durable resistance to yellow rust.