Male-sterility for recurrent selection in Wheat (Male Sterile Facilited Recurrent Selection: MSFRS) is a technique that requires a source of sterility that is not linked to deleterious effects, which preferably is governed by a single dominant gene and is effective in joining elite germplasm base (^{Villaseñor et al., 2014}). In autogamous species has been little used because naturally no male sterile germplasm allowing recombination and improvement with the same efficiency achieved in cross-pollinated (^{Sorrels and Fritz, 1982}; ^{Bockelman and Sharp, 1986}) In order to obtain male sterile sources in wheat, mutants induced by recurrent or due to spontaneous mutations radiation have been isolated, such as those recognized as Pugsley (Suneson, 1962); Probus (^{Fossati and Ingold, 1970}) Cornerstone (^{Driscoll, 1977}); Taigu-1 (^{Liu et al., 1986}) and LZ (^{Zhou et al., 2008}), which are mostly linked to deleterious effects, which have been ineffective in population improvement.

In small-grain cereals, the genetic advances in population improvement have been recognized when MSFRS is used (^{Ramage, 1977}). In Mexico, the technique has been used by ^{Villaseñor et al. (2002a)}, who reported genetic advances for gains yield of 4.7% cycle selection, and by ^{Solís et al. (2002)} indicating that after seven cycles of recurrent selection, increased the frequency of genotypes with high yield and stripe rust resistance. It is important to note that, the success of population improvement when MSFRS is used depends on the source of infertility; however, it is also important the germplasm base to be used for making the populations (^{Ramage, 1977}; ^{Geraldi and Souza, 1997}; ^{Villaseñor et al., 2002b}), since it should contain the recombinant gene of interest to obtain genetic program progress.

Once the base germplasm is chosen, we proceed to incorporate the source to form the recombinant male-sterility populations (^{Ramage, 1977}; ^{Geraldi and de Souza, 1997}). The backcross is a breeding technique that has been effective to incorporate qualitative characters as male-sterility (^{Márquez, 1988}) and even more so when the character to be incorporated is dominant (^{Geraldi and Souza, 1997}; ^{Villaseñor et al., 2014}); more backcrosses between operations on the recurrent parent, the greater the similarity. ^{Villasenor et al. (2014)} conducted four backcrossing in eight varieties of wheat and assessed the similarity in six qualitative characteristics, finding between 80% and 90% effective. Accordingly, the objective of this research was to evaluate the advantages of the dominant male sterile mutant “Oly” in the conversion and incorporation of character elite in wheat material.

The source of male-sterility “Oly”, due to a single dominant gene of bread wheat (Triticum aestivum L.) was used to incorporate a 20 progenitors of the rainfed wheat program INIFAP. The conversion process began in spring-cycle summer of 2005 in the Valley of Mexico Experimental Field (CEVAMEX) located in Chapingo, Texcoco, Mexico and, finished in autumn-winter 2009-2010 in the Experimental Bajío (CEBAJ) located in Celaya, Guanajuato. Recombinant population identified as PANDOLY, carrying the dominant male sterile gene that segregated in a 1: 1 sterile and fertile (^{Villasenor et al., 2014}) were seeded 2000 seeds at a spacing therebetween of 15 cm (spaced planting); were also planted the seeds of the 20 parents at a distance of 15 cm in two separate rows and 30 cm 3 m long; before flowering, ears of male sterile plants were covered to prevent pollinate; subsequently covered groups of five ears were chosen to be pollinated with each of the 20 parents; recombinant seeds were harvested for the F₁ crosses (F₁C). For the first backcross, the seed was sown F₁C spaced at 15 cm in two separate lines of 30 cm and 5 m long, together with their respective parent (paired plots); before flowering spikes of male sterile plants of each F₁C were covered; subsequently were pollinated with its father and that´s how the seed F₁ from the backcross 1 was obtained (F₁RC1); this procedure was repeated until obtaining the seed of the F₁ from the backcross 6 (F₁RC6); special care was taken to make the backcross to increasingly similar to the male-sterile parent plants.

