Simple sequence repeat (SSR)-based diversity analysis of groundnut (Arachis hypogaea L.) germplasm resistant to bacterial wilt

Mace, E S and Yuejin, W and Boshou, L and Upadhyaya, H D and Chandra, S and Crouch, J H (2007) Simple sequence repeat (SSR)-based diversity analysis of groundnut (Arachis hypogaea L.) germplasm resistant to bacterial wilt. Plant Genetic Resources: Characterization and Utilization, 5 (1). pp. 27-36.

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Abstract

Groundnut is one of the most important oilseed crops in the world. Bacterial wilt, caused by Ralstonia solanacearum E. F. Smith, is one of the major biotic constraints to groundnut production particularly in South-East Asia and East Africa. Several sources of resistance to bacterial wilt have been identified through field screening of groundnut germplasm. The aim of the present study was to quantify the genetic diversity among selected bacterial wilt-resistant lines, in comparison with the levels of variation observable within the cultivated A. hypogaea gene pool. Thirty-two SSR markers were used to assess the degree of molecular polymorphism between 46 selected genotypes revealing 107 alleles, of which 101 (99.4%) were polymorphic with gene diversity scores ranging from 0.103 to 0.669, averaging 0.386. Cluster and multidimensional scaling analysis revealed two distinct groups within the germplasm broadly corresponding to the two subspecies (hypogaea and fastigiata) of A. hypogaea. However, accessions of varieties peruviana and aequatoriana grouped together with the varieties from subsp. hypogaea, rather than grouping with the other varieties of subsp. fastigiata. Analysis of molecular variance (AMOVA) revealed that 15% of the total observed variation was accounted for by disease response groups. This analysis will be useful in the selection of parental genotypes for mapping populations and breeding programmes attempting to broaden the genetic base of future groundnut cultivars. In particular, this opens up significant opportunities for the development of intraspecific mapping populations that will be highly relevant to modern groundnut breeding programmes.

Item Type:	Article
Divisions:	UNSPECIFIED
CRP:	UNSPECIFIED
Subjects:	Mandate crops > Groundnut
Depositing User:	Library ICRISAT
Date Deposited:	04 Sep 2011 18:00
Last Modified:	04 Sep 2011 18:00
URI:	http://oar.icrisat.org/id/eprint/917
Official URL:	http://dx.doi.org/10.1017/S1479262107390916
Projects:	UNSPECIFIED
Funders:	Asian Development Bank, Government of Japan , Government of UK, European Union
Acknowledgement:	The authors gratefully acknowledge Mr A. Gafoor for technical assistance, Mr S. Hari Krishna for biometrical advice and Dr M. Ferguson for early access to SSR markers. This research was undertaken as part of the Asian Development Bank-funded project ‘Rapid Crop Improvement for Poor Farmers in the Semi-Arid Tropics of Asia’ (RETA 5945). Biotechnology research at ICRISAT is grateful for unrestricted grants from the governments of Japan and the UK and from the European Union
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