Effects of Polyamines on Growth and Morphological Characteristics of the Microtubers in Potato (Solanum tuberosum L.)

Abstract

Potato (Solanum tuberosum L.) is the most widely produced tuberous crop all over the world because of its high nutritional values. Tissue culture practices are commonly used to produce trueto-type and virus-free planting materials of potato as compared to traditional means. Various plant growth regulators (PGRs) and polyamines (PAs) are known to influence the initiation and growth of microtuber. The aim of the study was to see the effects of different concentrations of 6-benzylaminopurine (6-BAP), Putrescine (PUT), Indole-3-butyric acid (IBA) either singly or in combination on microtuberization of some Indian potato cultivars namely Kufri Pukhraj (KPu), Kufri Jyoti (KJy), Kufri Chipsona-2 (KC-2); the exotic cv. Desiree (DE) was used as a reference. In the first set of experiments, Murashige and Skoog (MS) medium containing 80 g/L sucrose was supplemented with 500mg/L Cholorocholine chloride (CCC) with different concentrations of BAP (0-100 µM). TB3 medium (50 µM BAP) was found to be most suitable for microtuberization in terms of number, fresh weight and yield of microtubers. This medium was found to be most effective for DE with regard to shoot survival (84 ± 3.16%), number of microtubers per bottle (56.0 ± 1.26), tuber weight (4554.3 ± 54.8 mg), and diameter (0.58 ± 0.01 cm). For the second set of experiments, MS media with 80 g/L sucrose, 10 mg/L BAP and 500 mg/L s(CCC) with different concentrations of Putrescine (0 µM-1000µM) were used. In this case, microtuber production was significantly improved in TP4 medium (600 µM PUT) for the cultivars KPu and KJy; whereas TP5 medium (800 µM PUT) remained most effective for the cv. DE as evident from maximum tuber number (55.4 ± 0.94 per bottle), tuber weight (6391.9 ± 100.88 mg) and diameter (0.65 ± 0.05 cm). In the third sets of experiments, the media formulations were MS medium supplemented with 80 g/L sucrose, 2.5 mg/L BAP with different conc. of IBA (0 ̶50 µM). TI3 medium (10 µM), was found to be most effective in microtuberization for the cultivars, KC-2, KJy and DE. KC-2 showed best results in terms of microtuber weight (2357.2 ± 61.35 mg) and diameter (0.71 ± 0.02 cm) in TI3 medium in comparison to KJy and DE. Effects of 6-BAP, PUT and IBA appeared to be distinct in the process of microtuberization. All these data would be helpful to understand the process of microtuberization in potato. Keywords: Potato (Solanum tuberosum L.) cultivars, 6-benzylaminopurine, Putrescine, Indole-3- butyric Acid, Microtuberization, Morphological parameters and yield of microtubers