Influence of Culture Media and Their Compositions on Haploid Induction in Indian Short Day Onion

Abstract

Two media, Gamborg’s medium (B5) and Murashige and Skoog’s medium (MS) with various combinations, were used to study their effect on haploid induction efficiency from unpollinated flowers or ovaries in tropical short day onion. In B5 medium, highest induction efficiency (1.9%) was observed on HAP18 followed by HAP17 and HAP05 whereas in MS medium, HAP40 recorded highest induction frequency (5.0%) followed by HAP32. Kinetin, meta-topolin, thidiazuron did not influence embryo induction. Sucrose at 7.5% in B5 medium and at 10% in MS medium was found to be optimum for induction. Days for plantlet induction were 98.9 ± 3.9 days in B5 medium and 83.1 ± 2.7 days in MS medium. Induction rate of 0.51% and survival of 27.8% in B5 medium and induction rate of 0.72% and survival of 33% in MS medium were observed. Three haploids, 1 mixoploid and 1 diploid in B5 medium and 2 haploids, one diploid in MS medium were obtained. Flow cytometry and cytology confirmed the status of haploid plants. MS medium was found to be better than B5 medium and newer combinations for haploid induction were identified. Plant Preservative Mixture (PPM™) at 1 mg/l was found to be efficient for inhibiting contamination from field grown flower buds. These combinations will be helpful in devising new strategies for faster and higher rate of haploid induction in tropical short day Indian cultivars.