Evaluation of Elite Sorghum Accessions for Multiple Disease Resistance
Several plant diseases reduce grain and fodder yields of sorghum (Sorg/jum bicolor) and its stover quality (Bandyopadhyay et al. 2001). Participatory rural appraisal studies In India by Rama Devi et al. (2000) Indicated that sale of crop residues to perl-urban milk producers accounted for approximately 50% of the income from sorghum cropping In rural areas of the Deccan Plateau of Andhra Pradesh, Karnataka and Maharashtra, and diseased residues command much lower price In the fodder market. Adverse effects of foliar and panicle diseases on quality and quantity of sorghum grain, fodder and residues have recently been reported (Bandyopadhyay et al. 2000, 2001). Most sorghum diseases can be effectively managed through host-plant resistance. The objective of this study was to Identify resistance to multiple diseases in the selected agronomic elite landrace accessions and breeding lines of sorghum. In this article we report both agronomic features and multiple disease resistance of some of the accessions for their possible use in resistance breeding program.
Sorghum pathology and biotechnology - a fungal disease perspective: Part II. Anthracnose, stalk rot, and downy mildew
Foliar diseases and stalk rots are among the most damaging diseases of sorghum in terms of lost production potential, thus commanding considerable research time and expenditure. This review will focus on anthracnose, a fungal disease that causes both foliar symptoms and stalk rots along with the stalk rots caused by Fusarium spp. and Macrophomina phaseolina. Although the downy mildews are caused by oomycetes rather than true fungi, recent outbreaks have revealed resistance to previously effective chemical seed treatments and the evolution of new pathogenic races, once again pointing out the need for continuous vigilance. Sorghum diseases are described with respect to the causal organism or organisms, infection process, global distribution, pathogen variability and effects on grain production. In addition, screening methods for identifying resistant cultivars and the genetic basis for host resistance including molecular tags for resistance genes are described where possible along with prospects for future advances in more stable disease control. _____________________________________________________________________________________________________________
Pasteurella haemolytica serotype 1 colonization of the nasal passages of virus-infected calves.
Nasal passages of calves with a virus-induced respiratory tract disease became colonized by Pasteurella haemolytica serotype 1 after they were inoculated intranasally with P haemolytica. Inoculation with infectious bovine rhinotracheitis virus caused a more severe clinical illness and resulted in a greater degree of colonization with P haemolytica than developed after inoculation with parainfluenza-3 virus. Nasal passages of parainfluenza-3 virus-inoculated calves were colonized to a greater degree with P haemolytica than were those of healthy, nonstressed calves. Calves were susceptible to P haemolytica colonization during or shortly after virus-induced illness, even though they had been previously exposed to P haemolytica and had serum antibody and nasal secretion antibody to P haemolytica.