INTER-SIMPLE SEQUENCE REPEAT ANALYSIS AND ALLELIC DIVERSITY AMONG GENOTYPES OF CULTIVATED Digitaria species

J A Morakinyo,R Krishnamurthy,D A Animasaun,K F Awujoola

doi:10.3329/bjpbg.v30i2.32473

Abstract

Acha (Digitaria exilis Kipps. and D. iburua Stapf.) are valuable indigenous food crops in West Africa, but despite several economic potentials of this crop, little or no attention is paid to its germplasm evaluation and improvement. In this study, we assessed genetic diversity and relationship among genotypes of cultivated acha in Nigeria using Inter-Simple Sequence Repeat (ISSR) markers for the first time. Genomic DNA were extracted from the genotypes and we performed fragment amplification by Polymerase Chain Reaction (PCR). A total of 95 loci consisting of 790 bands were amplified by 13 ISSR primers, out of which 53.37% were polymorphic. Loci amplification per primer ranged from 5-10, with an average of 7.30 loci per primer. Eight of the primers had above 50% polymorphism. Cluster analysis separated the genotypes into two major groups; a group consisting of two D. exilis genotypes and the other comprising a mixture of genotypes. The D. exilis in the latter group were distant members and was only similar at 0.72 similarity index. The polymorphism we obtained in the present study showed that the ISSR markers are effective for assessment of genetic diversity of the genotypes. Clustering of D. exilis and D. iburua together suggests a common progenitor but could have been separated by geographical isolation mechanism

Highlights

Digitaria exilis (Kipps) Stapf. and D. iburua Stapf. called fonio millets represent an integral component of millet biodiversity in the savannah zone of West-Africa
Final extension was at 72 oC for 10 minutes and the system was put on hold for at 4oC for 10 minutes. 5 μl of the Polymerase Chain Reaction (PCR) products was mixed with 1 μl of 6 X gel loading dye and electrophoresed on 1.5% agarose gel stained with ethidium bromide using 1X TAE buffer
The concentrations of genomic DNA extracted from the genotypes of acha ranged from 123.81-186.03 g/ μl, the OD (Optical Density) at 260/280 nm was between 1.51 and 1.72 (Table 2)

Summary

Introduction

Digitaria exilis (Kipps) Stapf. and D. iburua Stapf. (acha) called fonio millets represent an integral component of millet biodiversity in the savannah zone of West-Africa. A number of wild species occurred as forage grasses, D. iburua (black acha) and D. exilis (white acha) are used for food in West and other parts of Africa (Adoukonou-Sagbadja et al, 2006). Acha is native to West-Africa where it is cultivated in the savannah regions, but the species D. iburua is currently limited in areas of cultivation. It is only found in Northern Nigeria, Togo and Benin, which represent a relic of formerly wider cultivation (Porteres, 1946; Haq and Ogbe, 1995). Unlike D. iburua, D. exilis has wider areas of cultivation and had been reportedly cultivated in Dominican Republic (Morales-Payan et al, 2002). The protein composition is rich in methionine and cystine, two vital amino-acids usually deficient in major cereals (Vietmeyer et al, 1996)

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Results

Conclusion