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Different inoculation techniques viz. inoculation of sets by dipping in spore suspension, bud inoculation with hypodermic syringe, bud wrapping by cotton swab dipped in smut suspension and inoculation of underground bud at the time of tillering (end May) were tested to screen against sugarcane smut in the field as well as in the laboratory conditions. In the field, out of the tested inoculation techniques, the maximum disease incidence (60.63%) was observed when buds were inoculated with hypodermic syringe and minimum (8.55%) in inoculation of underground buds at the time of tillering stage. The result showed that inoculation through mechanical injury significantly increase disease incidence but at the same time also affect the bud germination (15.56%). Significant difference in smut incidence was also observed when the inoculation was carried by teliospores and sporidia separately. Key words: Ustilago scitaminea, inoculation technique, screening, resistance, sugarcane.

A comprehensive germplasm evaluation study of wheat accessions conserved in the Indian National Genebank was conducted to identify sources of rust and spot blotch resistance. Genebank accessions comprising three species of wheat-Triticum aestivum, T. durum and T. dicoccum were screened sequentially at multiple disease hotspots, during the 2011-14 crop seasons, carrying only resistant accessions to the next step of evaluation. Wheat accessions which were found to be resistant in the field were then assayed for seedling resistance and profiled using molecular markers. In the primary evaluation, 19,460 accessions were screened at Wellington (Tamil Nadu), a hotspot for wheat rusts. We identified 4925 accessions to be resistant and these were further evaluated at Gurdaspur (Punjab), a hotspot for stripe rust and at Cooch Behar (West Bengal), a hotspot for spot blotch. The second round evaluation identified 498 accessions potentially resistant to multiple rusts and 868 accessions potentially resistant to spot blotch. Evaluation of rust resistant accessions for seedling resistance against seven virulent pathotypes of three rusts under artificial epiphytotic conditions identified 137 accessions potentially resistant to multiple rusts. Molecular analysis to identify different combinations of genetic loci imparting resistance to leaf rust, stem rust, stripe rust and spot blotch using linked molecular markers, identified 45 wheat accessions containing known resistance genes against all three rusts as well as a QTL for spot blotch resistance. The resistant germplasm accessions, particularly against stripe rust, identified in this study can be excellent potential candidates to be employed for breeding resistance into the background of high yielding wheat cultivars through conventional or molecular breeding approaches, and are expected to contribute toward food security at national and global levels.

Two field experiments were conducted to ascertain the potential of micropropagation technique for faster production of seed cane by using tissue culture plants raised through apical meristem culture in first generation (TC 0) followed by clonal propagation through cane setts in next generation (TC1). About 18, 520 plants, produced from a single shoot through micropropagation, were required at row to row and plant to plant spacing of 90 and 60 cm, respectively as compared to 88 quintal of cane seed in conventional methods for planting in an area of one hectare. Multiplication ratio was 100–150 times using tissue culture plants as compared to 11–12 using conventional cane setts, leading to drastic reduction in seed cane requirement. The TC 1 exhibited superiority over vegetatively propagated conventional crop for millable canes and stalk yield by 17 and 10.4 per cent, respectively. Though the single cane weight and cane diameter (non-significantly) were slightly lesser in TC1 as compared to conventional crop, this did not distress its potential as seed crop. The incidence of Ratoon Stunting Disease (RSD) and Leaf Scald Disease (LSD) was very low in TC 1 crop as compared to conventional crop. The findings established the potential of tissue culture technique for the production of quality seed free of pests and pathogens in the existing varieties and rapid multiplication of newly released varieties for quick adoption by the growers.