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.
Screening of Rice Germplasms for Their Resistance against Sheath Rot Disease (Sarocladium oryzae) at Fogera, Ethiopia
Sheath rot, caused by Sarocladium oryzae (Sawada) is one of the major diseases of rice. The pathogen mainly infects the upper most flag leaf sheaths that enclose the emerging young panicle during the boot stage. The lesions are oblong or irregular oval spot and usually expressed as a reddish-brown discoloration of the flag-leaf sheath. Early or severe infection affects the panicle so that it only partially emerges. The unmerged portion of the panicle rots, turning florets red-brown to dark brown. Grains from damaged panicles are discolored reddish-brown to dark brown and may not fill the affected grains, are known as chaffy grains and the disease is appropriately known as “empty head” and is familiar as “rice abortion” [1]. Moreover, the pathogen is mostly observed on the entire seed (about 46%) and on the lemma and/or palea (about 31%) [2]. Sheath rot is one of the most serious and devastating rice diseases in wetland rice growing regions [3]. The pathogen attacks flag leaf sheaths and grains and yield losses result mainly from poor panicle formation and exertion, spikelet sterility (80-100%), reduced grain filling, and losses in milling [4]. Quality is also affected as severe attacks lead to chaffy, discolored grains and affect viability and nutritional value of the grains followed by a decrease in the protein and starch contents of infected seeds [5]. Seeds from infected panicles become discolored and sterile, thereby reducing grain yield and quality significantly. Since the pathogen attacks the crop at maturity starting from panicle initiation stages; its impact is direct to minimize the crop yields. There was a yield loss report ranging from 20% to 85% in Taiwan and 30 to 80% in Vietnam, the Philippines and India [6]. Variability in yield loss depends upon prevailing favorable conditions under which rice is grown and the level of susceptibility of the grown cultivar [7]. In Ethiopia, diseases of rice in general, and sheath rot in particular is not well studied. This is because rice cultivation in the country is at infant stage, and that associated production constraints are not well known along with the fact that importance of diseases of newly introduced crops are expanding and manifesting them gradually with the time. However, now a day sheath rot becomes major rice disease especially in Fogera plains with prevalence, incidence and severity of 100, 47 and 44%, respectively (unpublished). Therefore, unless effective management measure is taken, the disease will cause high yield loss with the consequence that leads the rice crop to be out of production in the area. Thus, there is a need to establish
Experimental models in antifungal chemotherapy
Summary. This review summarizes detailed information about a wide variety of animal models of fungal infections used for research and in the pharmaceutical industry.