In Veracruz and Chiapas, almost all bean plantings are made with materials of black beans, because they have the greatest commercial demand in southeastern Mexico. In both entities, plantings residual moisture cycles autumn-winter and winter-spring, it is common the occurrence of terminal drought, which occurs after flowering crop when bean plants are more sensitive to lack of moisture (^{Acosta et al, 2004}; ^{Muñoz-Perea et al., 2006}; ^{López et al., 2011}) and depended on its duration and magnitude, can cause losses of 20 to 100% in grain yield (^{De Allende et al, 2006}; ^{López et al., 2008}).

Breeding for drought resistance is one of the best ways to increase the productivity of bean production under these conditions (^{Frahm et al., 2003}). In the Bean Program Experimental Cotaxtla the National Institute of Forestry, Agriculture and Livestock (INIFAP), from 2007, they have conducted studies on drought in black bean plantings for residual moisture. Of these, some advanced lines and varieties showed good adaptation to conditions of moisture deficiency (^{López et al., 2008}; (²⁰¹¹) were identified which was necessary to continue evaluating them to determine more accurately their productive behavior under stress humidity. So was generated the Verdín variety, which is tolerant to drought terminal, and has high yield potential and wide adaptation in different areas where bean occurs in the states of Veracruz and Chiapas.

This variety originated from triple crosses (SXB 114 x DOR 605) x SXB 123 and obtained by gametic selection (individual plant) in F₁ and mass selection in F₂ under drought stress at the International Center for Tropical Agriculture (CIAT) in Cali , Colombia; individual selection in F₃ anthracnose in Popayan, Colombia; mass selection in F₄ by angular leaf spot in Quilichao, Colombia; F₅ masal compound under drought stress; individual selection in F₆, masal in F₇ and masal compound F₈ in Cali, Colombia the SXB 114 and SXB 123 lines were used as sources of resistance to drought and DOR 605 as a source of resistance to bean golden yellow mosaic virus (BGYMV).

The SEN-70 line which was derived Verdin was introduced to Mexico in 2009, through a nursery of advanced lines CIAT Bean Program. From 2011 to 2013 we were evaluated in an elite trial in 11 environments of Veracruz and Chiapas, for high performance, wide adaptation and disease tolerance and 2013-2014 in performance testing for tolerance to terminal drought conditions residual moisture.

The plants of Verdín variety are indeterminate growth habit, erect shrub and type II (^{Singh, 1982}), with medium guides and canopy height of about 59 centimeters. Its flowers are purple, yellow pods at physiological maturity and grain is black, opaque and small. One of the most outstanding characteristics of this variety is its earliness, as in tropical and subtropical areas, flowering occurs between 34 and 37 days and reaches physiological maturity between 67 and 70 days after planting, which allows you lower risk of yield loss due to the occurrence of drought periods terminal, which commonly occur in crops of residual moisture. Another quality that stands out in this variety is its tolerance to anthracnose disease virus and bean golden yellow mosaic, which affect the bean field areas of the states of Veracruz and Chiapas.

From 2011 to 2013, Verdin was compared with the varieties Black Papaloapan and Black Comapa latest release by the Bean Program INIFAP in Veracruz, (^{Lopez et al., 2007}; ²⁰¹⁰), through an essay elite performance, which it was established in 11 environments Veracruz and Chiapas, during cycles autumn-winter and winter-spring conditions and residual moisture in the summer cycle under temporary. The new variety exceeded by 5.5 and 10.4% yield varieties Black Papaloapan and Black Comapa, respectively, residual moisture conditions and at 46.4 and 9.6% temporary low. The overall average yield of the new variety was higher by 12.8 and 10.2%, the varieties obtained by Black Papaloapan and Black Comapa (Table 1).

Table 1 Grain yield (kg ha^-1) comparative bean variety Verdín in nine environments in Veracruz and two in Chiapas. 

OI= otoño-invierno; IP= primavera- verano; V= verano; HR= humedad residual.

In the winter-spring cycle of 2013, in the town of Cotaxtla, in central Veracruz, Verdin was evaluated along with other 22 lines and commercial varieties Black INIFAP, Black Tacaná and Black Jamapa (regional control), using the methodology irrigation-drought, in order to classify them for their tolerance to drought, as well as its efficiency in performance in both moisture conditions (^{Fisher and Maurer, 1978}; ^{Graham, 1984}). The new variety was selected, along with 10 other lines, for their tolerance to terminal drought (ISS= 0.8) and high efficiency in performance in both moisture conditions (IER= 1.45) (^{Tosquy et al., 2014}). Under drought conditions, the performance of Verdin was 47.8, 19.1 and 63.7% higher than those obtained by the varieties INIFAP Black, Black Tacaná and Black Jamapa respectively.

During cycles 2013-2014 autumn-winter and winter-spring 2014, Verdín was also evaluated in a uniform test performance conformed with the 10 selected trials irrigation-drought and regional witnesses lines Black Tacaná and Black Jamapa, which were conducted under conditions of residual moisture in four locations in Veracruz and two in Chiapas. According to the results of soil moisture balance (^{Hillel, 1980}), in four of six environments, there was occurrence of drought during the growing season; Verdin was the most productive in both drought conditions, as moisture stress. The overall average yield of Verdín was 34.6 and 41% higher than the average obtained by the varieties Black Tacaná and Black Jamap, respectively (Table 2).

Table 2 Grain yield (kg ha^-1) and two regional witnesses Verdín evaluated in four environments with drought and two moisture stress in Veracruz and Chiapas. 

OI= otoño-invierno; IP= invierno-primavera.

The results show the greatest potential performance and better adaptation to the conditions of moisture stress, which has the variety Verdín, with respect to the varieties commonly used by farmers in Veracruz and Chiapas.

The Verdín variety has adaptability in tropical and subtropical areas of both entities, as well as similar regions of southeastern Mexico. It can be grown under conditions of residual and temporary humidity in areas with rainfall greater than or equal to 300 mm, well distributed during the crop cycle, with altitudes of 0 to 1 200 m in soils of different textures, preferably well drained with pH of 5.5 to 7.

In Cotaxtla Experimental INIFAP, there is the original seed Verdin, to produce registered seed, if seed producer associations or companies wishing to acquire, to produce certified seed. The number of recorded final of this cultivar in the National Catalogue of Plant Varieties established by the SNICS is: FRI-091-050315.