Abstract
Cowpea varieties that are more competitive against weeds are, by themselves, not enough to control the weeds. However, the adoption of more-competitive varieties, together with other cropping practices, including planting density and weeding, can provide greater weed control in addition to affording the farmer more time to carry out this control. This study had the following objectives: a) to identify, in a preliminary evaluation (E-1), varieties that are the most competitive against weeds, based on dry grain yield; b) among the most-competitive varieties, identify the most productive in terms of green and dry grain yield (E-2). The seeds used for E-1 were obtained from producers chosen at random from each of 48 districts in the State of Rio Grande do Norte. A randomized block design with five replications was used. In E-2, the twelve varieties presenting the highest grain yield in E-1 were evaluated in a randomized block design with five replications. In both evaluations, only one weeding was carried out, 30 days after sowing. In E-1, the Umarizal, Itau, Upanema, Lagoa de Pedras, Jose da Penha and Sao Tome varieties were superior. The second experiment demonstrated that Umarizal is the most productive variety in terms of pod yield and green grain. There is no difference between the varieties for dry grain yield. The Umarizal variety has potential for use in the production of green pods and grains, and of dry grains. The preliminary evaluation is effective in identifying superior varieties.
Highlights
The Northeast of Brazil covers an area of 1,561,178 km2 (18.3% of the country)
The aims of this study were a) to identify, in a preliminary evaluation based on grain yield, traditional varieties that are more competitive against weeds; and b) among the most competitive varieties, identify the most productive in terms of green grain and dry grain yield
The weed species occurring during experiment-1 were: Adenocalymma sp. (80), Alternanthera tenella Colla (40), Borreria verticillata L. (40), Cenchrus echinatus L. (100), Commelina benghalensis L. (20), Dactyloctenium aegyptium (L.) Willd. (20), Digitaria sp. (100), Panicum maximum Jacq. (20) and Turnera subulata Sm. (40)
Summary
The Northeast of Brazil covers an area of 1,561,178 km (18.3% of the country). Of this area, 62% corresponds to the semi-arid region, with 56,760,780 inhabitants (27.2% of the total population) (BNB, 2018). In the semi-arid region, weed management in the cowpea is by hoeing, which is arduous, time-consuming and expensive. Each requiring the work of one man over ten days, would currently cost at least BRL 1,000.00 (MEKONNEN et al, 2017). This activity, made more difficult on rainy days, is often carried out by poor and undernourished people. The adoption of cowpea varieties with greater competitive ability against weeds can help reduce the work of the farmer and maintain higher yields
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