ارزيابي ويژگي هاي فيزيكوشيميايي ميوه ي نارنگي هاي جديد نوشين (Citrus reticulata cv. Noushin) و شاهين (Citrus reticulata cv. Shahin) طي زمان هاي مختلف برداشت

Evaluation of fruit physico-chemical characteristics of new mandarins - Noushin (Citrus reticulata cv. Noushin) and Shahin (Citrus reticulata cv. Shahin) - during different harvesting time

در اين پژوهش شاخص هاي كيفي رسيدن ميوه دو رقم جديد نوشين و شاهين (حاصل از دورگ گيري نارنگي و پرتقال) روي پايه نارنج طي دو سال (1394-1393) در پژوهشكده مركبات و ميوه هاي نيمه گرمسيري (رامسر) بررسي گرديد. از نارنگي شاهين از آبان تا اسفند و از نارنگي نوشين از آبان تا دي به صورت ماهيانه نمونه گيري شد. نتايج نشان داد اندازه ميوه، ميانگين قطرهاي حسابي، هندسي و هم ساز در هر دو رقم طي برداشت هاي بعدي نسبت به برداشت اول تغيير معني داري (p<0.01) نداشت. بين ميزان كرويت ميوه و ميانگين قطرهاي حسابي، هندسي و معادل همبستگي مثبت وجود داشت. ميوه ي شاهين ضريب رعنايي بالا (پخ تر)، كرويت كمتر و چگالي كمتر از يك داشت. دانسيته ميوه نسبت به زمان برداشت روندي افزايشي داشت. رنگ سبز پوست نارنگي نوشين در آذر و نارنگي شاهيندر اوايل دي به نارنجي تغيير كرد. نسبت TSS:TAدر ميوه نوشين در آبان (9/81) و در ميوه شاهين (8/32) در دي به حد نصاب برداشت رسيد. شاخص تكنولوژي در هر دو رقم تغيير معني داري طي دفعات برداشت نداشت (p<0.01) ليكن نارنگي شاهين شاخص تكنولوژي (متوسط 50 درصد) بالايي داشت. متوسط ضخامت پوست نارنگي هاي نوشين و شاهين به ترتيب 3 و 2 ميلي متر بود و تغيير معني داري (p<0.01)طي زمان هاي مختلف برداشت نكرد. در رقم نوشين تعداد بذر در دامنه 19 تا 27 عدد و در رقم شاهين در دامنه 15 تا 35 عدد بود كه هر دو در گروه پربذر قرار گرفتند. به طوركلي نارنگي نوشين و شاهين به ترتيب به عنوان ارقامي زودرس و ميان رس داراي ويژگي هاي كيفي مناسب مصرف در بازار مركبات ايران هستند.

Background and objectives: According to a breeding program carry out in Citrus and Subtropical Fruits Research Center (Ramsar)، ‘Noushin’ and ‘Shahin’ mandarins were created from crossing between Clemantin mandarin×Salustiana orange and Clemantin mandarin×Hamlin orange، respectively. The fruits of this new varieties on Sour orange rootstock did not study yet، completely. Therefore، the aim of this study was to investigate the Noushin and Shahin physico-chemical characteristics on Sour orange rootstock during two years. Materials and methods: ‘Noushin’ sampled from October to December during three months. ‘Shahin’ fruits were collected from October to February (5 times) as monthly. Various physico-chemical characteristics evaluated including fruit lenght، width، thickness; arithmetic، geometric، equivalent and harmonic diametrics means; aspect ratio، sphericity، surface area، true volume، apparent volume، volume error، density، peel thickness، Easy of peeling، weight، juice percentage، seed number، peel color indices (L*، a*، b*، hue angle، chroma and CCI)، total soluble solid (TSS)، titratable acidity (TA)، technological index (TI) during experiment. Results: The results showed that fruit size، arithmetic، geometric، equivalent and harmonic means of both varieties had not significantly (p<0.01) changes from the first to final time of harvesting. There was a positive correlation between fruit sphericity and arithmetic، geometric، equivalent diametric means. Fruit of ‘Shahin’ had high aspect ratio، less sphericity and low density (<1). Fruit density showed an increasing trend during the harvest time. The green colour of peel in ‘Noushin’ and ‘Shahin’ changed to orange colour at the last week of November and December، respectively. Based on citrus colour index (CCI)، no cultivars necessary to de-greening after the last week of November. The TSS:TA ratio was optimum for harvesting in late of October (9.81) in ‘Noushin’ and at the last week of December (8.32) in ‘Shahin’. Although the technology index in both varieties had not significantly (p<0.01) changes from the first to final harvesting but it was high in ‘Shahin’ with 50 percent nearly. The peel thickness in ‘Noushin’ and ‘Shahin’ was 3 and 2 mm respectively which had not significantly (p<0.01) changes during harvesting time. The seed number in ‘Noushin’ was 19 to 27 and in Shahin was 15 to 35 that revealed both of them belonged to high seed content category. Conclusion: According to TSS:TA ratio index، ‘Noushin’ as an early ripening variety can harvested in the last October and ‘Shahin’ as mid ripening variety can harvested in late of December. Both of varieties is sutaible for the north of Iran climate. Based on juice percentage and TI data، the amount of juice with about 50% was higher in ‘Shahin’ that sutaible for prosessing industries. Due to empty space inside the fruit skin and flesh of ‘Noushin’ and low dansity (<1)، fruits are floating on washing water during prosessing. The skin colour was green in both of varity in late of October. Becase of TSS:TA ratio is sutaible at this time in ‘Noushin’، there fore growers can harvested ‘Noushin’ variety with green skin colour in late of October but ‘Shahin’ must be remained on tree until late December.