Are Portuguese Cowpea Genotypes Adapted to Drought? Phenological Development and Grain Quality Evaluation

Abstract

Along with population growth, global climate change represents a critical threat to agricultural production, compromising the goal of achieving food and nutrition security for all. It is urgent to create sustainable and resilient agri-food systems capable of feeding the world without debilitating the planet. The Food and Agriculture Organization of the United Nations (FAO) refers to pulses as a superfood, as one of the most nutritious crops with high health benefits. Considered to be low-cost, many can be produced in arid lands and have an extended shelf-life. Their cultivation helps reduce greenhouse gases and increases carbon sequestration, also improving soil fertility. Cowpea, Vigna unguiculata (L.) Walp. is particularly drought tolerant, with a wide diversity of landraces adapted to different environments. Considering the importance of knowing and valuing the genetic variability of this species in Portugal, this study assessed the impact of drought on four landraces of cowpea (L1 to L4) from different regions of the country and a national commercial variety (CV) as a reference. The development and evaluation of morphological characteristics were monitored in response to terminal drought (imposed during the reproductive phase), and its effects were evaluated on the yield and quality of the produced grain, namely the weight of 100 grains, color, protein content, and soluble sugars. Under drought conditions, the landraces L1 and L2 showed early maturation as a strategy to avoid water deficit. Morphological alteration of the aerial part of the plants was evident in all genotypes, with a rapid reduction in the number of leaves and a reduction in the number of flowers and pods by between 44 and 72%. The parameters of grain quality, the weight of 100 grains, color, protein, and soluble sugars did not vary significantly, except for sugars of the raffinose family that is associated with the adaptive mechanisms of plants to drought. The performance and maintenance of the evaluated characteristics reflect the adaptation acquired in the past by exposure to the Mediterranean climate, highlighting the potential agronomic and genetic value, still little exploited, that could contribute to production stability, preserved nutritional value, and food safety under water stress.

Drought Stress Under a Nano-Farming Approach: A Review

“…Drought related grain yield reduction when comparing organic farming and conservation tillage practices was 34, 23 and 17% lower in the organic system for maize, pea-barley, and winter wheat, respectively (Wittwer et al 2023). Several studies have been published on the impacts of drought stress under different farming systems in many regions, such as rainfed farming in Afghanistan (Aliyar et al 2022), agroforestry and goat system in India (Palsaniya et al 2023), wet crop farming in Indonesia (Irawan et al 2023), rice farming in Vietnam (van Aalst et al 2023), semi-arid farming in Zimbabwe (Mupepi and Matsa 2023), organic farming and conventional farming in Switzerland (Wittwer et al 2023;Gavín-Centol et al 2023), cowpea farming in Portugal (Moreira et al 2023), agricultural drought in northeast Italy (Sofia et al 2023) and southern China (Pan et al 2023), and meteorological droughts in China (Zhang et al 2023). Drought stress has been found to reduce invertebrate feeding activity in soils under conventional agriculture, which is associated with mesofauna and their vertical migration, and which decreased with soil depth (Gavín-Centol et al 2023).…”