小原 均

This experiment was conducted to induce seedless fruit set and growth in the triploid loquat by applying GA3, GA4, GA7 or GA4+7 at 200 mg L-1 in combination with forchlorfenuron (CPPU) at 20 mg L-1 to flowers and fruitlets two times, at bloom and 57 days after bloom. The flowers were not emasculated. Treatment solutions of 100 μL were applied to each flower and fruitlet. Untreated control fruit gradually abscised and final fruit set was 0%. When GA3, GA 4, GA7 or GA4+7 in combination with CPPU were applied, fruit sets at harvest were about 61%, 40%, 74% and 56%, respectively. The harvested fruits were all seedless. GA3+CPPU produced the largest fruits (51.4 g), whereas GA4+CPPU produced the smallest (23.3 g). Brix and fruit flesh firmness did not show marked differences among GAs treatments. Titratable acidity in GA3+CPPU treated fruits was the lowest and in GA4+CPPU treated fruits was the highest. These results suggest that GA3+CPPU is more effective than other combinations of GA+CPPU for seedless fruit production in the triploid loquat without decreasing the fruit quality.

三倍体ビワを利用した無種子品種育成のための育種材料となる四倍体ビワの作出を，アミプロホスメチル（APM）およびコルヒチンの2薬剤を用いて，いくつかの処理方法により試みた．その結果，APMの処理により4個体，コルヒチンの処理により2個体の四倍体を得た．<br> 1．'楠'実生の長さ3～10 cmに達した新梢先端部に対する0.005％APMの14日間の浸漬処理および0.2％コルヒチンの14日間の浸漬処理，2％の4日間の浸漬処理により四倍体をそれぞれ1個体得た．<br> 2．'富房'成木の発芽・伸長期の新梢先端部に対する0.005％APMの14日間の浸漬処理により四倍体を1個体得た．<br> 3．幼根の長さが3～4 cmの'楠'発根種子の根に対する0.005％APMの14日間の浸漬処理により，四倍体を1個体得た．<br> 4．2週間APM無添加MS培地で馴化培養した23～24年生'楠'成木の新梢茎頂組織を0.005％APMを含むMS培地に移植し，7日間処理することにより四倍体を1個体得た．<br>