Ártico-Common bean cultivar with export-standard white grain

BRS Ártico is a common bean cultivar with white grains with international standard size (62 g per 100 seeds), appropriate for cultivation in the Central region of Brazil and the state of Paraná. The cycle is semi-early, the yield potential 2677 kg ha-1 and BRS Ártico has moderate resistance to rust and curtobacterium wilt.


INTRODUCTION
Brazil is one of the world's largest producers of common bean (Phaseolus vulgaris L.) and a traditional staple food of Brazilians, being consumed across all social classes.However, for lower-income groups, it is the main source of protein, minerals, vitamins, and fiber.The total output of common bean in Brazil was 2.5 million tons in 2013 (Feijão 2014).The market groups carioca and black have Mesoamerican origin and represent 85% of the Brazilian production.However, there is a demand for other grain types with higher added value and possibility of export (Del Peloso and Melo 2005).Among the market groups of major international interest is the white grain group of Andean origin, with 100-grain weight between 55 and 65 g, which is sold and consumed in Europe, Asia and the United States (Gonzales et al. 2009).Historically, in Brazil little effort has been invested into breeding programs of Andean common bean, especially for grain types of the international market, including the white grain type.As a result, few cultivars are available, resulting in low domestic production and high imports of this grain type into the country.Currently, some breeding programs have been working on this kind of grain, with a view to develop and identify lines with better adaptation to the soil and climatic conditions of the country (Gonçalves et al. 2010, Pereira et al. 2014).
The release of new cultivars has contributed to increase the common bean yield in Brazil (Feijão 2014).Therefore, the search for new lines with superior phenotypes must be maintained constantly.The common bean breeding program of Embrapa Rice and Beans is focused on the search for varieties with high yield potential, better disease resistance and upright plant architecture, to enable HS Pereira et al. direct mechanical harvesting, so that farmers can offer a high quality product to consumers and obtain higher yields with this crop.In this sense, new cultivars with other grain types than carioca and black have been released in the past years, e.g.: BRSMG Realce (Melo et al. 2014), with red speckled grains; BRS Embaixador (Aidar et al. 2008a), with DRK (dark red kidney) grains; BRS Executivo (Aidar et al. 2008b), with sugar bean grain; and BRSMG União (Ramalho et al. 2012), with jalo (yellow) grains.However, for the white group, only two cultivars are registered, with smaller grain size than required for the international market: Ouro Branco (Chagas et al. 1994), indicated by Epamig/UFV; and IPR Garça, indicated by IAPAR.

BREEDING METHODS
BRS Ártico was derived from a cross {(G13922 x G13145) x {(G13922 x [G07930 x (A156 x A494)]}}, performed in 1985 at CIAT (International Center for Tropical Agriculture, Cali, Colombia).The following generations and lines were also grown in Colombia.The line WAF 75 was introduced and evaluated in the field in Brazil, between 2000 and 2010, for plant architecture, lodging, yield, reaction to angular leaf spot, anthracnose, fusarium wilt, rust, common bacterial blight, curtobacterium wilt, and for commercial quality of grains.In 2000 and 2001, the line was evaluated in the winter season at three locations in a total of 13 tests in the State of Goiás. In 2007, 2008, 2009and 2010, it was also evaluated in the winter, in Goiás and Minas Gerais and in the rainy and dry seasons in Paraná, totaling 31 evaluation environments.In all 44 tests, four controls were used: Ouro Branco, with white beans, BRS Radiante, with red speckled grains; BRS Executivo, with sugar bean grain; and Jalo Precoce, with jalo grain.The experiments were arranged in a randomized block design with three replications and plots of four 4-m rows, using recommended technologies for the different common bean cropping systems.

GRAIN YIELD AND YIELD POTENTIAL
In 44 VCU tests conducted in 2000VCU tests conducted in , 2001VCU tests conducted in , 2007VCU tests conducted in , 2008VCU tests conducted in , 2009VCU tests conducted in , and 2010, in , in the "winter" growing season in Goiás and Minas Gerais and in the "rainy" and "dry" seasons in Paraná, a yield of 92.1% was observed for BRS Ártico (WAF 75), compared to the mean of the controls (Ouro Branco and BRS Executivo/BRS Radiante/Jalo Precoce) (Table 1).These controls were chosen for being cultivars with Andean origin with "large" grain and suited for export, although not belonging to the same market group as BRS Ártico.This procedure was adopted because there were no other cultivars with the same grain pattern as BRS Ártico at the beginning of the VCU tests.BRS Executivo has sugar bean grains.BRS Radiante has red speckled grains and Jalo Precoce, yellow (jalo) grains, typical of the domestic market, which are occasionally exported when the production in countries which traditionally export other grain types is low.Cultivar Ouro Branco was represented in all experiments, as the standard control.As a second control in the experiments we used BRS Radiante, BRS Executivo or Jalo Precoce.It is worth remembering that Jalo Precoce and BRS Radiante are cultivars with grain types that were already improved in long-term breeding programs and consequently have a better agronomic performance.
The overall mean yield of BRS Ártico was 1632 kg ha -1 , compared with 1819 kg ha -1 of the controls (Ouro Branco 1870 kg ha -1 and the others 1768 kg ha -1 ).In the different States and test regions (Pereira et al. 2009), BRS Ártico produced a mean yield of 1847 kg ha -1 in Goiás and 1511 kg ha -1 in Minas Gerais.In region II (Espírito Santo, Rio de Janeiro, Mato Grosso, Goias, Distrito Federal, Bahia, Tocantins, and Maranhão) (Table 1), the mean yield was 1757 kg ha -1 .In the State

Table 1 .
Grain yield (kg ha -1 ) of BRS Ártico, compared to the control mean in the tests of Value for Cultivation and Use (VCU), per State and growing season *Region II -ES, RJ, GO, DF, MT, TO, BA and MA.