Cytokinin induced shoot regeneration and flowering of Scoparia dulcis L.(Scrophulariaceae)-an ethnomedicinal herb

Objective:To develop an improved protocol for micropropagation of ethnomedicinally important Scoparia dulcis(S.dulcis) L.Methods:Explants were inoculated on MS basal medium supplemented with kinelin and 6-benzylaminopurine for shoot bud induction.To enhance the shoot induction,various auxins like 3-indoleacetic acid or 3-indolebutyric acid or a-naphthylacetic acid were tested along with 2.32 M KI and 4.44 μ M BAP.The regenerated shoots were rooted in half strength MS medium supplemented with various concentrations of IAA,IBA or NAA.After roots were developed,the plantlets were transplanted to pots filled with vermiculate and sand and kept in growth chamber with 70%-80%humidity under 16 h photoperiod.After acclimatization,the plantlets were transferred to the garden and survival percentage was calculated.Data were statistically analyzed and means were compared using Duncan's multiple range test(P<0.05).Results:An in vitro method was developed to induce high frequency shoots regeneration from stem,mature leaf and young leaf explants of S.dulcis.Shoot induction on young leaf explants was most successful in MS medium supplemented with combination of two cytokinins(2.32 μ M KI and 4.44 μ M BAP) 2.85 μ M IAA,10%CM and 1 483.79 μM adenine sulfate.A single young leaf explant was capable of producing 59 shoots after 13 days of culture. Flower was induced in medium supplemented with combination of KI and BAP.Conclusions: Cytokinins are the key factor to induce the direct shoot regeneration and flowering of S.dulcis.

DNA polymorphisms and genetic relationship among populations of Acacia leucophloea using RAPD markers

RAPD （randomly amplified polymorphic DNA） markers were employed to characterize polymorphisms among 5 provenances of Acacia leucophloea and to detect genetic relatedness of the species with 6 other acacias （A. holosericea, A. auriculiformis, A. mangium, A. dealbata, A. ferruginea, and A. nilotica） widely grown in India. Of 194 markers scored for the provenances, 29.38% exhibited polymorphism. Also, 326 markers were generated among 7 species of Acacia, accounting for 55.82% of the polymorphisms. The fifteen 10-mer primers employed were capable of producing 1-8 polymorphic bands for the provenances, and 6-17 for all seven species of Acacia. The genetic similarity coefficient based on Jaccard＇ s coefficient revealed that provenances Thirumangalam and Dharmapuri were closely related. The dendrogram based on a sequential agglomerative hierarchical non-overlapping （SAHN） clustering analysis grouped 4 provenances of A. leucophloea （Dharapuram, Thirumangalam, Pudukottai and Dharmapuri） into one cluster and the other provenance, Sendurai, into a separate cluster. The genetic similarity matrix for 7 Acacia species showed that A. nilotica and A. dealbata were distantly related, while A. holosericea and A. ferruginea were very closely related. Cluster analysis grouped the species of Acacias into 3 major groups of which A. dealbata alone formed a separate group. The RAPD markers generated 36 provenance-specific markers and 162 species-specific markers that could have strong applications for species identification and tree breeding programs for A. leucophloea and for other Acacia species included in this study.

Potential Impact of Spacing and Fertilizer Levels on the Flowering, Productivity and Economic Viability of Hybrid Bhendi (<i>Abelmoschus esculentus</i>L. Moench) under Drip Fertigation System

Drip irrigation provides an efficient method of fertilizer delivery and allows precise timing and uniform distribution of applied nutrients. Fertilizer application through drip irrigation (fertigation) can reduce fertilizer usage and minimize groundwater pollution due to fertilizer leaching from excessive irrigation. For this purpose, field experiments were carried out in the farmers’ field at Thoppur, Dharmapuri District, Tamil Nadu, during 2010-2012 to study the effect of spacing and fertilizer levels on the flowering, pod yield and economic viability of Bhendi Hybrid (Abelmoschus esculentus L. Moench) under drip fertigation system. The treatments consisted of two spacings (M1—60 × 45 cm and M2— 60 × 30 cm) and eight drip fertigation levels (S1—Drip fertigation with WSF at 125 per cent RDF + Azophosmet + Humic acid, S2—Drip fertigation with WSF at 100 per cent RDF + Azophosmet + Humic acid, S3—Drip fertigation with WSF at 75 per cent RDF + Azophosmet + Humic acid, S4—Drip fertigation with WSF at 100 per cent RDF, S5—Drip fertigation with SF at 125 per cent RDF + Azophosmet + Humic acid, S6—Drip fertigation with SF at 100 per cent RDF + Azophosmet + Humic acid, S7—Drip fertigation with SF at 75 per cent RDF + Azophosmet + Humic acid, S8—Drip fertigation with SF at 100 per cent RDF), and were replicated thrice in a split plot design. Results showed that the earliest flowering (26.21 days), 50% flowering (51.31), number of flowers per plant (25.33) and highest pod yield of 596.70 g/plant, 24.91 t/ha was registered in drip fertigation at 100 per cent recommended dose of fertilizers as water soluble fertilizer combination with Azophosmet and humic acid under wider spacing. The economics of the study clearly showed that drip fertigation at 100 per cent recommended dose of fertilizers as water soluble fertilizer along with Azophosmet and humic acid under wider spacing was found to record higher BCR of 2.99.