Executive Summary : | Lack of sufficient quantity and quality of fodder is the major constrain to livestock productivity in India. Presently country is facing net deficit of 31% of green fodder and 12% of dry fodder. Further, the average cow milk yield in India is 1014kg/animal/year which is 52% lesser than world average. Pearl millet (Cenchrus americanus L.) is cultivated in 26 million hectares mainly in arid and semi-arid regions . This crop is popular kharif and summer season fodder crop. Forage digestibility is highly correlated with quality biomass supplies and milk and meat productivity of the livestock. Lignin in forage limits access of cellulolytic enzymes or rumen microorganisms to cellulose and hemicelluloses. Lignin content is negatively correlated with either in vitro or in vivo cell wall digestibility. The reduction of lignin, an indigestible phenolic polymer, directly increases the digestibility of dry matter and bioethanol production. The brown midrib (bmr) lines having characteristic reddish-brown to tan-coloured midribs in leaf blades contrasts with the pale green midrib leaf blades are associated with reduced lignin content and altered lignin composition; traits very useful to improve forage digestibility for livestock and for bioethanol production. Presently, three brown midrib mutants have been reported in pearl millet and these genes are relatively uncharacterized. The mapping of bmr genes will aids in accelerated incorporation into high biomass, multicut genotypes, leads to development of high-quality forage cultivars. The present study is designed to map and identify the genomic regions associated with bmr loci in recombinant inbred line population (RIL1) developed from crossing between a bmr line (ICBbmr07) and non bmr line (ICBP 19) using QTL mapping approach. The identified bmr loci will be validated in another RIL population (RIL2) developed from crossing between bmr line (ICBbmr09) and non bmr line (ICBP 01). The ICBbmr07 and ICBbmr09 are sister lines derived from same parent. The RIL population will be phenotyped for lignin content at two locations Jhansi and Dharwad for two years and genotyping by sequencing (GBS) approach will be used for genotyping. The SNP markers linked to bmr loci will be validated in the RIL 2 population. Further, through Insilco approach using pearl millet genome sequence we will identify the candidate bmr genes underlying genomic region flanking between markers harbouring QTL for bmr trait. The functional PCR based markers of bmr loci will be identified and validated in the RIL2 population. These validated markers subsequently can be used to transfer bmr loci into modern varieties through MABB technology to achieve cultivars with higher forage digestibility. So far, there is no reports on molecular mapping of the bmr loci in pearl millet as compared to other major forage crops sorghum and maize. This study will help in application of molecular breeding approaches for quality improvement in forage pearl millet. |
Co-PI: | Dr. Anup Kumar, ICAR-Indian Grassland and Fodder Research Institute, Jhansi, Uttar Pradesh-284003, Dr. Brijesh Kumar Mehta, ICAR-Indian Grassland and Fodder Research Institute, Jhansi, Uttar Pradesh-284003 |