جستجوی مقالات مرتبط با کلیدواژه « titratable acidity » در نشریات گروه « زراعت »

Tomatoes are highly sensitive to a variety of environmental stresses, including drought stress, so the selection of hybrids adapted to dehydration and have good performance by studying the effects of GCA, SCA and physiological response of parents and tomato hybrids in conditions of dehydration It can help to better understand the mechanisms of drought resistance and their use in tomato breeding programs.

In this study, 12 hybrids obtained from the combining four testers and three commercial lines of tomato in terms of response to water deficit stress and evaluation of cross combinations in the layout split plots according to randomized complete block design with three replications and three stress levels (100% FC, 60% FC and 40% FC) in the research farm of the Faculty of Agriculture of Ilam University. Dates were evaluated by line × tester method. The studied genotypes were L1: Bitstoik, L2: Kingstone, L3: Petoearly, as lines, and T1: LA1607, T2: LA2656, T3: LA2080 and T4: LA1579 as Testers. Plant yield traits, average fruit weight, fruit length and diameter, pericarp thickness, Number of Locules, total acidity, pH and total soluble solids were measured.

The analysis of genetic variance indicated the more contribution of non-additive variances in the occurrence of the studied traits. The analysis of variance indicated that genotype, parents, crosses and line×tester effects were significant for all of the studied traits, which showed high differences between general combinig ability of parents and specific combinig ability of hybrids. The effect of the line under stress-free conditions was not significant for total acidity and soluble solids. For plant yield and average fruit weight, the parental line Bitstoik under severe drought stress conditions (0.83 kg and 1.26 g, respectively) and the tester LA2656 in non-drought stress (0.321 Kg and 2.18 g, respectively) were found to be the best general combiner. The crosses Kingstone×LA157 under drought stress condition (0.083 kg) and Petoearly×LA1579 in non-drought stress conditions were the best combination for plant yield, which can be suggested for use in drought stress breeding programs.

These results can be used in breeding programs and develop tolerate tomato hybrids as suitable experimental cultivars in hybrid production programs under stress conditions.

The citrus fruit coating is a common postharvest treatment before storage. It seems necessary to study fruit quality and nutritional value changes in this condition. Orange fruits including, Thomson, Siavaraz (A local cultivar), Moro, and Page mandarin were used in this experiment. Treatments were included control (Non-coating), wax coating (Britex Ti) and storage duration (0, 30, 60 and 90 days). Treated fruits were stored at 5°C for 90 days and some qualitative properties of fruits were evaluated with fruit taken from 0, 30, 60 and 90 days during storage. The results showed that fruit weight loss in non-waxed fruits were higher than wax-coated fruits during storage. Wax treatment only had a significant effect on losses of Thomson cultivar during storage. The peel color indices did not change during storage significantly. No significant differences were observed between coated and non-coated fruits about juice percentage, pH, TA and TSS during storage. The TSS: TA ratio decreased in all cultivars significantly. Wax caused an enhancing in antiradical efficiency (in pulp) during two month storage, but reduced again at the end of storage. Finally, sensory analysis revealed that, waxed fruits had better sense and quality conditions -except of page mandarin- compared with non-coated fruits.

In order to investigate the effect of different concentrations of putrescine and wax coating on qualitative and quantitative characteristics of ‘Kara’ mandarin in storage, an experiment was performed based on a completely randomized design (CRD). The effect of four levels of coating including BRITEX commercial wax, 0.2, 0.4 and 0.6 mm putrescine was studied on qualitative and quantitative characteristics of this cultivar in 3 replications and in three stages (20, 40 and 60 days of storage). Results showed that the coating type, storage time and interaction between them were significant at 1% on Kara mandarin fruits characteristics including fruit weight loss, skin to pulp ratio, fruit juice percentage, total soluble solid (TSS), TSS/TA ratio and vitamin C, but they were not significant on pH and titratable acid (TA). Generally, among all applied treatments, 0.2 mm putrescine application and the storage for 40 days coould be introduced as the most effective treatment to maintain quality of Kara mandarin and it can be used to improve the postharvest life of this fruit.

In this study, the effects of foliar application of potassium sulfate were evaluated on yield and quality of grape (Vitis vinifera cv. Rashe). Five foliar spray treatments including control, once foliar spray at two concentrations of 1.5 g.l-1 and 3 g.l-1 and two foliar sprays at two concentrations of 1.5 g.l-1 and 3 g.l-1 were used. The first and second foliar spray were done at the end of flowering period and fifteen days after the first spraying, respectively. The results showed that the average berry and cluster weight, total soluble carbohydrates and vitamin C significantly increased compared to control in potassium applied treatments. The difference was not significant between different treatments of potassium sulfate. Foliar application of potassium sulfate significantly increased the average berry volume, berry pulp and berry skin anthocyanin. Twice foliar applications of potassium sulfate treatment at concentration of 3 g.l-1 had the highest amounts of anthocyanin contents. Potassium-sprayed treatments increased total soluble solids and pH of the fruit juice. Titratable acidity was at least in 3 g.l-1 treatment and other treatments were not significantly different. In general, the results of this experiment showed that foliar application of potassium sulfate improves the quantity and quality of the grape berry.

Grape is non-climacteric fruit and as a result, the quality of fruit does not change after harvest. Application of ethephon in recent years is known as an effective way to increase the quantity and quality of grape. In this study, the effect of pre harvest application of ethephon at four levels (0, 150, 250 and 300 mg/l) and ethephon treatment time at two levels (10-20% and 50-70% of berry veraison) were evaluated on quality indices of Bidane -Ghermez grape cultivar at harvest time. The experiment was carried out with a factorial design in a randomized complete block with three replications. Evaluated indices were soluble solids content, titratable acidity, palatability, pH, ascorbic acid content, tissue firmness and fruit color. Application of ethephon increased soluble solids content, ascorbic acid content, palatability and fruit color but had no effect on pH. Colorimetric results showed that ethephon treatment reduced L parameter, Hue angle and Chroma and increased a/b ratio. Titratable acidity and tissue firmness were decreased with application of ethephon. Results showed that spray of 150mg/l ethephon at 50-70% of berry veraison increased soluble solids content, palatability and fruit color but had no more effect on reducing tissue firmness. Based on the obtained results, application of ethephon with the optimum concentration in the proper time can be an effective strategy to improve color and optimum quality of berries.