Somatic Embryogenesis And Regeneration Of Maize Genotypes Sc Duma 43 And Dho4 At Coastal Region Of Kenya

ABSTRACT

Maize (Zea mays L.) is the world third most important cereal crop after rice and wheat. It can been used as fodder crop, food crop for human consumptions, also used as raw material for manufacture of sweetener, starch and biofuel. However, tropical maize breeding is faced by many challenges which are biotic, abiotic and most genotypes are recalcitrant and genotype dependent. In this study, two tropical coastal maize genotypes SC DUMA 43 and DHO4, were evaluated for embryogenesis and regeneration. The main aim of this study was to establish a regeneration system of maize genotypes and evaluate the effect of age of immature embryos at different levels of growth regulators. Callus induction was achieved using Murashige and Skoog (MS) basal medium supplemented with 1mg/L, 2mg/L, 3mg/L, 4mg/L and 5mg/L of 2,4-D and dicamba. Immature embryos were used as the source of explants harvested at the age of 8, 10, 12, 14, 16 and 18 days after pollination. All data collected were analyzed using ANOVA at 95% confidence interval with MINITAB statistical computer software (version 23.22). Among the coastal varieties evaluated SC DUMA 43 had the highest callus induction frequencies of 97% and 96% in media amended with 2, 4-D and dicamba using immature embryos harvested at age of 12 and 10 days after pollination. Great variations was observed among the coastal genotypes evaluated in this study in regard to their embryogenic and regeneration frequencies. DHO4 was most regenerable variety with regeneration frequencies of 44% using immature embryos that were initially induced in media amended with dicamba while regeneration frequency of 34% was obtained using immature embryos harvested 12 days after pollination and initially induced in media amended with 2,4-D. Great interaction was also observed between age of immature embryos and genotypes on embryogenic callus induction and subsequent regeneration of coastal maize genotypes evaluated in this study. This regeneration protocol will be a good platform for maize breeding programme of coastal maize genotypes using coastal ecosystem hence food sustainability.