During the last decade, the effects of climate change have intensified. In various parts of the world, dependence on fossil fuels begins to be reduced with the impulse to the use of renewable energies, such as biodiesel, which has encouraged technological innovation, both in the field of energy and in the sustainable use of natural resources (^{Huang et al., 2012}; ^{Zamarripa and Solis, 2013a}, ^2013b; ^{WorldAtlas, 2018}; ^{Gielen, et al., 2019}; ^{Laviola et al., 2019}).

In this regard, Mexico has demonstrated a great commitment to the international environment and sustainable development agenda and participates in more than 90 agreements and protocols in force, including the Kyoto protocol and the Paris agreement, being a leader in issues such as climate change and biodiversity (^{INECC, 2016}). However, the country’s economic growth remains closely linked to greenhouse gas emissions and the loss of forests and jungles. This implies important challenges to promote economic growth and development, but at the same time ensure that natural resources continue to provide the environmental services on which the welfare of the population depends.

In addition to the above, the Jatropha curcas L. species has been considered one of the viable alternatives for the production of biodiesel in Mexico (^{Zamarripa and Solis, 2013a}; Sujatha et al., 2019). However, the lack of improved varieties with high yield of grain and oil, being one of the main limitations of this crop. Given this problem, INIFAP through the National Bioenergy Research Program has worked on the search, development and selection of varieties of Jatropha curcas with high grain yield, oil content and good oil quality, as well as climate adaptation dry and wet

The investigations carried out in the South of Mexico allowed the obtaining of the clone variety ‘Doña Aurelia’ of high productive capacity for use in system interspersed with the female clonal cultivar ‘Gran Victoria’ and the pollinator cultivar ‘Don Rafael’ also generated in INIFAP and that will later be described in future issues of this magazine. In this way, the yield of grain and oil can be increased up to 1 200% in the first year, compared to the average of plantations without the use of improved varieties (^{Solis et al., 2016}). The improvement method used to obtain this variety was clonal selection, with an evaluation and selection period of more than eight years (^{Zamarripa and Pecina, 2012}; ^{Solis et al., 2019}). This method has been used successfully in many species such as coffee, cocoa, sugar cane, cassava (^{Montagnon, 2000}; ^{Resende and Barbosa, 2005}; ^{Cueto et al., 2007}).

The genetic improvement and varietal selection began with the morphological, agronomic, biochemical and genetic characterization of more than 1 600 plants J. curcas established in the National Germplasm Collection of nine states of southern Mexico (^{Zamarripa et al., 2012}). Phenotypic studies and selection of outstanding individuals by some particular character, were carried out during the years 2008 to 2010. Based on agronomic and industrial characteristics, promising genotypes were selected and variety trials were established in four environments in Mexico, to assess agronomic behavior. The main selection criteria used were grain yield, oil content, growth habit (bearing, branching pattern) and high presence of female flowers. These genetic materials were assessed for an evaluation and selection period of more than eight years.

Doña Aurelia, is an early variety of medium vigor, has an abundant branch, open cup and drip area of 4 m², an average of 61 branches per plant. Doña Aurelia produces semi-compact clusters with medium-sized elliptical fruits (Figure 1). One of the important characteristics of this variety is the inflorescences, with fully pistillated flowers that remain for most of the year (^{Zamarripa et al., 2017}). It has an average yield of 211 clusters, with 909 female flowers.

Figure 1 Characteristics of the plant of the clonal cultivar ‘Doña Aurelia’: branching from the base, canopy cover and plant height.  

Being plants with 100% female flowers, it is considered a highly productive material (Figure 2). The use of the clonal cultivar ‘Doña Aurelia’ in a system interspersed with the clonal cultivars ‘Don Rafael’ and ‘Gran Victoria’; from the fourth year of age it is feasible to obtain grain yields greater than 1.5 t per hectare. The seed is medium in size, with an average weight of 0.83 g. This cultivar has proven to be stable in terms of its characteristics over years of study and to produce an average yield in good environments of 0.49 t ha^-1 in the first year of production.

Figure 2 Cultivate clonal ‘Doña Aurelia’: a) plant architecture; b) and c) ripe and green fruits; and d) 100% female flowers. 

Reaching three tons of dry grain per hectare in the fourth year of production. The average oil content in the seeds of the cultivar is 53.4%. The sowing of 36.5% of the total area corresponds to the ‘Doña Aurelia’ clonal cultivation interspersed with the ‘Gran Victoria’ clonal cultivation in 36.5% and with 27% of the ‘Don Rafael’ pollinator cultivar allows an increase of 20 to 240 kg ha^-1 the grain yield obtained by the producer’s materials in the first year, with greater increases in successive years and yields exceeding the fourth year of production.

The clonal cultivar ‘Doña Aurelia’ can be sown, in areas of the tropics identified as environments with high and medium productive potential, with an height of 0 to 900 meters above sea level, temperature between 18 °C and 28 °C and rainfall between 900 and 1 500 mm per year, from the states of Chiapas, Tamaulipas, Michoacán, Yucatan, Veracruz, Oaxaca and Guerrero.

Table 1 provides information on the physicochemical composition in seeds and oil of the cultivar ‘Doña Aurelia’. As for the composition of fatty acids, this cultivar has a larger portion of polyunsaturated fatty acids (39.75%) than saturated (35.36%). The smallest portion of fatty acids is monounsaturated (24.89%). The main fatty acids in the seed oil of this cultivar are oleic acid with a content of 30% and linoleic acid with a content of 32% (^{Zamarripa et al., 2017}; ^{Solis et al., 2019}).

Table 2 shows the physicochemical characteristics of biodiesel from the J. curcas oil of the clone cultivar ‘Doña Aurelia’, obtained by a heterogeneous transesterification using potassium hydroxide with methanol. The biodiesel obtained from the oil of the clonal cultivar ‘Doña Aurelia’ is within the ranges of the American standard ASTM and European EN-14214.

The clonal cultivar ‘Doña Aurelia’, was officially registered for protection in September 2014 in the national catalog of plant varieties (CNVV) with provisional registration number 3055-JAT-002-260914/C, of the inspection and certification service of Seeds (SNICS) belonging to the Ministry of Rural Development (SADER), with definitive registration number JAT-003-050615 and obtaining the title of breeder number 1541 in the month of July 2016 for its use and exclusive exploitation until the month July 2034.