تعیین زمان برداشت مناسب و قابلیت انبارمانی تعدادی از ارقام و ژنوتیپ های امیدبخش ”به“ (Cydonia Oblonga Mill.) در شرایط سردخانه

نتیجه شناسایی و جمع آوری ژنوتیپ های ”به“ در استان اصفهان، دستیابی به ژنوتیپ های امید بخش”به“ بوده است. با توجه به اینکه ارزیابی خصوصیات انبارمانی و تعیین میزان مقاومت به نابسامانی های پس از برداشت در محصولات باغی از اهمیت وافری برخوردار است، این تحقیق با هدف تعیین مناسب ترین زمان برداشت و بررسی طول دوره انبارمانی برخی ژنوتیپ های امید بخش ”به“ حاصل از جمع آوری ژرم پلاسم انجام گرفت. به این منظور میوه های ارقام ”به“ ویدوجا و ”به“ اصفهان به همراه ژنوتیپ های kvd2 و kvd4 به عنوان ژنوتیپ های امید بخش در تاریخ های 15، 23 و 30 مهر ماه سال 1395 از ایستگاه تحقیقات مبارکه برداشت شدند. میوه ها به سردخانه با دمای 1±0 درجه سانتی گراد و رطوبت نسبی 5±90 درصد منتقل گردیدند. صفات مورد ارزیابی در زمان برداشت و نیز در فواصل یک ماهه به مدت پنج ماه پس از نگهداری در سردخانه طی آزمایش فاکتوریل در پایه طرح کاملاً تصادفی با سه تکرار و 10 میوه در هر تکرار مورد ارزیابی قرار گرفتند. طبق نتایج، بیش ترین کاهش وزن در ماه پنجم انبارمانی دیده شد. در این ماه، ”به“ اصفهان و ویدوجا به ترتیب بیش ترین و کم ترین درصد کاهش وزن را نشان دادند. بیش ترین مواد جامد محلول و شاخص طعم در برداشت سوم و ماه پنجم و چهارم انبارمانی دیده شد. بیش ترین شاخص طعم متعلق به ”به“ اصفهان و ویدوجا بود. بیش ترین سفتی بافت میوه در زمان برداشت برای ”به“ اصفهان و ژنوتیپ kvd2 و کم ترین آن برای ژنوتیپ kvd4 و پس از پنج ماه انبارمانی به دست آمد. ژنوتیپ kvd4 در زمان برداشت، بیش ترین و ”به“ اصفهان، ویدوجا و kvd2 پس از انبارمانی پنج ماهه کم ترین محتوای فنول کل را نشان دادند. ژنوتیپ kvd4 و ”به“ اصفهان در زمان برداشت بیش ترین محتوای پکتین را نشان دادند. افزایش دوره انبارمانی مقدار پکتین و فنول را کاهش داد. قهوه ای شدن سطحی از ماه چهارم انبارمانی آغاز شد و اختلاف معنی داری با مقدار این صفت در ماه پنجم نداشت. در نهایت بهترین زمان برداشت برای ارقام و ژنوتیپ های اصفهان، ویدوجا، kvd2 و kvd4 به ترتیب 185، 200، 200 و 193 روز پس از تمام گل بود. نگهداری میوه ارقام ”به“ اصفهان و ویدوجا و ژنوتیپ kvd4 به مدت چهار ماه و میوه ژنوتیپ kvd2 به مدت پنج ماه در سردخانه قابل توصیه است.

