NISCAIR Online Periodicals Repository Community: IJBT Vol.05 [2006]

In vitro corm induction and genetic stability of regenerated plants in taro [Colocasia esculenta (L.) Schott]

Title: In vitro corm induction and genetic stability of regenerated plants in taro [Colocasia esculenta (L.) Schott]

Authors: Hussain, Z; Tyagi, R K

Abstract: In vitro corm formation was achieved on Murashige and Skoog’s (MS) medium, containing 8-10% sucrose, 22 µM N⁶-benzyl aminopurine (BAP), 0.6 µM α-naphthaleneacetic acid (NAA) and 0.8% agar, in taro (IC 420791). The corm forming cultures could be conserved up to 15 months at 25+2^oC, whereas shoot-forming cultures could last for only 6 months on MS medium, containing 3% sucrose + 2.2 µM BAP + 0.6 µM NAA + 0.8% agar. Plantlets with in vitro-formed corms showed 100% survival in the field, and developed normal uniform corm-producing plants. Uniformity of tissue culture regenerated plants with corm (Ro) was determined on the basis of 12 qualitative and 10 quantitative morphological traits related to leaf, petiole, corm and root. Additionally, two PCR-based markers—RAPD and ISSR were also applied to determine the genetic stability of Ro plants. A total of 13 RAPD primers (of 35 tested initially) and 6 ISSR primers gave 111 distinct bands in RAPD and 43 in ISSR, and exhibited uniform RAPD and ISSR banding patterns for Ro plants tested. Our results suggested that present protocol used for in vitro corm formation may cost-effectively be applied for conservation of taro germplasm along with maintaining the genetic stability and functionality of plants. Further possibility may also be explored to use this protocol for production of disease-free planting materials. This will facilitate the national and international exchange of taro germplasms.

Page(s): 535-542

Micropropagation of Embelia ribes Burm.f. using inflorescence segments

Title: Micropropagation of Embelia ribes Burm.f. using inflorescence segments

Authors: Shankarmurthy, K; Krishna, V

Abstract: An efficient micropropagation protocol was developed for a threatened medicinal plant, Embelia ribes using inflorescence explants. The immature ovaries of the inflorescence segments proliferated into luxuriant mass of callus on Murashige and Skoog’s (MS) medium supplemented with IBA (3.5 mg/L) and Kn (0.5 mg/L). The combination of Kn and NAA in the range of 2.0 to 4.0 mg/L and 0.2 to 0.6 mg/L, respectively provoked the calli to differentiate into both shoot and root initials from the ovary callus. Highest number of regenerants (25±0.81per callus) were obtained at the concentration of 3.0 mg/L Kn and 0.4 mg/L NAA. The regenerants were transferred to the pots containing sterilized soil and hardened for a week. A mean of 21.82±1.02 regenerants per harvest were well acclimatized to the natural conditions exhibiting a normal development.

Page(s): 551-554

In vitro cloning of apple (Malus domestica Borkh) employing forced shoot tip cultures of M9 rootstock

Title: In vitro cloning of apple (Malus domestica Borkh) employing forced shoot tip cultures of M9 rootstock

Authors: Dalal, M Amin; Das, B; Sharma, A K; Mir, M Amin; Sounduri, Amarjeet Singh

Abstract: For micropropagation of adult apple (Malus domestica Borkh) rootstock M9, explants were harvested from pre-chilled (4±3°C) dormant cuttings forced in growth chamber. Primary explants were established by using a slightly modified version of culture initiation procedure developed earlier. Multiple shoots, raised by axillary branching of surviving explants, were obtained from established cultures in two cultural pathways: (i) repeat transfer of primary explants on the MS supplemented with BAP (2.22 µM), IBA (0.49 µM) and Kn (2.2 µM), and (ii) repeat subculture of harvested microshoots and basal portion of sectored proliferating clumps on the same but suitably PGR amended medium, in which cytokinins concentration was reduced by half. A 4-fold shoot multiplication was achieved during each sub culture of 3±1 week’s duration that repeatedly produced crop of proliferated shoots without loss of vigour. Nodal segments (5-15 mm), obtained from in vitro raised microshoots were also used to initiate a new cycle of proliferating cultures. Isolated cloned microshoots (15-20 mm) with apical bud were cultured on MS basal medium supplemented with IBA (14.70 µM) for 8±3 d to initiate root. The microshoots were re-implanted in PGR free half strength basal MS medium with full complement of organics for 4±1 week for root development. The transferred in vitro hardened plantlets to polyvinyl cups or polybags, under carefully controlled descending RH regime of 95% to 70±5% over a period of 5±1 week, resulted in 80% ex vitro survival. The present protocol highlighted a novel strategy of micropropagation of apple rootstock M9 using three-step culture initiation procedure of forced primary explants.

Page(s): 543-550

Assessment of variability in the regenerants from long-term cultures of ‘safed musli’ (Chlorophytum borivilianum)

Title: Assessment of variability in the regenerants from long-term cultures of ‘safed musli’ (Chlorophytum borivilianum)

Authors: Arora, Dilip K; Suri, Sarabjeet S; Ramawat, K G

Abstract: Somatic embryogenesis in long-term calluses of seedling and leaf explants, obtained from in vitro grown plants of Chlorophytum borivilianum—an endangered medicinal herb, has been achieved. Large number of plants were established in the field and evaluated for variability among the regenerants. The plantlets obtained through seedling-derived embryonic callus showed high level of morphological and cytological variations, which increased with the increase in age of cultures. Occasionally, variegated plants were also observed. Variation in leaf size, stomatal number, epidermal cell size and chromosomal number was observed in regenerants. Chromosomal variation was the least (3X-3 to 3X+3) in regenerants from 1 to 4-month-old cultures and increased (5X-1 to 7X) with the age in regenerants from cultures older than 6 months. Alternatively, regenerated plants from somatic embryos recurrently obtained from leaf explants showed very little variation (0.62%) in RAPD fingerprinting. However, further improvement in somatic embryogenesis is required for domestication of the plant using biotechnological method of propagation.

Page(s): 527-534