Comparative study of the physiological and health quality of traditional and biofortified cowpea seeds.

Cowpea is one of the main crops in family agriculture, especially in the Northeastern region of Brazil, and it is expanding to other regions in Brazil. The use of seeds with low physiological and health quality is reflected in the plant development and consequently yield, making it important to study the seed physiological and health quality. The objective of the present study was to assess the physiology and health of traditional and biofortified cowpea seeds. The traditional cowpea varieties (Angelim, Mercado and Manteguinha) and the biofortified cowpea cultivars (BRS Aracê, BRS Xique-Xique and BRS Tumucumaque) were assessed for the following physiological parameters: water content (WC), first count (FC), germination test (G), germination speed index (GSI), seedling emergence in the greenhouse (E), emergence speed index (ESI), seedling aerial part and root length (APL and RL) and electric conductivity test (EC). The seed health quality was assessed by the Blotter Test. The water content present in the seeds of the traditional and biofortified varieties ranged from 10% to 14%. All the traditional and biofortified varieties showed high germination and emergence value in the greenhouse. The germination and emergence speed indexes indicated the BRS Aracê and BRS Xique-Xique cultivars as the most vigorous. In the health tests the highest indexes were the storage fungi Aspergillus sp., Cladosporium sp. and Penicillium sp., with the highest prevalence in the BRS Tumucumaque variety, which was probably related to the higher water content present in this variety.

Identification and pathogenic characterization of endophytic Fusarium species from cowpea seeds.

Isolates of Fusarium were obtained and identified from seeds of cowpea, Vigna unguiculata (L.) Walp., by means of blotter tests and slide cultures. Species were differentiated according to the morphology of the macroconidia, microconidia and their arrangement in chains or false heads, the size and type of conidiophore, and the presence or absence of chlamydospores. The species were identified as F. semitectum, F. equiseti, F. oxysporum, F. solani, F. anthophilum, F. sporotrichioides, F. moniliforme, and Fusarium sp. Among the species, F. semitectum was the most frequently detected. None of these species were pathogenic when inoculated in susceptible cowpea cultivar (BR 17-Gurgueia). But, an isolate of F. oxysporum f. sp. tracheiphilum used as a standard of comparison for pathogenicity (control) induced symptoms of yellowing, vascular wilting, and death of a susceptible cowpea cultivar under the same environmental conditions.