Marker Assisted Breeding to Transfer Striga Resistance in Sorghum from a Mapped Donor Source N13 to a Farmer Preferred Kenyan Variety Ochuti

Ngugi, Jackyline Abigail W. (2014) Marker Assisted Breeding to Transfer Striga Resistance in Sorghum from a Mapped Donor Source N13 to a Farmer Preferred Kenyan Variety Ochuti. Masters thesis, University of Nairobi.

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Abstract

The genus striga (Orobanchaceae) causes substantial losses in sorghum [(Sorghum bicolor (L.) Moench] production in sub- Saharan Africa. Yield losses in Western Kenya can range from 20 % in low infested areas to 100 % in highly infested areas. Conventional breeding methods have been used in the past, but have not been successful, however, molecular breeding have proved to be promising . Marker Assisted Selection (MAS) was used to introgress striga resistance Quantitative Trait Loci (QTLs) from the donor source N13, an Indian durra sorghum with mechanical and antibiosis resistance mechanism to striga, into a Kenyan adapted farmer preferred sorghum variety, Ochuti. Five genomic regions and molecular markers associated with stable striga resistance have been identified, these QTL are on chromosomes, A (LG1), B (LG2), I (LG6) and 2 QTLs on J (LG5) and each of these QTL accounts for 12 to 30% of the total variation observed for striga resistance. BC3F1 seeds obtained from the previous BMZ project were advanced to BC5F1 and BC3F3. At the same time, two field trials consisting of eight BC3F1 lines were laid out in a randomized complete block design during May 2010 to October 2010 and October 2010 to March 2011 at Alupe and Kibos field stations and they were artificially infested with striga. Eleven polymorphic markers flanking the five QTL were used to select for striga resistance in the BC3F2 generation. In the results two plants in the BC3F1 generation and three plants in the BC3F2 generation with four and one striga resistance QTL were identified respectively. The backcrossed lines 33 and 87 had lower striga scores than the susceptible parental check Ochuti. The study showed the success of MAS to transfer Striga resistance QTL

Item Type:	Thesis (Masters)
Subjects:	S Agriculture > SB Plant culture
Divisions:	Africana
Depositing User:	Mr. Senay Abate
Date Deposited:	29 Jul 2016 10:55
Last Modified:	18 Jul 2017 12:48
URI:	http://thesisbank.jhia.ac.ke/id/eprint/1257

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