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Blast caused by Pyricularia grisea [teleomorph: Magnaporthe grisea] is an economically important and widespread disease of finger millet in the world. Host resistance is the most economical and effective means of combating this disease as finger millet is predominantly grown by resource-poor and marginal farmers. At International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), we evaluated a finger millet mini-core collection of 80 germplasm accessions (about 1% of the total germplasm collection representing major trait variability) for blast resistance both in field and greenhouse. Field evaluation was done using a refined screening technique that included new improved rating scales for leaf, neck and finger infection. Sixty six of the 80 accessions showed combined resistance to leaf, neck and finger blast in two seasons (2009 and 2010) of field screening. A highly significant and positive correlation was found between neck and finger blast ratings (r = 0.92), whereas small but significant correlations were found between leaf blast and neck blast (r = 0.25) and between leaf blast and finger blast (r = 0.30). These accessions were also screened for leaf blast resistance in the greenhouse by artificial inoculation of seedlings to confirm field observations. Fifty-eight of the 80 accessions were resistant to leaf blast in the greenhouse screen as well. These resistant accessions represented one wild (africana) and four cultivated races (vulgaris, plana, elongate and compacta) of finger millet that originated from 3 13 countries in Asia and Africa and exhibited considerable diversity for agronomic traits, such as maturity period, plant height and panicle type. These blast resistant accessions from the mini-core collection would be useful in finger millet disease resistance breeding programs.

Castor (Ricinus communis L.) a chief non-edible oilseed crop has numerous industrial applications. Systematic genetic diversity analysis utilizing DNA based markers has been quick and reliable method that ensures selection of diverse parents for exploitation of higher levels of heterosis in breeding programs. From NCBI database, 63,852 EST sequences of castor were mined. One thousand one hundred and five (1105) EST-SSRs and 1652 repeat motifs sequences were identified from 20,495 non-redundant unigene sequences. Repeat motifs consisted of 29.7 % mono nucleotide repeats, 24.8 % di nucleotide repeats, 27.27 % tri nucleotide repeats and 3.94 % tetra nucleotide repeats. Twenty eight primer pairs were chosen from SSRcontaining ESTs to determine genetic diversity among 27 castor accessions. Twelve EST-SSRs showed polymorphism. Number of alleles detected were 2-3 with an average of 2.33 per locus. 150-400 bp was the size of an allele. Dendrogram analysis grouped the 27 accessions into two separate clusters. Genetic similarity coefficient of dendrogram ranged from 0.24 to 0.83. The polymorphic information content value of 0.28-0.49 revealed medium level of diversity in castor. Results of present study indicated that EST-SSRs to be efficient markers for genetic diversity studies. Knowledge on level of diversity existing in castor genotypes would be useful for breeders to plan efficient hybrid breeding programme.

Finger millet blast caused by Magnaporthe grisea(anamorph: Pyricularia grisea) is a great threat to finger millet production worldwide. Genetic diversity and population structure of 72M. griseaisolates collected from finger millet (56), foxtail millet (6), pearl millet (7) and rice (3) frommajor crop growing areas inIndiawas studied using 24 SSR markers. None of the SSRs detected polymorphism in the M. grisea isolates from pearl millet. Seventeen SSR markers were polymorphicin the 65 non pearl millet isolates anddetected 105 alleles, of which one was rare, 83 common, 9 frequent and 12 most frequent. A model-based population structure analysis of the genomic data identified two distinct populations with varying levels of ancestral admixtures among the 65M. griseaisolates. Analysis of molecular variance (AMOVA)indicated that 52% of the total variation among the isolates used in this study was due to differences between the pathogen populations adapted to different hosts, 42% was due to differences in the isolates from the same host, and the remaining 6% due to heterozygosity within isolates. High genetic variability present in M. grisea isolates calls for the continuous monitoring of M. grisea populations anticipating blast resistance breakdown in finger millet cultivars grown in India. Key words:Genetic diversity, Simple sequence repeats, Magnaporthe grisea, Eleusine coracana Highlights: Seventeen of the 24 SSR markers were polymorphic and detected 105 alleles in the 65Magnaporthegriseaisolates.  Cluster analysis of SSR data classified the isolates into three major groups that corresponded with the host specificity.  A model-based population structure analysis identified two distinct populations with varying levels of ancestral admixtures.Kiran Babu et al., 2013 Physiological and molecular plant pathology 3 IntroductionFinger millet (Eleusine coracana L. Gaertn) is a widely grown grain cereal in the semi- grisea populations adapted to finger millet, foxtail millet, pearl millet and rice. Material and Methods Pathogen isolatesBlast infected (leaf, neck and finger) samples of finger millet, foxtail millet and rice were collected from Vizianagaram, Patancheru, and Nandyal in Andhra Pradesh, Mandya and Naganahalli in Karnataka, and Dholi in Bihar, India during 2008-10 rainy seasons (Table 1).In addition, seven M. grisea isolates from four major pearl millet growing states in IndiaRajasthan, Haryana, Maharashtra and Uttar Pradesh [25] were also included in this study (Table 1). Isolations of M. grisea were made from the blast-infected tissue on oatmeal agar medium (rolled oats 50 g, agar 15 g, distilled water 1 L) and incubated at 25±1°C for 15 days.After incubation, a dilute spore suspension (3×10 3 spores/ml) was prepared in sterile doubledistilled water and plated onto 4% water agar in Petri plates. Single germinating conidia were marked after 10-12 h of incubation under a microscope and transferred to test tubes containing oatmeal agar for further studies. Isolation of genomic DNAKiran Babu et al., 2013...

Blast, caused by Pyricularia grisea (teleomorph: Magnaporthe grisea), is the most devastating disease of finger millet affecting production, utilization, and trade in Africa and Southeast Asia. An attempt was made to select a set of putative host differentials that can be used to determine virulence diversity in finger-millet-infecting populations of M. grisea. Thus, a differential set comprising eight germplasm accessions selected from finger millet core collection (IE 2911, IE 2957, IE 3392, IE 4497, IE 5091, IE 6240, IE 6337, and IE 7079) and a resistant (‘GPU 28’) and a susceptible (‘VR 708’) variety was developed. This differential set was used to study pathogenic variation in 25 isolates of M. grisea collected from Karnataka, Telangana, and Andhra Pradesh states in India. Based on the reaction (virulent = score ≥4 and avirulent = score ≤3 on a 1-to-9 scale) on host differentials, nine pathotypes were identified among 25 M. grisea isolates. Pathotype 9, represented by isolate Pg23 from Vizianagaram, was the most virulent because it could infect all of the host differentials except GPU 28. This study will be helpful in devising strategies for monitoring virulence change in M. grisea populations, and for identification of blast resistance in finger millet for use in disease resistance breeding programs.