Direct Shoot Regeneration from Unfertilized Ovaries in Heterotic Maize Hybrids HQPM-1 and HM-5

摘要

Development of haploids in heterotic maize hybrids has great potential application in maize breeding and is first step to obtain doubled haploid lines. To achieve this, protocol for direct shoot regeneration response has been developed in two important heterotic maize hybrids (HQPM-1 and HM-5), using unfertilized ovaries as explants. In vitro contamination free cultures were obtained maximum (90%), when ears bearing unfertilized ovaries of all stages in both the hybrids were surface sterilized with 0.1% mercuric chloride for 8 min, without giving any pre-surface sterilization treatment. MS basal medium was found best for direct shoot regeneration response among different basal media used (MS, LS, Chu and Nitsch). Maximum percentage of explants (36.7%) turned green showing response was found in hybrid HQPM-1 on kinetin supplemented medium. Maximum shoot regeneration response (30%, 2-3 shoots/explant) was observed on MS basal medium, supplemented with kinetin alone, among different combinations of media tried in HQPM-1 hybrid followed by HM-5 hybrid (14.1 %, 1 -2 shoots/explant) on the same medium. Genotypically, maize hybrid HQPM-1 was found better for direct shoot regeneration response than maize hybrid HM-5.