Yield gap in cowpea plants as function of water déficits during reproductive stage

Abstract

<jats:p>ABSTRACT The cowpea bean presents low productivity in the Pará state, Brazil, due to low soil fertility and climatic adversity, mainly water deficiency. The aim of this study was to evaluate the yield gap of cowpea bean in northeast of Para state in response to water deficit during its reproductive phase. The experiment was carried out in Castanhal, PA, Brazil, during 2015 and 2016. A randomized block design with six repetitions and four treatments was used; where T1 consisted of 100% replacement of the crop evapotranspiration (ETc), T2 to 50%, T3 to 25% and T4 without irrigation, in the reproductive phase. The yield was determined at R9 stage. The simulations with the SARRAZON model were carried out with different sowing dates. The total deficiencies in the reproductive phase were spatialized considering the 30 locations in order to assess the temporal and spatial seasonality of water availability and the sowing period in the study region. The cowpea bean was sensitive to soil water availability with considerable reductions in productivity due to the increase in water deficit compared to the treatment T1 (100% ETc). When water deficits reached more than 47 mm, there were yield gaps over 20%. According to the spatial variability of simulated water deficiency, the sowing of cowpea bean in regions located above 2° latitude may extend until June 20 without showing high yield gaps.</jats:p>

Impacts of climate changes on risk zoning for cowpea in the Amazonian tropical conditions

“…The highest yields of cowpea for the northeast region of Pará are obtained when it is sown between April 1st to 20th (Nunes et al 2019). After May 20th, yield gaps of more than 20% are expected due to the climatological water deficit in the region during reproductive stage of this culture (Souza et al 2020). In similar studies carried out for different regions of Brazil, water deficit seems to be the main limiting factor for cowpea production.…”

“…Such scenarios may increase the possibility of greater yield gap for cowpea due to the higher frequency of water deficiencies during the reproductive phase, considering J.V.N. Pinto et al that for this region and for this crop, when water deficits during reproductive stage reach more than 47 mm, yield gaps greater than 20% can occur (Souza et al 2020).…”

“…Water deficits higher than 47 mm during reproductive stage promote larger yield gaps on cowpea cultivated in northeastern Pará state, which defines an optimal sowing season for the cultivar BRS-Tracuateua up to June 20th as the limit optimal sowing date in order to avoid yield gaps higher than 20% (Souza et al 2020). The ideal final sowing date for cowpea in this region in order to guarantee the highest yield (90% of probability) and yield gaps less than 10% would be between April 1st to 20th (Nunes et al 2019).…”

Cowpea Ecophysiological Responses to Accumulated Water Deficiency during the Reproductive Phase in Northeastern Pará, Brazil

“…Results were submitted to regression analysis, and the significance of the generated equations was verified according to the F test [4], considering them valid as long as they were greater than 95% of probability. Productivity and ecophysiological variables data were subjected to analysis of variance and the means were compared by Tukey's test at 5% probability, using ORIGIN PRO 8.0v software (OriginLab Corp., Northampton, MA, USA) [11].…”

Selection of Soybean and Cowpea Cultivars with Superior Performance under Drought Using Growth and Biochemical Aspects

“…On the other hand, the global production of cowpea reached around 9.6 million tons in 2021, with highlights in African countries [9,10]. Moreover, Brazil is among the largest producers with one million hectares of land, despite its production mainly being concentrated in the Northeast region where the drought and soil quality are abiotic factors limiting cowpea's ability to grow satisfactorily, especially during the pod filling stage, resulting in losses above 30% [4,11,12].…”