Fundamental studies for cross breeding in taro

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The purpose of the present study was to obtain the fundamental findings for cross breeding in taro. The main findings obtained are shown as follows.Meiosis of pollen mother cells was relatively normal and pollen fertility was high in wild diploid taros from Bangladesh investigated. These wild taros flowered and fruited well. The seeds obtained by artificial crossings germinated easily. These results indicated that these wild taros have high ability to perform seed propagation. In these experiments, a large amount of selfed and crossed seedlings were obtained. Both the selfed and crossed seedlings contained triploid ones with low frequency in addition to diploid ones. This proved that triploid taros originated in selfing and crossing between diploid ones. Through isozyme analysis of the triploid hybrids, it was indicated that there are two ways of forming triploid taros. These two ways are 1)zygosis between unreduced female gamate and reduced male gamate and 2)zygosis between reduced female gamate and unreduced male gamate.The data obtained by isozyme analysis using Japanese and foreign varieties/accessions of taro gave some clues to clarify the origin of the Japanese lateral tuber varieties(triploid varieties).Shoot apex culture was revealed to be useful for long term preservation of taro plants in vitro. The simple freezing method was suggested to be suitable for cryopreservation of taro.