Tea leaves have economic importance in preparation of the popular beverage of the world "tea". Bird's eye spot disease of tea leaves creates significant revenue loss in tea trade of many tea plant cultivating countries. Management of this disease by silver (AgNps) and copper (CuNps) nanoparticles that are biosynthesised by efficient antagonists was studied. The biocontrol agents like Pseudomonas fluorescens, Trichoderma atroviride and Streptomyces sannanensis were evaluated for nanoparticle synthesis against Cercospora theae isolates namely KC10, MC24 and VC38. Initially, the freshly prepared extracellular AgNps showed high disease control (59.42 - 79.76%), but the stability of antagonistic property in stored nanoparticles were significantly high in CuNps (58.71 - 73.81%). Greenhouse studies on various treatments imposed also showed reduced disease incidence percentage of 13.4, 7.57 and 10.11% when treated with CuNps synthesized by P. fluorescens, T. atroviride and S. sannanensis respectively. Various treatment schedule in fields suggested the use of Bionanocopper@1.5 ppm for highest yield (3743 kg/ha) with 66.1% disease prevention. The results suggest the use of biosynthesised CuNps using Streptomyces sannanensis for controlling the tea plant pathogens causing foliar disease with higher stability in releasing the antagonistic activity during sporadic disease incidence of bird's eye spot disease in tea plants.

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Seven cucumber (Cucumissativus L.) genotypes (3 lines and 4 testers) were crossed in a line × tester mating design. The resultant 12 hybrids and their parents were evaluated using Randomised Block Design with two replications during Kharif 2018. Sufficient genetic variability was observed for all the characters under study. In this study, the parents L2 (Koradacherry local), T2 (Orathanadu local) and T3 (Aipatti local) exhibited high positive GCA (General Combining Ability) effects for yield related traits and high negative GCA effects for earliness characters. The parent T2 identified in this study may be used in multiple crossing programme to isolate high yielding varieties. Among the hybrid combinations, L2xT3, L1xT2 and L3xT4 expressed the maximum positive significant SCA (Specific Combining Ability) effects for yield and yield associated characters. In the above cross combinations one parent was a good combiner and the other was an average/poor combiner; hence the hybrids can be exploited for transgressive selection.

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