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Wetland species mat rush (Juncus effusus L.) is an important economic plant, but no information is available regarding plant regeneration, callus induction, and its proliferation from in vitro seed grown plantlets. The present study investigates the effects of growth regulator combinations and medium innovation on tissue culture system of five mat rush varieties. Addition of N6-benzyladenine (BA) and 2,4-dichlorophenoxyacetic acid (2,4-D) in Murashige and Skoog (MS) medium showed significantly positive effect on callus proliferation, plant regeneration, and its multiplication compared to the medium devoid of BA. The highest callus induction frequency (80.95%, 90.48%, 75.40%, 70.83%, and 83.33%) was observed in MS medium containing 0.5 mg L −1 (2.2 μM) BA in Yinlin-1, Nonglin-4, Gangshan, Taicao, and Taiwan green, respectively. Various growth regulator combinations with successive subculture (medium replacement) were found essential to develop organogenic calluses and to regenerate shoots. The combination of 0.1 mg L −1 BA (0.4 μM) and 2 mg L −1 2,4-D (9.0 μM) in MS medium was found best for callus proliferation for all the varieties under trial. The plant regeneration required two steps involving successive medium replacements as well as optimal hormonal balances. Successful plant regeneration (over 70%) was observed only by transferring the organogenic callus from regeneration medium I [MS medium containing 0.5 mg L −1 BA (2. μM) and 1.0 mg L −1 kinetin (KT; 4.6 μM)] to the regeneration medium II [MS medium containing 0.5 mg L −1 BA (2.2 μM), 1.0 mg L −1 KT (4.6 μM) and 3.0 mg L −1 indoleacetic acid (IAA; 17.1 μM)]. Our results confirmed the importance of the ratio of auxin (IAA) to cytokinin (BA and KT) in the manipulation of shoot regeneration in J. effusus L. The maximum plant survival frequency and multiplication rates (90.97% and 5.40 and 94.23% and 8.25) were recorded in the presence of 0.5 mg L −1 BA (2.2 μM) in the 1/2 MS multiplication medium for the varieties of Nonglin-4 and Taicao, respectively. About 100% survival rate was also observed for all the varieties in soil conditions. The efficient plant regeneration system developed here will be helpful for rapid micropropagation and further genetic improvement in J. effusus L.

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To estimate combining ability and heritability of F2 populations of 4 x 4 full diallel crosses and parents, an experiment was carried out at The University of Agriculture, during 2012-2013. Four parental lines and F2 populations of six direct and six reciprocal crosses were planted in the experiment using RCB design. Data were recorded on phenological and vegetative growth traits: Days to flowering, plant height, main stem length, main raceme length, primary branches, and days to maturity. Analysis of variance revealed significant variation among genotypes for all the parameters studied. The results of combining ability analysis showed that general combining ability (GCA) was highly significant for primary branches plant-1 , significant for plant height and days to physiological maturity and non-significant for the remaining traits. Specific combining ability (SCA) and reciprocal effects (RE) were significant for plant height, days to flowering, main raceme length and days to physiological maturity. Genotype AUP-401 was best general combiner for main raceme length, primary branches plant-1 and days to physiological maturity. Among the crosses, AUP-404 x AUP-402 was best specific combiner for plant height, days to flowering and main stem length. Broad sense heritability was high (>70%) for plant height, main stem length and primary branches. Moderate heritability was observed for main raceme length, days to 50% flowering and days to physiological maturity. The variance components of SCA were greater than respective GCA components of all the characters signifying the presence of non-118