Quality Seed Production, Nutritionally Enriched Variety Development and Potato Germplasm Conservation Through in Vitro and Ex Vitro Techniques

Abstract

Potato is the 2nd most important crop after rice in Bangladesh where 147.9 million people live in a small 147570 square kilometer space. The cultivable land scarcity is the major limitation for the horizontal increase of food production for the future food security of the country in terms of yield and nutritional values. The potato is the most energy efficient crop in the world that can contribute to vertical increase in food production for insuring food security in Bangladesh. Keeping this notion in mind the present research work was undertaken with a view to improve potatoes for both quantitative and qualitative attributes. In the present study the following research issues were addressed: I) The improvement of tissue culture technology for the production of high quality seed potato; ii) The development of nutritionally enriched potato cultivars through selective biochemical property profiling; iii) The improvement of pro-vitamin A and iron (Fe) content in selected potato cultivar through the induction and evaluation of soma clonal variation and iv) the improvement of the in vitro conservation method for potato germplasm conservation. For the production of high-quality seed potato using tissue culture, apical meristems of 25-35 days old field grown plants were cultured onto filter paper bridge in liquid MS medium supplemented with different formulation of GA3 and Kin. Among the various growth regulator formulations 0.5 mg/l GA3 + 0.4 mg/l Kin was found the most effective medium formulation for the primary establishment of meristem culture. The cultured meristem tips were found to grew into healthy shoots. The meristem grown plants were found free of the presence of PVX, PVY and PLRV as reveled by ELISA test. In order to improve the micropropagation method for virus free planting materials the meristem grown plantlets were cut into individual nodes and cultured separately onto MS0 medium. This experiment reveals that healthy shoot growth along with the highest numbers of culturable nodes was found when 3rd node was used as explant. In order to optimize the requirement of organic components in MS medium the individual node cuttings of six potato cultivars was sub cultured onto different MS media formulations viz. M1 (Thiamine HCl free MS medium), M2 (Nicotinic acid free MS medium), M3 (Pyridoxine HCl free MS medium), M4 (Myo-inositol free MS medium), M5 (Glycine free MS medium) and MS0. It is noticed that M2 and M3 media had no significant effect on micropropagation of six potato cultivars. Among the different cultivars, Asterix was found to be the most responsive cultivar followed by Diamant to micropropagation. Single nodal cuttings of in vitro grown plantlets of six potato cultivars were cultured onto agar solidified MS medium supplemented with different concentrations of sucrose and different BA or Kin formulations for microtube development. Single nodal cuttings were also cultured onto cotton based and cotton free MS liquid medium. Among the different treatments 8% sucrose with 10 mg/l BA or 3.5 mg/l Kin was found the most effective media formulations for microtuberizaton. The plantlets (PL) and the micro tubers (MT) of six potato cultivars were transplanted in to field in order to study their field performance. The performance of plantlet derived plants was significantly better than that of micro tuber grown plants for various characters used as assessment parameters including tuber yield. Field performance of minituber, breeder and foundation seed tubers of PL and MT groups were also studied. The tuber yield of the tissue culture derived plants was significantly higher than that of source seed propagated crop. Asterix was found to be superior to other cultivars in tuber weight. Nutritional quality of field grown fresh potato tubers of 44 potato cultivars was studied. Among the cultivars, All Red possessed the highest concentration of iron (Fe) and pro-vitamin A (β-carotene); Indurkani was possessed of high concentrations of soluble protein, iron (Fe) and phenolic compounds; Lady Rosetta had highest Zn and Co; JPR was abundant in K and Cd respectively. The cultivars Baraka, Hagri, Jam Alu and Lal Pakri were rich in Ca, starch, vitamin C and Co, respectively. On other hand cultivars Banana, Chipeta, Kenne, Blondy, Martin, Fibula and Call White were abundant in total sugar, reducing sugar, Mn, Cu, Cr, Pb and As, respectively. Callus was induced and plant was regenerated form the Calli for the induction and evaluation of soma clonal variation with a view to increase pro-vitamin A and iron (Fe) content in selected potato cultivar. The higher shoot regeneration rate was found in MS medium supplemented with 1.0 mg/1 BA + 0.1 mg/I GA3. In the field evaluation of soma clones AR-01 line appeared to show significantly higher content of iron. For in vitro germplasm conservation, single nodal explants of five potato cultivars were sub cultured onto MS medium supplemented with different sorbitol and mannitol formulations. In this experiment MS medium with 20 g/l sucrose + 40 g/l sorbitol was the most effective medium formulation where the survivability of plantlet was the longest.