摘除老葉、走莖與花對臺灣冬季草莓生長發育與生產之影響

Abstract

摘除走莖、葉片管理與疏花疏果作業為草莓田間栽培的慣行作業，但這些田間操作對草莓植株生理與生產上的影響及帶給農民的效益尚未經詳細評估，因此本論文分為兩部分進行探討。一為以摘除走莖（RR）、摘除老葉（LR）、摘除走莖加上老葉（RR + LR）與對照組（CK）等四處理，探討摘除老葉與走莖對草莓植株生長、光合作用能力與產量之影響。田間試驗結果顯示，栽培期內摘除老葉與走莖不會影響第一期、第二期開花時間與第一期果實採收日數，但第二期果實數（p = 0.007）與採收日數（p = 0.002）受葉面積影響，隨著葉面積增加果實採收日數亦增加。對全季而言，隨著葉面積增加產量、果實數及單果重亦增加；摘除走莖則可以提昇產量、果實單果重及果實可溶性固形物。另以盆栽植株為材料測量葉片光合作用，於摘除老葉後1日，葉片光合作用能力提昇15%至30%。試驗結束後測得植株鮮重與乾重，摘除老葉降低植株總鮮重、地下部鮮重、總乾重、地上部乾重與地下部乾重，而摘除走莖則無影響。 另一試驗以摘除每期第一級花（或果實）（primary flower removed, PR）、摘除每期第四級以後之花朵（或果實）（quaternary flower removed, QR）、摘除每期第五級以後之花朵（或果實）（fifth flower removed, FR）與對照（CK）等處理探討不疏花疏果對草莓植株生長、果實發育及產量之影響。各處理對植株葉面積生長影響不顯著，僅在處理後56 日PR 葉面積較其他處理高150平方公分；處理後70 日PR 與QR 葉面積高於其他處理150 平方公分。疏花疏果處理僅對第二、三期三級果實有所影響且皆以PR表現較佳。疏花疏果對各期可銷售產量、可銷售總產量及第一、二期及全季可銷售果實可溶性固形物皆無影響，僅減少不合品果實數。

Removing runners, old leaves and flowers are three major routine tasks in a strawberry (Fragaria ×ananassa Duch.) field for winter berry production in central Taiwan. However, their effects on growth and fruit development have yet to be evaluated. To document the effects of partial defoliation and runner removal on plant growth, photosynthesis and yield, field and potted plants were treated with: 1) LR: partial defoliation of old leaves; 2) RR: runner removed; 3) LR + RR; 4) CK: controls. Neither defoliation nor runner removal affected the initial dates of first bloom, second bloom, and first harvest, but affected second harvest. Multiple linear regressions indicated that canopy leaf area had greater overall effects than the existence of runners on runnering and fruiting. Pot experiment showed that removing old leaves (leaf ages about 45days) temporary increased photosynthesis of the remaining leaves by 15% to 30%. Neither defoliation nor runner removal affected of crown fresh weight but deceased fresh weight of root. In addition, defoliation but not runner removal deceased dry weight of crowns and roots. To document the effects of flower or fruit thinning on plant growth, fruit development and yield, field plants were treated with: 1) PR: primary flower or fruit removal; 2) QR: quaternary or fruit removal; 3) FR: fifth flower or fruit removal; 4) CK: controls. Leaf area development, yield of individual harvest, total seasonal yield and soluble solids content were not affected by flower removal treatments. PR increased tertiary fruit growth of second crop and third crop. The results indicated that flower or fruit thinning increased average weight of marketable berries without compromising yield.