Selection of cowpea populations tolerant to water deficit by selection index

Erina Vitório Rodrigues,Kaesel Jackson Damasceno-Silva,Maurisrael de Moura Rocha,Adriano dos Santos,Edson Alves Bastos

doi:10.5935/1806-6690.20170105

Abstract

The objective of this work was to use different selection criteria to identify cowpea genotypes tolerant to water deficit to be used in recurrent selection programs aiming to reduce the cowpea crop cycle and improve its productive components. Six cowpea genotypes were crossed in a complete diallel scheme. The experiment was conducted in an incomplete block experimental design in a triple lattice arrangement, with the 30 F2 populations of cowpea. The genetic variability of 10 traits was verified, and the following selection criteria were used: direct and indirect selection, classical index, index based on desired gains, and index based on sum of ranks. The number of days to flowering (NDF), number of days to maturity (NDMD), pod weight (PW), grain weight per pod (GWP) and 100-grain weight (100GW) were classified as primary traits, and the others as secondary. The direct selection based on the pod weight was the most efficient criterion to reduce the crop cycle and improve productive components of the cowpea genotypes subjected to water deficit conditions. The genotypes Pingo-de-Ouro-1-2 × MNC99-510F-16-1, CNCx698-128G × MNC99-510F-16-1, MNC99-510F-16-1 × Pingo-de-Ouro-1-2, Pingo-de-Ouro-1-2 × BRS Paraguacu, Santo-Inacio × Pingo-de-Ouro-1-2, BRS Xiquexique × Pingo-de-Ouro-1-2 and Pingo-de-Ouro-1-2 × Santo-Inacio were the most suitable to be used in interpopulation recurrent selection programs aiming to reduce the crop cycle and improve productive components of cowpea grown under water deficit conditions.

Highlights

Cowpea [Vigna unguiculata (L.) Walp] is one of the most important and strategic food sources in tropical and subtropical regions of the world (AGBICODO et al, 2009)
The direct selection based on the pod weight was the most efficient criterion to reduce the crop cycle and improve productive components of the cowpea genotypes subjected to water deficit conditions
The genotypes Pingo-de-Ouro-1-2 × MNC99-510F-16-1, CNCx698-128G × MNC99-510F-16-1, MNC99-510F-16-1 × Pingo-de-Ouro-1-2, Pingo-de-Ouro-1-2 × BRS Paraguaçu, Santo-Inácio × Pingo-de-Ouro-1-2, BRS Xiquexique × Pingo-de-Ouro-1-2 and Pingo-de-Ouro-1-2 × SantoInácio were the most suitable to be used in interpopulation recurrent selection programs aiming to reduce the crop cycle and improve productive components of cowpea grown under water deficit conditions

Summary

Introduction

Cowpea [Vigna unguiculata (L.) Walp] is one of the most important and strategic food sources in tropical and subtropical regions of the world (AGBICODO et al, 2009). Brazil is the third largest world producer of this crop, which is cultivated in the North and Northeast regions of the country and is the basic food of low-income populations (OLIVEIRA et al, 2013). According to Almeida et al (2014), there are frequent supply deficits in these regions due to the cowpea low national average yield (300 kg ha-1). Water deficit is common in these regions of Brazil and is one of the factors that reduce the cowpea yield (MENDES et al, 2007). Agbicodo et al (2009) point out that the cowpea ‘drought scape’ by shortening its cycle is one of the main mechanism used by this species to avoid water deficit. Identifying genotypes with early cycles is one of the most promising strategies to minimize the water deficit in this crop

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