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Drought is a serious bottleneck in the production of rice globally. For this, an experiment was conducted in-vitro on six rice genotypes viz. BRRI Dhan-28, Begunbahar, Burikatari, Pashpai, Dular and Begunbichi to investigate the effect polyethylene glycol (PEG) mediated artificial drought on morpho-physiological parameters such as germination percentage, shoot length, root length, fresh weight, dry weight, turgid weight, relative water content and proline accumulation. Here, different doses of PEG-6000 viz. 0gL-1, 15gL-1, 30gL-1, 45gL-1 and 60gL-1 were used with Murashige and Skoog (MS) medium. The results demonstrated that BRRI Dhan-28, Burikatari and Dular revealed greater performance at control conditions but at the highest degree of water stress conditions only Burikatari showed higher mean value for all parameters studied. Again, Begunbichi followed by BRRI Dhan-28 exhibited the lowest mean value for almost all traits except for proline accumulation. Here, water stress decreased the performance of morpho-physiological characters except proline accumulation in rice. The cluster analysis was performed and distributed into three groups where there was a significant variation among the clusters at different water stress conditions. Here, the genotype Burikatari is more diverse giving maximum Euclidian distances in drought treatments. It could be considered as a parent in the hybridization program against Begunbahar, Dular and Paspai. Therefore, considering the mean performances and cluster analysis, Burikatari exhibited greater performances against the highest degree of drought conditions. This genotype may bear drought-tolerant gene for which could be utilized for further development of drought-tolerant variety and gene transfer.

Keywords: Zea mays L.; Embryo Rescue; Embryo Culture; In vitro ConditionThe experiment was conducted with six selected inbred lines of maize (Zea mays L.) viz. ML-15, ML-10, ML-8, ML-28, ML-22 and ML-9 to assess regeneration ability from immature embryo at the tissue culture laboratory of the department of Genetics and Plant breeding, Hajee Mohammad Danesh Science and Technology, Dinajpur, Bangladesh from November 2017 to February 2018. Here, four different concentrations and combinations of hormones viz. 1.0 mgl -1 2,4-D (2,4-Dichlorophenoxyacetic Acid), 1.0 mgl -1 BAP (6-Benzyl Amino Purine), 1.0 mgl -1 Kinetin and BAP (1.0 mgl -1 )+ Kinetin (1.0 mgl -1 ) supplemented with N6 (Chu) medium were used for embryogenic callus formation and plantlet regeneration. The inbred lines ML15, ML22 and ML9 revealed 100% direct somatic embryogenesis (germination) under treatments BAP (1.0 mgl -1 ) + Kinetin (1.0 mgl -1 ), Kinetin (1.0 mgl -1 ) and control treatments, respectively. The root length among the regenerated plantlet ranged from 0.66 to 4.83cm. Here, the longest root length was recorded in inbred line ML10 (4.83 cm) under 2,4-D (1.0 mgl -1 ) treatment. The shoot length was ranged from 1.40 to 5.43 cm. The inbred line ML-15 of BAP (1.0 mgl -1 ) treatment exhibited maximum shoot length (5.43cm) followed by ML15 of treatment BAP (1.0 mgl -1 ) + Kinetin (1.0 mgl -1 ).After hardening, the highest establishment rate was observed on ML10 as 100% under all treatment derived plants. And the plantlet derived from BAP and Kinetin combinations produced the maximum establishment rate (100%) for all the genotypes. The maximum root length was observed from 2,4-D regenerated inbred line ML15 (5.8cm) followed by the same genotype (5.5cm) from BAP and Kinetin combinations. The plantlet derived from BAP and Kinetin revealed maximum shoot length by genotype ML9 (9.2cm). Overall, in pot conditions, the superior shoot length performances were recorded in inbred regenerated plants from BAP + Kinetin and BAP treatments. Among the six inbred line of maize, ML-10 of treatment 2, 4-D and ML-22 of treatment BAP were successfully established in soil with the highest survival rate (100%). Again, the correlation studies revealed significant positive relationship between root length and shoot length. Considering the seedling vigour index, the genotype ML10 and ML 28 revealed superior index value in most of the treatments. Overall, the inbred lines ML10 and ML28 identified as superior genotypes for plant regeneration and the treatment combination BAP (1.0 mgl -1 ) +Kinetin (1.0 mgl -1 ) were identical for immature embryos generation. Furthermore, this novel protocol might play a significant role in overcoming further interspecific and intrageneric maize hybrids. Maize (Zea mays L.) is a member of the Gramineae or grass family. It is a monocotyledonous plant with a diploid chromosome number of 2n = 2x = 20 [1]. It is a particularly convenient plant for genetic studies because it can readily be either self or cross-pollinated with large numbers of se...