Determination of the Appropriate Harvest Time and Storability of some Cultivars and Promising Genotypes of Quince (Cydonia oblonga Mill.) in Cold Storage Conditions

Introduction: The evaluation of storage characteristics and determination of resistance to postharvest disorders in horticultural crops is highly important. ‘Viduja’ as new quince cultivar and KVD2 and KVD4 promising quince genotypes were collected from different regions of Isfahan Province. As these cultivar and promising genotypes are new, it is necessary to determine the most appropriate harvest time for them based on effective harvest indices. This research was carried out for the determination of the best harvest time and storage period of these promising quince cultivar and genotypes.;Material and Methods: This experiment was carried out on apos;Viduja apos; as new cultivar and KVD2 and KVD4 genotypes as promising genotypes and apos;Isfahan apos; cultivar as control, which was grafted on hawthorn seedling rootstock. In April, the full bloom time of these cultivars and genotypes was monitored to report harvest time based on the number of days after flowering for each cultivar and genotype. Fruits were harvested on October 6th, 14th, and 21th, 2016 in the horticultural research station of Mobarakeh. Fruits were transferred to cold storage with 0±1°C and 90±5% R.H. for five months. Some traits were measured in the harvesting date and also at the end of every month. These traits included weight loss percentage, fruit firmness, TSS, TSS/TA, pectin, total phenol, surface browning and decay percentage. The experiment was carried out as a factorial experiment in a completely randomized design with three replicates (10 fruits in each replicate).;Results and Discussion: apos;Viduja apos; cultivar and KVD2 and KVD4 genotypes were early flowering and had similar flowering time. Isfahan quince cultivar was late flowering and had moderate overlap with KVD2 and KVD4 genotypes. According to the results, the highest weight loss was observed in the fifth month of storage. In this month, apos;Isfahan apos; and apos;Viduja apos; cultivars showed the most and the least weight loss, respectively. Others showed increased water loss and reduced fruit weight with increased storage time. For example, with increasing the duration of storage in the cold storage, the weight loss of apos;Gorton apos; quince cultivar increased. In all cultivars and genotypes, the highest TSS and TSS/TA were founded in the third harvest and fifth and fourth month of storage. Mosharraf and Ghasemi (34) reported that TSS in the last harvesting time and after five months of storage time was 20.16% in apos;Isfahan apos; cultivar. In their research, TSS was 14.75% in harvesting time that was less than the rate of this trait in the current study. The highest TSS/TA belonged to apos;Isfahan apos; and apos;Viduja apos; cultivars. The highest fruit firmness was obtained at harvest time of apos;Isfahan apos; and KVD2 genotype, and the lowest of that was observed in five months after the storage of KVD4 genotype. In the Esme quince cultivar, the fruit firmness in the third harvest quickly decreased, and after six months it was 3 kg cm2. At harvesting time of KVD4 genotype, the highest phenol content was observed. apos;Isfahan apos;, apos;Viduja apos; cultivars and KVD2 genotype showed the lowest phenol content after five months of storage. Increasing the storage period resulted in a decrease in phenol content in all cultivars and genotypes. Similarly, other researchers showed that the total phenol content gradually decreased with prolonged fruit storage (6 and 7). KVD4 genotype and apos;Isfahan apos; cultivar showed the most pectin content at harvesting time. Increasing the storage time reduced the rates of pectin. According to Mosharraf and Ghasemi (39), increased storage period reduces pectin content in Isfahan cultivar fruits. The fruit surface browning was begun from the fourth month of storage, and there was no significant difference with the amount of this trait in the fifth month. Surface browning in the third harvest of Esme cultivar was also more than the previous harvestings, and eventually reached 70% (30). With prolonging storage time, the decay percentage increased. The first decay was observed from the third month of storage and reached its highest level in the fifth month. Isfahan cultivar had the highest percentage of decay. Other cultivar and genotypes had no significant difference in decay percentage.;Conclusions Finally, the best harvesting time for apos;Isfahan apos;, apos;Viduja apos;, KVD2 and KVD4 cultivars and genotypes were 185, 200, 200 and 193 days after full bloom respectively. Fruit storage in the cold for four months is advisable for apos;Isfahan apos; and apos;Viduja apos; cultivars and KVD4 genotype. In KVD2 genotype fruits, fivemonth storage is recommended.