تاثیر خاکپوش‌های پلی‌اتیلنی رنگی بر خصوصیات کیفی، میزان عملکرد و پارامترهای فلورسانس کلروفیل توت‌فرنگی رقم ’کاماروسا‘

مدیریت ناکارآمد مزارع توت فرنگی، یکی از عوامل مهم در کاهش قابل توجه عملکرد و کیفیت میوه توت فرنگی (fragaria × ananassa, duch.) به حساب می آید. در این پژوهش، به منظور بررسی تاثیر خاکپوش های پلی اتیلنی رنگی بر خصوصیات کیفی، میزان عملکرد، پارامترهای فلورسانس و کلروفیل برگ گیاه توت فرنگی رقم ’کاماروسا‘، آزمایشی در قالب طرح بلوک های کامل تصادفی با چهار تیمار آزمایشی شامل؛ خاکپوش پلی اتیلنی رنگی (سیاه، قرمز، سفید) و شاهد (بدون خاکپوش) در سه تکرار در طی سال های زراعی 96-1395 و 97-1396انجام شد. بر پایه یافته ها، تاثیر رنگ خاکپوش های پلی اتیلنی بر میزان عملکرد میوه دارای تفاوت معنی دار بود (p ≤ 0.01). به طوری‌که عملکرد کل میوه در زمان های برداشت اول و دوم به ترتیب (175 و 185روز پس از کاشت) به گونه ای بود که بیشترین عملکرد میوه توت فرنگی در کاربرد خاکپوش قرمز و کمترین آن در گیاهان بدون خاکپوش ( شاهد) مشاهده گردید. در حالی که در زمان برداشت سوم (200 روز پس از کاشت)، این خاکپوش های سیاه و سفید بودند که بیشترین مقدار عملکرد را به خود اخنتصاص دادند. بیشترین میزان مواد جامد محلول (tss) میوه، مربوط به تیمارهای دارای خاکپوش در مقایسه با شاهد بود، اما تفاوت چندانی میان خاکپوش های پلی اتیلنی رنگی مشاهده نشد. همچنین نتایج گویای آن بود که، تاثیر خاکپوش های پلی اتیلنی رنگی بر پارامترهای فلورسانس و شدت سبزینگی برگ معنی دار بود (p ≤ 0.05). نتایج حاکی از آن بود که رنگ خاکپوش های پلی اتیلنی تاثیر چشمگیری بر میزان فلورسانس اولیه، نسبت فلورسانس اولیه به فلورسانس متغیر (fv/fo) و شدت سبزینگی برگ داشت. به طوریکه در هر دو سال زراعی، بیشترین میزان نسبت fv/fo ، fo  و شدت سبزینگی مربوط به خاکپوش های پلی اتیلنی رنگی بود و کمترین میزان آن در تیمار شاهد مشاهده شد. این در حالی بود که رنگ خاکپوش ها تاثیر چندانی بر میزان نسبت fv/fm نداشت. در واقع می توان اینگونه اظهار داشت که، پاسخ گیاه نسبت به رنگ خاکپوش های پلی اتیلنی در مقایسه با تیمار شاهد، سبب بهبود عملکرد میوه و افزایش بهره وری سیستم فتوسنتزی گیاه توت فرنگی می شود.

The Effect of Colored Polyethylene Mulch on Quality Characteristics, Yield and Chlorophyll Fluorescence Parameters of Strawberry Cv. Camarosa

Introduction Inefficient management of strawberry fields is one of the important factors in significantly reducing the strawberry fruit yield and quality. Nowadays application of polyethylene soil mulch is widely considered in the cultivation of fruits and vegetables, with various purposes such as improving quality, increasing yield and reducing weeds. The thermal and light environment around the plant due to the use of polyethylene mulch, can affect the quality and yield of strawberry fruit.Material and Methods In this study, In order to investigate the effect of colored polyethylene mulch on fluorescence parameters, leaf chlorophyll and strawberry fruit yield (cv. Camarosa), an experiment was carried out as completely randomized block design with four experimental treatments including; colored polyethylene mulch (black, red, white) and control (traditional cultivation without mulch) in three replication in the Caspian Sea region, Iran during the 201617 and 20172018 years. The experimental plots were 5 m long and 1.5 m wide, with 4 planting rows separated by 30 cm in each plot. Then polyethylene mulch was laid on the ridge and the plants were planted at a distance of 20 cm in a row (1 October). Three harvest times (170, 185 and 200 days after planting) were determined to assess the characteristics of harvested fruits.Result and Discussion Based on the results, the effect of mulches color on fruit yield was significantly (P ≤ 0.01). Considering fruit yield at the first harvest (175 DAP) and the second (185 DAP), red mulch showed the highest fruit yield and the lowest was observed in the control treatment. While at the third harvest time (200 DAP), it was the black and white mulches that resulted in the largest amount of yield. The effect of colored polyethylene mulch on the acidity (pH) and titratable acid (TA) of the fruit was not significant, but the amount of soluble solids (TSS) of the fruit at different harvest times showed a significant difference between the experimental treatments. So that in the first harvest time (170 DAP) and the second (185 DAP), the highest amount of soluble solids was observed in treatments with colored polyethylene mulch. The results also showed that colored polyethylene mulches effect on fluorescence parameters and leaf chlorophyll content was significant (P ≤ 0.05). The results showed that mulch color had a significant effect on Fv/Fo ratio, Fo and leaf chlorophyll content. During the both years, the highest Fv/Fo ratio, Fo and leaf chlorophyll were related to colored polyethylene mulches, and the lowest was observed in the control treatment, while colored mulches did not affect the Fv/Fm ratio. In fact, it can be explain that the plant’s response to the colored polyethylene mulches, compared to the control treatment, improves fruit yield and increases the strawberry photosynthetic system.ConclusionComparison of the average effect of polyethylene mulch on strawberry fruit yield during the growing season in both years, showed similar results. Polyethylene mulches can increase yields by increasing soil temperature, increasing nutrient availability, increasing root uptake in nutrients and increasing the efficiency of soil microorganisms. Based on the results, in the first harvest time (170 DAP), second harvest time (185 DAP) and third harvest time (200 DAP), the yield of strawberry fruit in both growing season showed that the highest yield was related to treatments with The colored polyethylene mulch and the lowest yield was observed in the control treatment. Red mulch had the highest fruit yield during the first and second harvests, but gradually decreased during the third harvest. It seems that red color, in addition to increasing yield, has also caused early ripening of the fruit. The amount of soluble solids (TSS) of the fruit at different harvest times showed a significant difference between the experimental treatments. During the first harvest (170 DAP) and the second (185 DAP), the highest amount of soluble solids was observed in treatments with colored polyethylene mulch. Based on the findings, the effect of colored polyethylene mulch on fluorescence parameters and chlorophyll content of leaves indicated that the color of polyethylene mulch had a significant effect on the amount of Fo and chlorophyll content of leaves. Therefore, the use of polyethylene mulch due to the increase in yield and quality of strawberry fruit compared to its traditional cultivation method seems very beneficial.