イチゴ’女峰’花粉稔性の変化と日射量、気温並びに体内炭水化物、無機養分濃度との関係

Changes in pollen fertility in forcing strawberry cv. Nyoho(Fragaria×ananassa Duch.)were investigated to clarify the factors affecting fruit malformation caused by poor fertilization which occurs with plant dwarfing and yeild decreace in February to March .Pollen were sampled from 15 greenhouses of strawberry growers,and relationships between pollen germination and climatic factors,mineral and carbohydrate concentration in leaves were analyzed.Pollen fertility decreased in January and February with decrease in light intensity and outside air temprerature,and increace in fruit load.It was suggested that the occurrence of fruit malfomation may be mainly caused by the decrease in pollen fetillity. There were highly significant relationships between the pollen fertility and light intensity in 1 to 3 days before anthesis,minimum outside air temperature on the day of anthesis,and carbohyrates,P,K and Ca concentration in the leaves.No constant relationship could be found between polln fertility and leaf N concentration.Pollen fertility at the beginning of harvest for second inflorescence(January)was improved with CO2 enrichment.These results indicate that the poor pollen development may result from the shortage of photosynthate caused by low light and fruit load.

促成栽培したイチゴ’女峰’の’成り疲れ’と同時に発生する受精不良による奇形果発生要因を明らかにするため、イチゴ生産者の15棟のビニルハウスの花粉稔性の変化を調査し、気象要因、葉中無機養分および炭水化物濃度との関係について解析した。花粉稔性は、気温、日射量が低下し、着果負担が増大する1,2月に急激に低下したことから、奇形果発生の原因が花粉稔性の低下にあることが示された。花粉稔性と開花前1～3日の日射量、当日の戸外の最低気温、葉中炭水化物濃度との間に高い相関が認められなかった。CO2施肥によって腋果房収穫開始期（1月）の花粉稔性が高まったことから、低日射と過重な着果負担による光合成産物不足が花粉稔性低下の大きな原因であると考えられた。