|Budget Amount *help
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1994 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1993 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1992 : ¥900,000 (Direct Cost : ¥900,000)
Flowers and fruits of wild pear species (Pyrus serotina) were collected in Oshika Village, Nagano Prefecture and were compared with those of the cultivars "Nijisseiki" and "Atago" which were grown in Experimental Farm of Kyoto University, in 1992,1993 and 1994. The variability of characters of floral organs in wild pears was observed. There were several individuals which have larger flowers than them of "Nijisseiki" . At 5 weeks after blooming, there was no difference between in wild pears and in the cultivars in the length of fleshy parenchymatic cells which was measured in the transection of young fruits. The number of the cells per a fruit was greater in the cultivars, especially, in a big fruit variety "Atago" , than in the wild pears. In the harvest time, obviously, the size and number of the fleshy parenchymatic cells were greater in the cultivars than in the wild pears. Consequently, distinctive points which have caused to be difference of fruit development between in wild pears and in the cultivars, are based on the ability of initial cell devision and also subsequent cell enlargement. Although, therefore, it seems that the low fruit productivity in wild pears is an inherited character, there may be a possiblity to be affected by growing environment. Because, usually, nutrient deficiency, poor pollination, water stress and the likes will take place there.
As a further study, we are preparing to carry out a comparison research with them under the condition of cultivation. There is a reason to expect that we can recognize what the productivity of cultivars distinguishes as being different from wild species and we can understand the way to control the productivity.