An alternative source for regenerable embryogenic callus induction from shoot tips of wheat [Triticum aestivum L.]

Abstract

A reliable and efficient protocol for the regeneration of fertile plants derived from wheat [Triticum aestivum L.] shoot tips has been developed in present study. Shoot tips of 3, 4 and 5 days old seedlings of six wheat genotypes were cultured on T medium containing 10 mgll 2, 4-0 for callus induction. Callus induction was significantly best in 3 days old shoot tips. Therefore, only 3 days old shoot tips were further used as a source of explant. Callus induction was significantly higher (82.9%) on T medium than 85 medium (76.3%) from 3 days old shoot tips. Callus initiation took place after 15 days on both the media. Regeneration took place through embryogenesis followed by shoot morphogenesis. Only 20 to 25 per cent shoot regeneration was obtained when both the calli (T and 85 medium derived) after 6 weeks of inoculation were transferred on MS medium without growth regulators or supplemented with 1 mgti SAP + 0.2 mgll NAA. Kinetin at all levels (0 to 5 mgt1) also failed to induce shoot regeneration. However, 3 days old shoot tips when cultured on MS medium beatified with 2.5 mgll 2, 4-0 (MS1) or 2 mgll 2, 4-0 + 0.2 mgll casein hydrolysate (MS2). Callus initiation took place within 6-7 days. Callus induction percentage was observed upto 94.4 on MS1 medium while 95.2 on MS2 medium. Shoot regeneration was achieved when calli were transferred after 5 weeks on MS medium bestified with 0.2 mgtl NAA. Regeneration percentage ranged from 75.2 (MS1 derived calli) to 83.3 (MS2 calli). Number of shoots per callus ranged from 3-8 and highest number was observed in WH 542. Regenerated plants were transferred to potted soil where normal growth stages proceeded with 75 per cent survival.