PEARL MILLET IMPROVEMENT FOR RESISTANCE AGAINST DISEASES
Kushal Raj, R. K. Arya and R. Kumar
*Department of Plant Pathology
CCS Haryana Agricultural University- Hisar
(Received 29 Nonember; Accepted 27 December 2014)
Bajra is the fourth most important crop, whose cultivation mainly confines to dry land regions. Gene manipulation using conventional and advanced approaches as well as genetic resource conservation and evaluation is an activity that supports the national crop improvement programme to cope with the biotic and abiotic stresses while maintaining high level of productivity, profitability and quality. It’s wild species are tertiary gene pool species as reservoir of important genes such as apomixis, perenniality, fodder characteristics, stress tolerance thereby pearl millet improvement has potential of utilizing interspecific hybridization. Plant pathological research in pearl millet did not receive adequate attention until the F1 hybrids, based on cytoplasmic male sterile line, released for commercial cultivation in India in the mid-1960’s and become susceptible to downy mildew in early 1970’s. The superiority of hybrids over open pollinated varieties for grain yield, uniform growth and shorter duration resulted in substantial increase in area under hybrid cultivation and this favoured incidence of diseases. The crop yield is adversely affected by several biotic factors which cause substantial yield losses and also adversely affected the quality of produce and thus reduce its market value. Among these, downy mildew (Sclerospora graminicola), smut (Tolyposporium penicillariae.) and ergot (Claviceps fusiformis) are of economic importance in major pearl-millet growing areas of the country. Disease management using resistant cultivars is the most feasible way in pearl millet production. Attempts have been made in the past to identify sources of resistance to downy mildew in India Based on resistant sources, several resistant hybrids and varieties were released for general cultivation in India. However, identification of new sources of resistance is required to find resistance against evolving virulence where pearl millet is widely cultivated. Plants use a wide range of mechanisms to resist infection and disease caused by pathogenic organisms. Mechanical or chemical barrier present in the epidermal layer of plant tissue prevent the successful establishment and growth of many potential pathogens. A common strategy of resistance breeding utilizing major genes involves: an effective screening method, availability of diverse germplasm, confirmed sources of resistance, knowledge of genetics of resistance, information on variability in virulence, effective utilization of resistance in breeding, and deployment and on-farm monitoring of performance of cultivar. Different breeding methods i.e. Mutation, Recombination / back cross and biotechnological tools are used for incorporation of resistance / tolerance genes and obtained several interspecific cross, identified genomic regions. In the light of past studies, it is proposed that future downy mildew and other disease management need based strategy in pearl millet should be focussed on based on future thrust.
Key words:pearl millet, resistance, breeding, diseases.