Callus Induction And Plant Regeneration Of Different Elite Wheat (Triticum Aestivum L.) Varieties

Wheat is one of the most important crops in the world, and many researchers always attach importance to its genetic improvement. With the development of biotechnology, great progresses have been made in upgrading wheat varieties by means of cell and gene engineering. Compared to the characteristics of callus induction and plant regeneration of different wheat varieties, and the correlation between callus induction and plant regeneration under the conditions of four callus induction media and three differentiation media, immature embryos of 24 elite wheat varieties which are cultivated widely in the Yangtze River valley and the central region of China were used to research. At the same time, mature embryos of 24 elite wheat varieties were also studied to compare the characteristic of callus induction and plant regeneration of different wheat varieties under the conditions of three callus induction media and one differentiation medium. In addition, the characteristics of tissue culture (in vitro) between immature embryos and mature embryos of wheat were compared and analyzed. In this paper, some experimental results are concluded as follows:1. Significant difference had been observed when immature embryos of 24 elite wheat varieties were cultured on four callus induction media. Especially, MM2 medium with the average callus induction frequency of 98.5% is the most efficient callus induction medium, and there were significant differences among media and genotypes in callus induction frequency. Except for 13397 and yumai60, the average callus induction frequency of other wheat varieties are more than 90%.Germination happened in every wheat genotype which was cultured in four callus induction media; there were also significant differences among media and genotypes. When calli inducted from immature embryos were cultured on three differentiation media, significant differences among media and genotypes were present. Especially, M5B medium with the average differentiation frequency of 39.80% is the best differentiation medium, and the wheatvarieties carrying excellent agronomic characters, such as Zheng9023, Yangmail58, Huamail2, YangmailO, Email4, Yumail8,Yangmai9 and Hua9943 had high regeneration capacity, suggesting that those varieties were suitable for genetic improvement. In addition, there was no significant correlation between callus induction frequency and differentiation frequency.2. Mature embryos of 24 elite wheat varieties were cultured on three callus induction media, and siginificant difference had also been achieved. Among callus induction meida MB5 supplemented with ABA induced the highest numbers of calli. Different varieties showed significantly different responses under various culture conditions. There are four wheat varieties including Hua9943 and Hua9914 that displayed comparable induction frequencies in three induction media, whereas the remaining varieties showed a significantly different response in different media. Different varieties varied very significantly in their differentiations of green spot and plant regeneration. Several varieties such as Nongdal46, Sumai3, Yangmail58, Huamail2 and Huamai8 exhibited much higher regeneration rate than others. Consequently, it is important to screen best combinations of medium and genotype in the culture of wheat mature embryos for callus induction and plant regeneration.3. There was no significant correlation between the culture of immature embryos and the culture of mature embryos of the same wheat variety not only in the process of callus induction but also in plant regeneration, while the culture efficiency of immature embryo is higher than mature embryo.