Regeneración de maíces blancos subtropicales vía embriogénesis somática

Abstract

Maize (Zea mays L.) is destined mainly for animal feed (yellow maizes) and in a smaller proportion for human consumption (white). The subtropical white maizes are important for humans. However, there are problems of regeneration, via somatic embryogenesis, that limit its genetic transformation. Therefore the objective of the present study was to evaluate somatic embryogenesis in nine lines of subtropical white maize. In the induction of somatic embryogenesis, 1, 2 and 5 mg L−1 of 2,4-D and Dicamba were evaluated. Lines 78, 395 and 444 produced 70.1 to 87.2% of embryogenic calluses, similar to the controls (67.2 to 74.7%). Lines 442 and 332 presented a mean induction rate of calluses of 48.4 to 60.6%, whereas 330, 202, 204 and 331 showed the lowest percentages (3.9 to 26.2%). Lines 330, 331 and the control 216×72 presented the highest percentages with Dicamba, whereas line 442 had its highest percentage with 2,4-D. The induction of the lines varies among doses. Line 395 regenerated 1.11 plants per callus, similar to the three controls (0.74-0.95 plants), while 442, 78 and 332 regenerated 0.67, 0.37 and 0.33. Rooted seedlings (92-99%) and acclimatization (95-100%) were obtained in lines 395, 442, 78 and 332. The number of fertile regenerated plants was 228, 187, 108 and 79 in lines 395, 442, 78 and 332. Four embryogenic lines of subtropical white maize (395, 442, 78 and 332) were identified with regeneration capacity of fertile plants in 17 weeks and with potential for being subjected to genetic transformation.