The seed of the 40 genotypes F₁ from the backcross 6 “F₁RC6” from each parent and 20 parents was planted during the spring- summer cycle 2012 at the CEVAMEX, spaced at 15 cm in paired plots, each of two grooves spaced 5 m and 30 cm for a total of approximately of 60 plants per plot. Agronomic management of the experimental plot was conducted under rainfed conditions and according to the suggestions of INIFAP. During the spiking a spike covered in all male-sterile plants isolines to determine the fertile segregation: sterile. In grain-filling the incidence of yellow rust (Puccinia striformis f.sp. tritici) in each of the plots and maturity, in each parent and their respective conversion, were randomly selected 20 plants were evaluated in which they measured the plant height and spike length, which are the most visible variables in the process of backcrossing, and that somehow indicative of the efficiency of technical MEFSR. With the data obtained we proceeded to conduct an analysis of overall variance by completely randomized design with SAS (SAS-Institute 2002) statistical package thus obtaining the averages of each genotype for each variable.

A total of 556 plants were in the 20 androsterile isolines; fertile ratio was determined: Sterile, resulting in 268 288 were fertile and sterile, which according to the Chi- square test (ji² tables= 3.6> Ji² calculated= 0.93) is set to a 1: 1, like the expected segregation for a single dominant gene (^{Sun et al., 1994}; ^{Villaseñor et al., 2014}). All the fertile plants which were 100% and all the sterile plants were 100%, confirming that Oly mutant male-sterility is caused by a single dominant gene (^{Villasenor et al., 2014}).

The Table 1 shows the averages per variable for each parent and male sterile isoline, where we can see that for plant height only in the varieties Norteña F2007, Eneida F94 and Gálvez M87 haf significant difference while in the remaining 17 groups of genotype there was no difference detected, information indicating that this character incorporating male sterile gene was effective; for the three varieties where there was significant difference, male-sterile isolines were higher by up to 12 cm, indicating that male-sterile plants backcrossed were not well chosen at the time, since in androsterile recombinant populations carrying of high plant is one of characters altered when no proper selection of recombinant plants or when is left to chance (^{Sun et al., 1994}; ^{Villaseñor et al., 2002b}). In the variable ear length (Table 1), only varieties Altiplano F2007 and Gálvez M87 had significant difference, while in the other 18 groups of genotypes there was no difference detected this information also confirms that, the incorporation of male sterile gene was effective. Also, in Table 1, the reaction occurs in the foliage to yellow rust (Puccinia striformis f.sp. tritici) in the genotypes evaluated, where it is observed that the response in 15 parents and their respective androsterile isolines were virtually the same as a percentage of infection and type of reaction, while in the remaining five groups slightly varied the type of reaction or the rate of infection, information that helps determine that this qualitative also incorporating male sterile gene was effective.

Table 1 Agronomic and plant pathology of parents and male sterile after 6 backcross of conversion variables. INIFAPCEVAMEX, Chapingo, State of Mexico, spring-summer-2012. 

§líneas avanzadas; **= diferencia altamente significativas; F= fértiles; E= estériles; R= resistente; MR= moderadamente resistente; MS= moderadamente susceptible; S= susceptible.

The results presented indicate that backcrossing scheme applied to elite germplasm of wheat program from INIFAP-CEVAMEX was effective to incorporate the dominant sterile gene "Oly" as great similarity between parents and their androsterile isolines was achieved. This conversion to male-sterility is quite important because according to ^{Geraldi and Souza (1997)}, an elite germplasm breeding program is the bearer of favourable genes that will enable progress in the medium and long term. Moreover, the aforementioned conversion allow recombinant formation populations for recurrent selection, as reported ^{Sun et al. (1994)} when they evaluated the effect of improvement using the dominant mutant gene Taigu-1, who concluded that the reconversion of its most outstanding male sterile germplasm allowed further progress.