|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1991 : ¥200,000 (Direct Cost : ¥200,000)
Fiscal Year 1990 : ¥1,800,000 (Direct Cost : ¥1,800,000)
The purpose of this studies is to define a possibility of improving the phenotype of Allium wakegi Araki by using its cytochimeras. The cytochimeras (4-2-2; 2-4-4) and the polyploids (2-2-2; 4-4-4) of A.wakegi and/or those of A. fistulosum L. were used for the studies, and the following subjects were investigated: 1) a method for analyzing chimerisum by the number of nucleoli per cell; 2) cytochimeral stability during propagation; 3) stomata and 4) growth characteristics; and 5) photosynthetic capability.
1. In the polyploids and cytochimeras of A. fistulosum, the ploidies of L1 and L2 could be easily identified by the maximum number of nucleoli per epidermal and mesophyll cell, respectively. While, in those plants of A. wakegi, ploidies in the layers could be also determined by the maximum number or a modal number of nucleoli per epidermal and mesophyll cell.
2. The first generation of colchicine treated plants frequently varied with their chimeral nature during in vivo propagation, whe
reas the cytochimeras cultivated in vivo for three years after the treatment were stable for their chimerisum. On the medium containing 0.1 - 1.0 ppm BA and 0.5 ppm NAA, the polyploids and the cytochimeras drastically changed their chimerisum during in vitro propagation, but did not on the medium containing a range of 0 - 0.125 ppm BA.
3. The 4-2-2 and 4-4-4 plants had lower stomatal density and larger sized stomata than the 2-2-2 and the 2-4-4. Total stomatal pore area/mm2, which was obtained by multiplying stomatal density by stomatal size, was larger in the 4-4-4 and the 4-2-2 than in the 2-2-2 and the 2-4-4.
4. The 2-4-4 showed the highest yield under warm autumn conditions, while the 4-2-2 achieved the highest productivity under cool winter conditions.
5. Under the cool winter conditions, a stomatal conductance, a transpiration rate and a photosynthetic rate were higher in the 4-4-4 and the 4-2-2 than in the 2-2-2 and the 2-4-4.
From the above results, it is suggested that the highest productivity of the 2-4-4 under the warm conditions is attributed to its higher draft tolerance, and that the highest yield of the 4-2-2 under the cool conditions is due to its higher photosynthetic capacity under the cool conditions. The breeding of A. wakegi is, therefore, most likely activated by the use of the cytochimeras. Less