International Journal of Plant Breeding and Genetics

International Journal of Plant Breeding and Genetics ISSN 5756-2148 Vol. 4 (6), pp. 292-299, July, 2017. © International Scholars Journals

Full Length Research Paper

Quantitative trait loci (QTL) for cowpea resistance to flower bud thrips (Megalurothrips sjostedti Trybom)

Gonné Sobda1*, Ousmane Boukar2, Pangirayi Bernard Tongoona3, Jonathan Ayertey3 and Kwame Samuel Offei3

1Institute of Agricultural Research for Development, P.O.BOX 33 Maroua, Cameroon.

2International Institute of Tropical Agriculture, Sabo Bakin Zuwo Road PMB 3112, Kano, Nigeria.

3West Africa Centre for Crop Improvement, University of Ghana, PMB 30, Legon, Accra, Ghana.

*Corresponding author: sobdagonne@gmail.com. Tel: +237 699 98 83 11

Accepted 12 July, 2017

Abstract

Cowpea flower bud thrips causes about 80% yield losses in cowpea. Host plant resistance is the most easy and durable solution to the damaging effects caused by this insect. However, resistance to thrips is quantitatively inherited, thus less amenable through conventional breeding. The objective of this study was to identify QTL associated with resistance to cowpea flower bud thrips in a bid to facilitate the improvement of cowpea resistance to thrips. A mapping population consisting of 150 F2 plants derived from cross between the highly resistant SANZI (female) and the highly susceptible VYA (male) was screened under artificial infestation in the screen house. Thrips damage scores were used as the parameter for resistance. A total of 232 polymorphic Single Nucleotide Polymorphism (SNP) markers were used for genotyping of F2 and the parents. Three significant QTLs for thrips resistance Fthp28, Fthp87 and Fthp129were detected on chromosomes 2, 4 and 6 accounting for 24.5, 12.2 and 6.5 % of the total phenotypic variation respectively. Transgressive segregation was observed towards the susceptible phenotype. Both additive and non-additive QTL effects were observed with additive effects being predominant. Further studies to validate these QTL for their useful exploitation in marker-assisted breeding programme are essential. 

Key words: Cowpea, flower bud thrips, Quantitative Trait Loci, polymorphic SNP.