Effect of plumule maturity on embryogenic callus induction in Vietnamese aromatic coconut (cocos nuciferal.) variety

Abstract

Coconut (Cocos nucifera L.) has become one of the most essential palm crops for several countries in tropical and subtropical regions over many years. It is based on the abundantly valuable products derived from this palm crop. Among other varieties , aromatic coconut variety (Dừa Dứa in Vietnamese) has been prioritized and promoted due to the unique fragrance of its coconut water. Unfortunately, the number of coconut palms is dropping down due to many factors such as natural disasters, serious diseases and rapid senility. This leads to the lack of coconut- derived products. Therefore, the need of large scale re-plantation of this palm crop has been become one of the important missions for coconut producing countries. Microporpagation technique, also known clonal propagation technique, is believed to provide the largest number of coconut plantlets, based on its propagation capacity and ideal growth condition. There have been many studies which reported that it is possible to propagate coconut plantlets using plumule as explant. However, there is no study report on the effect of plumule maturity on embryogenic callus induction. This research was conducted to investigate the effect of plumule maturity on the induction of embryogenic callus (EC) in aromatic coconut variety with the objective to optimize the embryogenic callus formation. Five treatments with different stages of plumule tissue were used to test its effect on callus induction. Results showed that the most effective stage for embryogenic callus formation was recorded at treatment 1 week after induction. All treatments involved with pre-culture with Y3 media before initiate on callus induction media (CIM) showed more rapid change in embryogenic callus morphology than the direct one. Also, plumule maturity significantly affect the fresh weight of initial callus, the longer time plumule tissue cultured in Y3 media the larger weight callus gained. The results are promising and hoped to become the basic knowledge for further studies, which should aim to improve the protocol for mass propagation using plumule tissue in known traits of the coconut palm. Keywords Coconut Somatic embryogenesis Embryogenic callus Plumule tissue Abbreviations